Katmai National Park and Preserve and 

Alagnak Wild River

Geologic Resources Inventory Report

Natural Resource Report NPS/NRSS/GRD/NRR—2016/1314

National Park Service

U.S. Department of the Interior

Natural Resource Stewardship and Science
ON THE COVER

Photograph of the Baked Mountain huts, a shelter for hikers and a temporary home for scientists, with 

Mount Griggs in the background. The huts were built by the University of Alaska Fairbanks (UAF) Geophysical 

Institute in 1965. At 2,330 m (7,650 ft) above sea level, Mount Griggs is the highest peak in Katmai National 

Park and Preserve. It lies 12 km (7 mi) behind the main volcanic front and has superheated, sulfur-precipitating 

fumaroles near its summit. The flanks of the volcano are covered with ash from the 1912 Novarupta eruption. 

Ignimbrite from the 1912 eruption fills the Knife Creek arm of the Valley of Ten Thousand Smokes. Alaska 

Volcano Observatory (AVO)/UAF Geophysical Institute photograph by Pavel Izbekov taken in 2008 during the 

International Volcanology Field School held annually in Katmai National Park (https://www.uaf.edu/geology/

academics/international-volcanology/).

THIS PAGE

Photograph of the ignimbrite from the 1912 Novarupta eruption. The lower end of the ignimbrite is weakly 

consolidated, so was quickly dissected by the Ukak River after the eruption. The ignimbrite is approximately 

15 m (50 ft) thick. The photograph was taken downstream of Ukak River falls, which is 20 km (12 mi) from the 

Novarupta source vent. NPS photograph by Chad Hults.
Katmai National Park and Preserve and 

Alagnak Wild River

Geologic Resources Inventory Report

Natural Resource Report NPS/NRSS/GRD/NRR—2016/1314

Chad P. Hults

Geologist

National Park Service Geologic Resources Inventory

Alaska Regional Office

240 W. 5th Ave.

Anchorage, AK 99501

Judy Fierstein

Research Geologist

US Geological Survey

California Volcano Observatory

345 Middlefield Road

Menlo Park, CA 94025

September 2016

U.S. Department of the Interior 

National Park Service 

Natural Resource Stewardship and Science 

Fort Collins, Colorado

National Geographic photograph of the Novarupta area by Clarence F. Maynard, 1917 (Griggs 1922, p. 194).

The sight that flashed into view as we surmounted the hillock was one of the most 

amazing visions ever beheld by mortal eye. The whole valley as far as the eye could reach 

was full of hundreds, no thousands—literally, tens of thousands—of smokes curling up 

from its fissured floor.

From our position they looked as small as the little fumaroles nearby, but realizing 

something of their distance we knew many of them must be gigantic. Some were sending 

up columns of steam which rose a thousand feet before dissolving.

After careful estimate, we judged there must be a thousand whose columns exceeded 

500 feet. A dozen miles away the valley turned behind a blue mountain in the distance. 

Plainly the smokes extended that far. How much farther we could not tell...

It was as though all the steam engines in the world, assembled together, had popped their 

safety valves at once and were letting off surplus steam in concert.

—Griggs (1922, p. 191)
ii

The National Park Service, Natural Resource Stewardship and Science office in Fort Collins, Colorado, publishes a 

range of reports that address natural resource topics. These reports are of interest and applicability to a broad audience 

in the National Park Service and others in natural resource management, including scientists, conservation and 

environmental constituencies, and the public. 

The Natural Resource Report Series is used to disseminate comprehensive information and analysis about natural 

resources and related topics concerning lands managed by the National Park Service. The series supports the 

advancement of science, informed decision-making, and the achievement of the National Park Service mission. The 

series also provides a forum for presenting more lengthy results that may not be accepted by publications with page 

limitations.

All manuscripts in the series receive the appropriate level of peer review to ensure that the information is scientifically 

credible, technically accurate, appropriately written for the intended audience, and designed and published in a 

professional manner. This report received informal peer review by subject-matter experts who were not directly 

involved in the collection, analysis, or reporting of the data.

Views, statements, findings, conclusions, recommendations, and data in this report do not necessarily reflect views and 

policies of the National Park Service, U.S. Department of the Interior. Mention of trade names or commercial products 

does not constitute endorsement or recommendation for use by the U.S. Government. 

This report is available from the Geologic Resources Inventory website (http://go.nps.gov/gripubs), and the Natural 

Resource Publications Management website (http://www.nature.nps.gov/publications/nrpm/). To receive this report in 

a format optimized for screen readers, please email irma@nps.gov.

Please cite this publication as:

Hults, C. P. and J. Fierstein. 2016. Katmai National Park and Preserve and Alagnak Wild River: Geologic Resources 

Inventory report. Natural Resource Report NPS/NRSS/GRD/NRR—2016/1314. National Park Service, Fort Collins, 

Colorado.

NPS 127/134578, September 2016
iii

Contents

Page

Figures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . v

Tables . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Plates (in pocket) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . vii

Executive Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . ix

Products and Acknowledgments . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

GRI Products . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xv

List of Abbreviations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . xvii

Geologic Setting and Significance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Geologic Features and Processes . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

1912 Eruption and Formation of the Valley of Ten Thousand Smokes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Volcanoes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22

Geothermal Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Glaciations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 41

Modern Glacier Features and Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46

Permafrost Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51

Coastal Features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Modern Surficial Deposits and Processes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Mesozoic Bedrock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 56

Tertiary Sedimentary and Igneous and Bedrock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Faults and Folds . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 67

Terrane Translation and Accretion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Geologic History . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Late Triassic (237–201 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Early Jurassic (201–174 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Middle Jurassic (Bathonian(?) to Callovian, 168–164 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Late Jurassic (164–145 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Early Cretaceous (145–135 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Early to Mid-Cretaceous (135–90 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Latest Cretaceous (80–68 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Late Paleocene to Early Eocene (59–49 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Late Eocene to Pliocene (40–2.6 MYA) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Quaternary (2.6 MYA–Present) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

Geologic Resource Management Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Preservation of Katmai’s Natural Features for Inspiration and Study . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 73

Geohazards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 74

Geothermal Features Inventory and Monitoring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Coastal Issues . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82

Fluvial Erosion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Glacier Changes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Paleontological Resource Inventory, Monitoring, and Protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84

Abandoned Mineral Lands (AML) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Potential Petroleum Development . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85

Soils and Permafrost . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Geologic Map Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Geologic Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87

Source Maps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
iv

Contents (continued)

GRI GIS Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Use Constraints . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88

Literature Cited . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Additional References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Geology of Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Geology of National Park Service Areas . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

NPS Resource Management Guidance and Documents . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

Climate Change Resources . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

Geological Surveys and Societies . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 103

US Geological Survey Reference Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103

Appendix A: History of Exploration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105

Appendix B: Potential Geologic Research, Inventory, and Monitoring Projects . . . . .. . . . . . . . . . . . . 109

Appendix C: Geologic Resource Laws, Regulations, and Policies . . . . . . . . . . . . . . . . . . . . . . . . . 113

Appendix D: Scoping Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

2005 Scoping Meeting Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121

2015 Report Kick-off Participants . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122

Page
v

Figures

Figure 1. Map showing the location of Katmai National Park and Preserve and Alagnak Wild River . . . . . . . . . . . . . . . . . . . . . . . xviii

Figure 2. Map of Holocene volcanoes along the Aleutian volcanic arc, Kamchatka Peninsula, and Kurile Islands . . . . . . . . . . . . . . . . . . 2

Figure 3. Schematic cross section of oceanic crust subducting under continental crust. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Figure 4. Map showing earthquake epicenters. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Figure 5. Chart showing a cross section of earthquakes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4

Figure 6. Geologic time scale showing the onset of major global evolutionary events and tectonic events of the North 

American continent and the Northern Cordillera . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Figure 7. Aerial photograph of the Valley of Ten Thousand Smokes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Figure 8. Diagram showing comparisons of the 1912 Novarupta erupted magma volume to other historic eruptions in North 

America and the world . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Figure 9. Diagram showing the explosiveness and eruption column heights of different types of eruptions . . . . . . . . . . . . . . . . . . . . 8

Figure 10. Chronology of 1912 eruption. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

Figure 11. Generalized 1912 eruptive sequence and chronology of ash fall recorded at Kodiak village . . . . . . . . . . . . . . . . . . . . . . 11

Figure 12. Photograph showing representative pumices from 1912 eruption . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Figure 13. Simplified geologic map of the Valley of Ten Thousand Smokes and volcanoes of the Katmai cluster . . . . . . . . . . . . . . . . . 14

Figure 14. Photograph of fall deposits at different distances from vent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 15

Figure 15. Inferred cross section of Novarupta vent area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 16. Photograph showing the Katmai Canyon landslide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Figure 17. Photograph of a very large boulder in the Mageik Landslide . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 18. Photographs of the Valley of Ten Thousand Smokes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Figure 19. Photograph of an inactive fumarolic fissure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Figure 20. Simplified cross section of a glacial valley filled with a thick pyroclastic flow followed by rapid incision of streams . . . . . . . . . . 18

Figure 21. Photograph of deep incisions by creeks into the ignimbrite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19

Figure 22. Photograph of the Ukak River and Savonoski River deltas showing the brown waters of the sediment laden rivers. . . . . . . . . . 19

Figure 23. Map showing the progradation of the Ukak River and Savonoski River delta from 1951 to 2010 . . . . . . . . . . . . . . . . . . . 19

Figure 24. Photograph of biological soil crust . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Figure 25. Map of Alaska and adjacent parts of North America showing the location of Novarupta and the region impacted by ash fall . . . . 20

Figure 26. Graph showing the timing of major volcanic eruptions compared to Northern Hemisphere climate records . . . . . . . . . . . . . 21

Figure 27. Map showing the locations of Quaternary volcanoes in the Katmai area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Figure 28. Aerial view looking northwestward of Katmai caldera with Mount Griggs and the Valley of Ten Thousand Smokes . . . . . . . . . . 25

Figure 29. Photograph of the glacially eroded summit of Alagogshak volcano . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Figure 30. Photograph of the fumarolically active Mount Martin summit cone and shallow lake . . . . . . . . . . . . . . . . . . . . . . . . . 26

Figure 31. Photograph of ice-clad Mount Mageik from Baked Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 32. View of the Trident Volcano from Baked Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27

Figure 33. Photograph of the early stages of the Southwest Trident eruption taken 21 February 1953 . . . . . . . . . . . . . . . . . . . . . 28

Figure 34. Time series showing the chronology of the Southwest Trident 1953–1964 eruptions . . . . . . . . . . . . . . . . . . . . . . . . . 28

Figure 35. 1960 photograph showing the lava flows of Southwest Trident that formed from 1953 to 1959. . . . . . . . . . . . . . . . . . . 29

Figure 36. Photograph of Mount Griggs, the highest peak in the Katmai cluster. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

Figure 37. Photograph of Snowy Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 38. Photograph of the Snowy Mountain "Snowy Hole." . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 39. Photograph of the volcanic peaks Mount Denison and Mount Steller . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

Figure 40. Photograph of the summit of Mount Steller. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 41. Photograph of the summit of Kukak Volcano . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 42. Photograph of Devils Desk volcanic neck . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 43. Photograph of the Rainbow River Cone. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Figure 44. Photograph of Cone 3601 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 45. Photograph of Cone 3110. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 46. Photograph of Iron Trig Cone . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32

Figure 47. Photograph of the Savonoski crater. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 33

Page
vi

Figures (continued)

Figure 48. Photograph of Kaguyak Crater with its 150 m (490 ft) deep lake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

Figure 49. Photograph of fumaroles on the west side of Fourpeaked Mountain, 24 September 2006. . . . . . . . . . . . . . . . . . . . . . 35

Figure 50. Photograph of a non-venting fumarole pit in glacier ice on the summit of Fourpeaked Mountain . . . . . . . . . . . . . . . . . . . 35

Figure 51. Photograph of the debris outflow below the canyon and the deep chasm formed below the eruption site at Fourpeaked Mountain . 35

Figure 52. Photograph of debris flow on the north flank of Fourpeaked Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 53. Photograph of Mount Douglas in the foreground and Fourpeaked Mountain in the background . . . . . . . . . . . . . . . . . . . 36

Figure 54. Photograph of the north flank of Kejulik Mountain . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

Figure 55. Photographs of an inactive fumarole and alteration halos along fumarole cracks . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

Figure 56. Photograph of the fumarole on the west flank of Mount Griggs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 38

Figure 57. Photograph of warm springs originating from the toe of a Trident lava flow . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Figure 58. Photograph of the Mount Martin crater lake and fumaroles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39

Figure 59. Photograph of Mount Mageik crater and lake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 60. Photograph of Mount Douglas crater lake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 61. Photograph of the crater lake on Mount Katmai in 2015 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 62. Photograph of a mud geyser on the floor of the Katmai crater in the year 1923 . . . . . . . . . . . . . . . . . . . . . . . . . . . 40

Figure 63. Satellite image of the crater lake in Mount Katmai overlain by shoreline outlines in 1951, 1974, and 2010. . . . . . . . . . . . . . 41

Figure 64. Map showing the glacier extents during glaciations and stades of the Katmai area . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Figure 65. Diagram showing common types of glacial deposits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

Figure 66. Photograph of the Iliuk stade moraine dividing the Iliuk Arm from the greater Naknek Lake . . . . . . . . . . . . . . . . . . . . . 43

Figure 67. Diagram showing the distance from the mountain crest for the various glacial advances and their absolute age 

ranges based on radiocarbon ages. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Figure 68 Map showing the extent of the proglacial lake Naknek at varying lake levels defined by major wave-cut terraces . . . . . . . . . . . 47

Figure 69. Satellite image mosaic of beach ridges along the eastern shore of Kukaklek Lake at the outlet of Moraine Creek. . . . . . . . . . . 47

Figure 70. Photograph showing glacial features . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48

Figure 71. Photograph of Hallo Glacier in 2007 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Figure 72. Photograph of one of the Knife Creek Glaciers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 49

Figure 73. Map showing the extent of the glaciers as mapped on 1950s USGS topographic maps as compared to the 

modern glacial extent derived from satellite images mostly from 2009. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 50

Figure 74. Comparative photographs of the north side of the Katmai caldera showing the growth of the northern glacier . . . . . . . . . . . 51

Figure 75. Photograph of the icefall from the glacier on the southwest wall of the Katmai caldera . . . . . . . . . . . . . . . . . . . . . . . 51

Figure 76. Photograph of a rock glacier in the hills of the headwaters of Ikagluik Creek . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 52

Figure 77. Map showing the permafrost extent in the Katmai area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 53

Figure 78. Photographs of three major types of coastline in the Katmai area. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Figure 79. Satellite image of beach berms forming at the outlet of the Swikshak River . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

Figure 80. Photograph of a raised marine terrace . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55

Figure 81. Photograph of marine terraces, sea cliffs, and sea caves raised above the modern high tide level . . . . . . . . . . . . . . . . . . . 55

Figure 82. Diagram showing the depositional environments of Mesozoic nonmarine and marine rocks of the Katmai area . . . . . . . . . . . 56

Figure 83. Photograph of bedding forms in the Naknek Formation, Snug Harbor Siltstone Member near Ukak Falls . . . . . . . . . . . . . . . 58

Figure 84. Map showing the extent of the Naknek Formation along the Alaska Peninsula and Talkeetna Mountains. . . . . . . . . . . . . . . 59

Figure 85. Photograph of Buchia mosquensis bivalve fossils in the Naknek Formation Snug Harbor Siltstone member near the Ukak River. . . . 60

Figure 86. Photograph of the bivalve Inoceramus ovatoides in the Herendeen Formation . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Figure 87. Photograph of dark gray, fine-grained sedimentary rocks of the Kaguyak Formation in the hills above Big River . . . . . . . . . . . 62

Figure 88. Photograph of the ammonite Pachydiscus kamishakensis from the Kaguyak Formation. . . . . . . . . . . . . . . . . . . . . . . . 62

Figure 89. Photographs of the Ketavik Formation at Brooks Falls. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 63

Figure 90. Photograph showing moderately dipping, bedded rocks of the Copper Lake Formation along sea cliffs north of Cape Douglas . . . 64

Figure 91. Map showing the extent of Tertiary igneous rocks along the Alaska Peninsula and into the Alaska Range . . . . . . . . . . . . . . 65

Figure 92. Photograph of columnar jointed lava flow of the volcanic rocks of the Barrier Range on Takli Island in Amalik Bay . . . . . . . . . . 66

Figure 93. Photograph showing drag folds in the Naknek Formation along the Bruin Bay Fault . . . . . . . . . . . . . . . . . . . . . . . . . 67

Figure 94. Map showing the terranes of Alaska . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68

Figure 95. Paleogeographic map showing the Wrangellia composite terrane translation history from the Late Triassic to the present . . . . . . 69

Page
vii

Figures (continued)

Figure 96. Diagram showing the types of volcanic hazards that have and could occur at Katmai. . . . . . . . . . . . . . . . . . . . . . . . . 74

Figure 97. Map showing active volcanoes and drainages at risk for lahar flows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75

Figure 98. Map showing the locations of seismic stations maintained and monitored by AVO . . . . . . . . . . . . . . . . . . . . . . . . . . 76

Figure 99. Satellite image of ash being resuspended from the Valley of Ten Thousand Smokes and creating an ash cloud over Shelikof Strait . . 78

Figure 100. Cursory hazard map showing volcanic rocks, volcanic ash, pyroclastic flow deposits, landslide deposits, colluvial 

deposits, and slopes susceptible to rockfall or landslides. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Figure 101. Map showing the probability of earthquake of magnitude 5.5 or greater over the next 20 years in the Katmai area. . . . . . . . . 81

Figure 102. Map showing location of oil and gas wells near the Katmai area . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Figure A1. Griggs expedition, Baked Mountain Camp in 1919. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105

Figure A2. Bernard Hubbard inspecting a bread-crust bomb adjacent to the steaming Novarupta dome in 1935 . . . . . . . . . . . . . . . .106

Page

Tables

Page

Table 1. Volcanic explosivity index (VEI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

Table 2. Simplified volcanic rock classification and characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13

Table 3. Volcanoes within Katmai National Park and Preserve. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24

Table 4. Geomorphic and ecological processes following a large volcanic eruption. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Table 5. GRI GIS data layers for the Katmai area. . . . . .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89

Plates (in pocket)

Plate 1. Geologic map of Katmai National Park and Preserve and Alagnak Wild River.

Plate 2. Stratigraphic chart of the bedrock units of the Katmai area.

Plate 3. Cross section through Katmai National Park from near Lake Brooks to Amalik Bay showing the bedrock and volcanic units.

Plate 4. Map showing the locations of geothermal features and crater lakes of Katmai National Park and Preserve.

ix

Executive Summary

The Geologic Resources Inventory (GRI) is one of 12 inventories funded by the National Park 

Service (NPS) Inventory and Monitoring Program. The Geologic Resources Division of the NPS 

Natural Resource Stewardship and Science Directorate administers the GRI. This GRI report was 

written for resource managers to support science-informed decision making. It may also be useful for 

interpretation. The report was prepared using available geologic information. Chapters of the report 

discuss distinctive geologic features and processes, describe the geologic history leading to the presentday landscape, highlight geologic issues facing resource managers, and provide information about the 

associated GRI geologic map data. A poster (Plate 1, in pocket) illustrates these data.

The largest volcanic eruption of the 20th century 

exploded 6 June 1912, from a new volcanic vent, 

Novarupta, creating the Katmai caldera and the Valley 

of Ten Thousand Smokes. The magnitude and volume 

of the eruption at Novarupta in 1912 were exceptional, 

far larger than any other historical eruption in North 

America. Katmai National Monument was established 

in 1918 to preserve the volcanic features formed by 

this eruption, and provide for the scientific study of 

these features and how the landscape recovers from the 

eruption. The monument was greatly expanded and 

redesignated as Katmai National Park and Preserve in 

1980. Alagnak Wild River was also established in 1980 to 

protect the Alagnak River system, which is an important 

sockeye (red) salmon fishery, and critical to the 

economy, culture, recreation, and history of southwest 

Alaska. In this report the term “Katmai area” refers to 

Katmai National Park and Preserve, Alagnak Wild River, 

and the immediate surrounding area on the geologic 

map (see Plate 1, in pocket).

The primary geologic features and processes within the 

Katmai area are associated with the 1912 eruption and 

formation of the Valley of Ten Thousand Smokes. Two 

dozen volcanoes in the park have erupted in the past 2.6 

million years. 

● Eruption Episodes. The 1912 Novarupta-Katmai

eruption consisted of three main explosive episodes

originating from the Novarupta vent. Episode I,

on 6 June, produced widespread fallout and ash

flows from a high eruption column. Episodes II

and III, on 7 and 8 June, were similar to each other;

each began after an eruptive lull, and deposited

widespread fall layers. These three episodes formed

the ignimbrite (pumice rich ash flow deposit) of

the Valley of Ten Thousand Smokes. The explosive

episodes were followed by extrusion of three

lava domes. Although the eruption took place at

the Novarupta vent, the bulk of the magma was 

sourced from a chamber under Mount Katmai. As 

the magma chamber was depleted, the summit of 

the mountain collapsed and formed the Katmai 

caldera.

● Landscape Changes Caused by the 1912

Eruption. The eruption deposited 13 to 15 km3

(3.1 to 3.6 mi3) of mostly loose volcanic material

on the surrounding landscape, which increased the

sediment supply in streams. The valley of the River

Lethe was filled with the ignimbrite sheet, which

changed the valley from U-shaped and heavily 

vegetated to flat and nearly barren of vegetation.

The accumulation of warm ash fall on snow

caused rapid melting, which formed lahars that

flowed down drainages surrounding Novarupta.

Numerous, large landslides were caused by 

concurrent earthquakes, most notably the Katmai

Canyon landslide, and the great Mageik Landslide.

The Katmai Canyon landslide dammed the river for

three years. The geomorphic and biologic processes

in the first few years following the eruption were

documented by the Griggs expeditions, but many 

of the processes observed then are continuing and

evolving today.

● Global Climate Effects of the 1912 Eruption.

Volcanic ash, more than from all other historical

eruptions in Alaska combined, devastated areas

hundreds of miles away, and the huge eruption

column rose greater than 30,000 m (100,000 ft),

where stratospheric winds carried the ash around

the world. The ash shrouded most of southern

Alaska and the Yukon Territory, and haze was

noticed within a day of the eruption as far away as

British Columbia, and in Europe two weeks later.

The ash and aerosols shielded the sun’s rays and

lowered average temperatures about 1°C (2°F) in

the Northern Hemisphere for more than a year.
x

● Volcanoes. The Katmai area contains the most

active and dense group of stratovolcanoes of any 

national park. Katmai has 24 volcanoes that erupted

in the last 2.6 million years (the Quaternary Period)

with 36 volcanic vents. Ten of the Katmai volcanoes

are considered active (Douglas, Fourpeaked,

Kukak, Snowy, Griggs, Katmai, Novarupta,

Trident, Mageik, Martin), and five of the volcanoes

erupted during historic time (Fourpeaked, Kukak,

Katmai, Novarupta, Trident). Trident Volcano 

erupted intermittently for 21 years between 1953

and 1974, forming lava flows and a lava dome on

the southwest flank of the volcano. Fourpeaked

volcano was thought to be dormant, so the small

eruption on 17 September 2006 was a surprise. The

eruption caused a glacial outburst flood and debris

flow, and fumaroles emitted gases near the summit

for a year after the eruption.

In addition to features and processes associated with 

volcanic eruptions and their deposits, the Katmai 

area contains other significant geologic features and 

processes, including the following:

● Geothermal Features. Katmai National Park

and Preserve is one of 16 units of the National

Park System with significant thermal features as

designated by the Geothermal Steam Act of 1970

(amended in 1988).

□ Fumaroles. Fumaroles of the Valley of

Ten Thousand Smokes made the Katmai

area famous and prompted the formation

of a national monument to preserve these

unique features. Groundwater in the Valley 

of Ten Thousand Smokes interacted with the

hot ignimbrite and steam escaped through

fractures, forming the “smokes.” As the

ignimbrite sheet cooled, the smokes of the

valley slowly extinguished. The fumaroles

that are active today, at the summits and along

the flanks of the volcanoes, expel volcanic

gases, which are sourced from magma within

the active volcanic systems. Active fumaroles

exist on the following volcanoes: Novarupta

dome, Trident, Martin, Mageik, Griggs, Kukak,

Snowy, Fourpeaked, Douglas, and under the

crater lakes of Katmai and Kaguyak.

□ Warm Springs and Warm Ground. Warm

springs are present throughout the volcanic

area of Katmai. In particular, warm springs still

issue from the 1912 ignimbrite sheet and the

Trident Volcano 1953–1960 lava flows. Warm 

ground has been documented near Novarupta 

dome and on Mount Griggs.

□ Crater Lakes. Six of the volcanoes in the

Katmai area (Mageik, Martin, Katmai,

Kaguyak, Douglas, and Savonoski) contain

crater lakes. Mageik and Martin have shallow,

very warm lakes fed by numerous fumaroles.

The Katmai crater lake formed after the top of

the mountain collapsed as a result of the 1912

eruption. The lake has progressively filled since

the eruption.

● Glaciations. The Katmai area contains abundant,

well preserved glacial moraines and other

landforms created by past glacial advances. During

the Pleistocene Epoch (2.6 million–0.01 million

years ago [MYA]), the Alaska Peninsula held the

western extent of the continental ice sheet that

spanned northern North America. During the last 

glacial maximum, the entire Katmai area was

covered by glacier ice, except for the highest peaks.

Three major glaciations are recognized in the

Katmai area: Johnson Hill glaciation (>43,000 years

ago); Mak Hill glaciation (>43,000 years ago); and

Brooks Lake glaciation (30,000–20,000 years ago).

The Brooks Lake glaciation is divided into four

stades: Kvichak; Iliamna; Newhalen; and Iliuk.

Glacial deposits, Ukak drift and Katolinat till, from

two younger (17,000–10,000 years ago) advances,

are present near the Valley of Ten Thousand

Smokes. Beach ridges and wave-cut terraces are

found tens of meters above the present lake levels.

The ridges and wave-cut terraces were formed by 

proglacial lakes that were larger and deeper than

the present day lakes.

● Modern Glacier Features and Changes. Katmai

contains an estimated 300 glaciers that more-orless cover the volcanoes. Glacial area has decreased

14% since the 1950s. Most glaciers in the Katmai

area are retreating, including notable retreats of up 

to 4 km (2.4 mi) for glaciers on Fourpeaked

Mountain and Mount Douglas, and Hallo Glacier

and others on Kukak Volcano. Some of the glaciers, 

however, have advanced, for example those that 

were covered by thick deposits of 1912 ash. 

Additionally, two glaciers have formed in the

Katmai crater since the 1912 eruption.

● Permafrost Features. Although the average annual

temperature at King Salmon is above freezing,

isolated permafrost is present in the western 
xi

portion of the park unit, namely on the coastal 

plain under areas insulated by peat and thick 

vegetation mats. The presence of the permafrost is 

possibly due to the thermal properties of overlying 

peat, or remnants of the Pleistocene (2.6–0.01 

MYA) glaciations. Polygonal ground is present at 

higher elevations on a pass near Kaguyak Crater. 

Climate scenarios indicate a rise in average annual 

temperature of 2.6°C (4.7°F) by 2040 in the Katmai 

area, and permafrost melting was identified as 

a potential major change to the park. Periglacial 

features in the Katmai area also include patterned 

ground, solifluction deposits, and rock glaciers.

● Coastal Features. The Katmai coast is a mix of

rugged wave-eroded sea cliffs on the headlands

and protected bays.

□ Beach Berms. Beach berms are present in

many of the protected bays, including some

places with stranded shorelines far inland from

the modern shoreline.

□ Raised marine terraces and sea caves. Raised

marine terraces are present along the coast

of Shelikof Strait and Katmishak Bay at 15 m

(50 ft), 27 m (90 ft), and between 40 and 45 m

(130 and 150 ft) above the modern high tide

line. Relict beaches, sea caves, and sea cliffs are

found well above modern sea level, as a result

of ongoing uplift. The uplift rate of the coast is

approximately 3–8 mm/yr (0.1–0.3 in/yr).

● Modern Surficial Deposits and Processes.

Modern surficial deposits have formed in the last

few thousand years, and many are still forming

today. They include swamp deposits in bogs and

ponds, alluvium along modern rivers, alluvial fans

along mountain fronts, landslide and colluvium

below cliff faces and along steep slopes, and dunes

in the Valley of Ten Thousand Smokes and near

beaches along the coast.

● Mesozoic Bedrock. Katmai contains a nearly

complete sequence of rocks that spans the

Mesozoic era (252–66 MYA). Triassic (252–201

MYA) greenstone is overlain and intruded by

Lower Jurassic (201–174 MYA) plutonic and

volcanic rocks of the Talkeetna volcanic arc.

Sedimentary rocks formed predominately along a

narrow shelf at the edge of the eroding Talkeetna

volcanic arc. Many of the Jurassic and Cretaceous

sedimentary rocks contain abundant marine fossils.

The Mesozoic rocks formed offshore in the protoPacific Ocean.

● Tertiary Sedimentary Rocks. Tertiary sedimentary 

rocks crop out along the Katmai coast and on the

west side of the mountains north of Naknek Lake.

The Oligocene (34–23 MYA) or, possibly, earliest

Miocene (23–20 MYA) Hemlock Conglomerate

crops out on the Katmai coast and is a fluvial

(river) sandstone and conglomerate deposited in a

braided fluvial system with highly sinuous channels.

The Eocene (56–34 MYA) and possibly upper

Paleocene (60–56 MYA) Copper Lake Formation

crops out near Kukaklek Lake on the north

and around Fourpeaked Mountain and Mount

Douglas. It consists of fluvial conglomerate and

interbedded sandstone and siltstone that represent

predominantly braid-plain fluvial deposits. The

Ketavik Formation is an upper Paleocene to lower

Eocene (59–49 MYA) fluvial sandstone and

conglomerate that crops out in small, obscure

exposures along Naknek Lake west of Brooks

Camp and at Brooks Falls. The Tertiary sedimentary 

units contain abundant and well-preserved plant

fossils.

● Tertiary Igneous Rocks. Four groups of Tertiary

(66–2.6 MYA) igneous rocks are recognized

throughout the map area: (1) the Meshik Volcanics

north of Naknek Lake, (2) the Gibraltar Lake Tuff

on the most northern edge of the map area, (3)

volcanic rocks of the Barrier Range near Katmai and

Snowy mountains, and (4) undivided intrusive

rocks underlying Fourpeaked Mountain and Mount

Douglas. The rocks range in age from the late

Eocene to Pliocene epochs (40–2.6 MYA) and

represent an episodic period of volcanism that

started in the early Tertiary and continues today.

● Faults and Folds. The major geologic structure of

the Katmai area is the inactive Bruin Bay

fault, which runs through the middle of the

park and extends nearly the entire length of the

Alaska Peninsula from near Aniakchak National

Monument and Preserve through Lake Clark

National Park and Preserve. It is a major reverse

fault that dips to the northwest with the upthrown

side on the northwest. The fault was active

during deposition of the Upper Jurassic to Lower

Cretaceous (145–100 MYA) marine sedimentary

rocks. The magmatic arc rocks on the northwest

side of the fault were uplifted and eroded, which

provided sediment to a shallow marine shelf on the

southeast side of the fault.
xii

● Terrane Translation and Accretion. The 

Mesozoic rocks belong to a group of rocks called

the Peninsular terrane, which is thought to have

originated far to the south and to have been

added to southern Alaska in late Mesozoic time.

Evidence from paleomagnetism, fossil assemblages,

and depositional environments suggests that the

Mesozoic rocks formed originally in tropical

waters in the Late Triassic (237–201 MYA), were

transported to polar (boreal) environments by the

Late Jurassic (164–145 MYA), back down to low

latitudes in the mid-Cretaceous (110–90 MYA),

then slid northward to its present location. Plate

tectonics has played a major role in the formation of

the rocks of Katmai, transporting across the protoPacific Ocean, and causing the deformation and

uplift that is still ongoing today.

Three meetings were held to discuss GRI products, 

geology of the park units, and resource management 

issues. These meetings were held with NPS natural 

resource managers, NPS Southwest Alaska Network 

staff, NPS Alaska Region specialists, and geologists 

with experience in the Katmai area. At these meetings, 

participants discussed the following geologic resource 

management issues:

● Preservation of Katmai’s Natural Features for

Inspiration and Study. The primary purpose of

establishing Katmai National Monument was to

preserve the spectacular volcanic features of the

1912 eruption, specifically for inspiration and

research. The Katmai area is ideal for studying

volcanic processes and monitoring the regeneration

of ecosystems after a catastrophic eruption.

● Geohazards. The Katmai area has a very high

potential for natural hazards. It contains many 

active volcanoes and adjacent active volcanoes

could impact the area. Strong wind events

frequently re-suspend ash from the 1912 eruption.

Hydrothermal processes produce acidic waters

(such as crater lakes) that can cause ecological

harm to sensitive riverine or lacustrine ecosystems.

The area overlies the tectonically active Aleutian

megathrust, and movement on this thrust causes

frequent and large earthquakes. The steep slopes in

the mountainous areas are prone to landslides and

rockfall. The coastal areas are exposed to tsunamis

originating from earthquakes or volcanic mass

flows.

□ Dynamic Volcanic Landscapes. Volcanic

landscapes are constantly changing. The

intermittent addition of volcanic materials

and gases affects streamflow, lakes, glacial

processes, and atmospheric conditions.

Volcanic eruptions can disturb ecosystems,

and in very large eruptions, like the 1912

Novarupta-Katmai eruption, can bury or

sterilize landscapes.

□ Crater Lake Explosions and Acidic-Water

Flooding. Lakes in the active volcanic craters

of Mounts Douglas, Martin, Mageik, and

Katmai create the potential hazard of lake

water and magma violently mixing to generate

an explosive eruption. The water-magma

interaction acts as an intensifier for the

eruption. The violence of the interaction is

controlled by a number of factors, including

magma type, volume, rate of extrusion,

degree to which the magma is fragmented

by expanding internal gas bubbles, and

water depth. The disruption of such acidic

lakes also increases the possibility of local

acid rainfall and of sending acid-water-rich

lahars and debris flows downhill from those

summits. Acidic volcanic lake water can have

catastrophic effects on riverine and lake

ecosystems.

● Geothermal Features Inventory and Monitoring.

The Geothermal Steam Act of 1970, as amended

in 1988, lists Katmai National Park and Preserve

as containing significant geothermal features. The

act prohibits geothermal leasing in parks, and

authorizes the Secretary of the Interior to mitigate

or not issue geothermal leases outside parks that

would have a significant adverse impact on notable

thermal features within the park. The act also

requires inventorying and monitoring significant

geothermal features of the park.

● Coastal Issues. The rugged Katmai coast is

dynamically changing. Uplift of the coast in the

last few thousand years is evident by raised marine

terraces and stranded sea caves. Climate change

may lead to sea level rise, increased storm strength,

and ocean acidification, which could alter the

current coastal geomorphic processes and coastal

ecosystems. Intergovernmental Panel on Climate

Change (IPCC) models predict that absolute sea

level in the region will increase about 37 cm (1.2 ft)

by the end of the century, but the uplift rate of the
xiii

Katmai coast is projected to outpace the rise in sea 

level. The uplift of the coastline is primarily caused 

by plate tectonic forces, but isostatic rebound 

from the melting of the glaciers from the last ice 

age may be a contributor. The uplift has preserved 

archeological sites from inundation and erosion. 

However, increased erosion from increasing storm 

frequency should also be expected in the future.

● Fluvial Erosion. Fluvial erosion along steep river 

banks is a threat to archeological sites, especially 

along the Brooks and Alagnak Rivers. As the 

rivers naturally change their courses, erosion will 

continue to impact the shoreline and associated 

cultural resources. This is of particular concern 

along braided sections of the rivers where change 

can occur over relatively short amounts of time.

● Glacier Changes. About 915 km2 (350 mi2) of the 

Katmai area is covered in ice. Glaciers are affected 

by temperature and precipitation, so they are 

indicators of long-term climate change. The overall 

coverage of glacial ice in Katmai has decreased 14% 

since 1950. Most glaciers in the Katmai area are 

receding, like most glaciers in Alaska, but glaciers 

that were covered by thick deposits of 1912 ash are 

not receding and some have advanced.

● Paleontological Resource Inventory, Monitoring, 

and Protection. The Katmai area contains more 

than 550 fossil localities. The Mesozoic sedimentary 

rock units contain mostly invertebrate marine 

fossils, and the Tertiary sedimentary rock units 

contain well-preserved plant fossils and petrified 

wood. The units with the most abundant fossils are 

the Ketavik Formation, Copper Lake Formation, 

Hemlock Conglomerate, Herendeen Formation, 

Kaguyak Formation, and the Naknek Formation. 

Fossil bone material was found in the Naknek 

Formation near Ukak Falls and adjacent to the park. 

Dinosaur tracks have been found in the Naknek 

Formation outside the park boundary, so dinosaur 

tracks or bones could be present within the park 

units. The abundance of fossils in the wide-spread 

sedimentary units in the park provides that 

potential for unauthorized collection and a need for 

a paleontological survey and field site assessment 

and monitoring plan.

● Abandoned Mineral Lands (AML). The Katmai 

area contains 31 locations with notable mineral 

resources. Between the early 1900s and the 1980s, 

small-scale mining and prospecting took place at 11 

of these sites. Mineral occurrences and prospected 

mineral resources included pumicite from the 

1912 eruption, placer gold, coal, and copper. No 

known safety issues exist at any AML sites within 

Katmai. Diesel-contaminated soil at one site is the 

only documented resource issue that has been 

associated with AML in the park and preserve. 

In 2011, after several years of soil treatment, the 

Alaska Department of Environmental Conservation 

(DEC) declared the site to be adequately cleaned 

up. The abandoned mine structures on the 

site are unsightly but pose no known safety or 

environmental threat.

● Potential Petroleum Development. The Katmai 

area is surrounded by oil and gas reservoirs. 

The Cook Inlet area contains reserves of oil and 

natural gas. More than a century of petroleum 

exploration has occurred in the Iniskin Peninsula 

area of the Alaska Peninsula. Offshore exploration 

wells have been drilled less than 25 km (16 mi) 

from the northeastern coast. The Bureau of Ocean 

Energy Management (BOEM) is preparing an 

environmental impact statement for a potential 

lower Cook Inlet lease sale. The Katmai coast 

supports a complex ecosystem that was impacted 

by the Exxon Valdez oil spill. Oil spills from 

exploration or production activity in Cook Inlet 

have the potential to severely harm the coastal 

ecosystems of Katmai.

● Soils and Permafrost. Soil temperature and 

permafrost were listed as important physical 

elements of the Southwest Alaska Network vital 

signs monitoring plan. Climate scenarios indicate a 

rise in average annual temperature of 2.6°C (4.7°F) 

by 2040 in the Katmai area, and permafrost melting 

was identified as a potential major change to the 

park due to climate change.

xv

Products and Acknowledgments

The NPS Geologic Resources Division partners with the Colorado State University Department of 

Geosciences to produce GRI products. The US Geological Survey developed the source maps and 

reviewed GRI content. This chapter describes GRI products and acknowledges contributors to this 

report.

GRI Products

The GRI team undertakes three tasks for each park in 

the Inventory and Monitoring program: (1) conduct a 

scoping meeting and provide a summary document, 

(2) provide digital geologic map data in a geographic

information system (GIS) format, and (3) provide a GRI

report (this document). These products are designed

and written for nongeoscientists.

Scoping meetings bring together park staff and geologic 

experts to review and assess available geologic maps, 

develop a geologic mapping plan, and discuss geologic 

features, processes, and resource management issues 

that should be addressed in the GRI report. Following 

the scoping meeting, the GRI map team converts the 

geologic maps identified in the mapping plan to GIS 

data in accordance with the GRI data model. After the 

map is completed, the GRI report team uses these data, 

as well as the scoping summary and additional research, 

to prepare the GRI report. The GRI team conducts no 

new field work in association with their products.

The compilation and use of natural resource 

information by park managers is called for in the 1998 

National Parks Omnibus Management Act (§ 204), 2006 

National Park Service Management Policies, and the 

Natural Resources Inventory and Monitoring Guideline 

(NPS-75). The “Additional References” chapter and 

Appendix C provide links to these and other resource 

management documents and information.

Additional information regarding the GRI, including 

contact information, is available at http://go.nps.gov/gri. 

The current status and projected completion dates of 

products are available at http://go.nps.gov/gri_status.

Acknowledgments

This compilation was built from over a century of 

research in the Katmai area and could not have been 

completed without the efforts of the many geologic 

explorers and writers. Two of these geologists that 

have extensive experience with Alaskan geology 

provided thorough technical reviews of this report: 

Wes Hildreth (research geologist, USGS-California 

Volcano Observatory) and Will Elder (interpreter, 

NPS Golden Gate National Recreation Area; and 

former USGS paleontologist). We thank all the people 

that attended the pre-report meetings that pointed 

the authors to sources of information that may not 

have been obvious, and ideas for topics to include. In 

particular, we thank Troy Hamon (chief of resources, 

NPS Katmai/Aniakchak) for taking time to discuss 

the resource management issues. The clarity of the 

manuscript was improved by informal reviews by 

Mike Fitz (visual information specialist, NPS Katmai/

Aniakchak). We greatly appreciate the thorough 

edits completed by Katie KellerLynn (research 

associate, Colorado State University). Katie Meyers

(collections manager, NPS Katmai/Aniakchak) was a 

great help sleuthing through the archives in the Alaska 

Regional Office Curatorial Center to provide many 

interesting documents about the geologic exploration 

history. Thomas Hamilton (former USGS research 

geologist) provided unpublished manuscripts from his 

geologic explorations in the 1960s. The paleontology 

information provided in the report was compiled by 

M. Mark Turner (Geoscientists-in-the-Parks intern,

Alaska Regional Office). Sea level change scenarios

were provided by Maria Caffrey (research associate,

University of Colorado and Geologic Resources

Division) and Rebecca Beavers (geologist, Geologic

Resources Division and Climate Change Response

Program). Sarah Venator (geologist, Alaska Regional

Office) provided information about AML sites. Some

of the graphics were provided by Trista ThornberryEhrlich (research associate, Colorado State University).

The lead author greatly appreciates the many reviews

of this document by Jason Kenworthy (geologist,

Geologic Resources Division) and his persistent efforts

to keep up the momentum.

Review

Wes Hildreth (USGS California Volcano Observatory)

Will Elder (NPS Golden Gate National Recreation 

Area)

Jason Kenworthy (NPS Geologic Resources Division)
xvi

Editing

Katie KellerLynn (Colorado State University)

Report Formatting and Distribution

Jason Kenworthy (NPS Geologic Resources Division)

Rebecca Port (NPS Geologic Resources Division

Source of the Digital Data for the Geologic Map

Frederic Wilson (USGS Alaska Science Center)

Source maps listed in “Geologic Map Data” section

GRI Digital Geologic Data Production

Jim Chappell (Colorado State University)

Chad Hults (NPS Alaska Regional Office)

Nancy Norvell (USGS Alaska Science Center)

GRI Poster Design

Chase Winters (Colorado State University)

Georgia Hybels (Colorado State University)

GRI Poster Editing

Georgia Hybels (Colorado State University)

Rebecca Port (NPS Geologic Resources Division)

Jason Kenworthy (NPS Geologic Resources Division)
xvii

List of Abbreviations

For a geologic glossary with simplified definitions, refer to

http://geomaps.wr.usgs.gov/parks/misc/glossarya.html.

● AVO: Alaska Volcano Observatory

● BOEM: Bureau of Ocean Energy Management

● CalVO: California Volcano Observatory

● cal. yr BP: calibrated years before present

● GRD: Geologic Resources Division

● GRI: Geologic Resources Inventory

● K/Ar: potassium/argon (an isotopic ratio used to determine the age of volcanic rocks)

● MYA: million years ago

● NASA: National Aeronautics and Space Administration

● NOAA: National Oceanic and Atmospheric Administration

● NPS: National Park Service

● UAF: University of Alaska Fairbanks

● USGS: United States Geological Survey

● VABM: vertical angle bench mark

● VEI: Volcanic Explosivity Index (see Table 1)

● yr BP: years before present
xviii

Figure 1. Map showing the location of Katmai National Park and Preserve and Alagnak Wild River. The Katmai area 

spans the northern Alaska Peninsula from Cook Inlet to Bristol Bay MODIS satellite imagery from 2013.
1

Geologic Setting and Significance

This section describes the regional geologic setting of the Katmai area and summarizes connections 

among geologic resources, other park resources, and park stories.

Katmai National Park and Preserve and the contiguous 

Alagnak Wild River encompass an active geologic 

landscape shaped by the dynamic forces of volcanoes, 

glaciers, rivers, waves, currents, wind, and plate 

tectonics. In this report the term “Katmai area” refers to 

Katmai National Park and Preserve, Alagnak Wild River, 

and the immediate surrounding area on the geologic 

map (see Plate 1, in pocket). Located along the Alaska 

Peninsula, the Katmai area spans from the Pacific Ocean 

nearly to Bristol Bay (Figure 1). The principal geologic 

feature of the Katmai area is the spectacular landscape 

created by the 1912 Novarupta-Katmai eruption, 

which formed the Valley of Ten Thousand Smokes. 

The valley so impressed its first explorer, Robert F. 

Griggs, that he urged President Wilson’s administration 

to preserve it for posterity, and Katmai National 

Monument was established in 1918. The monument 

was created with the dual intention of both protecting 

the scenic wonders and preserving possibilities for 

continued scientific study of phenomena related to the 

1912 eruption. Expansion of the protected area and 

redesignation as a national park and preserve in 1980 

validated and supported both values. The volcanoes 

of Katmai National Park and Preserve have provided 

geologists and other scientists with many opportunities 

for exploring and understanding volcanic phenomena 

and their ecological effects.

The preserved area encompasses 1,656,405 ha 

(4,093,067 ac) or 16,564 km2 (6,395 mi2) and Katmai 

National Park and Preserve is the fourth largest unit in 

the National Park System. The Katmai area consists of 

a rugged volcanic spine; long lakes and rivers draining 

to the west; and steep, short river valleys flowing to the 

complex, dynamic coast on the east. The 13 highest 

mountains, which rise more than 1,500 m (5,000 ft) 

above the coast, are heavily glaciated volcanoes. The 

Katmai area is home to 24 Quaternary volcanoes (active 

in the last 2.6 million years), more than any other 

national park. Ten of the volcanoes are considered 

active, and five had eruptions in historic time. Nearly 

300 glaciers cap the mountain crest that covers 915 km2

(353 mi2). These glaciers are the source of turbulent 

braided rivers that flow down U-shaped valleys that 

were sculpted by glacial action during the last ice age. 

Glacier advances left numerous terminal moraines that 

dam the many lakes of the region. Naknek Lake is the 

largest of these lakes and, at 627 km2

 (242 mi2), is the 

largest lake in the National Park System. Notably, the 

lake was much larger during the Pleistocene (2.6–0.01 

MYA) glaciations.

The Alagnak River flows northwest for 119 km (74 

mi) from Kukaklek Lake (in Katmai National Park

and Preserve) to where it joins the Kvichak River

then flows to Bristol Bay. The Alagnak Wild River area

encompasses 12,409 ha (30,741 ac) or 124 km2 (48 mi2).

The Alagnak Wild River protects a pristine river system,

which hosts significant Bristol Bay sockeye (red) salmon

runs, as well as artifacts that preserve the history of

habitation in southwest Alaska. The river changes from

braided to meandering as it flows through subdued

terrain that was formed during some of the oldest

Pleistocene glaciations.

The Katmai area is known best for the 1912 NovaruptaKatmai eruption and many active volcanoes. The 

dominant geologic feature, and principal reason Katmai 

National Park and Preserve was established, is the 

Valley of Ten Thousand Smokes ignimbrite (pumice 

rich ash flow deposit) that was emplaced during the 

1912 eruption; the largest volcanic eruption of the 20th 

century. Lesser known is the eruption from a new vent 

on the southwest flank of Trident Volcano, which lasted 

from 1953 to 1974 and produced numerous lava flows.

These volcanoes are part of a dense cluster of 24 

volcanoes that are the most tightly spaced line of 

stratovolcanoes in Alaska (Figure 2). Crater-to-crater 

spacing between adjacent (commonly contiguous) 

edifices is typically 5 km (3 mi) or less. The volcanoes of 

the Katmai area are part of the larger Aleutian volcanic 

arc that spans 2,500 km (1,600 mi) from the Alaska 

Range to the far western Aleutian Islands (Figure 2). 

The volcanoes of the Aleutian arc are the result of 

subduction of the Pacific oceanic plate under Alaska. 

Subduction occurs where denser oceanic crust moves 

toward and sinks below less dense continental crust 

(Figure 3). The subducting Pacific oceanic plate under 
2

Figure 2. Map of Holocene volcanoes along the Aleutian volcanic arc, Kamchatka Peninsula, and Kurile Islands. 

Red triangles are volcanoes (Smithsonian Holocene volcano list: http://www.volcano.si.edu/list_volcano_holocene.

cfm). Arrows show the direction of motion of the Pacific plate relative to the North American and Asian continents 

(Haeussler and Plafker 2004). National Park System units in Alaska are outlined in brown.

Figure 3. Schematic cross section of oceanic 

crust subducting under continental crust. 

Water in the subducting plate reacts with 

the dry mantle, which causes melt to form 

and rise into the overlying plate. Volcanoes 

form where this melt reaches the surface 

of the earth and erupts as lava. “Arcs” 

are linear features. Fore arcs are areas of 

a subduction zone between the trench 

and the volcanic arc. Back arcs are on the 

opposite side of a volcanic arc from the 

subduction-related trench. Graphic modified 

from original provided by Trista ThornberryEhrlich (Colorado State University).
3

Alaska is denoted by the earthquakes that progressively 

get deeper under the Aleutian volcanic arc as the plate 

sinks deeper into the mantle (Figures 4 and 5). The 

boundary between the plates is called the Aleutian 

megathrust and is the focus of frequent earthquakes, 

some of which can be very large and cause tsunamis.

The Katmai area was mostly covered by glaciers during 

the last glacial maximum, during the Pleistocene Epoch 

(2.6 million–11,700 years ago), so the landscape was 

shaped by glacial processes. The gently sloping western 

side of the Alaska Peninsula contains many glacial 

moraines that define the maximum reach of the glaciers 

during glaciations and intermediate stades (advances). 

The lakes of the Katmai area are dammed by glacial 

moraines, and abundant evidence shows that the lakes 

were higher and more expansive in the past. Post-glacial 

mass wasting (slope movement) has eroded the highest 

peaks and is more common near the range crest and 

along the foothills. The many lakes and streams support 

extensive runs of anadromous fish that were a source 

of food for human populations for thousands of years. 

As a result of deglaciation, dropping water levels of the 

greater Naknek Lake stranded salmon, creating the 

endemic Kokanee populations. Dropping water levels 

also allowed post-glacial erosion to form the famous 

Figure 4. Map showing earthquake epicenters. Only earthquakes greater than magnitude 3.0 are shown from 1889 

to present (http://www.aeic.alaska.edu). The Aleutian arc volcanoes (black triangles) form where the subducting 

Pacific plate reaches 100 km deep (where the earthquake epicenters transition from green to red dots). At this 

depth, the water retained within the subducting plate reacts with the dry mantle to form magma. The Pacific plate 

motion relative to the North American plate is shown with arrows. The Pacific plate is subducting under Katmai 

at a convergence rate of about 60 mm/yr (2.4 in/yr). A cross-section in Figure 5 shows the location and depth of 

earthquakes along the line A–A’.
4

Brooks Falls. Low passes, like Katmai Pass, formed 

by glacier erosion, were ancient and historic trade/

migratory routes that provided a pathway for travel and 

trade across the Alaska Peninsula between the Pacific 

coast and Bristol Bay.

Underlying the volcanic carapace are ancient 

sedimentary and volcanic rocks (Plate 2) that have 

been uplifted by tectonic forces and carved by glaciers. 

The east half of the Katmai area is mostly made up of 

Mesozoic (252–66 MYA) marine sedimentary rocks 

that are gently folded (Plate 3). The Bruin Bay fault 

cuts across the center of the park from northeast 

to southwest (Plate 1). Movement along the fault 

uplifted rocks to the southwest of the fault, and 

erosion exposed Mesozoic plutonic (intrusive) and 

metamorphic (altered) rocks that formed deep in the 

crust. Overlying the Mesozoic rocks northeast of the 

fault are Tertiary (66–2.6 MYA) sedimentary, volcanic, 

and minor plutonic rocks that formed on land at or near 

the surface. The Mesozoic rocks include rocks of the 

Talkeetna arc, which formed in the Early Jurassic Period 

just after the start of the breakup of Pangea (Figure 6).

Figure 5. Chart showing a cross section of earthquakes along line A–A’ in Figure 4. The colors correspond to 

earthquake depth ranges shown in Figure 4. The Aleutian trench, which is 5–6 km (3–4 mi) below sea level, is 300 km 

(190 mi) southeast of the Katmai volcanoes. The inclined seismic zone shows where the Pacific Plate subducts under 

Alaska and is defined by an area of earthquakes that is 20–30 km (12–19 mi) wide (Kienle et al. 1983; Page et al. 1991). 

It dips about 10 ̊ NNW for some 300 km, then steepens to about 45 ̊ beneath the present-day volcanic arc. The plate 

is about 100 km deep under the Katmai area volcanoes, and continues behind the volcanoes to depths as great as 

220 km. The cluster of shallow earthquakes in the Katmai area were generated from magma movement under the 

volcanoes (Ward et al. 1991; Moran 2003; Dixon and Power 2009). 
5

Figure 6. Geologic time scale showing the onset of major global evolutionary events and tectonic events of the North 

American continent and the Northern Cordillera. SCAK = south-central Alaska. SEAK = southeast Alaska. The divisions 

of the geologic time scale are organized stratigraphically, with the oldest divisions at the bottom and the youngest at 

the top. GRI map abbreviations for each time division are in parentheses. Plate 2 (in pocket) shows the ages of rock 

types within the Katmai area. Ages are millions of years ago (MYA) from the International Commission on Stratigraphy 

(http://www.stratigraphy.org/index.php/ics-chart-timescale).

7

Geologic Features and Processes

This section describes and explains the formation of the distinctive geologic features of Katmai 

National Park and Preserve and Alagnak Wild River, and describes the processes of their formation. 

The geologic features are presented generally from youngest to oldest. The formation of the volcanic 

features is presented first, starting with the 1912 Novarupta-Katmai eruption and the features formed 

during the eruption. The many volcanoes that make up the mountain crest are listed and described. 

Surficial features, including glacial, coastal, and alluvial; and processes that shaped the landscape are 

discussed. The underlying bedrock units are then presented from oldest to youngest.

Much has been written about the 1912 Novarupta-Katmai eruption and the volcanoes of the Katmai 

area because they are features that formed in historic time and have potentially large impacts on 

human and natural resources. Instead of re-writing these works, much of the text for the following 

volcanic features section was taken from three sources: Fierstein (2012a), Fierstein (2012b), and the 

centennial report by Hildreth and Fierstein (2012).

1912 Eruption and Formation of the Valley of 

Ten Thousand Smokes

Map units: Qpd (in part), Qhvd (in part), and Qafd (in 

part)

The largest volcanic eruption of the 20th century 

began on 6 June 1912 from a new volcano, Novarupta. 

The great eruption of 1912 lasted for three days and 

consisted of three explosive episodes. The eruption 

created Katmai caldera and the Valley of Ten Thousand 

Smokes (Figure 7). Volcanic ash, more than from 

all other historical eruptions in Alaska combined, 

devastated areas hundreds of kilometers away, and the 

huge eruption column rose so high that stratospheric 

winds carried the ash around the world. 

Figure 7. Aerial photograph of the Valley of Ten Thousand Smokes extending 20 km (13 mi) northwest from vent at 

Novarupta to distant Mount Katolinat. Novarupta dome is encircled by an asymmetrical ring of accumulated pumice 

from eruptive Episodes II and III. USGS California Volcano Observatory (CalVO) photograph.
8

The magnitude and volume of the eruption at 

Novarupta in 1912 were exceptional, far larger than any 

other historical eruption in North America (Figure 8; 

Table 1). This fueled early US Geological Survey and 

National Geographic Society scientific investigations 

that helped to shape thinking about volcanoes and 

magmas (Martin 1913; Griggs 1922). For the first time in 

recorded history, a great explosive eruption deposited 

its pyroclastic flows on land rather than in the sea (as 

at Krakatau in 1883), so that they could be studied in 

detail. It was also one of the few places where scientists 

recognized a wide range of magma compositions having 

erupted together. Over the past three decades, detailed 

studies of Novarupta deposits have contributed to a 

better understanding of how volcanoes work, how 

explosive pumice and ash erupt and are emplaced, how 

calderas collapse, and what happened at the vent during 

Figure 8. Diagram showing comparisons of the 1912 Novarupta erupted magma volume to other historic eruptions in 

North America and the world. Figure 2 from Fierstein (2012a).

Figure 9 (right). Diagram showing the explosiveness and 

eruption column heights of different types of eruptions. 

The “colossal” Novarupta eruption is considered Plinian 

to Ultra-Plinian eruption. See Table 1 for how these 

classifications fit into the volcanic explosivity index. 

Graphic by Trista Thornberry-Ehrlich (Colorado State 

University), modified from Cas and Wright (1988).
9

the three day eruption (Hildreth 1983, 1987, 1991; 

Fierstein and Hildreth 1992; Fierstein and Nathenson 

1992; Fierstein et al. 1997; Hildreth and Fierstein 2000, 

2012; Houghton et al. 2004; Fierstein and Wilson 2005). 

These unusual conditions and fascination with the “Ten 

Thousand Smokes” led President Wilson to establish 

Katmai National Monument in 1918.

Reports of an Eruption

Initial signs of an impending eruption began with severe 

earthquakes felt at Katmai village on the Shelikof Strait 

coast “for at least 5 days prior to the eruption” (Martin 

1913). More were felt on 4 and 5 June, including as 

much as 250 km (160 mi) to the northeast, prompting 

the few inhabitants at Katmai village to evacuate by 

canoe down the coast toward Cold Bay (now Puale 

Bay). Unrest continued, as explosions were heard

230 km (140 mi) away on the morning of 6 June. 

Not until 1 pm (Alaskan time) was the first towering 

eruption cloud witnessed by crew members of the 

steamer SS Dora, then in Shelikof Strait. Two hours 

later darkness abruptly enveloped the vessel as it 

was overtaken by the choking ash. Lightning flashed 

from the black cloud overhead as Captain McMullen 

changed course from the intended stop at Kodiak and 

headed toward the open Gulf of Alaska. Even “full 

steam ahead,” the Dora remained under the ash cloud 

until early the next day.

At Kodiak, 160 km (100 mi) southeast of the eruption 

center, the air became thick with ash and, for 60 

hours, darkness was so complete that a lantern held 

at arm’s length could scarcely be seen. The terrified 

townspeople, some temporarily blinded by the 

sulfurous gas, crowded onto the US Revenue Cutter 

Manning docked in Kodiak harbor, while 30 cm (1 ft) 

of ash smothered their town with three closely spaced 

periods of ash fall. The weight of the ash collapsed roofs 

in Kodiak; buildings were wrecked by ash avalanches 

that rushed down from nearby hill slopes; other 

structures burned after being struck by lightning from 

the ash cloud; water became undrinkable.

By midnight of the first day, 11 hours into the eruption, 

about 5 km3

 (1.2 mi3) of the Mount Katmai summit 

collapsed. The collapse resulted in a 2.5 km (1.5 mi) 

wide caldera, which has since accumulated a lake about 

Table 1. Volcanic explosivity index (VEI).

VEI

Ejecta 

Volume in 

km3

 (mi3)

Column 

Height in 

km (mi)

Classification Description Examples

0 0.00001 

(0.000002)

<0.1

(0.06) Hawaiian Effusive Kilauea (ongoing)

1 0.001 

(0.0002)

1

(0.6) Hawaiian/Strombolian Severe Stromboli (numerous)

2 0.01

(0.002)

5

(3) Strombolian/Vulcanian Explosive Fourpeaked (2006), Cleveland (ongoing), Shishaldin (ongoing)

3 0.1

(0.02)

15

(9) Vulcanian/Sub-Plinian Catastrophic Katmai (1912), Redoubt (1989, 2009), Trident (1953–1974), Augustine (2003), Lassen Peak (1915)

4 1

(0.2)

25

(16) Sub-Plinian Cataclysmic Aniakchak (1931), Eyjafjallajökull (2010), Crater Peak (1992), Kasatochi and Okmok (2008)

5 10

(2)

>25

(16) Plinian Paroxysmal Mount St. Helens (1980), Vesuvius (1979)

6 100

(20)

>25

(16) Plinian/Ultra-Plinian Colossal Aniakchak I and II (approximately 9,000 and 3,700 years ago), Novarupta (1912), Krakatoa (1883), Pinatubo (1991)

7 1,000

(200)

>25

(16) Ultra-Plinian Mega-colossal Mount Mazama (7,550 years ago), Tambora (1815)

8 >1,000

(200)

>25

(16) Ultra-Plinian Apocalyptic Yellowstone (640,000 years ago), 

Modified from Newhall and Self (1982).

For eruption classification descriptions see Figure 9. Alaska volcanoes in bold and NPS volcanoes in green. The VEI scale is logarithmic, and each 

interval on the scale indicates a tenfold increase in erupted volume, except for VEI 0–2 events Modified from Newhall and Self (1982).

Find GRI reports for descriptions of eruptions of Kilauea (Hawaii Volcanoes NP), Lassen Peak (Lassen Volcanic NP), Aniakchak (Aniakchak NM&P), and 

Mount Mazama (Crater Lake NP) at http://go.nps.gov/gripubs.
10
11

Figure 10 (facing page). Chronology of 1912 eruption. Earthquakes felt by local residents during the five days before 

the eruption prompted evacuation to what they hoped were safer havens. Ms = earthquake surface-wave magnitude 

as measured on the Richter scale (Abe 1992). Although only one seismograph was operating in Alaska at the time of 

the eruption, many of the earthquakes were big enough to be recorded by instruments in Europe, Asia, Japan, Hawaii, 

North Africa, and North America. Modifed from Figure 5 of Fierstein (2012a) 

Figure 11 (above). Generalized 1912 eruptive sequence and chronology of ash fall recorded at Kodiak village, about 

170 km (100 mi) downwind. Four hour offset at base represents time between initial sighting of eruption column by SS 

Dora and the beginning of ash fall at Kodiak. All of the tephra fall layers are mapped on Plate 1 as Qpd. Figure 2 from 

Hildreth and Fierstein (2012).
12

250 m (800 ft) deep. Caldera collapse was accompanied 

by 14 earthquakes of magnitudes 6 to 7, 100 

earthquakes greater than magnitude 5, and countless 

smaller earthquakes (Figure 10). By 9 June, when the 

main outpouring finally ceased at Novarupta and the 

day dawned clear at Kodiak, the advancing ash cloud 

had begun dropping sulfur-permeated fallout on Puget 

Sound in Washington State. On the following day, the 

cloud passed over Virginia, and by 17 June it reached 

Algeria.

The 60-hour-long explosive sequence at Novarupta 

consisted of three discrete episodes (Figure 11) 

separated by lulls of at most a few hours (Martin 1913; 

Hildreth 1983; Fierstein and Hildreth 1992). During 

Episode I, the volume and rate at which the pumice and 

ash were ejected from the vent were so great that some 

of it went upward into the towering eruption column to 

be distributed as ash fall, while some flowed down the 

surrounding valleys forming ash flows. The ignimbrite 

(pumice rich ash flow deposit) remained hot for several 

decades, earning the name “Ten Thousand Smokes” for 

the many steaming cracks and fissures on the ignimbrite 

(see Figure 18). Episode I left a depression 2 km (1.3 mi) 

wide, filled with pumice and ash from its own eruption. 

Fault scarps caused by collapse and subsidence in 

1912 encircle the area that provided the vent for the 

first day of eruption (Figure 7). Within this large vent, 

the subsequent eruptions (Episodes II and III) bored 

through the partly consolidated deposits of Episode I 

through a smaller vent that produced the ash falls of the 

next two days. Eruption episodes II and III also built 

a ring of pumice-rich ejecta around their smaller vent, 

which was plugged by the Novarupta lava dome that 

developed following the explosive episodes.

The deposits from these three eruption episodes are 

distinguishable by the ratios of the three pumice types 

they contain: white rhyolite with few phenocrysts 

(mineral crystals); white to gray dacite with abundant 

phenocrysts; and brown to black andesite, also with 

abundant phenocrysts (see Table 2 for an explanation 

of volcanic rock classifications). Although ejected 

together throughout much of the eruption, their relative 

proportions varied with time. These variations are 

used to track the dispersal, character, and thickness of 

each layer, both around the vent and in more distant 

locations. That information was used to piece together 

Figure 12. Photograph showing representative pumices from 1912 eruption. From left to right, the pumice from 

the 1912 eruption included white crystal-poor rhyolite, pale gray crystal-rich dacite, black crystal-rich andesite, and 

rhyolite-andesite banded pumice. USGS-CalVO photograph by Wes Hildreth.
13

what happened during those three days in 1912 

(Hildreth 1983; Fierstein and Hildreth 1992).

Episode I

Episode I began with widespread dispersal of 

purely rhyolitic fallout (Layer A) and synchronous 

emplacement of rhyolitic ash flows from the same high 

eruption column. After ejection of approximately 3 km3

(0.7 mi3) of rhyolitic magma over the course of a few 

hours, small amounts of andesitic and dacitic magma 

began contributing to the eruption column, marking 

the onset of Plinian Layer B (Figure 11). Pumice 

proportions in Layer B change from more than 99% 

rhyolite at its base to only about 15% rhyolite at its 

top, matching the progressive shifts in (rhyolite/dacite/

andesite) pumice proportions in the main sequence 

of pulses, or packages, emplaced concurrently in the 

Valley of Ten Thousand Smokes (Fierstein and Hildreth 

1992; Fierstein and Wilson 2005). Rhyolite, dacite, and 

andesite magmas (each containing different amounts 

of silica; see Table 2) swirled together to create white 

and black “banded” pumice (Figure 12), an unusual 

occurrence that instigated debates about how these 

evolved together in the underground plumbing system. 

Banded pumice is most abundant in Layer B and in 

the layers that make up the ignimbrite. By 9:10 am on 

7 June, emplacement was over and ash fall stopped at 

Kodiak for a short time. Episode I lasted about 16 hours 

and produced almost all of the Valley of Ten Thousand 

Smokes ash flows, which cover 11 km3

 (2.6 mi3), and 

roughly half of the ash-fall deposits, covering 8.8 of 17 

km3 (2.1 of 4 mi3; Figure 13).

Episodes II and III

Episodes II and III were similar to each another; each 

began after an eruptive hiatus (see Figure 9) then 

erupted from a smaller vent nested inside 

the larger one of Episode I. Each deposited 

widespread fall layers (Layers C–D and F–G, 

respectively), which were almost entirely 

dacitic. As with the preceding ash falls, 

Layers C and D were strongly dispersed eastsoutheastward, but the wind relented and the 

subsequent ash falls were less strongly directed 

toward Kodiak (Figure 14). Layers E and H 

are mostly accumulations of fine ash that 

settled regionally in the relative calm after each 

eruptive episode. Almost all of the deposits 

from these two episodes are widespread ash 

falls, but near the vent, short-traveled ash flows 

are preserved as well. Some of these proximal deposits 

were from small explosions during the lull between the 

Episode II and III eruption columns, which indicate the 

vent still remained unsettled during this lull.

Three Lava Domes

The explosive episodes were followed by extrusion of 

three lava domes. Compared to the explosive violence 

of 6–9 June, the growth of the domes was an uneventful 

expulsion of molten rock that was largely rid of its 

former gas content and slowly squeezed out of the vent. 

Though the exact timing is not known, these domes 

may have formed within days or as long as a year after 

the Plinian events. One small dacite lava dome that 

plugged the Episode III vent was destroyed by small 

explosions; all that remains are lava blocks scattered 

around the Novarupta dome (Adams et al. 2006). The 

same vent was plugged again by the rhyolitic Novarupta 

dome, which survives today. The third one is a dacite 

lava dome extruded on the floor of the Katmai caldera, 

then partially disrupted explosively. Photographed by 

Griggs in 1916 and sampled by Fenner in 1923, it is now 

covered by a crater lake. Figure 15 shows a conceptual 

cross section of the Novarupta vent area.

Landscape Changes Caused By the 1912 Eruption

The landscape of the Katmai area was forever changed 

by the 1912 eruption. The geomorphic and biologic 

processes in the first few years following the eruption 

were documented by the Griggs expeditions, but 

many of the processes observed then are continuing 

and evolving today. The eruption occurred in early 

summer when snow was still covering some areas. The 

accumulation of warm pumiceous tephra fall on this 

snow led to lahars down drainages surrounding Mount 

Katmai (Hildreth and Fierstein 2012). Numerous slope 

Table 2. Simplified volcanic rock classification and characteristics. 

Name

Percent 

Silica 

(SiO2

)*

Viscosity Typical 

Explosiveness

1912 

Eruption 

Products

Rhyolite >72%

Viscosity 

ranges 

from high 

for rhyolite 

to low for 

basalt.

Explosiveness 

ranges from high 

for rhyolite to low 

for basalt.

Yes

Rhyodacite 68%–72% Yes

Dacite 63%–68% Yes

Andesite 57%–63% Yes

Basaltic andesite 53%–57% No

Basalt <53% No

* From Clynne and Muffler (2010).
14

Figure 13. Simplified geologic map of the Valley of Ten Thousand Smokes and volcanoes of the Katmai cluster. The 

map shows the volcanic rocks by source volcano. The Valley of Ten Thousand Smokes ignimbrite (VTTS, tan) extends 

northwest 20 km from the Novarupta lava dome (hachured vent depression) and across Katmai Pass (KP) for 10 km 

down Mageik Creek. Knife Creek Glaciers (blue stippled areas) are numbered 1–5; other glaciers are omitted for 

clarity. The Alagogshak volcano, long extinct, is indicated only by its eroded crater. Mount Mageik consists of four 

overlapping centers (in shades of blue); only the youngest and easternmost center (for which individual lava flows 

are indicated) is Holocene. Mount Martin (green), entirely Holocene, consists of a small fragmental summit cone and 

several overlapping flows. The Trident group of volcanoes (pink) consists of three Pleistocene (2.6–0.01 MYA) cones: 

East Trident (Te), Trident 1 (T1), and West Trident (Tw), as well as the historical [caption continues on next page]
15

[caption continued from previous page] (1953–1974) Southwest Trident (Tsw, dark pink) lavas and fragmental cone; 

several peripheral Pleistocene lava domes (also pink), comagmatic with Trident, include Mount Cerberus (MC) and 

Falling Mountain (FM). Mount Katmai consists of two overlapping centers, Northeast Katmai (Ke) and Southwest 

Katmai (Kw), both truncated by the 1912 collapse of Katmai caldera (hachured), which is now partly filled by a 

lake (white with blue “waves”). The five youngest eruptive units of Mount Katmai are numbered (1–5): 1, leveed 

dacite lava flows; 2, south-rim rhyodacite lavas; 3, scoria fall atop unit 2; 4, dacite flow on caldera rim and at Knife 

Creek; and 5, Horseshoe Island dacite dome. Remnants of the 22,500-year-old rhyodacite pumice-fall deposits (and 

ignimbrite) in Windy and Mageik creeks (sites indicated by red X) are related to the most evolved lava of unit 2. 

Products of Mount Griggs are subdivided by age into older (o, middle Pleistocene), middle (m, late Pleistocene), and 

younger (y, postglacial) exposures. Holocene debris-avalanche deposits are in bright yellow; those emplaced in 1912 

are labeled KC, Katmai Canyon landslide; KRdf, Katmai River pumiceous debris flow; ML, Mageik Landslide; NM, Noisy 

Mountain landslide. Uncolored basement rocks are the Naknek Formation or undivided intrusions. Miscellaneous 

features: BM, Baked Mountain; BR, Broken Mountain; FL, site of Fissure Lake; GF, Griggs Fork of Knife Creek; JF, Juhle 

Fork of Knife Creek; T, Turtle; WR, Whiskey Ridge; hut, Baked Mountain Hut research shelter. Island Camp and Camp IV 

were way stations between Katmai Bay and the Valley of Ten Thousand Smokes. Refer to Hildreth and Fierstein (2003) 

for a detailed map of the volcanic units by source volcano, as the volcanic rocks are not differentiated by source on 

the GRI geologic map in Plate 1. Figure 5 in (Hildreth and Fierstein 2012).

Figure 14. Photograph of fall 

deposits at different distances 

from vent. Deposits are 

coarsest and thickest closest 

to vent, and get finer and 

thinner with distance.

(A) Large block about 1 km 

(0.6 mi) from Novarupta dome 

never went into the high 

eruption column. (B) Coarse 

dacite pumice fall deposits of 

Episodes II and III 4 km (2.5 mi) 

northeast of Novarupta are 

12 m (36 ft) thick. Fall layers 

are labeled C–G. (C) Complete 

section of dacite fall deposits 

of Episodes II and III about 11 

km (7 mi) northwest (upwind) 

of Novarupta are about 1 m (3 

ft) thick. Fall layers are labeled 

C–H. Episode I ignimbrite (ig) 

underlies the fall layers. Debris 

flow (df) on top is a flood 

deposit that covered the 1912 

fall soon after the eruption. 

(D) Structureless fine white ash 

about 50 km (30 mi) upwind 

northwest of Novarupta at 

Brooks Camp is about 20 cm (8 

in) thick. This distal ash layer 

includes contributions from 

all three eruptive episodes. 

Photographs A–C: USGS-CalVO 

photographs by Judy Fierstein 

and Wes Hildreth; D: NPS 

photograph by Mike Fitz.
16

failures were caused by the concurrent earthquakes; one 

of which dammed the Katmai River resulting in a large, 

subsequent flood in 1915. Systematic documentation 

of these geomorphic changes was not a primary 

focus of the initial studies, but some key geomorphic 

features and processes were discovered during those 

explorations.

Landslides during the Eruption

Map units: Qls (in part)

During the night of 6–7 June 1912, the Katmai Canyon 

landslide (unit KC in Figure 13; Figure 16) was triggered 

by earthquakes associated with collapse of the Katmai 

volcano. Rhyolitic fallout layer A is missing from the 

ash overlying the landslide debris, indicating that the 

landslide occurred early during the eruption (Hildreth 

and Fierstein 2012). Major seismicity probably shook 

the landslide loose. Griggs (1922) surmised that water 

was dammed by the landslide deposit, which breached 

catastrophically in 1915, causing flooding down the 

Katmai River valley three years after the eruption. 

Griggs found evidence of high water marks downstream 

of the landslide that indicated the flood waters flowed 

over a rock promontory forming a waterfall 30 m (100 

ft) high and 300 m (1000 ft) wide at the end of Katmai 

Canyon, and that the flood filled the mouth of the 

Katmai River 3 m (10 ft) deep where the floodplain is 

10 km (6 mi) wide. The Mageik Landslide (unit ML in 

Figure 15. Inferred cross section of Novarupta vent area. Representation is based on surface exposures, geophysical 

interpretations, regional Mesozoic stratigraphy, and estimates of volumes of basement lithic ejecta and recycled 

welded ejecta. Beneath the Katmai volcanic cluster and adjacent to the Valley of Ten Thousand Smokes, exposed 

basement rocks belong exclusively to the Naknek Formation, which supplied all the non-volcanic lithic fragments 

ejected at Novarupta, including sparse granitoid cobbles from its conglomerate members. No vertical exaggeration. 

Figure 96 in Hildreth and Fierstein (2012).

Figure 16. Photograph showing the Katmai Canyon 

landslide. The hummocky area on both sides of the Katmai 

River is the landslide deposit, marked by a dashed line, 

with the crest of the scarp shown with a solid black line. 

The landslide dammed the river, creating a temporary lake 

that flooded in 1915. Subsequently, the river has cut down 

through the landslide deposit. USGS-CalVO photograph by 

Wes Hildreth.
17

Figure 13; Griggs 1920, 1922) consists mostly of angular 

blocks (Figure 17) of fresh dacite that broke loose from 

a stack of lava flows low on the Southwest Summit 

flank evidently triggered by shaking that accompanied 

caldera collapse at neighboring Mount Katmai. Leaving 

behind a scarp 120 m high, the deposit extends 6 km 

(4 mi) down valley and is 5–30 m (15–100 ft) thick. The 

Noisy Mountain landslide, in upper Katmai Canyon 

(unit NM in Figure 13), is avalanche debris consisting 

of andesite from Noisy Mountain; the headwall scarp 

extends as high as 900 m (3,000 ft) above the valley floor 

on the south slope of the mountain. Large parts of this 

avalanche broke loose during eruptive Episode I. Griggs 

(1922) noted that when his party camped there in 1917, 

rockfalls large and small had continued on the scarp 

every few minutes, inspiring the name Noisy Mountain. 

It was quiet when USGS scientists Wes Hildreth and 

Judy Fierstein investigated the area in the 1990s. The 

deposit impounded Upper Katmai Lake, which was 

approximately 2 km (1.5 mi) across in 1917 (Griggs 

1922), but is only a shallow pond today.

Figure 17. Photograph of a very large boulder in the 

Mageik Landslide. National Geographic Society photograph 

by Robert Griggs from Griggs (1920, p. 326).

Figure 18. Photographs of the Valley of Ten Thousand Smokes. Top: In 1917, the northwest arm of the valley was filled 

with steaming fumaroles. The view is looking northwest toward the Buttress Range on the left side of the photograph. 

National Geographic Society photograph by Robert Griggs (Griggs 1922, p. 234). Bottom: The photograph, taken 

in 2013, shows the same area but devoid of fumaroles. Fog is visible at the end of the valley. AVO-UAF Geophysical 

Institute photograph by Taryn Lopez.
18

Changes in the Valley of Ten Thousand Smokes

The eruption inundated Knife Creek, the River Lethe, 

and upper Mageik Creek with ignimbrite. Today, the 

once steaming ignimbrite that formed the Valley of Ten 

Thousand Smokes (Figure 18) only contains a handful 

of fumaroles (vent from which gases and vapors are 

emitted). Voids left by the fumaroles are filling up with 

sediment from material that is frequently transported by 

the strong winds (Figure 19).

The River Lethe, Knife Creek, and other small creeks 

in the valley incised (cut) rapidly into the ignimbrite 

soon after it was deposited. The River Lethe, Knife 

Creek, and other small creeks in the valley have 

changed little since they were first explored in 1917. 

The emplacement of the ignimbrite changed the valley 

from a U-shaped valley shaped by ice age glaciers to a 

relatively flat-bottomed valley abutting steeper slopes 

(Figure 20). The amount of downcutting relates to the 

amount of welding or sintering of the ignimbrite with 

rapid downcutting in nonwelded (“softer”) deposits 

and slower downcutting in stronger sintered deposits 

(Figure 20). The nonwelded, stratified fall deposits of 

Episodes II and III had been eroded away along the 

main stream channels by 1917, and incision of the 

underlying ignimbrite was generally only a few meters 

in the upper valley but about 20 m (70 ft) in the central 

valley. No quantitative measurements of erosion rates 

has been made, but erosion slowed greatly after the first 

few years. A century after the eruption, streams in the 

upper River Lethe and Knife Creek arms of the valley 

have eroded steep-sided gorges only 2–8 m (7–25 ft) 

deep into sintered ignimbrite. In the lower valley, where 

the tuff is nonwelded, the underlying bedrock (10–20 

m, 33–66 ft deep) is exposed, but for only 2 km (1.2 

mi) upstream from the toe of the ignimbrite. Today the 

gorges are deepest in the central Valley of Ten Thousand 

Smokes, where the ignimbrite grades from sintered to 

nonwelded. The greatest depths are 30–35 m (100–115 

Figure 19. Photograph of an inactive fumarolic fissure. 

This fumarole formed along a fracture that is near the 

edges of the ignimbrite (see Figure 20). Deposits at the 

top of fissure are windblown accumulations of pumice, 

with colorful alteration from steam and hot gases that 

deposited their dissolved minerals in and around the 

pieces of pumice. When this photograph was taken in 

1982, a weak vapor plume was still coming through this 

fumarole, but it is now filled in by windblown pumice 

and ash. USGS-CalVO photograph by Wes Hildreth.

Figure 20. Simplified cross section of a glacial valley 

filled with a thick pyroclastic flow followed by rapid 

incision of streams. The depth and rate of down-cutting 

relates to the amount of sintering or welding of the 

ignimbrite. The initial thickness of the ignimbrite was 

about 240 m (790 ft). After cooling and welding of 

the ignimbrite, it compacted in the center portion to 

about 170 m (560 ft) thick, which left terraces on the 

edges of the valley that are about 70 m (230 ft) above 

the central portion of the ignimbrite (Kienle 1991). 

Fumaroles are aligned along the fractures on the edges 

of the terraces. Re-drafted from figure 3 of Waythomas 

(2015).
19

ft), along the gorges of the main and Juhle forks 

of Knife Creek, 1–2.5 km (0.6–1.5 mi) above their 

confluence (Figure 21).

Glaciers were somewhat more advanced during the 

time of the 1912 eruption than they are today and 

some of the glacier termini were overtopped by the 

hot ash flow (Hamilton 1973). This caused rapid ice 

melt that formed explosive generation of steam. Pits 

from the phreatic eruptions are present around the 

toes of the glaciers at the upper reaches of the Valley 

of Ten Thousand Smokes (see map by Hildreth 

and Fierstein 2003). Ice melt following subsidence 

of the ignimbrite formed closed basins ringed 

concentric fault scarps. A lake formed in one of these 

depressions at the base of Mount Mageik that has 

since drained (see repeat photographs in figure 89 of 

Jorgenson et al. 2008).

Sediment Output in Katmai and Savonoski Rivers

Map unit: Qaf (in part)

The 1912 eruption deposited pumice-rich tephra 

10–15 km (6–9 mi) from the caldera and ash beyond. 

This massive amount of mostly loose material has 

had a major impact on the sediment flux of the rivers 

and melting rates of the glaciers. Griggs (1922) noted 

that the streams were choked with sediment in the 

Katmai River valley. The influx of sediment caused 

fluvial aggradation (deposition of sediment) of the 

Ukak, Ikagliuk, Rainbow, Savonoski, and Katmai 

rivers. The abundant sediment (Figure 22) caused 

the Ukak River and Savonoski River deltas to grow 

1–2 km (0.5–1.5 mi) into Naknek Lake from 1951 to 

2010 (Figure 23).

Vegetation Changes

The 1912 eruption has provided opportunities for 

integrated biological research for understanding 

disturbance ecology. Griggs was a botanist who, 

before the eruption, was studying colonization 

of marginal habitats in Alaska. After the eruption 

he was sent to the Katmai area by the National 

Figure 21. Photograph of deep incisions by creeks into the 

ignimbrite. Gorges are approximately 30 m (100 ft) across.

NPS photograph.

Figure 22. Photograph of the Ukak River and Savonoski River 

deltas showing the brown waters of the sediment laden rivers. 

NPS photograph by Kaiti Critz.

Figure 23 (left). Map showing the progradation 

(growth) of the Ukak River and Savonoski River delta 

from 1951 to 2010. The abundant loose material 

produced by the 1912 eruption has inundated the 

rivers with sediment, which has been transported 

downstream and is being deposited at the mouths 

of the rivers. Satellite (IKONOS) imagery from 2010.
20

Figure 24 (left). Photograph of biological soil crust. In 

places less exposed to high winds, biological soil crusts 

have formed. This is a living crust that can be made 

up of bacteria, cyanobacteria, fungus, moss, and other 

organisms. Trekking pole is approximately 130 cm (50 

in) long. NPS photograph by Mike Fitz.

Figure 25 (below). Map of Alaska and adjacent parts 

of North America showing the location of Novarupta 

and the region impacted by ash fall. Within a few days 

after the 1912 eruption, the ash was carried by winds 

across the North American continent. The limited 

distribution from other recent Alaska eruptions is 

shown for comparison. Figure 2 in Fierstein (2012c).
21

Figure 26. Graph showing the timing of major volcanic eruptions compared to Northern Hemisphere climate records. 

The timing of eruptions since 1850 with a VEI≥5 are compared with changes to Northern Hemisphere solar radiation, 

aerosol optical depth (“haze”), and the US temperature anomaly. The eruptions produce aerosols that increase the 

aerosol optical depth (haze), which decreases the solar radiation. This decrease in solar radiation commonly reduces 

temperatures. The 1912 Novarupta-Katmai eruption is correlated with the second lowest measured temperature 

anomaly measured across the United States. Graph incorporates data from Kimball (1918), NASA (2012, 2015), and 

NOAA (2012); also see Antón et al. (2014) and Sigl et al. (2015).
22

Geographic Society to document the volcanic features 

of the eruption and the effects of the eruption on the 

ecology of the area. During these expeditions to Kodiak 

and the Katmai area, he found that plants recovered 

well in places where the accumulated ash was less than 

1 m (3 ft) thick, but thick, windswept surfaces remained 

barren (Griggs 1917, 1918a, 1919, 1922, 1933). He tested 

the fertility of the ash and found that it was severely 

depleted in the necessary nutrients, especially nitrogen, 

for plant growth. This lack of nutrients and the 

constantly shifting surface are why vegetation has been 

slow to return where there were thick deposits of ash 

in and near the Valley of Ten Thousand Smokes. Where 

fallout was thin, the ash acted like mulch preventing 

some plants from growing (Griggs 1918a). Plants that 

were able to sprout through the ash flourished because 

of the lack of competition. On the thick, barren surface 

of the ignimbrite, in 1917 Griggs witnessed moss and 

algae growing around the fumaroles (Griggs 1922). 

By 1930, a surface made up exclusively of liverworts 

developed in thick areas of the ignimbrite that are 

protected from the strong winds (Griggs 1933). When 

the area was visited by V. Cahalane in 1953–54 the 

extensive mats of liverworts had vanished; whereas, 

in places of moderate stability and on the slopes 

surrounding the valley seed plants had multiplied 

(Cahalane 1959).

Today’s sparse vegetation on the ignimbrite provides 

little cover and meager food for the few animals that 

do venture into the Valley of Ten Thousand Smokes. 

Meager vegetation and thin biological soil crusts 

(Figure 24) have grown on the thick ignimbrite in places 

protected from the winds that constantly scour much of 

the surface with blowing sand. Comparing photographs 

taken during the Natural Geographic expeditions to 

those of today, Jorgenson et al. (2007) noted very slow 

succession in the valley, with exception of the growth 

of a few plants only in a few areas near Novarupta and 

near the Knife Creek Glaciers.

Global Climate Effects of the 1912 Eruption

Large Plinian eruptions produce atmospheric aerosols 

(fine particles in air) that reduce the solar radiation 

reaching the Earth’s surface, which can cause global 

cooling (Sigl et al. 2015). Effects of the ash from 

the 1912 eruption were felt across the Northern 

Hemisphere. From the vent at Novarupta, the towering 

column of ash jetted skyward with only two short 

interruptions for 60 hours. Concurrently, it distributed 

ash flows that filled the valley of the River Lethe and 

fed a cloud more than 1,600 km (1,000 miles) wide 

that shrouded most of southern Alaska and the Yukon 

Territory. The ash cloud rapidly rose to more than 30 

km (100,000 ft), where the jet stream carried much 

of it eastward (Figure 25). Strongly aided by winds 

blowing east-southeastward, ash fall began at Kodiak 

within 4 hours and by the next day had spread 1,000 

km (630 miles) east and at least 100 km (60 miles) 

west. Atmospheric effects (haze, smoke, red twilights) 

had been observed downwind, beginning in British 

Columbia on 6 June, and in Europe two weeks later. 

The great quantity of ash and aerosol not only caused 

unusually brilliant sunsets, but, by shielding the sun’s 

rays, lowered average temperatures by about 1°C (2°F) 

in the Northern Hemisphere for more than a year 

(Figure 26; Griggs 1922).

Volcanoes

Map units: Qv, Qvd, Qpd, Qafd, and QTv

Katmai contains the most active and dense group of 

stratovolcanoes of any unit in the National Park System. 

The explosive eruption of Novarupta on 6–8 June 1912 

was the world’s most voluminous of the 20th century 

and made the remote Katmai region famous. The 

Novarupta volcanic vent is part of the Aleutian volcanic 

arc, which is one of the most active volcanic regions 

in the world (Simkin and Siebert 1994). Novarupta is 

one of 24 Quaternary (erupted in the last 2.6 million 

years) volcanoes in Katmai that trend northeast to 

southwest (Table 3, Figure 27). Together, the volcanoes 

form 36 volcanic vents (Cameron and Nye 2014). 

Ten of the Katmai volcanoes are considered active 

(Madden et al. 2014). Five of the volcanoes erupted 

during historic time (CE 1760–present). “Active” 

refers to volcanoes with historical (CE 1760–present) 

eruptions, or considered hazardous because of plausible 

historical eruptions, vigorous fumarolic activity, intense 

earthquake swarms, or volcanic deformation (Madden 

et al. 2014). Geologic studies in the last three decades 

have identified more than 50 discrete volcanic vents in 

Katmai; 35 of these have been named (Cameron and 

Nye 2014). Most of these vents form a narrow line of 

ice-clad stratovolcanoes on the drainage divide of the 

Alaska Peninsula, which makes up the Aleutian arc 

segment that stretches from Mount Douglas on the 

north, south to Alagogshak. What follows is a brief 

geologic summary of the volcanoes in Katmai National 

Park and Preserve.
23

Katmai Cluster

Twenty of the volcanic vents in the park are within 

15 km (9 mi) of Novarupta (Hildreth and Fierstein 

2003; Cameron and Nye 2014). This unusually dense 

grouping around Novarupta, informally referred to as 

the Katmai cluster, includes six stratovolcanoes Snowy, 

Katmai, Griggs, Mageik, Martin, and Alagogshak; the 

cluster of volcanic vents making up Trident Volcano; 

and the three lava domes Novarupta, Cerberus, and 

Falling Mountain.

The Katmai cluster is very active, with fumaroles 

and steam vents on all of the stratovolcanoes but 

Alagogshak. The most recent eruptions were from 

Figure 27. Map showing the locations of Quaternary (<2.6 MYA) volcanoes in the Katmai area. Active volcanoes are 

shown in red as identified in the Alaska interagency operating plan for volcanic ash episodes (Madden et al. 2014). See 

Table 3 for information about Quaternary volcanoes within Katmai National Park and Preserve.
24

Table 3. Volcanoes within Katmai National Park and Preserve.

Volcano1 Active2 Historic2 Last eruption

(yr BP)3 History and Notes

Douglas Yes No <11,700 Ice-clad stratovolcano with a small crater lake and active fumarole field on 

north side of crater.

Fourpeaked Yes Yes CE 2006

17 September 2006 eruption formed a 6,100 m (20,000 ft) high plume from 

phreatic explosions (VEI 2). Unusual radar cloud height was measured at 6 km 

(4 mi). Volcanic steam was observed through 2007.

Kaguyak No No 1,060

A stratovolcano with a 3 km (2 mi) wide caldera and lake with CO2 bubbling 

up from the bottom. Pyroclastic flows from the caldera-forming eruption filled 

surrounding valleys with over 30 m (100 ft) thick.

Iron Trig Cone No No 88,000±27,000 Mafic scoria cone of the Savonoski River Cluster of volcanoes.

Cone 3110 No No 235,000±30,000 Partly erupted under a glacier.

Cone 3601 No No 132,000±27,000 Mafic cone of the Savonoski River volcanic cluster.

Knob 1000 No No Unknown Remnant of a volcanic cone and part of the Savonoski River cluster of 

volcanoes.

Rainbow River 

Cone No No 390,000±39,000 Small basaltic volcano of radially dipping stacks of thin lavas and breccia that is part of the Savonoski River cluster of volcanoes.

Devils Desk No No <11,700 Ice-clad volcanic neck of a stratovolcano.

Kukak Yes Yes? CE 1889 Ice-clad stratovolcano that contains a vigorous fumarole field near the northern 

summit. Report of an eruption in 1889.

Steller No No <11,700 Ice-clad stratovolcano

Denison No No <11,700 Ice-clad stratovolcano.

Snowy Yes No <11,700 Ice-clad stratovolcano with fumaroles on the peak.

Folsoms Bluff No No Unknown Andesitic vent complex with a mass of curving glassy lava columns indicative of 

ice-contact emplacement.

Griggs Yes No <11,700 Numerous fumaroles. 10 km (6 mi) behind (northwest of) the volcanic front 

defined by Martin, Mageik, Trident, Katmai, and Snowy Mountain centers

Katmai Yes Yes CE 1912 A stratovolcano with a 10km (6 mi) diameter caldera formed by collapse 

during the 1912 Novarupta eruption (VEI 3). 

Novarupta Yes Yes CE 1912 Vent source of the 1912 eruption that is plugged with a 400 m (1,300 ft) in 

diameter dome (VEI 6). 

Trident Yes Yes CE 1953–1974

Volcanic complex consisting of four stratovolcanoes and numerous domes. 

1953–1960 intermittent eruptions formed numerous lava flows and a volcanic 

dome (VEI 3). Numerous steam eruptions until 1974.

Cerberus No No 114,000±46,000 Andesite to dacite peripheral dome of Trident.

Falling Mountain No No 70,000±8,000 Andesite to dacite peripheral dome of Trident.

Mageik Yes No Unknown A stratovolcano with a phreatic crater on the northeast side that contains a 

crater lake and has vigorous fumarolic activity.

Martin Yes No <11,700 A stratovolcano with a 300 m (1,000 ft) diameter crater that has intense 

fumarolic activity, and an ephemeral lake.

Alagogshak No No 2,600,000–11,700 Several eruptions spread intermittently over at least 600,000 years.

Kejulik No No Unknown Heavily eroded remnant of a stratovolcano.

1

The order of the volcanoes is presented from northeast to southwest. See Figure 27 for a location map of Quaternary volcanoes. See Table 1 for 

description of Volcanic Explosivity Index (VEI) values in "History and Notes" column. AVO information for each volcano is available at

https://www.avo.alaska.edu/volcanoes/ (volcano names in table are linked to this website).

2

“Active” refers to volcanoes with historical (CE 1760–present) eruptions, or considered hazardous because of plausible historical eruptions, vigorous 

fumarolic activity, intense earthquake swarms, or volcanic deformation (Madden et al. 2014). Historic and last eruption data is from the Global 

Volcanism Program global list of volcanoes (Smithsonian Institution 2015). List of active volcanoes is from Madden et al. (2014, Appendix A). 

3

CE (Common Era; preferred to “AD”) years are given for historic eruptions. All other dates are in years before present (yr BP).
25

a new vent on Trident Volcano (Southwest Trident, 

1953–1974), but ash deposits indicate that at least 

eight other explosive events in the past 10,000 years 

are associated with the volcanoes of this area. Activity 

continues in the northeast corner of the park as well, 

including steam explosions from Fourpeaked Mountain 

in 2006, prolonged vigorous steaming that has coated 

snow-covered Kukak Volcano with yellow sulfur, 

and gas bubbling up through the Kaguyak crater lake. 

All of these rugged and active volcanoes contribute 

to spectacular scenery in this remote and sparsely 

inhabited wilderness on the Alaska Peninsula. 

The eruptive history for each of the Katmai volcanoes 

was derived by mapping the distribution of eruptive 

products, and by describing in detail both lava flows and 

ash layers (Hildreth and Fierstein 2003; Fierstein 2007). 

Combined with the mapping, information about the 

ages of the deposits constrains the timing and frequency 

of past eruptions, which was used to make a volcanohazard assessment for the Katmai cluster (Fierstein and 

Hildreth 2001). 

Katmai Cluster: Mount Katmai

Mount Katmai, centered 10 km (6 mi) east of 

Novarupta, is a stratovolcano that once consisted of a 

pair of large cone-shaped volcanoes with interfingered 

lava flows, which had been active for more than 70,000 

years. Both cones caved in during the caldera collapse 

of 1912 (Figure 28). Thick stacks of lava flows and 

sequences of pyroclastic deposits from at least 20 

explosive eruptions are exposed in the caldera walls. 

Mount Katmai has a varied volcanic history, erupting 

products with a wide compositional range (basalt to 

rhyodacite). 

One of the largest and most explosive events ever to 

occur at the Katmai volcanic cluster originated from 

Mount Katmai about 23,000 years ago. Rhyodacite 

pumice-fall and deposits from that eruption were 

widely distributed but have since been largely scoured 

away by glaciers. Remnants of the pumice fall preserved 

in nearby creeks are so thick that it seems likely the 

eruption was more voluminous than that of Novarupta 

in 1912. 

Figure 28. Aerial view looking northwestward of Katmai caldera with Mount Griggs and the Valley of Ten Thousand 

Smokes in the background and part of Trident Volcano on the left. NPS photograph by Chuck Lindsay.
26

Since 23,000 years ago, Mount Katmai has erupted 

at least four more times, with both lava flows and 

ash falls. The largest of these is an explosive eruption 

thought to have occurred sometime between 16,000 

and 12,000 years ago. Because pumice that fell near 

the vent landed on glaciers that occupied the valleys 

at that time, no undisturbed fall deposits remain near 

the volcano (Hildreth and Fierstein 2000, 2003), but a 

fine ash layer on the Kenai Peninsula, 225 km (140 mi) 

away, is probably equivalent (Reger et al. 1996; Fierstein 

2007). Clearly, Mount Katmai has had a history that 

includes more explosive eruptions than any of the other 

stratovolcanoes in the cluster.

Katmai Cluster: Alagogshak Volcano

Alagogshak volcano, the most southwestern 

member of the Katmai volcanic cluster, is marked by 

hydrothermally altered remnants of the summit crater 

of a severely eroded vent complex (Figure 29). Such 

rocks, when permeated by acidic hot water and gas 

from the volcano’s core, turn into colorful red, white, 

yellow, and orange remnants rich in clay minerals. 

Lava flows extending as much as 10 km (6 mi) in most 

directions are all glacially ravaged. Alagogshak, oldest by 

far of all the Katmai cluster volcanoes, is made of lavas 

as old as 680,000 years and no younger than 40,000 

years (Hildreth et al. 1999). This is the only Katmai 

cluster volcano that is not considered active.

Katmai Cluster: Mount Martin

Mount Martin, southwest of Mount Mageik, consists 

of a small volcanic cone and ten overlapping blocky 

lava flows that stretch northwestward for10 km (6 

mi). The cone is smaller than it seems, for although its 

summit exceeds 2,030 m (6,100 ft) in elevation, it is built 

Figure 29. Photograph of the glacially eroded summit 

of Alagogshak volcano (center), about 3 km (2 mi) 

southwest of Mount Martin (left cone). USGS-CalVO 

photograph by Wes Hildreth.

Figure 30. Photograph of the fumarolically active Mount Martin summit cone and shallow lake. USGS-AVO photograph 

by Cyrus Read.
27

on a high ridge of sedimentary rocks of the Naknek 

Formation. Several ash-fall layers from Mount Martin 

are preserved in soils nearby and suggest that at least 

three eruptive episodes separated by at least a thousand 

years to as much as several thousand years built Mount 

Martin between about 6,000 and 2,800 years ago 

(Fierstein 2007). Still active, the cone is marked by a 

persistent steam plume that coalesces from as many as 

20 fumaroles that precipitate sulfur around a shallow 

lake on the floor of its 100-m- (300-ft-) wide summit 

crater (Figure 30). Since seismic monitoring of the 

volcano was initiated in the early 1990s, the volcano has 

had five spikes in seismicity due to volcanic activity deep 

within the volcano (Dixon and Power 2009; Neal et al. 

2009).

Katmai Cluster: Mount Mageik

Mount Mageik (Figure 31) is a compound stratovolcano 

just higher than 2,370 m (7,100 ft); it rivals Mount 

Katmai as the largest edifice in the Katmai cluster 

(Hildreth et al. 2000). Each of its four ice-mantled 

summits is a discrete eruptive center, and each is the 

source of numerous lava flows. Three of the eruptive 

centers are severely eroded by glaciers, indicating 

that they are older than the fourth. The three eroded 

centers each made up of sets of lava flows piled on top 

of one another that erupted during intervals 10,000 to 

20,000 years long with some as old as 93,000 years. The 

eruptions at these three centers were long over by the 

time the fourth, youngest eruptive center formed.

The east summit was the only part of Mount Mageik 

built during the last 10,000 years. It erupted a dozen 

lava flows and seven explosive ash fall–producing 

events, the youngest of which is about 4,000 years old. 

Soil has developed on some of the lava flow surfaces 

but not on others in the sequence, indicating that at 

least hundreds, if not thousands, of years has passed 

between eruptive episodes. The youngest Mageik 

eruption about 2,500 years ago was an explosion that 

formed a crater between two of the summits. Evidently, 

no magma erupted from this vent, but the crater is filled 

with a yellow-green acid lake that sends up curls of 

steam often mistaken for eruption plumes.

Katmai Cluster: Trident Volcano

Trident Volcano (Figure 32) is a group of four 

overlapping stratovolcanoes and several lava domes as 

old as 150,000 years (Hildreth et al. 2003a). Although 

more deeply eroded by glaciers and in part older than 

the adjacent Mageik and Katmai volcanoes, Trident 

Volcano produced the area’s most recent eruptive 

episode, from 1953 to 1974 (see Coombs et al. 2000; and 

Hildreth et al. 2003a). The eruption was intermittent 

over the 21-year span, and National Park Service 

photographs show that the cone had attained nearly 

its full height by 1960, although explosive showers 

of blocks continued to augment the cone until 1974. 

The central and highest cone is considerably eroded 

and certainly inactive over the last 10,000 years, 

but nonetheless supports a vigorous field of sulfurproducing fumaroles on its lower southeast flank, first 

Figure 31. Photograph of ice-clad Mount Mageik from 

Baked Mountain. Mount Cerberus is in the foreground 

and the small plume on the right flank of the mountain 

is actually from Mount Martin, which is behind Mount 

Mageik. Photograph by Alexander Prusevich (University 

of New Hampshire).

Figure 32. View of the Trident Volcano from Baked 

Mountain. Although named Trident, the peak is made 

up of four eroded andesite and dacite cones. The 

Novarupta lava dome is visible at the bottom, center. 

Photograph by Alexander Prusevich (University of New 

Hampshire).
28

Figure 33. Photograph of the early stages of the Southwest Trident eruption taken 21 February 1953, showing a small 

lava flow and ash plume. Mount Griggs is on the left and Mount Katmai is on the right under the ash plume. US Navy 

photograph.

Figure 34. Time series showing the chronology of the Southwest Trident 1953–1964 eruptions. The eruption started in 

1953 with the main eruption and the lava flows formed up until 1959, and then minor ejections of tephra continued 

intermittently until 1974. Modified from Figure 14 in Fierstein and Hildreth (2001).
29

recorded in 1916 by botanist R. F. Griggs (Griggs 1922). 

Another fumarole, visible in 1951 aerial photographs 

as a 60-m- (200-ft-) wide steaming pit on the southwest 

ridge of the central cone, became the vent site for the 

new volcanic cone (Southwest Trident) that began 

to grow in 1953 (Figure 33). The eruption lasted 

intermittently for 21 years with the last episode in 1974 

(Figure 34). In contrast to Mount Katmai, no large 

explosive deposits have come from any of the Trident 

peaks, although a few small remnants of pyroclastic flow 

deposits south of the peaks are evidence of some minor 

explosive activity. Most of the eruptions of Trident 

Volcano have been lava domes and short-traveled 

blocky lava flows (Figure 35) accompanied sporadically 

by small ash plumes.

Katmai Cluster: Mount Griggs

Mount Griggs (formerly Knife Peak Volcano) is the 

tallest peak in the Katmai area, rising to 2,530 m (7,600 

ft) in elevation on the eastern margin of the Valley 

of Ten Thousand Smokes (Figure 36). A relatively 

symmetrical cone, it has three nested summit craters 

and several small glaciers radiating from its summit. 

Mount Griggs is largely armored by young lava flows, 

but a few remnants of older lavas show that the volcano 

has existed for at least 290,000 years. Much of the 

volcano was built by dozens of overlapping lava flows 

between 85,000 and 10,000 years ago. Within the last 

10,000 years, collapse of the southwest part of the 

volcano left an amphitheater near the summit and shed 

a large debris avalanche (rapidly moving mass of rock 

and debris) into the river valley below. Subsequent 

andesite lava flows nearly filled this scoop-shaped 

depression and covered the southwest slope of the 

volcano with a fan of blocky lava flows. Small-volume 

lavas have characterized most of the activity of Mount 

Griggs, and the volcano has had no recognized large ash 

fall-producing explosive events (Hildreth et al. 2002). 

Yellow sulfurous fumaroles discharging vigorously near 

its summit show the volcano is still active.

Katmai Cluster: Snowy Mountain

Snowy Mountain, the most northeastern volcano of the 

Katmai cluster, is largely ice covered (Figure 37) and 

has active fumaroles that create holes in the glaciers 

(Figure 38). It is made of a contiguous pair of small, 

deeply glaciated volcanic cones as well as a young 

lava dome that fills what was the summit crater for the 

northeastern cone. The youngest dacite lava dome was 

emplaced less than 490 cal. yr BP (calibrated 14C age in 

years before 1950; Fierstein 2007). The other two peaks 

are eroded remnants of lava flows from the two cones 

that are as much as 200,000 years old. The young lava 

Figure 35. 1960 photograph showing the lava flows 

of Southwest Trident that formed from 1953 to 1959. 

NPS photograph by Robert Peterson, accession number 

KATM-399.

Figure 36. Photograph of Mount Griggs, the highest 

peak in the Katmai cluster. The slopes of the volcano 

are coated with ash fall from the 1912 eruption. The 

hikers shown in the photograph are walking on the 

1912 eruption ignimbrite that fills the Knife Creek 

valley. The toe of one of the ash-covered Knife Creek 

Glaciers is visible on the right. USGS-AVO photograph 

by Game McGimsey.
30

dome sits in a scoop-shaped amphitheater created by 

collapse of the upper part of the northeastern cone that 

had been weakened by persistent hydrothermal activity 

in the volcano’s core. The collapse produced a 22 km2

(9 mi2) debris-avalanche deposit that came down in the 

last 1,500 years (Hildreth et al. 2001); the lava dome, 

therefore, is younger still.

Denison, Steller, Kukak, and Devils Desk

Denison, Steller, Kukak, and Devils Desk (Figure 39, 

Figure 40, Figure 41, Figure 42) make up a heavily 

glaciated cluster of closely spaced volcanoes at the 

headwaters of the Savonoski River. This poorly known 

cluster has only been studied at the reconnaissance level 

(Hildreth et al. 2003b, 2004). Mount Denison has lava 

flows and cross-bedded tephra, but the precise age of 

volcanic activity is not known (Smithsonian Institution 

2015). Mount Steller is suspected to have erupted in 

the Holocene Epoch (Nye 1998), but the precise age of 

activity and the location of source vents are not known 

(Smithsonian Institution 2015). Kukak Volcano has a 

vigorous summit fumarole field and abundant subglacial 

fumaroles (Hildreth et al. 2003b, 2004), which suggests 

that it is an active volcano. Kukak Volcano may have 

erupted as late as 1889, but the effects were insignificant 

and signs of the eruption were gone in a few years 

(Erskine 1962). Devils Desk is a 2 km (1.2 mi) wide by 

900 m (2,950 ft) high mafic andesite cone that resembles 

a great lectern surrounded by glaciers (Figure 42; 

Hildreth et al. 2004). Three dikes extend outward from 

the peak toward the east (Wood and Kienle 1990). 

Using potassium/argon (K/Ar) dating, Hildreth et al. 

(2003b) established an age of 245,000±42,000 years old 

for Devils Desk. Also, they suggested that the eruption 

that formed the peak was short lived.

Figure 37. Photograph of Snowy Mountain. The tallest 

peak, 2,161 m (7,090 ft) above sea level, has an active 

fumarole field. The dome at the summit was formed in 

the Holocene Epoch (<11,700 yr BP) following creation 

of the amphitheater below it, which formed from a 

sector collapse (flank collapse, like the 1980 Mount 

Saint Helens eruption). USGS-CalVO photograph by Judy 

Fierstein.

Figure 38. Photograph of the Snowy Mountain "Snowy 

Hole." The hole formed on the south flank of the 

volcano as a result of melting and collapse of glacial ice 

over a fumarole. USGS-AVO photograph by Cyrus Read.

Figure 39. Photograph of the volcanic peaks Mount 

Denison (right) and Mount Steller (left). USGS-CalVO 

photograph by Judy Fierstein.
31

Savonoski River Cluster

The Savonoski River cluster includes six volcanoes 

located in the headwaters of the Savonoski River and 

behind (west of) the main trend of the Denison to 

Devils Desk volcanoes (Figure 27). Five of the volcanoes 

formed during the Quaternary Period (2.6–0.01 

MYA); one is somewhat older, forming during the 

Pliocene Epoch (5.3–2.6 MYA). The descriptions of the 

Savonoski River cluster volcanoes below are abridged 

from Hildreth et al. (2004).

Savonoski River Cluster: Rainbow River Cone

The Rainbow River Cone along the Rainbow River 

valley, (Figure 43), also known as “Peak 3980,” is a small 

basaltic stratocone with a lava-flow apron perched on 

a ridge. The peak is labeled with 3980 feet elevation on 

the USGS topographic maps; hence, “Peak 3980”. The 

cone and a lava plateau that extends 1 km (0.6 mi) from 

the cone are glacially scoured. Rocks on the plateau 

yielded a K/Ar age of 390,000±39,000 years old.

Savonoski River Cluster: Cone 3601

Cone 3601, near the toe of the Hook Glacier on the 

west side of the Savonoski River, is the largest mafic 

cone at 2.5 km (1.6 mi) wide (Figure 44). It is made up 

of blocky columnar lavas, breccia (cemented angular 

fragments) sheets, and scoria (lava with a frothy 

texture). A K/Ar age on the lava indicates the cone is 

132,000±27,000 years old.

Figure 40. Photograph of the summit of Mount Steller. 

NPS photograph by Chuck Lindsay.

Figure 41. Photograph of the summit of Kukak Volcano. 

Steam from fumaroles rises in the bottom center of the 

photograph. USGS-CalVO photograph by Judy Fierstein.

Figure 42. Photograph of Devils Desk volcanic neck. A 

volcanic neck is intrusive rock that solidified within the 

vent of a volcano. NPS photograph by Chuck Lindsay.

Figure 43. Photograph of the Rainbow River Cone. 

USGS-CalVO photograph by Wes Hildreth.
32

Savonoski River Cluster: Dome 2115

Dome 2115, situated near the toe of the Hook Glacier 

and is across (east of) the Savonoski River from Cone 

3601, is a dacite lava dome approximately 1 km (0.6 mi) 

across and 300 m (1,000 ft) tall. The cone is glacially 

scoured and is ringed by vertically jointed cliffs. 

Although not a Quaternary (2.6 MYA or younger) 

volcano, a K/Ar age of 4.77±0.18 MYA indicates that it 

erupted during the Pliocene Epoch (5.3–2.6 MYA).

Savonoski River Cluster: Cone 3110

Cone 3110 (Figure 45), 3.5 km (2 mi) north of Cone 

3601, is a pile of basaltic breccia, scoria, and columnar 

lava that is about 2 km (1.5 mi) wide and 675 m (2,210 

ft) tall. The K/Ar age of the cone is 235,000±30,000 yr 

BP.

Savonoski River Cluster: Knob 1000

Knob 1000, 1.5 km (1 mi) northwest of Cone 3110, is a 

small, 400 m (1,310 ft) wide, glacially scoured basaltic 

cone consisting of vesicular (frothy) lava, layered 

breccia, and scoria rubble. Textures and jointing suggest 

that the lava was emplaced in contact with ice, referred 

to as “ice-contact emplacement.” No age was reported 

for the cone.

Savonoski River Cluster: Iron Trig Cone

Iron Trig cone (Figure 46), on the north side of the 

Savonoski River, is a glacially scoured mafic scoria cone 

that is 800 m (2,620 ft) across and 250 m (820 ft) high. 

It consists of thin lava sheets cut by a small intrusion. A 

lava-flow apron associated with the cone yielded a K/Ar 

age of 88,000±27,000 yr BP.

Savonoski River Cluster: Savonoski Crater

The Savonoski crater, 8 km (5 mi) southwest of the 

confluence of the Rainbow and Savonoski Rivers, 

is a curiously circular depression 520 m (1,700 ft) in 

diameter formed on a ridge of marine sedimentary 

bedrock (Figure 47). The feature formed either as 

a meteor impact crater or by volcanic processes. 

Reconnaissance geologic and geophysical study of 

the crater in the 1960s did not find clear evidence for 

either genesis (French et al. 1972). Neither distinctive 

shock-metamorphic features nor volcanic features were 

observed. Dikes were found near the rim, but they are 

not clearly related to the crater. Moreover, the feature 

was glacially scoured so much of the primary evidence 

of formation has been removed by erosion. The crater’s 

position between (in-line with) the Saddlehorn Creek 

and Savonoski River clusters suggests that it may be a 

rear-arc volcanic feature (volcanic feature set back from 

the main line of volcanoes making up the volcanic arc).

Figure 44. Photograph of Cone 3601. USGS-CalVO 

photograph by Wes Hildreth.

Figure 45. Photograph of Cone 3110. USGS-CalVO 

photograph by Wes Hildreth.

Figure 46. Photograph of Iron Trig Cone. USGS-CalVO 

photograph by Wes Hildreth.
33

Saddlehorn Creek Cluster

Saddlehorn Creek cluster, northwest of Mount Griggs, 

is made up of five small volcanic remnants surrounding 

the forks of Saddlehorn Creek (Hildreth et al. 2004). 

The remnants consist of deeply eroded vent complexes 

and lava flows of uncertain source; ages straddle 

the Pliocene-Quaternary boundary (2.6 MYA). The 

following descriptions of the volcanoes are paraphrased 

from Hildreth et al. (2004). Only Folsoms Bluff is listed 

as a Quaternary volcano in Table 3 and included in the 

Quaternary volcanoes map in Figure 27.

Saddlehorn Creek Cluster: Mount Juhle

Mount Juhle is made up of a dacite lava-flow remnant 

30–80 m (100–260 ft) thick that has a K/Ar age of 

2.97±0.03 MYA. No vent has been identified.

Saddlehorn Creek Cluster: Maynard Crag

Maynard Crag (Peak 4800) is a 600 m (1,970 ft) wide, 

250 m (820 ft) high, shallow basaltic plug (dome 

intrusion) that formed 2.6±0.05 MYA.

Saddlehorn Creek Cluster: Sayre Mesa

Sayre Mesa (Plateau 4500) is a mafic lava-flow remnant 

that is 20–50 m (70–160 ft) thick and 1.3 km (0.8 mi) 

long. A K/Ar age of 2.64 ±0.04 MYA was derived from 

plagioclase crystals separated from the lava.

Saddlehorn Creek Cluster: Fenners Saddlehorn

Fenners Saddlehorn (Crag 3200) is a 250- by 400-m- 

(820- by 1,300-ft-) wide, 200-m- (660-ft-) high basaltic 

remnant that forms a horn-like feature, the Saddlehorn 

Creek namesake. The lava contains horizontal and 

inclined columns in ten tiers that are 5–20 m (16–66 

ft) thick. It probably formed 2.27±0.11 MYA as magma 

intruded at shallow depths below the surface.

Saddlehorn Creek Cluster: Folsoms Bluff

Folsoms Bluff (Knob 3800) is an andesitic funnelshaped vent complex that is a multi-lobed mass of 

glassy lava, 500 m (1,600 ft) wide and 200 m (660 ft) 

high. The lava contains flow foliation and inclined to 

subhorizontal curving glassy columns that are indicative 

of ice-contact emplacement. The base is brecciated and 

overlies 8 to 15 m of proximal fallout of scoria bombs 

and blocks of basement granitoid rocks. No age is 

reported.

Northeast Volcanoes

Northeast Volcanoes: Kaguyak Crater

Kaguyak Crater (Figure 48), in the northeast corner 

of the park, is a steep-walled collapse caldera filled 

with a 150-m- (500-ft-) deep lake that was created 

approximately 5,800 years ago in a large explosive 

eruption. Once thought to be a collapsed stratovolcano, 

work by Fierstein and Hildreth (2008) showed that 

ancestral Kaguyak was, instead, nine closely spaced but 

discrete clusters of lava domes. The domes, ranging 

from basalt to rhyolite in composition, are each stacks 

of short-traveled lava flows. Kaguyak Crater is a good 

Figure 47. Photograph of the Savonoski crater. The circular depression, now filled by a lake, may have been formed by 

a meteor impact or is a volcanic crater behind the main trend of volcanoes. NPS photograph by Kaiti Critz.
34

example of the episodic nature of volcanic activity. The 

earliest lava flows are as much as 300,000 years old. An 

especially active eruptive period between 60,000 and 

30,000 years ago built five multi-component lava domes 

where the lake is now. All that activity was followed by 

a quiescent interval more than 20,000 years long. Then, 

about 6,000 years ago, another dome was extruded 

near the center of the cluster. This triggered explosions 

and culminated in the big event 200 years later that 

produced ash flows and ash falls, erupted enough 

magma that an area 2.5 km (2 mi) wide collapsed to 

form the caldera, and truncated the field of lava domes. 

Fine ash, largely winnowed out of the ash flows, is now 

found as a distinctive orange ash-fall layer preserved 

widely in soils as far as the Valley of Ten Thousand 

Smokes, 80 km (50 mi) to the southwest. Some activity 

continued after the caldera-forming eruption, with 

emplacement of two more domes inside the new 

caldera that are now islands in the lake. Gas seeps 

still bubble up to the lake surface, some with a strong 

sulfurous smell.

Northeast Volcanoes: Fourpeaked Mountain

Fourpeaked Mountain, adjacent to Mount Douglas, 

emitted a small eruption on 17 September 2006, 

which surprised AVO staff and residents of southcentral Alaska. Before this eruption, the volcano was 

not considered active (Neal et al. 2009). Late in the 

day, a large ash cloud was observed, which reached a 

minimum altitude of 6,100 m (20,000 ft). The ash drifted 

20 km (12 mi) downwind and deposited a dusting of 

very fine ash at the Nonvianuk Lake outlet, 110 km 

(70 mi) west northwest of Fourpeaked Mountain, and 

near Homer 150 km (90 mi) northeast of Fourpeaked 

Mountain. When AVO scientists visited the area by 

helicopter on 24 September, the vent area had nine 

craters or pits (Figure 49, Figure 50), with three to five of 

them venting steam and volcanic gas. Ash deposits were 

thickest west of the vent area at 1–2 mm (less than 0.1 

in) thick, and the other flanks of the volcano received a 

dusting (Neal et al. 2009).

A glacial outburst and debris outflow originated at 

about 1,500 m (5,000 ft) from underneath an unnamed 

glacier (Figure 51, Figure 52). The flood scoured a 

canyon more than 100 m (330 ft) deep in places, and 

blocks of ice up to 5 m (16 ft) were rafted in a mixture 

of water and debris for about 6 km (4 mi) down slope, 

where the material continued off the end of the glacier 

down the Douglas River drainage (Neal et al. 2009). 

A similar outburst flood could occur in association 

with any volcanic eruption in the Katmai area (see 

“Geohazards” section).

Analysis of the seismic stations in the Katmai area 

revealed a swarm of earthquakes between 11:48 am 

and 3:50 pm ADT on 17 September (Michael West, 

State Seismologist, UAF Geophysical Institute, personal 

communication, 2006, in Neal et al. 2009). A plume was 

observed at this time in radar images of the area and the 

UAF infrasound array detected a signal (Steve McNutt, 

Research Professor, AVO-UAF Geophysical Institute, 

personal communication, 2006, in Neal et al. 2009). A 

temporary seismic array of three stations was installed 

following the eruption, and they recorded low-level 

activity through the end of the year with a few volcanic 

earthquakes on most days (Neal et al. 2009).

AVO scientists concluded that the eruption was most 

likely caused by new magma rising to fairly shallow (less 

than a few kilometers) levels, which accounted for the 

seismicity and the degassing, and provided a heat and 

gas source for a phreatic explosion (Neal et al. 2009). 

Through the remainder of 2006 and into 2007, volcanic 

gas and vapor discharged from a chain of pits in the 

glacier ice. No other ash emissions observed, although 

yellow sulfurous deposits stained the snow around the 

summit.

Figure 48. Photograph of Kaguyak Crater with its 150 m 

(490 ft) deep lake. Nine separate dome complexes once 

made up the area in and around the lake until a large 

explosive eruption formed the crater about 5,800 years 

ago. NPS photograph by Chuck Lindsay.
35

Figure 49. Photograph of fumaroles on the west side of Fourpeaked Mountain, 24 September 2006. USGS-AVO 

photograph by Cyrus Read.

Figure 50. Photograph of a non-venting fumarole pit 

in glacier ice on the summit of Fourpeaked Mountain. 

The diameter of this pit is about 50 m (160 ft), and the 

floor is made of ash-covered blocks of ice. USGS-AVO 

photograph by Kristi Wallace.

Figure 51. Photograph of the debris outflow (black 

areas) below the canyon and the deep chasm formed 

below the eruption site at Fourpeaked Mountain. Steam 

from the summit fumaroles are visible. USGS-AVO 

photograph by Rick Wessels, 25 September 2006.
36

Figure 52. Photograph of debris flow on the north flank of Fourpeaked Mountain. A muddy debris flow emerged 

from cracks in the Fourpeaked Glacier about 4 km (2.5 mi) north of Fourpeaked Mountain’s summit on 17 September 

2006. The width of the flow is about 250 m (820 ft) and the white specks are rafted ice chunks up to 5 m (16 ft) across. 

Fine gray ash coats the glacier surface, except where winds scoured convex surfaces. AVO-UAF Geophysical Institute 

photograph by Guy Tygat, 20 September 2006.

Figure 53. Photograph of Mount Douglas in the 

foreground and Fourpeaked Mountain in the 

background. USGS-AVO photograph by Michael Poland, 

30 September 2006.

Figure 54. Photograph of the north flank of Kejulik 

Mountain. NPS photograph by Chuck Lindsay.
37

Northeast Volcanoes: Mount Douglas

Mount Douglas, the most northeastern volcano 

forming the main trend of arc-front volcanoes, is 

ice clad and poorly studied (Figure 53). Much of the 

volcano has been subjected to glacial erosion, but a 

ramp of lava flows on the northwest flank is relatively 

uneroded. Most of the volcano is ice covered, but 

isolated outcrops of high-silica andesite lava flows are 

found within the ice. The summit of the volcano has a 

small crater lake and fumaroles. No historic eruptions 

have been reported for Mount Douglas; however, 

unglaciated lava flows are present, and fumaroles are 

indicative of active thermal processes (Wood and Kienle 

1990).

Northeast Volcanoes: Kejulik Mountain

Kejulik Mountain (Figure 54), the southernmost 

volcano within the park boundary, is a deeply dissected 

central vent and dike complex (Kienle and Swanson 

1983). Its age is unknown.

Geothermal Features

Geothermal features of Katmai include fumaroles, 

warm springs, warm ground, and crater lakes. A map of 

these features is provided on Plate 4. 

Fumaroles

The numerous fumaroles of the Valley of Ten Thousand 

Smokes were what made the Katmai area famous and 

prompted the formation of a national monument 

to preserve these unique features. Fumaroles (vents 

from which volcanic gases escape) occur where 

shallow magma or hot igneous rocks release gases, or 

where groundwater contacts warm ground to create 

steam. The fumaroles (“smokes”) in the Valley of 

Ten Thousand Smokes formed along fractures in the 

ignimbrite, allowing gases trapped in the ash flow and 

steam from boiling meteoric water to escape into the 

atmosphere. 

In 1917, five years after the eruption, the ignimbrite 

was still extremely hot. Nearly everywhere on the 

ignimbrite sheet, 1 m (3 ft) deep pits dug into the 

surface approached the boiling point and Griggs 

estimated that plumes of gas more than 150 m (500 

ft) tall escaped from more than 1,000 fumaroles. 

Fumarole temperatures measured during the 1918 

and 1919 expeditions showed that 86 vents reached 

temperatures greater than 190oC (374oF), and 11 ranged 

from 400oC to 645oC (750oF to 1,190oF). By 1929, only 

a few hundred fumaroles were visible in the valley, and 

nearly all were below the boiling point. By the 1940s, 

less than a dozen fumaroles remained, and by the mid1960s, gases emitted from only weak fumaroles on the 

Novarupta dome. The last fumarole on Baked Mountain 

expired in the 1990s (see summary about fumaroles in 

chapter 9 of Hildreth and Fierstein 2012). Today, the 

locations of former fumaroles are recognizable by halos 

of geothermally altered rock along cracks and funnelshaped pits (Figure 55).

Although the fumaroles of the Valley of Ten Thousand 

Smokes slowly extinguished due to cooling of the 

1912 ignimbrite sheet, numerous active fumaroles 

occur on the flanks and in the craters of the active 

volcanoes. Active fumaroles are mapped on Plate 4. In 

contrast to the fumaroles of the Valley of Ten Thousand 

Smokes, which emitted boiling meteoric water and 

trapped gases from the ignimbrite, the currently active 

fumaroles are vents for gases formed at high 

temperatures and pressures within the active volcanic 

systems (Sheppard et al. 1992). 

Figure 55. Photographs of an inactive fumarole (top) 

and alteration halos along fumarole cracks (bottom). 

Trekking poles (for scale) are approximately 1.3 m (4 ft). 

NPS photographs by Mike Fitz.
38

Active fumaroles exist on the following volcanoes: 

Novarupta, Trident, Martin, Mageik, Griggs, Kukak, 

Snowy, Fourpeaked, and Douglas, as well as under 

the crater lakes of Katmai and Kaguyak (Sheppard 

et al. 1992; Motyka et al. 1994; Hildreth et al. 2003a, 

2004; Fierstein and Hildreth 2008; Neal et al. 2009). 

The fumaroles on the Novarupta dome are weak and 

only visible on cold days. Prior to the 1953 Trident 

Volcano eruption, a fumarole was visible in 1951 on the 

southwest ridge of the central cone, which became the 

vent site for the new volcanic cone (Southwest Trident). 

Fumaroles are currently present on the main Trident 

summit and the Southwest Trident cone (Sheppard et 

al. 1992; Taryn Lopez, postdoctoral researcher, AVO/

UAF-Geophysical Institute, written communication, 

October 2006). The numerous fumaroles on Mount 

Martin form a steam column that is commonly visible 

from Brooks Camp on clear days (Figure 30), which 

leads to many false eruption reports. Mount Mageik 

also has a crater lake surrounded by a fumarole field 

(see Figure 59). The fumaroles on Mount Griggs were 

noted by Forbes (1965) in a letter to the superintendent 

warning of a possible eminent eruption because he saw 

six new fumaroles form along a fissure on the west flank 

between 1,800 m and 2,100 m (6,000 and 7,000 ft). No 

eruption has yet occurred, but the fumaroles are still 

active today (Figure 56; see NPS video at

https://youtu.be/qZ3WQ7A6hpI). Little is known 

about the fumaroles near the summit of Kukak Volcano 

(Figure 41) or Snowy Mountain (Figure 38). A fumarole 

field formed on the summit of Fourpeaked Mountain 

after the 2006 eruption (Figure 49), and Mount Douglas 

has a fumarole field at its summit (Wood and Kienle 

1990). Also, the crater lakes of Mounta Katmai and 

Kaguyak Crater (shown on Plate 4) are thought to 

have fumaroles because the relative levels of sulfur and 

chlorine indicate that these lakes are fed by volcanically 

derived fluids that originate below the lakes (Sheppard 

et al. 1992; Fierstein and Hildreth 2008).

Warm Springs

Warm springs and cold springs are present throughout 

the volcanic area of Katmai (Plate 4). Warm springs, 

which have a temperature range of 15–30oC (60–86oF), 

issue from the ignimbrite sheet and consist of meteoric 

water heated by an incompletely cooled lens of welded 

tuff (Lowell and Keith 1991). A particularly dense 

collection of warm springs originate out of the Trident 

Volcano 1953–1960 lava flows (Figure 57); these springs 

are formed by the interaction of surface waters with the 

cooling Trident Volcano lava flows and the Southwest 

Trident plug dome (Keith et al. 1992). The temperatures 

of the springs were measured by Keith et al. (1992) 

and the northern group had a temperature of 15oC 

(60oF), and the southern group had a temperature of 

40oC (105oF). Concentrations of cesium, rubidium, 

strontium, arsenic, boron, sodium, and chlorine 

are higher in the southern group, indicating deeper 

circulation than the northern springs (Keith et al. 1992). 

Warm springs potentially exist in the remote areas away 

from the Valley of Ten Thousand Smokes, but have yet 

been inventoried and documented.

Warm Ground

Warm ground is any area where geothermal processes 

have raised the temperature above ambient ground 

temperature, but no fumaroles are present. Warm 

ground occurs near Novarupta dome (Hildreth and 

Fierstein 2012) and on the flanks of Mount Griggs 

(Plate 4; Forbes 1965). More areas of warm ground 

undoubtedly exist but have not yet been inventoried 

and documented.

Crater Lakes

Six crater lakes occur on the following volcanoes: 

Savonoski, Kaguyak, Martin, Mageik, Douglas, and 

Katmai (Plate 4; Savonoski not shown). Crater lakes are 

included in the geothermal features section because 

most are fed by hydrothermal fluids that keep them 

warm. The Savonoski crater (Figure 47) was examined 

to determine its origin as either an impact or volcanic 

crater (French et al. 1972), but no geochemical or 

temperature data were published for the lake. The 

lake in Kaguyak Crater (Figure 48) is 2.7 km (1.7 mi) 

Figure 56. Photograph of the fumarole (denoted by 

arrow) on the west flank of Mount Griggs. Photograph 

by Johan Gilchrist (University of British Columbia).
39

in maximum diameter, has a pH of 5.5, and a normal 

alpine lake temperature of 4.5oC (40oF) (Fierstein and 

Hildreth 2008). Fierstein and Hildreth (2008) suggested 

that the chloride and sulfate values indicated that the 

lake must have hydrothermal input. The geochemistry 

of the small shallow lake in Mount Martin summit 

crater is unknown (Figure 58). The Mageik crater lake 

is 110 m (360 ft) in diameter, very warm (92oC, 198oF), 

and very acidic (pH=1–2). Fumaroles under the lake 

make it appear to boil and sulfide minerals make the 

water yellow-green (Figure 59; Hildreth et al. 2000). 

Mount Douglas has a small crater lake with a maximum 

diameter of 200 m (700 ft); it is a cloudy light blue color 

and commonly has floating sulfur scum (Figure 60). The 

lake has very low pH of 1–2 and a warm temperature, 

25oC (77oF) (Wood and Kienle 1990).

Mount Katmai Crater Lake

The crater lake on Mount Katmai is the largest one in 

the Katmai area with a maximum diameter of 3 km 

(2 mi) (Figure 28, see Figure 63). Its average normal 

surface temperature is 5.8oC (42oF) and it has a pH of 

2.5–3 (Motyka 1977, 1978). However, Motyka (1977, 

1978) measured a temperature anomaly of 21oC (70 oF) 

Figure 57. Photograph of warm springs originating from the toe of a Trident lava flow. The orange color is formed by 

iron-concentrating bacteria. NPS photograph by Mike Fitz.

Figure 58. Photograph of the Mount Martin crater 

lake and fumaroles. AVO-UAF Geophysical Institute 

photograph by Taryn Lopez.
40

at the bottom of the lake below a yellow discolored area 

approximately 500 m (1,600 ft) northeast of the lake’s 

center (Figure 61). This discolored area is over the mud 

geyser that was observed on the floor of the caldera in 

1923 (Figure 62).

The Mount Katmai crater lake began to form after the 

top of the mountain collapsed during the 1912 eruption. 

When the Griggs expedition summited Mount Katmai 

in 1916 and 1917, its members saw a volcanic dome 

(Horseshoe Island) protruding through a shallow lake 

on the floor of the crater and estimated the elevation 

of the lake’s surface relative to the rim (Griggs 1922). 

When Fenner and Yori visited the Katmai crater in July 

1923, they found that the lake had drained and the floor 

had numerous mud pots, thermal springs, fumaroles, 

and a mud geyser (Figure 62) emanating from a flat lake 

bed (Fenner 1930, as summarized in Motyka 1977). 

Filling of Mount Katmai’s crater lake was initially rapid 

at an average rate of 5.7 m/yr (19 ft/yr); it has slowed to 

an average rate of 1.1 m/yr (4.3 ft/yr). 

A detailed history of Mount Katmai’s crater lake level 

changes is provided by Fenner (1930), Muller and 

Coulter (1957), and Motyka (1977, 1978). With financial 

support from the NPS, Motyka also spent four years 

Figure 59. Photograph of Mount Mageik crater and 

lake. Fumaroles surround the lake, and fumaroles under 

the lake make it appear to boil. AVO-UAF Geophysical 

Institute photograph by Taryn Lopez.

Figure 60. Photograph of Mount Douglas crater lake. 

The lake is very acidic and has a dark “scum,” which 

likely consists of sulfide minerals, floating on it. (Wood 

and Kienle 1990). AVO-UAF Geophysical Institute 

photograph by Taryn Lopez.

Figure 61. Photograph of the crater lake on Mount 

Katmai in 2015 showing a hole in the lake ice and a 

slight discoloration in the middle of the lake that is 

most likely from ongoing hydrothermal activity. AVOUAF Geophysical Institute photograph by Pavel Izbekov.

Figure 62. Photograph of a mud geyser on the floor of 

the Katmai crater in the year 1923. The raised mud ring 

around the geyser was estimated by Fenner (1930) to be 

30 m (100 ft) in diameter. Photograph by Charles Yori; 

NPS accession number KATM-93.
41

(1974–1977) studying the crater lake level changes and 

chemistry. In summary, when Griggs viewed the crater 

from the rim in 1917, he estimated that the lake was 

10–20 m (33–66 ft) deep. When Fenner and Yori visited 

the crater in 1923, the lake was gone (Figure 62) and the 

elevation of the crater floor was approximately 1,040–

1,050 m (3,410-3,440 ft). In 1951, the lake elevation was 

1,200 m (3,900 ft), which corresponds to an increase 

of about 160 m (524 ft) in 28 years, or an average rate 

of 5.7 m/yr (19 ft/yr). Motyka’s measurement in 1977 

determined the lake level was at 1,242 m (4,075 ft), 

which is an increase of 42 m (138 ft) since 1951 and 

corresponds to a rate of 1.6 m/yr (5.2 ft/yr). Motyka 

surmised that the significant drop in the rate of lake 

level rise was due to the increased hydraulic head 

forcing water through the underlying sandstones of the 

Naknek Formation.

IKONOS satellite imagery collected in 2010 shows the 

lake level at approximately 1,280 m (4,200 ft) when the 

lake outline is placed on the USGS topographic map 

(Figure 63). Comparing the 2010 lake level to the 1977 

elevation, the lake rose 38 m (125 ft) in 33 years, which 

corresponds to a rate of 1.2 m/yr (3.9 ft/yr). Assuming 

the rate averages 1 m/yr, the lake level could reach 

the lowest elevation on the rim of the crater (1,490 

m, 4,900 ft) in about 200 years. However, it may reach 

equilibrium like Crater Lake in Oregon has through 

loses by evaporation and groundwater leakage (see 

Crater Lake National Park GRI report by KellerLynn 

2013).

Glaciations

Map units: glacier deposits—Qhg, Qm, Qblu, Qblik, 

Qbld, Qblo, Qbln, Qblil, Qblk, Qmh, Qmhg, Qmho, 

Qjhd; glacial end moraines (“Glacial Feature Lines” 

layer); and associated alluvial and glaciolacustrine 

deposits—Qho, Qac, Ql, Qgl, Qglf, Qjho

The Katmai area is replete with well-preserved 

glacial landforms that are evidence of a long history 

of glaciation during the latter part of the Pleistocene 

Epoch (~100,000–12,000 years ago). The Alaska 

Peninsula held the western extent of the North 

American continental ice sheet, and glaciers covered 

most of map area, except for the highest ridges. Located 

along the south coast of Alaska, the Alaska Peninsula 

received (and still receives) abundant precipitation. 

During the Pleistocene Epoch, precipitation fell 

predominately as snow and formed glaciers that 

blanketed the mountain crest, blocked Cook Inlet, 

and formed an ice field between Kodiak Island and the 

Alaska Peninsula along Shelikof Strait. Glaciers north 

and south of the Katmai area had depocenters on the 

east side of the Alaska Peninsula in Cook Inlet, but the 

glaciers flowed west across the peninsula through the 

Iliamna Lake and Becharof Lake valleys. The glaciers 

that shaped the Naknek Lake area originated on the 

volcanoes and flowed down the Savonoski River and 

Rainbow River valleys where it merged, then split 

into three fingers that flowed down (1) Iliuk Arm and 

Lake Brooks, (2) North Arm of Naknek Lake, and 

(3) Grosvenor and Coville Lakes (Figure 64, Plate 1).

The terrain between the mountains and Bristol Bay is

wide and gently sloping, so it was a deposition zone

that preserved the deposits from the various glacial

advances. In contrast, the Pacific side of the mountain

crest is steep and had greater snowfall, so glaciers

persisted for a longer time at low elevations, which

left behind only a few small deposits of the latest

Pleistocene glaciations (Plate 1).

Figure 63. Satellite image of the crater lake in Mount 

Katmai overlain by shoreline outlines in 1951, 1974, 

and 2010. The lake is currently rising at a rate of 

approximately 1.2 m/yr (3.9 ft/yr).
42

All the types of glacial deposits shown in Figure 65 

were left behind after the retreat of the Pleistocene 

glaciers. Terminal (end) moraines mark the furthest 

extent of the glacial advances and are mapped on Plate 

1. The moraine deposits consist of coarse, angular, 

poorly sorted material forming ridges (Figure 66). The 

source maps (Detterman and Reed 1973; Detterman 

et al. 1987b; Riehle and Detterman 1993) include 

descriptions of knob-and-kettle topography, which 

refers to the lumpy deposits left behind as a glacier 

Figure 64. Map showing the glacier extents during glaciations and stades of the Katmai area. NP&P: National Park and 

Preserve. NM&P: National Monument and Preserve. WR: Wild River. Map created with information from Detterman 

and Reed (1973), Detterman (1986), Detterman et al. (1987b), and Riehle and Detterman (1993).
43

Figure 65. Diagram showing common types of glacial deposits. Graphic by Trista Thornberry-Ehrlich (Colorado State 

University).

Figure 66. Photograph of the Iliuk stade moraine dividing the Iliuk Arm (right) from the greater Naknek Lake (left). 

The moraine between the water bodies is approximately 3 km (2 mi) long. View is east-northeast, looking towards 

Mount La Gorce (center top of the photograph). Brooks Camp is located out-of-view to the left. NPS photograph by 

Kaiti Critz.
44

recedes (also referred to as kame topography). Kettle 

lakes formed when stranded ice blocks, which were 

incorporated in the unconsolidated glacier drift 

or alluvial deposits, later melted, leaving enclosed 

depressions. Proglacial lakes formed in front of receding 

glaciers where glacial deposits, typically moraines, 

created dams that blocked surface water. Glacial lake 

deposits (unit Ql on Plate 1) were left behind when 

these lakes drained after the dams eroded. Outwash 

deposits accumulated where meltwater streams or 

rivers deposited well-sorted gravel and sand, forming 

relatively flat areas downstream of terminal moraines 

(units Qho, Qblo, Qmho, Qjho on Plate 1). Where flow 

was more constrained to valleys, abandoned channels 

(Qac) also formed in areas draining the receding 

glaciers.

Abrahamson (1950) and Muller (1952, 1953) named and 

described the glacier deposits in the Naknek Lake area 

and developed a relative timeline of glacier advances 

for the Naknek Glacier. Three Pleistocene glaciations 

are preserved in the map area, from oldest to youngest, 

they are the (1) Johnson Hill, as indicated by map units 

Qjhd and Qjho; (2) Mak Hill (Qmh, Qmhg, and Qmho); 

and (3) Brooks Lake (Qblu, Qbld, Qblo, Qblk, Qblil, 

Qbln, and Qblik). Deposits from an older glaciation 

are present on the west side of Kvichak Bay, but the 

deposits are poorly preserved and little is known about 

their age. The Brooks Lake glaciation had four stades, 

from oldest to youngest, are the Kvichak (Qblk), Iliamna 

(Qblil), Newhalen (Qbln), and Iliuk (Qblik) (Detterman 

and Reed 1973). The absolute age ranges of the glacial 

advances are shown in Figure 67.

Johnson Hill Glaciation

The Johnson Hill deposits (Qjhd, Qjho) are the oldest 

deposits from the Naknek Glacier in the map area. 

Johnson Hill deposits are present in the map area 

between the Alagnak and Naknek Rivers (Plate 1). 

Glacial deposits of this age are severely degraded by 

erosion, and their kettle lakes have filled with sediment. 

A clear terminal moraine has not yet been identified. 

Similar deposits are recognized on the north side of 

Kvichak Bay. The age of the Johnson Hill deposit is 

older than can be dated using radiocarbon isotopes, so 

its age is unknown (Detterman 1986).

Mak Hill Glaciation

The Mak Hill glaciation was originally named after 

glacier deposits (Qmh, Qmhg, Qmho) on a hill with 

the vertical angle bench mark (VABM) named “Mak” 

located approximately 5 km west of King Salmon 

(Muller 1952). The Mak Hill glacial deposits are 

severely degraded, and no clear moraine deposits 

are observable in the area. The Mak Hill glaciation took 

place at least 43,000 cal. yr BP, as determined from 

radiocarbon ages of organic matter in syn- or postglacial deposits (Detterman 1986; Stilwell and Kaufman 

1996). However, this age is at the limit of the 

radiocarbon technique, so the deposits may be much 

older.

The correlation of the glacial deposits at Mak Hill and 

Naknek Lake with the terminal moraines at Iliamna 

Lake and Becharof Lake is in question (see Figure 

64). Riehle and Detterman (1993) reassigned the 

Mak Hill glacial deposits between Iliamna Lake and 

Becharof Lake to the Kvichak stade of the Brooks 

Lake glaciation, not the Mak Hill glaciation (as shown 

in Figure 64 and Plate 1). By doing so, the sequence 

of moraines in the Naknek area matched the number 

of moraines in the Iliamna Lake and Becharof Lake 

areas, north and south respectively. However, Stilwell 

and Kaufman (1996) correlated the Naknek Lake 

moraine with both the Kvichak River and Iliamna Lake 

moraines. They proposed that the northern (Iliamna 

Lake) and southern (Becharof Lake) areas had different 

advance histories than the Naknek area because 

they were sourced from the Cook Inlet and Shelikof 

Straits area, not from the western side of the Aleutian 

Range like the glaciers in the Naknek Lake area. These 

changes were made on limited radiocarbon ages, so 

further geochronological work of the moraines in the 

Naknek Lake area may help resolve these differing 

interpretations.

Brooks Lake Glaciation

The Brooks Lake glaciation (Qblu, Qbld, Qblo, Qblk, 

Qblil, Qbln, and Qblik) was defined by Muller (1952) for 

the well-preserved glacial moraines around and in Lake 

Brooks and Naknek Lake. The Brooks Lake deposits are 

better preserved than those of earlier glaciations in that 

they have sharper moraine crests and are less eroded. 

The stades within the Brooks Lake glaciation were 

named after moraines in the Lake Iliamna area.

The oldest stade of the Brooks Lake glaciation is 

the Kvichak stade (Qblk). It was named after the 

Kvichak River, which drains Iliamna Lake. Part of the 

Kvichak River moraine is located in the map area to 
45

the north of the Alagnak River. This oldest stade is 

not well represented by a distinct end moraine in the 

Lake Brooks and Naknek Lake area, but Riehle and 

Detterman (1993) mapped glacial deposits that they 

assigned to the Kvichak stade west of Lake Brooks near 

the King Salmon River and around the hill with the 

VABM named “Granite” at about the elevation of 183 

m (600 ft). Plant matter underlying outwash associated 

with the Kvichak moraine to the north of the map area 

provided a maximum age of 30,400±340 cal. yr BP for 

the Kvichak stade (Stilwell and Kaufman 1996).

Figure 67. Diagram showing the distance from the mountain crest for the various glacial advances and their absolute 

age ranges based on radiocarbon ages. The distances from source for the Ukak (25 km, 15 mi) and Katonlinat (30 km, 

20 mi) advances were measured at the head of the Valley of Ten Thousand Smokes; whereas, the older glaciations 

were measured at the head of the Rainbow River valley. Ages of overlying tephra deposits help constrain the age of 

some of the glacier deposits. Also shown is the global temperature deviation curve from Petit et al. (1999). Warmer 

temperatures are to-the-right; colder are to-the-left. Radiocarbon ages are reported in calibrated years before present 

(before 1950) from the following sources: (a) Pinney and Begét (1991b), (b) Pinney and Begét (1991a), (c) Brubaker et 

al (2001), (d) Reger et al.(1996), (e) Hildreth and Fierstein (2003), (f) Mann and Peteet (1994), (g) Stilwell and Kaufman 

(1996), (h) Detterman (1986), and (i) Riehle and Detterman (1993).
46

The Iliamna stade (Qblil) is named after the prominent 

end moraine that dams Iliamna Lake. Correlative 

moraines dam Kukaklek, Nonvianuk, and Naknek 

Lakes. The outer moraine located about 10 km 

southwest of Lake Brooks is also correlated with the 

Iliamna stade. The Iliamna moraine is overlain by the 

Windy River tephra, which has a maximum age of 

23,180±140 cal. yr BP, so the Iliamna stade took place 

more than 23,000 years ago (Stevens 2012). Mann and 

Peteet (1994) dated organic material below outwash 

associated with the Naknek Lake moraine, which 

provides a maximum age of 30,380±360 cal. yr BP for 

the Iliamna stade.

The Newhalen stade (Qbln) is named after moraine 

deposits along the Newhalen River, which flows into 

the north side of Iliamna Lake. In the map area, the 

moraines that dam Hammersly Lake, the North Arm of 

Naknek Lake, and Lake Brooks are correlated with the 

Newhalen stade by Riehle and Detterman (1993).

The Iliuk Arm moraine (Qblik) divides the Iliuk Arm 

from the rest of Naknek Lake and is the type moraine 

for the Iliuk stade. Additional moraines correlative 

with the Iliuk stade are the Lake Grosvenor moraine 

that separates Lake Grosvenor from Lake Coville; 

the Kulik Lake moraine that separates Kulik Lake 

from Nonvianuk Lake; and the Battle Lake moraine 

that separates Battle Lake from Kukaklek Lake. The 

Newhalen and Iliuk stades are constrained with 

radiometric ages between 19,880±210 and 23,180±140 

cal. yr BP (Pinney and Begét 1991a; Reger et al. 1996; 

Hildreth and Fierstein 2003).

Other Glacier Deposits

The Ukak drift and Katolinat till are two minor glacial 

advances that span the Pleistocene-Holocene boundary 

(11,700 years ago), and are present in the Three Forks 

area (Pinney and Begét 1991a). Ages of these advances 

are estimated to be approximately 12,000–8,500 years 

ago.

The Pacific side of the range contains only a few 

small areas with glacial deposits mapped as mapped 

undivided Brook Lake Glaciation (Qblu) and Iliuk 

Stade (Qbil) age deposits (Plate 1), but the ages of these 

deposits is not constrained. Steep mountain slopes 

and a short distance between the mountain crest 

and the coast was not an environment conducive for 

preservation of older glacial deposits. Only the most 

recent glacial deposits are preserved. One interesting 

exposure of glacier deposits underlies a lava flow from 

Mount Katmai in the Katmai River canyon (Griggs 

1917). 

Glacial Moraine Dammed Lake Levels

Map unit: Ql

As the glaciers receded, the freshly deposited end 

moraines dammed the water melting from the glaciers 

to form proglacial lakes. Nearly every proglacial lake 

in the Katmai area contained more water and covered 

a larger area than present-day lakes. For example, 

proglacial lake Naknek was up to 53 m (175 ft) above 

the present lake level (Muller 1952, 1963; Dumond 

1981; Kaufman and Stilwell 1997). When the Iliamna 

stade glacier retreated, a proglacial lake Naknek began 

to form, and the higher lake level eventually filled the 

many valleys of the area (Figure 68). The water flowing 

over the moraines slowly eroded into the moraines and 

lowered the lake levels. When the water was higher, 

waves on the lakes formed wave-cut terraces, wave-cut 

cliffs, and beach ridges on the hillslopes surrounding 

the lakes (e.g., Figure 69). Proglacial lake sediments (Ql) 

were deposited on the underlying glacier deposits and 

are exposed around the lakes in the area.

Dropping water levels of the proglacial lake Naknek 

left behind small lakes that were cut off from the path 

to the ocean, which stranded salmon that eventually 

became the Kokanee populations. As the lake level 

dropped, Lake Brooks and Brooks River formed. Water 

flowing over the newly exposed bedrock formed Brooks 

Falls, which now forms a constriction to salmon, which 

created a prime fishing area for indigenous humans and 

bears.

Modern Glacier Features and Changes

Map units: Qsg, Qrg; Qg; (“Glaciers” on Plate 1)

Glaciers of the Katmai area are clustered in three groups 

(1) in the Katmai volcanic cluster, (2) in the Fourpeaked

to Douglas volcanoes area, and (3) scattered in the

Walatka Mountains on the north (see Figure 73). An

example of typical glaciers on the ice-covered

volcanoes and their features are shown in Figure 70. As

of 2009, the Katmai Area had an ice-covered area of

around 915 km2

 (350 mi2) (Loso et al. 2014). There are

no glaciers in Alagnak Wild River.
47

Figure 68. Map showing the extent of the proglacial lake Naknek at varying lake levels defined by major wave-cut 

terraces. The colored lake terrace levels were created by “filling” the digital elevation model up to the major wave-cut 

terrace levels listed in Muller (1952, 1963), Dumond (1981), and Kaufman and Stilwell (1997). The asterisk next to 12 

m denotes the current lake level. The glacial moraines on the west end of Naknek Lake and southwest of Lake Brooks 

dammed the glacial melt waters to form the larger proglacial lake. Hillshade derived from National Elevation Dataset.

Figure 69. Satellite (IKONOS) 

image mosaic of beach ridges 

along the eastern shore of 

Kukaklek Lake at the outlet 

of Moraine Creek.
48

Loso et al. (2014) inventoried glacier changes of all the 

glaciers of Alaska by comparing topographic maps from 

the 1950s and 1960s to modern satellite imagery. In the 

Katmai area, these investigators counted 298 glaciers 

from the satellite imagery. The area covered by glaciers 

decreased from 1,060 km2 to 914 km2 (410 mi2 to 353 

mi2), or reduced by 14%. Error in the satellite analysis 

may result in the difficulty of identifying the glacial 

extent for glaciers with substantial superglacial drift 

(Qsg), like that which overlies the toes of the Serpent 

Tongue Glacier and the Knife Creek Glaciers (Plate 

1). Most glaciers in the Katmai area are retreating, like 

most glaciers in Alaska, but some of the glaciers still 

covered by thick deposits of 1912 ash (which provided 

an insulating “blanket”) have advanced (Figure 71, 

Figure 72, Figure 73). For a detailed overview of the 

effects of ash on the glaciers see Hildreth and Fierstein 

(2012, p. 171–173). Terminus retreat was the response 

seen in most glaciers, including notable retreats of up to 

4 km (2.4 mi) for glaciers on Fourpeaked Mountain and 

Mount Douglas, as well as Hallo Glacier (Figure 71) and 

others on the Denison to Devils desk volcanic cluster.

Following the 1912 eruption, new glaciers have formed 

in the Katmai caldera (Figure 74). The collapse of the 

glacier-clad summit during the eruption “beheaded” the 

glaciers and left steep ice cliffs on the west and north 

sides of the caldera (Griggs 1922). Sometime after 1923, 

a permanent ice field accumulated on the south wall of 

Figure 70. Photograph showing glacial features. The unnamed glaciers are sourced from a broad icefield on the 

northwest side of Mount Douglas. Where two glaciers meet, a medial moraine forms from the lateral moraines of 

each glacier. Arêtes are knife-edge ridges that form between two glaciers. Nunataks are isolated knobs of exposed 

bedrock surrounded by glacial ice. The ice-cored moraine at the toe of the glacier is hummocky debris covered ice that 

is also referred to as “dead ice,” because it is no longer part of the moving glacier. Kettle lakes form where moraine or 

outwash material buries glacial ice that has melted to leave a depression. NPS photograph by Chuck Lindsey.
49

Figure 71. Photograph of Hallo Glacier in 2007. The approximate extent of the glacier in 1951, based on USGS 

topographic map, is shown as a dashed line. NPS photograph by Chuck Lindsay.

Figure 72. Photograph of one of the Knife Creek Glaciers. Ash from the 1912 eruption still extensively coats the 

surface of the lower portion of the glacier more than 100 years after the eruption. The ash cover was thick enough 

to “insulate” the glacier, causing it to advance when the majority of glaciers in the Katmai area and Alaska have 

retreated. NPS photograph by Chad Hults.
50

Figure 73. Map showing the extent of the glaciers as mapped on 1950s USGS topographic maps as compared to the 

modern glacial extent derived from satellite images mostly from 2009. The top frame (1) of the Katmai volcanic cluster 

area shows the isopachs of the 1912 eruption ash-fall depths from Fierstein and Hildreth (1992) and Hildreth and 

Fierstein (2003). Many of the glaciers around the Novarupta vent area have advanced, but outside of the main ash fall 

area most glaciers have retreated. The glacier with the greatest advance, 1 km (0.6 mi), is on the north side of Mount 

Martin; whereas, the Hallo Glacier has retreated approximately 2 km (1.3 mi). Frame (2) is of the Fourpeaked Mountain 

and Mount Douglas area. It predominately shows extreme glacier retreat. Fourpeaked Glacier had the greatest retreat 

of about 4 km (2.4 mi). Frame (3) is of the Walatka Mountains area, where all the small alpine glaciers have retreated. 

Maps created with data from Arendt and Rich (2013).
51

the caldera, and by 1935, Hubbard observed glaciers 

forming on the caldera walls (summarized by Muller 

and Coulter 1957). As reported by Muller and Coulter 

(1957), two well-formed glaciers were clinging to the 

north and south sides of the caldera walls, and an icefall 

was cascading down the southwest side of the caldera in 

1953 (Figure 75); these features are still active today.

Thirty rock glaciers (Qrg) are mapped in the Katmai 

area (Plate 1; Figure 76). Rock glaciers are jumbled 

masses of boulders and smaller rock material that may 

bury an ice glacier (“ice-cored”) or have ice filling much 

of the spaces between the rocks (“ice-cemented”).

Permafrost Features

Map unit: Qsf

Although the average annual temperature at King 

Salmon is above freezing (1.8oC, 35.2oF; http://

akclimate.org/), isolated permafrost is present in the 

western portion of the Katmai area in the low hills 

and on the coastal plain and sporadic permafrost 

is present at higher elevations(Abrahamson 1950; 

Thompson 1954; Jorgenson et al. 2008; Figure 77). 

In low-lying areas, the presence of permafrost is 

commonly correlated with an insulating cover of peat 

and thick vegetation mats of sphagnum mosses, sedge, 

and cottongrass; and found in areas underlain by finegrained surficial deposits (Detterman and Reed 1973, 

p. 15). Permafrost is present in the loess-covered areas

of the Mak Hill Glaciation, and proglacial lake deposits

(Ql). Frost wedges have been observed along cut banks

Figure 74. Comparative photographs of the north 

side of the Katmai caldera showing the growth of 

the northern glacier. Top: The glacier started as a 

thin snowfield in 1917. National Geographic Society 

photograph by John Shipley (Griggs 1922, p. 172). 

Center: It was a large active glacier in 1989. USGSCalVO photograph by Judy Fierstein (figure 136B in 

Hildreth and Fierstein 2012). Bottom: The glacier had 

shown some retreat by 2007. NPS photograph by Chuck 

Lindsay. 

Figure 75. Photograph of the icefall from the glacier 

on the southwest wall of the Katmai caldera. NPS 

photograph by Chad Hults.
52

of the Naknek River and the coastal plain, and frostwedge crack nets are present at higher elevations on a 

pass near Kaguyak Crater (Thompson 1954; Cahalane 

1959). Abrahamson (1950) hypothesized that the 

presence of permafrost in an area with an annual 

temperature above freezing was due to the thermal and 

water absorption properties of peat allowing the winter 

cold to penetrate better than the summer heat; whereas, 

Muller (1952) suggested that the permafrost of the 

coastal area was instead a remnant from the Pleistocene 

glaciations.

Intense frost action has modified the landscape since 

deglaciation. Older glacial deposits are weathered 

smooth by prolonged frost action, but younger deposits 

that have been exposed more recently have sharper 

features. Frost action heaves large rock fragments to the 

surface that produces a striped pattern on hillslopes 

and polygonal structures on flatter surfaces (Muller 

1952). Solifluction deposits (Qsf) are found on slopes 

throughout the Katmai area and form where watersaturated lobes of soil creep downhill over underlying, 

frozen ground.

Coastal Features

Map units: Qtf, Qes, Qb, Qmt

The Katmai coast has 737 km (458 miles) of shoreline 

(Curdts 2011), which is a mix of rugged wave-eroded 

sea cliffs on the headlands and protected bays (Figure 

78). Beach deposits (Qb) are chiefly sand derived from 

local surficial deposits, but beaches along Katmai and 

Dakavak Bays include abundant pumice from the 1912 

eruption. Tidal flat (Qtf) and estuarine (Qes) deposits 

are present in many of the protected bays along the 

coasts and consist of silt and mud below mean high tide. 

Steep slopes that continue below the water level are 

common along the shoreline, but broad estuaries and 

large beaches are present along deltas fed by sediment 

laden glacially fed rivers. A simple classification of the 

morphologic features of the coast was developed by 

Harper and Morris (2005).

Beach Berms

Beach berms (Qb, in part), semi-parallel ridges located 

inland of the modern coastline, are present in many 

of the protected bays, some places with stranded 

shorelines far inland from the modern shoreline. For 

example, Hallo Bay has stranded logs on beach ridges 

as far as 1.5 km (1 mi) inland of the modern coastline. 

Beach berms are formed where sediment input from 

rivers is greater than erosion from waves (Figure 79). 

Longshore currents transport the sediment along the 

coast and during large storms, sediment and logs are 

piled up to form the berms. As the process continues, 

the berms build seaward.

Raised Marine Terraces and Sea Caves

Raised marine terraces are present along the coast of 

Shelikof Strait and Kamishak Bay (Qmt) (Detterman 

and Reed 1973; Detterman et al. 1987b; Riehle 

and Detterman 1993; Crowell and Mann 1996). In 

Kamishak Bay, well-developed wave-cut platforms 

(Figure 80) are covered by beach deposits and are 15 

and 27 m (50 and 90 ft) above the modern high tide 

line. The wave-cut platform and associated deposits 

constitute a marine terrace. On an island in Kamishak 

Bay, Harper and Morris (2005) documented relict sea 

caves and sea cliffs, well-above modern sea level, that 

formed before uplift of the island (Figure 81). Along 

Figure 76. Photograph of a rock glacier (Qrg) in the hills 

of the headwaters of Ikagluik Creek. This is an example 

of an ice-cored rock glacier that is glacier ice completely 

covered with rocky debris. NPS photograph by Bruce 

Giffen. 
53

the southern coast of the Katmai area, Detterman et 

al. (1987b) also found marine terraces at the 40–45 m 

(130–150 ft) level.

The terraces on the Katmai coast are much higher than 

the terraces on the Bristol Bay coast, which are found 

only as high as 12–18 m (40–60 ft) (Detterman et al. 

1987b; Riehle and Detterman 1993). Organic material 

on top of 4 m (14 ft) of sand overlying the 15 m (50 

ft) terrace in the Douglas River area was deposited 

Figure 77. Map showing the permafrost extent in the Katmai area. Sporadic: areas where 10–50% of the ground is 

underlain by permafrost; Isolated: areas where <10% of the ground is underlain by permafrost. Map created with data 

from Jorgenson et al. (2008). Hillshade derived from National Elevation Dataset.
54

2,720±310 years BP, which corresponds to an uplift rate 

of approximately 3–6 mm/yr (0.1–0.2 in/yr) (Detterman 

and Reed 1973). This rate is close to the 8 mm/yr (0.3 

in/yr) uplift rate measured using GPS at Dakovak Lake 

(Freymueller et al. 2008). For comparison, a GPS survey 

marker located 80 km (50 mi) inland, on an island in the 

North Arm of Naknek Lake, is rising at half the rate of 

the coast, 4 mm/yr (0.15 in/yr) (Freymueller et al. 2008).

The Katmai coast is rising in part from tectonic uplift 

and in part from isostatic adjustments following 

deglaciation. The weight of glacial ice can depress 

Earth’s crust and when it melts, the crust gradually 

rebounds. Detterman (1986) provided a brief overview 

of the tectonic and isostatic evidence for the Alaska 

Peninsula, suggesting that these marine terraces may 

be primarily the result of differential glacial isostatic 

rebound. Because the peninsula is located over the 

Aleutian megathrust, the relative effects of ongoing 

deformation, movement along faults that create 

earthquakes, and isostatic rebound are hard to decipher. 

Long-term uplift rates are sometimes disrupted by 

distinct events; for example, based on tide station level 

changes in Kukak Bay, the 1964 earthquake caused the 

area to subside 20 cm (0.5 ft) (Plafker 1969).

Modern Surficial Deposits and Processes

Map units: Qs, Qsw, Qa, Qaf, Qt, Qls, Qc, Qd

Modern surficial deposits have been formed in the last 

few thousand years, and many are still forming today by 

geomorphic processes. Some surficial deposits 

have not been differentiated and are mapped 

as Qs in Plate 1. Swamp deposits (Qsw), 

organic peat and silt accumulations, formed in 

closed basins in low-lying areas.

Figure 78. Photographs of three major types of coastline 

in the Katmai area. (A) Sea cliffs along the exposed 

Cape Nukshak, south side of Hallo Bay. Photograph 

katmai_5011 from the NOAA Alaska ShoreZone 

database: http://alaskafisheries.noaa.gov/mapping/

szflex/. (B) Protected but rocky Hidden Harbor. NPS 

photograph by M. Torre Jorgenson. (C) Large beach 

in Katmai Bay near the mouth of the sediment laden 

Katmai River. NPS photograph by Carissa Turner.

Figure 79. Satellite (IKONOS) image of beach 

berms forming at the outlet of the Swikshak 

River. Sediment output from the sedimentladen river is greater than the rate of erosion 

by waves.
55

Figure 80. Photograph of a raised marine terrace (Qmt). The island, located near the mouth of the Douglas River, was 

cut flat by waves. Subsequently, it has risen approximately 15 m (50 ft). The foreground is a modern wave-cut platform 

that cuts across dipping beds of the Naknek Formation, Snug Harbor Siltstone Member. Photograph ci09hm_08129b 

from the NOAA Alaska ShoreZone database: http://alaskafisheries.noaa.gov/mapping/szflex/.

Figure 81. Photograph of marine terraces, sea cliffs, and sea caves raised above the modern high tide level. This island 

near the mouth of the Douglas River in Kachemak Bay is a raised marine terrace about 15 m (50 ft) above the modern 

high tide level. The cliffs and sea caves have vegetation below them indicating that they are also raised above the high 

tide level. NPS photograph by Sara Venator.
56

Alluvial deposits (Qa) are found along all the modern 

river floodplains and consist primarily of sand and 

gravel deposits, but locally include boulders eroded 

from bedrock or glacial deposits. Alluvial fan deposits 

(Qaf) are fan-shaped alluvial deposits that form along 

moderately to steeply sloping areas. Alluvial terrace 

deposits (Qt) are sorted, stratified gravel and sand 

deposits that are higher than modern floodplains. They 

were formed by the complex interplay among uplift 

of the land by tectonic or glacial isostatic rebound, 

lowering of the outlet caused by sea level or lake level 

changes, or changes in sediment influx. Landslide 

deposits (Qls) are made up of unsorted deposits of 

chaotic debris forming lobate masses at the bases 

of steep slopes throughout the map area (Plate 1). 

Colluvial deposits (Qc) made up of loose, coarse angular 

blocks of rocks that form small cones and talus slopes 

are found throughout the map area on or at the base of 

steep slopes (Plate 1). Colluvium is indicative of rockfall 

and rockslides (see “Geohazards” section). Small dune 

fields (Qd) are found primarily along beaches and 

stream terraces and near the Valley of Ten Thousand 

Smokes (Plate 1). With the exception of Qls and Qc, all 

the units listed above are mapped within Alagnak Wild 

River (Plate 1).

Mesozoic Bedrock

The bedrock of the Katmai area includes a nearly 

complete sequence spanning the Mesozoic Era 

(252–66 MYA; Plate 2; Plate 3). Triassic (252–201 

MYA) greenstone (altered basaltic rocks) that made up 

an ocean floor was intruded and overlain by Lower 

Jurassic (201–174 MYA) plutonic (intrusive magma 

bodies) and volcanic rocks of the Talkeetna arc. The 

Bruin Bay fault uplifted the arc and sediment eroded 

from the arc was deposited along a narrow shelf (Figure 

82) during the Upper Jurassic to Lower Cretaceous

(164–100 MYA) (Burk 1965; Trop et al. 2005; Wartes

et al. 2013). Evidence from paleomagnetism, fossil

assemblages, and depositional environments suggests

that the rocks formed originally in tropical waters in

the Late Triassic (237–201 MYA), were transported to

boreal (high latitude) environments in the Late Jurassic

(164–145 MYA), moved back down to low latitudes

Figure 82. Diagram showing the depositional environments of Mesozoic nonmarine and marine rocks of the Katmai 

area. The Bruin Bay fault (left side of graphic) is a major reverse fault that pushed up the volcanic and plutonic rocks 

of the Talkeetna arc (see “Faults and Folds” section). Redrafted from Herriott et al. (2015) after Reading and Richards 

(1994).
57

in the mid-Cretaceous (110–90 MYA), then rapidly 

moved northward along the coast of North America 

to their present location (see “Terrane Translation 

and Accretion” section). Plate tectonics has played a 

major role in the formation of the rocks of Katmai, 

transporting them to the North American continent 

from out in the proto-Pacific Ocean, and causing the 

deformation and uplift that is still ongoing today.

Cottonwood Bay Greenstone

Map unit: TRc

The oldest rock in the Katmai area is the Upper Triassic 

(237–201 MYA) Cottonwood Bay Greenstone (TRc) 

that crops out in a small exposure near Takayofo Creek 

(Plate 1). It consists of slightly altered submarine basalt 

flows and diabase sills (Riehle et al. 1993). The rocks 

possibly represent a volcanic seamount.

Kamishak Formation

Map units: TRk, TRku, TRkm

The Upper Triassic (237–201 MYA) Kamishak 

Formation (Trk) consists of up to 800 m (2,600 ft) of 

limestone and interbedded basalt flows and breccia 

exposed along the King Salmon River in the southwest 

part of the map area and the McNeil River area on 

the most northern portion of the map area (Plate 1; 

Detterman and Reed 1980; Riehle et al. 1993). North of 

the map area, the unit consists of reef deposits formed 

on a shallow marine shelf (Riehle et al. 1993; Detterman 

et al. 1996). Interbedded volcanic rocks indicates 

that volcanism was coeval during deposition of the 

limestone. Fragments of unidentifiable fossil fragments, 

and coral fragments are found in the map area (Miller 

et al. 1995). North and south of Katmai the unit is 

fossiliferous, so the unit in the map area most likely 

contains fossils. The following fossils were identified 

in the Kamishak Formation north of Katmai in the 

Iliamna quadrangle (Detterman and Reed 1980), and 

south of the Katmai area at Puale Bay (Detterman et al. 

1996): Ammonites: Alloclionites, Holoritinid; Bivalves: 

Monotis, Plicatula, Halobia; Corals: Koilocoenia, 

Oppelismilia, Thamnasteria; Others: Heterastridium, 

bryozoans, crinoids, echinoderm spines, gastropods.

Talkeetna Arc

Map units: Jtk, Jgr, Jgd, Jqd, Jgb

The Talkeetna arc is made up of Lower Jurassic 

(201–174 MYA) volcanic rocks and plutons of the 

Peninsular terrane and crop out northwest of the Bruin 

Bay fault (Plate 1). The Talkeetna Formation (Jtk) was 

defined in the Talkeetna Mountains (hence the name), 

but the unit extends far down the Alaska Peninsula. It 

consists of up to 1,200 m (4,000 ft) of lava flows, tuff, 

volcaniclastic sandstone and conglomerate, volcanic 

breccia, and lahar deposits of basaltic andesite or 

andesite composition (Riehle et al. 1993). The Talkeetna 

Formation represents the volcanic carapace and 

interbedded marine sedimentary rocks of an island 

volcanic arc. No fossils have been reported from the 

Talkeetna Formation in the Katmai area. However, in 

the Talkeetna Mountains, the unit contains marine 

invertebrates. Fossil ammonites, gastropods, and the 

bivalves Corbicellopsis and Oxytoma are present in the 

Talkeetna Formation south of Katmai at Puale Bay 

(Detterman et al. 1996).

The volcanic rocks of the Talkeetna arc were fed by 

plutons that now crop out in the map area as the 

Jurassic (radiometric ages range from 190 to 160 MYA) 

plutonic rocks of the Alaska-Aleutian Range batholith 

(units Jgr, Jgd, Jqd, Jgb in Plate 1). These plutons 

consist of granite, granodiorite, tonalite, diorite, quartz 

diorite, and gabbro. The plutons locally intrude older 

rocks and metamorphosed them into quartzite, schist, 

amphibolite, gneiss, and migmatite. These rocks are 

metamorphosed older country rock that are mapped as 

the Kakhonak Complex (JPk). The Kahhonak Complex 

is mapped within Alagnak Wild River (Plate 1).

Shelikof Formation

Map unit: Js

The Middle Jurassic (Bathonian(?) to Callovian, 

168–164 MYA) Shelikof Formation (Js) crops out in the 

southern portion of the Katmai area (Plate 1; Detterman 

et al. 1987a, 1996). The unit is thick-bedded to massive 

graywacke and conglomerate that represents deep- to 

shallow-water deposition. The conglomerate contains 

abundant volcanic grains, so it represents erosion of 

the volcanic carapace of the Talkeetna arc. No fossils 

have been reported in the Katmai area, but at the type 

section (area where the unit is defined) in Puale Bay 

and in the Chignik and Sutwik quadrangles, south of 

Katmai, the unit contains Ammonites: Cadoceras, 

Pseudocadoceras, Stenocadoceras, Iniskinites; and the 

Bivalve: Meleagrinella (Detterman et al. 1981, 1996). 

There is potential for the outcrops in the Katmai area to 

yield fossils.
58

Naknek Formation

Map units: Jn, Jnk, Jnc, Jni, Jns, Jnn

The most extensive Mesozoic rock unit within the map 

area is the Upper Jurassic (164–145 MYA) Naknek 

Formation, which crops out east of the Bruin Bay fault 

(Plate 1). The type section is in the Mount Katolinat 

area. Maximum thickness of the Naknek Formation 

is 3,200 m (10,500 ft), with an average thickness of 

1,700–2,000 m (5,600–6,600 ft) (Detterman et al. 1996).

The formation is divided into six members; five of 

which crop out in the Katmai area (from bottom to top): 

Chisik Conglomerate (Jnc); Northeast Creek Sandstone 

(Jnn); Snug Harbor Siltstone (Jns); Indecision Creek 

Sandstone (Jni); and Katolinat Conglomerate (Jnk). 

Where these members cannot be distinguished, the 

formation was mapped as undivided (Jn). The following 

unit descriptions and interpretations of depositional 

environments were derived from Riehle et al. (1993), 

Miller et al. (1995), and Detterman et al. (1996).

The stratigraphically lowest member (oldest) is the 

nonmarine Chisik Conglomerate (Jnc), which is 600 m 

(2,000 ft) of massive thick-bedded conglomerate with 

lenses of cross-bedded sandstone, which was deposited 

in a fluvial environment (Figure 82). The unit contains 

clasts made up of granitic rocks, quartzite, schist, 

chert, and quartz. The second from lowest member is 

the nonmarine and shallow marine Northeast Creek 

Sandstone (Jnn), which is 200–600 m (660–2,000 ft) 

of fine to medium grained sandstone that is laminated 

and contains both eolian (windblown) and fluvial 

Figure 83. Photograph of bedding forms in the Naknek Formation, Snug Harbor Siltstone Member near Ukak Falls. 

These sedimentary structures are typical of submarine debris flows common in outer shelf and slope environments. NPS 

photograph by Chad Hults.
59

(river) cross-bedding that developed in fluvial and 

nearshore environments (Figure 82). Conglomerate 

beds in the Northeast Creek Sandstone contain 

predominately plutonic clasts, but also clasts of chert 

and white quartz. The next lower member in the map 

area is the marine Snug Harbor Siltstone (Jns) (Figure 

83) that consists of dark-gray sandy siltstone and

shale with a few sandstone interbeds and moderately 

abundant calcareous concretions. The unit is 200–600

m (660–2,000 ft) thick and was deposited in outer shelf

and slope environments (Figure 82). The Indecision

Creek Sandstone Member (Jni) is a marine arkosic

sandstone and siltstone 400–800 m (1,300–2,600 ft)

thick deposited in shallow-shelf to nearshore marine

environments (Figure 82). The highest member is the

nonmarine Katolinat Conglomerate (Jnk) that is 450 m

(1,500 ft) thick and consists of massive pebble-cobble

conglomerate and interbedded sandstone deposited 

in fluvial and beach environments (Figure 82). The 

conglomerate contains abundant clasts of plutonic 

rocks, quartz and minor chert, and metamorphic rocks.

The arkosic nature of the sandstones and the abundant 

plutonic clasts in the conglomerates suggest that 

the Naknek Formation was derived predominantly 

from plutonic rocks of the Talkeetna arc (Burk 1965; 

Detterman et al. 1996). In general, the lower members 

are marine and minor nonmarine sedimentary rocks 

that were deposited in braided river and deltaic 

environments. As marine waters transgressed (got 

deeper), the middle members were deposited along 

a marine shelf, slope, and submarine fan. Waters 

regressed (got shallower), so the upper Katolinat 

Conglomerate member was deposited in beach and 

Figure 84. Map showing the extent of the Naknek Formation (green area) along the Alaska Peninsula and Talkeetna 

Mountains; a distance greater than 1,100 km (700 mi). Major faults are shown as black lines. Drafted with map 

compilations from Wilson et al. (1998, 2006, 2012, 2013, 2015). Hillshade derived from National Elevation Dataset.
60

shoreface environments (Figure 82; Miller et al. 1995). 

These rocks represent a marine transgressive-regressive 

cycle (relative sea level rise then fall). Also, depositional 

environments change laterally in the Naknek Formation 

with coarser-grained nonmarine sedimentary rocks 

located on the northwestern margins of the Naknek 

Formation, and deeper marine facies occurring on the 

southeast (Detterman et al. 1996).

The Naknek Formation is an extensive unit found 

on the Alaska Peninsula and the southern Talkeetna 

Mountains (Figure 84). The Naknek Formation is 

present only on the southeastern side of the Bruin Bay 

fault, which was an active reverse fault during the time 

of deposition (Burk 1965; Trop et al. 2005; Wartes et al. 

2013). The rocks of the Peninsular terrane were uplifted 

on the northwest side of the fault and high-energy 

streams eroded older rocks and deposited the sediment 

on the southeastern flanks of the terrane (Figure 82). 

The rapid deposition of the Naknek Formation records 

a major uplift and unroofing (extensive erosion) event 

that affected the Peninsular terrane (Trop et al. 2005).

Diverse fossils, listed below, are found in the Naknek 

Formation of the Katmai area.

The undivided Naknek Formation (Jn) is known for 

its abundant Buchia bivalve fossils (Figure 85) but 

also contains the following: Ammonites: Phylloceras; 

Cardioceras; Bivalves: include abundant Buchia, 

as well as Astarte, Eumicrotis, Lima, Meleagrinella, 

Pholadomya, and Pleuromya; Brachiopod: 

rhynchonellid; Belemnite: Cylindroteuthis; Fish

(turbot): Scophthalmus; Other: bone fragments (Keller 

and Reiser 1958; Detterman and Reed 1980; Miller et al. 

1995).

The Northeast Creek Sandstone Member (Jnn) contains 

Bivalves: Buchia, Pleuromya, Tancredia (Elder and 

Miller 1993; Miller et al. 1995).

Figure 85. Photograph of Buchia mosquensis bivalve fossils in the Naknek Formation Snug Harbor Siltstone member 

near the Ukak River. NPS photograph by Chad Hults.
61

The Snug Harbor Siltstone Member (Jns) contains 

the following fossils: Ammonites: Cardioceras, 

Lytoceras, Phylloceras, Partschiceras, Perisphinctes, 

Aulocosphinctoides, Partschiceras; Belemnite: 

Cylindroteuthis; Bivalves: Arctica(?), Buchia, 

Camptonectes, Cardiid, Corbiculid, Entolium, 

Meleagrinella, Nuculana, Ostrea, Pectinid, Pholadomya, 

Pseudolimea, Thracia, Venerid, Astarte, Goniomya, 

Grammatodon, Isocyprina, Oxytoma, Pleuromya, 

Quenstedtia, Tancredia; Echinoderm: Cidarid; 

Polychaete (worm): Ditrupa; Gastropod: Turbo; 

Scaphopod: Dentalium; Other: bone fragments 

(Detterman and Hartsock 1966; Detterman and Reed 

1980; Miller et al. 1995; Fiorillo et al. 2004).

The Indecision Creek Sandstone Member (Jni) contains 

the following fossils: Ammonites: Amoeboceras, 

Lytoceras, Ochetoceras, Partschiceras, Phylloceras; 

Bivalves: Astarte, Buchia, Camptonectes, Corbiculid, 

Entolium, Lima, Limidae, Meleagrinella, Opis, Oxytoma, 

Ostreid, Pectinid, Pholadomya, Pleuromya, Pseudolimea, 

Tancredia; Belemnite: Cylindroteuthis; Scaphopod: 

Dentalium; Polychaete (worm): Ditrupa; Gastropod: 

Turbo; Other: barnacle (Miller et al. 1995).

The Katolinat Conglomerate Member (Jnk) contains 

the bivalve genera Buchia and Corbicula (Riehle et al. 

1993; Miller et al. 1995). 

Fossil plant debris is common in the Naknek Formation. 

South of the map area near the Kejulik River, petrified 

wood was found in the unit (Albanese and Goff 1987), 

so the outcrops in the park could also contain petrified 

wood.

Significant vertebrate paleontological resources found 

in the Naknek Formation include bone fragments in the 

Snug Harbor Siltstone that were found in the park and 

just south of the park along the shores of Becharof Lake 

(Weems and Blodgett 1996; Fiorillo et al. 2004). Farther 

south along the Alaska Peninsula, dinosaur tracks 

were discovered in the 1970s and revisited in 2011 

(Druckenmiller et al. 2011). The park contains extensive 

outcrops of the Naknek Formation, so the potential 

exists of finding more bone material and dinosaur 

tracks in the formation.

Staniukovich Formation

Map unit: Kst

The Lower Cretaceous (Berriasian to Valanginian, 

145–133 MYA) Staniukovich Formation (Kst) crops out 

in the hills east of Mount Griggs and consists of 100 

m (330 ft) of marine cross-bedded sandstone. It was 

deposited in shallow marine waters on a marine shelf 

(Figure 82), probably along offshore barrier bars (Riehle 

et al. 1993). It contains abundant Buchia bivalves (Riehle 

et al. 1993; Miller et al. 1995).

Herendeen Formation

Map unit: Khe

The Lower Cretaceous (Hauterivian and Barremian, 

133–125 MYA) Herendeen Formation (Khe) crops out 

in the Douglas River, American Creek, and Katmai 

River areas and consists of calcareous (consisting 

of calcium carbonate) sandstone that is commonly 

cross-bedded, and interbedded siltstone and shale 

(Riehle et al. 1993). The unit is mostly made up of 

Inoceramus fragments (Figure 86) that are so abundant 

that it was originally called a limestone (Atwood 

1911). In general, it is relatively thin, 25 m (80 ft), but 

is as much as 250 m (800 ft) thick in places (Riehle 

et al. 1993). The unit was deposited along a marine 

shelf (Figure 82; Miller et al. 1995). It unconformably 

underlies the Kaguyak Formation and is conformable 

with the underlying Staniukovich Formation (Miller 

et al. 1995). Fossils include Ammonites: Acrioceras, 

Hoplocrioceras?, Phylloceratid; Bivalves: Anomia, 

Entolium, Homomya, Inoceramus prisms, Pseudolimea; 

Belemnites: Acroteuthis, Cylindroteuthis; Brachiopods: 

indeterminate (Miller et al. 1995; Detterman et al. 

1996).

Figure 86. Photograph of the bivalve Inoceramus

ovatoides in the Herendeen Formation. Photograph by 

Robert Blodgett.
62

Pedmar Formation

Map unit: Kp

The Upper Cretaceous (Albian, 113–100 MYA) Pedmar 

Formation (Kp) crops out at two locations, one along 

the coast at Katmai Bay (type section) and another 

in the mountains between Mount Griggs and Snowy 

Mountain (Plate 1). The thin unit consists of 80 m 

(260 ft) of marine sandstone and minor amounts of 

siltstone and shale. No deposits are present to fill in 

the gaps in time between the underlying Herendeen 

Formation (Kh) and overlying Kaguyak Formation (Kk), 

so disconformities exist between the units. The Pedmar 

is unusual, because Albian age rocks are not common 

along the Alaska Peninsula (Detterman et al. 1996). 

Miller et al. (1995) suggested that the unit was deposited 

in a shallow marine shelf environment, indicated by 

the abundant plant detritus (Figure 82). Although 

the unit is thin, it contains the following diverse 

fossils: Ammonites: Anagaudryceras, Anisoceratid, 

Cleoniceras, Marshallites, Parajaubertella, Puzosia, 

Tetragonites, Zelandites, Mesopuzosia, Desmoceras; 

Bivalves: Anomia, Aucellina, Entolium, Panopea?, 

Trigoniid; Belemnites: Acroteuthis; Nautiloid; 

Gastropod: Polinices (Miller et al. 1995; Detterman et 

al. 1996).

Kaguyak Formation

Map unit: Kk

The Upper Cretaceous (upper Campanian to lower 

Maastrichtian, 80–68 MYA) Kaguyak Formation 

(Kk) crops out along the eastern portion of the map 

area (Plate , Figure 87) from Kamishak Bay to the 

Katmai River. The type locality is along the north 

shore of Kaguyak Bay. The unit is as much as 1,050 

m (3,400 ft) thick with lower beds consisting of thinbedded siltstone and thin limestone that contain 

abundant ammonites and Inoceramus bivalve fossils 

(Riehle et al. 1993). The upper beds consist of graded 

graywacke sandstone and siltstone beds that have 

flame structures, rip-up clasts, load casts, and flute 

casts (Riehle et al. 1993). These structures of the upper 

part are characteristic of turbidite (underwater debris 

flow) deposition in submarine fan environments 

(Figure 82; Miller et al. 1995; Detterman et al. 1996). 

The Kaguyak Formation contains abundant and 

diverse fossils including Cephalopod: Nautiloid; 

Ammonites: Baculites, Canadoceras, Didymoceras, 

Diplomoceras, Exiteloceras, Gaudryceras, Glyptoxoceras, 

Hypophylloceras, Lytoceras, Neophylloceras, Nostoceras, 

Pachydiscus, and Patagoisites; Belemnites: Acroteuthis

and Cylindroteuthis; Bivalves: Anomia, Acila, 

Arcid, Calva, Clisocolus, Glycymeris, Goniomya, 

Indogrammatodon?, Inoceramus, Lima, Nemodon, 

Nucula, Nuculana, Ostreid, Pectinid, Pholadomya, 

Pleuromya, Protocardia, Sphenoceramus, Teredo, 

Trigoniid, Venerid, Yaadia, and Yoldia; Brachiopod: 

Rhynchonellid; Echnioderm: Isocrinus; Gastropods:

Acteonid, Anisomyon, Biplica, Cerithiid, Forsia, Fusid, 

Gyrodes, Polinices, Remnita, Tessarolax, Trochus, and 

Zinsitys; Scaphopod: Dentalium (Keller and Reiser 

Figure 87. Photograph of dark gray, fine-grained 

sedimentary rocks of the Kaguyak Formation (unit Kk 

in Plate 1) in the hills above Big River. The hills include 

lighter gray dikes that intruded the formation and were 

probably offshoots from the nearby, larger Tertiary 

intrusive bodies (Ti). NPS photograph by Chuck Lindsay.

Figure 88. Photograph of the ammonite Pachydiscus 

kamishakensis from the Kaguyak Formation. This 

specimen is approximately 24 cm wide (scale in 

centimeters), but they can be 1 m (3 ft) or more in 

diameter. NPS photograph of accession number KATM00165 9080.
63

1958; Detterman and Reed 1980; Miller et al. 1995; 

Detterman et al. 1996). A notable fossil is the large 

ammonite Pachydiscus kamishakensis (Figure 88), which 

can be 1 m (3 ft) or more across.

Tertiary Sedimentary and Igneous and 

Bedrock

The sedimentary record of the Katmai area continues 

into the Tertiary, but unlike during the Mesozoic, 

the Tertiary rocks are nonmarine (Plate 2; Plate 3). 

The Paleocene (66–56 MYA) rocks consist of fluvial 

sandstone and conglomerate of the Ketavik Formation, 

and Copper Lake Formation. The units contain coal 

beds and plant fossils. Uplift must have been great to 

form coarse-grained nonmarine rocks. Clast types 

in conglomerate suggest the sediment was sourced 

from erosion of the Talkeetna Arc. The Paleocene 

sedimentary units do not contain volcanic rocks, so 

there was no active volcanism in the area at that time.

Igneous activity had been occurring on mainland Alaska 

during the early Tertiary. The center of the activity 

shifted to what is now the Alaska Peninsula and the 

Aleutian Island chain in the early Tertiary. The initiation 

of volcanism around 55 million years ago (early Eocene) 

suggests that a major change took place in the plate 

configuration along the western Alaskan margin (e.g., 

Scholl et al. 1986, 2015; Scholl 2007). The nature of the 

tectonic shift is still in question (see summary in Scholl 

2007). One explanation may be that before 55 MYA, 

an oceanic plate was subducting under the Beringian 

margin, but broke around 55 MYA. A piece of the 

oceanic plate currently floors the southern portion of 

the Bering Sea and a new subduction zone was initiated 

along what is now the Aleutian Island chain and 

Alaska Peninsula. Another possibility is that extension 

behind the arc front moved the arc southward from the 

Beringian margin to its present position. Research on 

this topic is ongoing.

Tertiary Sedimentary Rocks

Ketavik Formation

Map unit: not mapped

The upper Paleocene to lower Eocene (59–48 MYA) 

Ketavik Formation (Ketavik is the native name for the 

lagoon at the mouth of the Brooks River) is a fluvial 

sandstone and conglomerate that crops out in small, 

obscure exposures along Naknek Lake west of Brooks 

Camp (Parrish et al. 2010) and at Brooks Falls (Figure 

89). Although plant fossils have been recognized along 

Figure 89. Photographs of the Ketavik Formation at Brooks 

Falls. Above: The resistant bed of conglomerate that forms 

the falls makes up the rock on the far side of the river above 

the bear on the right side. NPS photograph by Chad Hults. 

Right: A close-up photograph of the conglomerate that shows 

clasts that are approximately 2 cm (1 in) in diameter. NPS 

photograph by Mike Fitz.
64

the shoreline near Brooks Camp for many years, this 

formation had not been mapped by previous authors, 

so does not show up on Plate 1. Conglomerate beds are 

more common near the lower portions of the unit and 

contain predominately volcanic and volcaniclastic rocks 

that are similar to the adjacent Talkeetna Formation. 

Fossil leaves and wood are common and include 

Platimeliphyllum, a genus known from the Kamchatka 

Peninsula and Sakhalin Island, but previously 

undocumented from North America. Coniferous 

wood fossils include genera Cedrus, Cupressinoxylon, 

Metasequoia, and Pinus; and a dicot wood of the genus 

Platanoxylon. Needles were identified as the genus 

Glyptostrobus. The following genera of leaf fossils were 

identified: Betulaceae (birch family), Cercidiphyllum

(saxifrage), Chaetoptelea (elm), Cocculus (vine), 

Corylites, Juglans or Carya (Juglandaceae) (walnut 

or hickory), Parashorea, Platanus (plane trees or 

sycamore), Platimeliphyllum, and Zizyphoides.

Copper Lake Formation

Map unit: Tc

The lower Eocene (56–48 MYA) and possibly upper 

Paleocene (59–56 MYA) Copper Lake Formation (Tc) 

crops out near Kukaklek Lake on the north and around 

Fourpeaked Mountain and Mount Douglas (Plate 1; 

Figure 90). The formation is made up of a sequence 

of massive fluvial conglomerate and interbedded 

sandstone and siltstone about 1,000 m (3,300 ft) thick 

that represents braided river deposits (Houston 1994; 

Detterman et al. 1996). Deposits are missing between 

the underlying Upper Cretaceous (100–66 MYA) 

Kaguyak Formation and the overlying late Oligocene 

(34–23 MYA) Hemlock Conglomerate, so the contacts 

are considered disconformable (Detterman et al. 

1996). The clasts in the conglomerate are volcanic, 

plutonic, metamorphic, and limestone. Paleocurrent 

structures suggest transport of material was directed 

to the southeast, indicating that the provenance was 

the Alaska-Aleutian Range batholith and Mesozoic 

sedimentary and metamorphic rocks (Houston 1994; 

Detterman et al. 1996). Carbonaceous debris and minor 

coal are present in finer-grained sediments (Detterman 

et al. 1996). The unit contains pollen and fossil leaves 

of the following genera: Acer (maple), Crataegus

(hawthorn), Dennstaedtia (fern), Equisetum (horsetail), 

Myrica (bayberry), Osmunda (fern), Sequoia (redwood), 

and Ulmus (hazel) (Hollick 1936; Detterman and Reed 

1980; Houston 1994).

Hemlock Conglomerate

Map unit: Th

The Oligocene or earliest Miocene(?) (34–20 MYA) 

Hemlock Conglomerate (Th) crops out on the Katmai 

coast and is a fluvial sandstone and conglomerate 

and minor siltstone, shale, and coal (Detterman et al. 

1996). Locally, the unit contains minor volcanic clasts, 

including pumice, and tuff beds (Detterman et al. 

1996). The unit is poorly consolidated and is as much 

as 550 m (1,800 ft) thick (Riehle et al. 1993). It was 

Figure 90. Photograph showing moderately dipping, bedded rocks of the Copper Lake Formation along sea cliffs north 

of Cape Douglas. The lighter beds are sandstone and the darker beds are carbonaceous siltstones or coal. Photograph 

katmai_0886 from the NOAA Alaska ShoreZone database: http://alaskafisheries.noaa.gov/mapping/szflex/.
65

deposited in a braided fluvial system with highly sinuous 

channels (Houston 1994). This unit disconformably 

overlies Copper Lake Formation at Cape Douglas and 

unconformably overlies the Kaguyak Formation (Kk) 

(Riehle et al. 1993; Detterman et al. 1996). The unit is 

locally altered to hornfels (heated and recrystallized) 

near the intrusions of Tertiary granitic intrusive rocks 

(Ti) (Riehle et al. 1993). The unit contains rare tree 

stumps in growth position, abundant plant fossils of 

broadleaf deciduous plants, evergreen needles, and 

pollen (Riehle et al. 1993; Houston 1994; Detterman 

et al. 1996). Genera identified include Acer (maple), 

Aesculus (soapberry), Alnus, Andromeda, Betula (birch), 

Corylus, Cupania (soapberry), Equisetum (horsetail), 

Hicoria, Ilex (holly), Juglans (walnut), Phyllites, Picea

(spruce), Populus (poplar), Pterospermites, Sequoia

(redwood), Taxodium (cypress), Ulmus (hazel), 

Vaccinium (heather), and Vetrix (Salix) (willow) 

(Knowlton 1904; Miller et al. 1995).

Tertiary Igneous Rocks

Map units: Tglv, Tab, Tiu, Togq, Tm, TKgd, Td

Tertiary plutonic, volcanic, and volcaniclastic rocks in 

the map area range in age from late Eocene to Pliocene 

(40–2.6 MYA; Plate 2). Four groups of Tertiary igneous 

rocks are recognized in the Katmai area:

(1) the Meshik Volcanics north of Naknek Lake 

(including Alagnak Wild River), (2) the Gibraltar Lake 

Tuff on the most northern edge of the map area, (3) 

the volcanic rocks of the Barrier Range near Katmai 

and Snowy Mountain, (4) the undivided intrusive 

rocks underlying Fourpeaked Mountain and Mount 

Douglas. The Tertiary igneous rocks are part of a larger 

belt of similar age igneous rocks that span the length 

of the Alaska Peninsula and continue up to the Alaska 

Range (Figure 91). The Tertiary igneous rocks represent 

initiation of volcanic activity that started in the early 

Tertiary (about 50 MYA) and continues today. Tertiary 

igneous rocks intrude and unconformably overlie 

(break in deposition) the Mesozoic rocks of the Katmai 

area (see “Mesozoic Bedrock” section).

Meshik Arc

Map units: Tm, Togq

The oldest Tertiary igneous activity resulted in the 

formation of the late Eocene to early Oligocene 

(40–28 MYA) Meshik Volcanics (Tm). Detterman and 

Reed (1980) identified numerous volcanic necks and 

domes that were the eruptive centers of the volcanic 

rocks (Plate 1). The Meshik Volcanics consist of 

basaltic to dacitic flows, agglomerate, ash, and minor 

volcaniclastic rocks (Wilson 1985; Detterman et al. 

1996). In the central portion of the map area, Riehle et 

al. (1993) measured 600 m (2,000 ft) of compact, highly 

porphyritic andesitic and dacitic lava flows and breccia. 

In the northern portion of the map area, Detterman and 

Reed (1980) estimated the volcanic rocks could be as 

much as 1,000 m (3,300 ft) thick. These rocks are highly 

varied in composition; most are intermediate andesite 

and basaltic andesite, but felsic rhyolite to mafic 

olivine basalt also occur. Most of the volcanic rocks 

have a distinctive texture where phenocrysts (mineral 

crystals) form clusters among finer-grained matrix that 

has tiny, elongated, typically parallel minerals (called 

glomeroporphyritic pilotaxitic). Other rocks are highly 

Figure 91. Map showing the extent of Tertiary igneous 

rocks (Eocene to Miocene, 56–5 MYA) along the Alaska 

Peninsula and into the Alaska Range. The Tertiary 

igneous rocks represent a belt of volcanic rocks that 

closely parallel the modern volcanic arc (shown as red 

triangles). Drafted with map compilations from Wilson 

et al. (1998, 2006, 2012, 2013, 2015). Hillshade derived 

from National Elevation Dataset.
66

vesicular (containing cavities formed by gas bubbles) 

and/or aphanitic (mineral crystals too small to see 

without a microscope). Ages of these volcanic rocks in 

the map area range from 45 to 25 MYA (Thrupp and 

Coe 1986; Shew and Lanphere 1992). The rocks contain 

minor interbedded mudflows, sandstone, coaly shale, 

and siltstone. Some of these sedimentary rocks locally 

contain petrified wood and leaf fossils that provide 

evidence for an early Tertiary age (Keller and Reiser 

1958). Early Eocene(?) (56–49 MYA) sedimentary rocks 

lie below the volcanic rocks and are rich in volcanic 

clasts, which suggests that volcanism may have started at 

that time.

Late Tertiary (Oligocene, 34–23 MYA) granodiorite 

and quartz diorite (Togq) plutons are mapped near the 

Meshik Volcanics (Plate 1) and have similar ages that 

range from 38 to 27 MYA (Detterman and Reed 1980; 

Shew and Lanphere 1992). These are most likely the 

plutonic roots of the Meshik Volcanics.

Volcanic Rocks of Barrier Range

Map units: Tab, Ti

The late Tertiary (Miocene to Pliocene 23–2.6 MYA) 

volcanic rocks of Barrier Range (Tab) crop out on the 

western portion of the map area along the coast, from 

Kukak Bay to the Katmai River (Plate 1; Figure 92). The 

rocks consist of up to 800 m (2,620 ft) of andesitic and 

dacitic porphyritic lava flows, tuffs, and breccias. The 

unit overlies the Hemlock Conglomerate (Th) and the 

contact between the two is gradational.

Gibraltar Lake Tuff

Map units: Tglv

The Gibraltar Lake Tuff (Tglv) consists of rhyolitic 

crystal and lithic tuff that unconformably overlies the 

Meshik Volcanics (Tm) in the northern part of the 

map area (Plate 1). The unit is made up of Pliocene(?) 

(5.3–2.6 MYA) white tuff that is as much as 180 m (600 

ft) thick that overlies Oligocene(?) to Pliocene(?) (34–2.6 

MYA) slightly to intensely welded light- to medium-gray 

and tan rhyolitic crystal and lithic tuff that is at least 300 

m (1,000 ft) thick and possibly as much as 730 m (2,400 

ft) thick (Detterman and Reed 1980). The Gibraltar 

Lake Tuff represents an isolated younger eruption event 

not directly related to the underlying Meshik Volcanics 

(Detterman and Reed 1980).

Figure 92. Photograph of columnar jointed lava flow of the volcanic rocks of the Barrier Range on Takli Island in 

Amalik Bay. Photograph katmai_0089 from the NOAA Alaska ShoreZone database: http://alaskafisheries.noaa.gov/

mapping/szflex/.
67

Other Tertiary Igneous Rocks

Map units: Tiu

Numerous undifferentiated and undated intrusive rocks 

(Tiu) are present throughout the map area. These rocks 

are mainly hypabyssal (shallow intrusive) rocks that 

are commonly porphyritic and consist chiefly of quartz 

diorite, granodiorite, or tonalite (Riehle et al. 1993; 

Hildreth and Fierstein 2003). These rocks intruded 

early Tertiary and older sedimentary rocks along the 

west coast from Cape Douglas to the Katmai River. 

The intrusive bodies probably were the sources of the 

volcanic rocks of the Barrier Range (Tab) and the small 

dacitic and andesitic lava flows (Tvu).

Faults and Folds

The major geologic structure of the Katmai area is the 

Bruin Bay fault, which runs through the middle of the 

park from the southwest to the northeast (Plate 1) and 

extends most of the length of the Alaska Peninsula, 

from near Aniakchak National Monument and Preserve 

through Lake Clark National Park and Preserve 

(Detterman and Hartsock 1966; Riehle et al. 1993; 

Stevens and Craw 2003; Gillis et al. 2013; Figure 84). 

It is a major reverse (high-angle thrust) fault, meaning 

that rocks above the fault plane were pushed “up” the 

fault relative to rocks below (Figure 82). The fault plane 

dips to the northwest with the “upthrown” side on the 

northwest. Uplift is as much as 3,000 m (10,000 ft), and 

the fault generally dips 60°–70°W. It produced a crushed 

zone hundreds of meters wide and caused drag folds in 

adjacent sedimentary rocks (Figure 93). During the Late 

Jurassic Period (164–145 MYA) it uplifted the plutonic 

roots of the Talkeetna volcanic arc on the west side of 

the fault, which led to marine deposition of the thick 

sequence of sedimentary rocks on the east side of the 

fault (Plate 3). The rocks on the northwest side of the 

fault are lightly to highly metamorphosed; whereas, 

sedimentary rocks on the southeast side of the fault are 

Figure 93. Photograph showing drag folds in the Naknek Formation along the Bruin Bay Fault. The southwest dipping 

fault has brought the Lower Jurassic Talkeetna Formation (Jtk) over the Upper Jurassic Naknek Formation (Jn). Bedding 

planes in the Naknek Formation (highlighted in yellow) are folded near the fault towards the direction of motion 

along the fault. Alaska Division of Geological and Geophysical Surveys photograph (modified from figure 32 in Gillis et 

al. 2013) taken at Contact Point in Bruin Bay, just north of the park boundary.
68

nearly flat lying with only mild, broad regional folds 

(Riehle et al. 1993). Evidence suggests that the fault 

may have been active (or reactivated) for about 118 

million years, until the late Oligocene Epoch (28 MYA) 

(Detterman and Reed 1980). Other minor faults are also 

present throughout the map area (Plate 1).

Anticlines (“A” shaped folds) and synclines (“U” 

shaped folds) are included in the geologic map in 

Plate 1. The folding involved the Miocene (23–5 MYA) 

volcanic rocks of the Barrier Range, so folding occurred 

sometime in the last 10 million years (Riehle et al. 1993). 

Terrane Translation and Accretion

Alaska is a collage of imported rocks called terranes 

(Figure 94). Terranes are packages of rocks that were 

transported on different plates and accreted together 

along suture zones (faults). Only a small area of Alaska 

along the Canadian border on the north end of YukonCharley National Preserve is an in-place, undisturbed 

part of the North American craton. The rest of Alaska 

consists of pieces of crust that arrived from elsewhere 

or are offset portions of the North American craton.

The Mesozoic rocks of Katmai belong to a group of 

rocks called the Peninsular terrane (Figure 94), which is 

thought to have originated far to the south in the protoPacific Ocean and was added to southern Alaska in the 

late Mesozoic (Stone and Packer 1977, 1979; Plafker et 

al. 1994; Kent and Irving 2010; Hults et al. 2013). The 

Mesozoic strata of the Alaska Peninsula are altogether 

as thick as 8,500 m (30,000 ft) and range in age from 

Late Triassic to Cretaceous (237–66 MYA); their base 

is nowhere exposed, although an islet of Permian 

Figure 94. Map showing the terranes of Alaska. The Alaska Peninsula is underlain by the Peninsular terrane (PE). 

The pre-Tertiary rocks of Katmai are a nearly complete section of the Peninsular terrane stratigraphy. Modified from 

Silberling et al. (1992).
69

(299–252 MYA) limestone crops out near Puale Bay 

south of Katmai (Detterman et al. 1987b, 1996). The 

key identifiers of the Peninsular terrane are the Lower 

Jurassic (201–174 MYA) volcanic rocks of the Talkeetna 

Formation, which represent an island arc that formed 

some distance off the North American margin in the 

proto-Pacific Ocean.

The Peninsular terrane is part of the larger Wrangellia 

composite terrane, which, in Alaska, spans from the 

Alaska Peninsula to southeast Alaska (Peninsular 

[PE], Wrangellia [Wr], and Alexander [AX] terranes in 

Figure 94). Paleomagnetic evidence from rocks of the 

Wrangellia composite terrane in other places in Alaska, 

including Wrangell-St. Elias National Park and Preserve, 

indicate that the terrane was in the equatorial region 

in the Triassic Period (252–201 MYA) (Hillhouse 1977; 

Hillhouse and Gromme 1984). Paleomagnetic evidence 

and fossil assemblages from these terranes suggest that 

the Lower Jurassic (201–174 MYA) Talkeetna arc most 

likely formed offshore and south of its current position 

relative to the North American continent (Figure 

95). By the mid-Cretaceous Period (110–90 MYA), 

the Peninsular terrane was somewhere off of Baja 

California. Stone and Packer (1977) coined the term 

“Baja Alaska” to represent the south to north translation 

history of these rocks. These original results have wide 

margins of error, but are similar to paleomagnetic 

measurements in other related Upper Cretaceous rocks 

of southern Alaska and British Columbia (Hillhouse 

and Coe 1994; Stamatakos et al. 2001; Kent and Irving 

2010). Because of the abundant Canadian studies, the 

idea is now referred to as the “Baja-BC hypothesis” (see 

summary in Cowan et al. 1997). These data initiated an 

ongoing debate over the amount of translation these 

rocks have undergone since the Cretaceous Period.

Figure 95. Paleogeographic map showing the Wrangellia composite terrane translation history from the Late Triassic 

to the present. Rocks of the Katmai area are located on the Peninsular terrane, which is the far western end of the 

Wrangellia composite terrane (Plafker et al. 1989; Nokleberg et al. 1994; Rioux et al. 2010). Evidence from fossils 

suggests that the terrane was far offshore of North America during the Late Triassic and Jurassic Periods, but how far 

offshore is not known. Modified from Kent and Irving (2010) to include the Peninsular terrane.
70

The geographic position of the Peninsular terrane 

through time (paleogeography) is important for 

understanding the past environments and habitats of 

extinct species found in the rock record of the Katmai 

area. For example, most dinosaurs lived on land, so 

dinosaur tracks in the Naknek Formation indicate that 

the Peninsular terrane was near a continent during 

the Late Jurassic (164–145 MYA). The Lower Jurassic 

(202–174 MYA) rocks of the Peninsular terrane were 

formed as an island arc separate from a continent, so 

an understanding of the terrane translations would 

shed light on the possible pathways dinosaurs followed 

to roam onto the terrane. A recent discovery of 

marine glacial deposits in the Upper Jurassic (164–145 

MYA) Naknek Formation (Wartes and Decker 2015) 

suggests that the Peninsular terrane experienced a 

very cold climate during a global period of greenhouse 

conditions. Translation of the Peninsular terrane, north–

south and east–west, affected the paleoenvironment of 

deposition and the biodiversity of fossils in the rocks of 

the Katmai area. However, investigators have studied 

the translation history of the terrane, and related 

terranes, but there is little consensus over the amount of 

translation experienced by the terranes of the northern 

Cordillera.
71

Geologic History

This section provides a condensed chronology of geologic events in the order that they formed the 

geologic features discussed in the Geologic Features and Processes section.

Late Triassic (237–201 MYA)

Cottonwood Bay Greenstone (TRc) and Kamishak 

Formation (Trk) represent oceanic crust (or a seamount) 

topped by coral reefs that formed near the equator.

Early Jurassic (201–174 MYA)

Subduction related to the Talkeetna arc formed plutons 

of the Alaska-Aleutian Range batholith (Jgr, Jgd, Jqd, 

Jgb) and volcanic rocks of the Talkeetna Formation 

(Jtk). These igneous rocks intruded and overlie the 

older rocks. Older rocks were altered by the heat from 

the intrusions, which formed the metamorphic rocks of 

the Kakhonak Complex (JPk).

Middle Jurassic (Bathonian(?) to Callovian, 

168–164 MYA)

The shallow to deep marine rocks of the Shelikof 

Formation (Js) formed offshore from sediment eroded 

off of the volcanic Talkeetna arc.

Late Jurassic (164–145 MYA)

The widespread Naknek Formation (Jn, Jnc, Jnn, Jns, 

Jni, Jnk) formed from the eroded sediment of the 

uplifted volcanic and plutonic rocks of the Talkeetna 

arc. The Bruin Bay fault was active during this time, 

uplifting the rocks on the northwest, which were eroded 

and shed into the adjacent basin, forming the Naknek 

Formation. The lack of limestone and abundance of 

boreal Buchia fossils indicate northerly transport of the 

Peninsular terrane through this time.

Early Cretaceous (145–135 MYA)

Continued uplift and erosion of the Peninsular terrane 

formed the sandstone of the Staniukovich Formation 

(Kst). However, by the time the overlying calcareous 

rocks of the Herendeen Formation (Khe) were 

deposited, the erosion (and possibly uplift) had begun 

to subside.

Early to Mid-Cretaceous (135–90 MYA)

Lack of significant deposition and the presence of 

disconformities and unconformities suggest that 

the mid-Cretaceous was a time of uplift. The Albian 

(112–100 MYA) Pedmar Formation (Kp) is a thin unit 

80 m (260 ft) thick that was deposited during the midCretaceous Period. During that time, the Peninsular 

terrane was far south of where it is today, somewhere 

between the latitude of Washington State and Baja 

California.

Latest Cretaceous (80–68 MYA)

Marine deposition picked up again with the deep-water 

turbidites of the Kaguyak Formation (Kk).

Late Paleocene to Early Eocene (59–49 MYA)

The Peninsular terrane was uplifted above sea level 

by the start of Tertiary time because the Ketavik 

(not mapped) and Copper Lake Formations (Tc) are 

nonmarine coarse sandstones and conglomerates 

deposited by rivers. During the Late Cretaceous Period 

to early Eocene Epoch, the Peninsular terrane was 

transported northward along the margin of North 

America.

Late Eocene to Pliocene (40–2.6 MYA)

After a short hiatus in deposition represented by an 

unconformity in the rock record, volcanism returned to 

the Peninsular terrane with the eruption of the Meshik 

Volcanics (Tm), volcanic rocks of the Barrier Range 

(Tab), and the Gibraltar Lake Tuff (Tglv). These volcanic 

rocks were fed by the various magmatic bodies (Tiu). 

The Oligocene, or possibly earliest Miocene (34–20 

MYA), Hemlock Conglomerate (Th) represents river 

deposits formed during the eruption of the Meshik 

Volcanics as indicated by its abundant volcanic clasts. 

Volcanism suggests that subduction picked up again 

along the margin, which is continuing today as the 

Aleutian arc.

Quaternary (2.6 MYA–Present)

Volcanism was nearly continuous through the late 

Eocene Epoch to the present day, and today’s volcanoes 

form the Aleutian arc. This volcanism, along with 

tectonic forces from the subduction of the Pacific 

Plate, formed the high mountains of the Katmai area. 

The mountains were sculpted by glaciers during the 

Pleistocene Epoch, which left wide U-shaped valleys 

in the mountains and deposited thick piles of glacial 

sediments on the lowlands. Glacial moraines left by 

these glaciers dam many of the lakes of Katmai. As the 
72

glaciers retreated, volcanic and fluvial processes began 

to dominate the landscape. For example, the 1912 

eruption filled the U-shaped valley of the River Lethe 

with a thick ignimbrite sheet and deposited ash fall over 

much of the surrounding region. This loose material is 

still shedding from the mountain sides and choking the 

rivers with sediment. Winds move the loose material, 

making it hard for life to take hold in the constantly 

shifting landscape.
73

Geologic Resource Management Issues

This section describes geologic features, processes, or human activities that may require management 

for visitor safety and preservation of natural and cultural resources in Katmai National Park and 

Preserve and Alagnak Wild River.

Three meetings were held to discuss GRI products, 

geology of the park units, and resource management 

issues. These meetings were held with NPS natural 

resource managers, NPS Southwest Alaska Network 

staff, NPS Alaska Region specialists, and geologists with 

experience in the Katmai area. A scoping meeting was 

held in 2005 (Graham 2005); a preliminary report kickoff meeting was held with Troy Hamon on 6 November 

2014, and a report kick-off call was held on 27 January 

2015. Attendees of the scoping meeting and report kickoff call are listed in Appendix D.

At these meetings, participants identified the following 

geologic resource management issue priorities:

● Volcanic Hazards

● Coastal Issues

● Seismic and Tsunami Hazards

● Glacier Changes

● Paleontological Resource Inventory, Monitoring, 

and Protection

Previously published NPS reports that address geologic 

resource management issues include:

● Katmai National Park and Preserve and Alagnak 

Wild River: Natural Resource Condition Assessment

(Zanon et al. 2015)

● Katmai National Park and Preserve foundation 

statement (NPS 2009a)

● Katmai National Park and Preserve, Aniakchak 

National Monument and Preserve, Alagnak Wild 

River long-range interpretive plan (NPS 2009b)

Resource managers may find the book Geological 

Monitoring (Young and Norby 2009; http://go.nps.gov/

geomonitoring) useful for addressing some of these 

geologic resource management issues. The manual 

provides guidance for monitoring vital signs; measurable 

parameters of the overall condition of natural resources. 

Each chapter covers a different geologic resource 

and includes detailed recommendations for resource 

managers, suggested methods of monitoring, and case 

studies.

Preservation of Katmai’s Natural Features for 

Inspiration and Study

The Katmai area has been an ideal laboratory for 

understanding volcanic processes and monitoring 

the regeneration of ecosystems after a catastrophic 

eruption. Since its inception, geologic research 

has been a primary mission for Katmai National 

Park and Preserve, and managers have supported 

or facilitated research that does not impinge on its 

wilderness character. The balance between preserving 

the wilderness character of the park and providing 

reasonable access for geologic research was tested with 

the proposal to drill into the Novarupta vent, termed 

the “The Katmai Drilling Project” (Sattler 1990). The 

scope of the proposal was large enough for the initiation 

of an extensive inter-agency evaluation of conducting 

important scientific research in an area designated 

as wilderness (National Research Council 1989). 

During the evaluation stage of the project, numerous 

research projects were permitted for collecting geologic 

information for supporting the Katmai Drilling Project 

(Eichelberger et al. 1991) and an environmental impact 

statement was prepared. In the end, the final project 

was not permitted. Even though this project was not 

permitted, many geologic research projects of various 

scopes have been permitted since the unit’s conception 

and, in some cases, led and supported by the National 

Park Service. For example, the 1953 Katmai Project 

was a multi-agency, multi-year, integrated research 

project that was supported and led by the National 

Park Service. Other government agencies have had 

teams of researchers study the geology of Katmai 

over many years. Since the 1980s, the Alaska Volcano 

Observatory (USGS, UAF, and State of Alaska Division 

of Geologic and Geophysical Surveys) has had ongoing 

research projects, held field classes, and installed and 

maintained a seismic network for real-time monitoring 

of the volcanoes. A concise chronology of the extensive 

geologic exploration over the last 100 years is presented 

in Appendix A and further detailed by Hildreth and 

Fierstein (2012, chapter 4). The results from these 

research projects provide material for Katmai staff to 

prepare interpretive programs, hikes, and products, 
74

which are used to educate visitors about the geologic 

processes that created Katmai’s spectacular landscape. 

The results are used to inform management decisions, 

protect visitors, and integrate with other natural 

resource sciences. 

Geohazards

The Katmai area has a very high potential for geologic 

hazards (“geohazards”). This section contains a list of 

potential geohazards in the Katmai area along with a 

brief description of each hazard and areas susceptible 

to them. When available, resources related to each type 

of hazard are provided. Katmai contains, and is adjacent 

to, active volcanoes. Strong wind events frequently 

resuspend ash from the 1912 eruption. Hydrothermal 

processes produce acidic waters, which can fill crater 

lakes and cause harm to sensitive riverine and lacustrine 

ecosystems. The area overlies the tectonically active 

Aleutian megathrust, and movement on this thrust 

causes frequent and large earthquakes. Steep slopes in 

the mountainous areas are susceptible to landslides 

and rockfall. Coastal areas are vulnerable to tsunamis 

originating from earthquakes or volcanic mass flows.

Volcanic Hazards

Map units: Qv, Qpd, Qafd, Qvd, QTv

Volcanic eruption potential is high in the Katmai 

area, because Katmai contains 24 Quaternary 

volcanoes, ten of which are considered active, and 

five have erupted in historic time (Table 3). According 

to the USGS volcanic threat assessment (Ewert et 

al. 2005), six volcanoes are listed as a high threat: 

Katmai, Novarupta, Trident, Griggs, Mageik, and 

Martin. Four are listed as a moderate threat: Denison, 

Douglas, Kukak, and Snowy. Fourpeaked was listed 

as a low threat volcano, but after the 2006 eruption 

it is a higher threat. Although 14 of the Quaternary 

volcanoes are not considered active, the eruption of 

Fourpeaked highlights the uncertainty of volcanic 

hazard assessments in the Katmai area.

The volcano hazard assessment for the Katmai cluster 

of volcanoes by Fierstein and Hildreth (2001) noted 

that all types of volcanic hazards depicted in Figure 

96 can be expected at Katmai. Areas farther away 

from the volcanoes are susceptible to tephra fall, and 

rivers flowing from the volcanoes are susceptible to 

lahar flows (Figure 97). Although volcanic deposits 

from past eruptions have been mapped (Plate 1), 

these deposits only provide evidence of past activity, so 

should not be considered a park-wide geohazards map 

or assessment.

The active volcanoes are monitored in near real-time 

by the USGS Alaska Volcano Observatory (for more 

information visit http://avo.alaska.edu). Generally, 

volcanic eruptions are preceded by earthquakes that can 

be detected by the AVO seismic network (Figure 98). 

Each seismic station consists of a buried seismometer, 

a power system (deep-cycle batteries and solar panel 

array), electronic processor, digitizer, and a radio and 

antenna. Data are examined daily by AVO analysts; 

some of the data are shared with the public via the 

AVO website: https://avo.alaska.edu/webicorders/. In 

addition to the seismic network, the following methods 

are used to detect volcanic unrest at Alaska volcanoes:

● Daily satellite analysis of images from space to 

look for signs of elevated surface temperatures or 

airborne volcanic ash.

Figure 96. Diagram showing the types of volcanic hazards that 

have and could occur at Katmai. USGS graphic by Myers and 

Driedger (2008).
75

● Regional infrasound capability that may be able to 

detect explosions, with potentially hours of delay.

● Space-based radar interferometry (InSAR) is 

used to detect uplift or subsidence that may occur 

prior to eruptions, though this is not a real-time 

technique.

● Pilot reports and other direct observations of 

changes at a volcano.

Much has already been written about the volcanic 

hazards of Katmai and plans for response to eruptions, 

so this report provides only a cursory review. For more 

detailed information of volcanic hazards, resource 

managers should consult the following resources:

● The Alaska Volcano Observatory website (http://

avo.alaska.edu) contains near real-time information 

Figure 97. Map showing active volcanoes and drainages at risk for lahar flows. Lahars are mud or debris flows from a 

volcano (see Figure 96). Red triangles are active volcanoes and orange shaded areas show river valleys that are at risk 

for lahar flows. Modified from Fierstein and Hildreth (2001).
76

regarding the status of volcanoes and hazards 

across the state. 

● Preliminary Volcano-Hazard Assessment for the 

Katmai Volcanic Cluster, Alaska (Fierstein and 

Hildreth 2001) is an assessment of the volcanic 

hazards for the Katmai volcanic cluster and is 

available at http://pubs.er.usgs.gov/publication/

ofr00489. 

● The Alaska Interagency Operating Plan for Volcanic 

Ash Episodes (Madden et al. 2014), available 

at http://avo.alaska.edu/downloads/reference.

php?citid=3996 provides federal and state agencies 

with guidance for responding to volcanic eruptions. 

● Volcanism in National Parks: Summary of the 

Workshop Convened by the US Geological Survey 

and National Park Service, 26–29 September 2000, 

Figure 98. Map showing the locations of seismic stations maintained and monitored by AVO. A meteorological station 

and webcam are also at station KABU in the Valley of Ten Thousand Smokes.
77

Redding, California (Guffanti et al. 2001) is a 

summary of resource management issues related to 

volcanoes in national parks and is available at http://

pubs.usgs.gov/of/2001/0435/.

Understanding the effects of volcanic eruptions to the 

physical morphology of the landscape and ecology was 

listed as a highly desirable objective for the inventory 

and monitoring plan for the Southwest Alaska Network 

parks (Bennett et al. 2006). In the Geological Monitoring

chapter about volcanoes, Smith et al. (2009) described 

six vital signs and methodologies for understanding 

and monitoring volcanoes: (1) earthquake activity, (2) 

ground deformation, (3) emission at ground level, (4) 

emission of gas plumes and ash clouds, (5) hydrologic 

activity, and (6) slope instability.

Dynamic Volcanic Landscape

Volcanic eruptions frequently change the landscape of 

the Katmai area. Geomorphic processes are affected 

by the intermittent addition of material into the 

active hydrologic and atmospheric systems. Volcanic 

eruptions and associated earthquakes potentially cause 

landslides that can flow for kilometers down valleys or 

cross valleys. Volcanic eruptions can disturb ecosystems 

and in very large eruptions, like the 1912 eruption, can 

obliterate all life and create a sterile landscape. The 

landscape and ecologic effects of the 1912 eruption are 

discussed in the “Geologic Features and Processes” 

section. Table 4 lists the geomorphic and ecologic effects 

of a major explosive volcanic eruption.

Crater Lake Explosions and Acidic-Water Flooding

Lakes in the active volcanic craters of Mounts Douglas, 

Martin, Mageik, and Katmai (Plate 4; see “Crater 

Lakes” section) create the potential hazard of lake water 

and magma violently mixing to generate an explosive 

phreatomagmatic eruption where water and magma 

interact, intensifying the eruption. The violence of 

the interaction is controlled by a number of factors, 

including magma type, volume, rate of extrusion, 

degree to which the magma is fragmented by expanding 

internal gas bubbles, and water depth. Typically, the 

most explosive water-magma mixing occurs if the water 

is shallow (a few meters to tens of meters deep), if the 

magma extrudes rapidly, and if the magma breaks into 

coarse particles before it is quenched. These conditions 

allow rapid transfer of heat from the magma to the 

water, generating steam and explosive eruptions. 

Eruptions beneath deep water, where the pressure is 

high enough to inhibit the expansion of steam, tend to 

be much less violent than those through shallow water. 

Slow rates of lava extrusion typical of lava flows and 

silicic domes also inhibit violent mixing with water. 

Faster extrusion rates and large volumes of gas-rich 

silicic magma could overcome even deeper water, with 

explosive results. The depth of water in the crater lakes 

of Mounts Martin and Mageik is very shallow, but the 

water in Katmai caldera is known to be more than 250 

m (820 ft) deep (Motyka 1977, 1978). With a surface 

area of 4.3 km2 (1.6 mi2), the lake volume is more than 

1 km3 (0.4 mi3). In contrast, the areas covered by the 

Martin and Mageik lakes are each less than 0.03 km2

Table 4. Geomorphic and ecological processes following a large volcanic eruption.

Timeframe Geomorphic Processes Ecologic Processes

Hours–Days

Deposition of meters thick pyroclastic debris and 

ash fall, debris flows, caldera collapse, damming 

of rivers, and lahars. Pyroclastic flows may form 

tsunamis.

Charring, burial, and suffocation of vegetation and wildlife. Acid rain 

falls and sulfur rich deposits increase acid levels in water bodies. 

Days–Years

Rapid erosion and deposition: gullying, sloughing

of steep slopes, and heavy sediment load in 

streams causes aggregation of river floodplains 

and rapid progradation of deltas. 

High acid levels in lakes and streams kill fish, aquatic life, and 

vegetation. Land animals must migrate or risk dying of starvation 

from lack of food or grinding down teeth from coarse tephra. Where 

deposits are thinner, native plants may grow through the deposits. 

Trees may temporarily benefit from the lack of competition from 

buried vegetation.

Years–Decades

Slowing erosion and deposition: gullies widen and 

slope angles decrease, wind deflation of loose 

surfaces in areas of thick deposits, and slower river 

aggregation and progradation of deltas.

Recolonization of stable surfaces by pioneer vegetation. Return of 

wildlife attracted to the new vegetation. Return of salmon runs and 

aquatic life.

Decades–Centuries Stabilization of surface morphology Maturation of ecosystems.

Centuries–Millennia Major eruption disrupts the landscape and starts the 

cycle over. Major eruption disrupts the landscape and starts the cycle over

Modified from Waythomas (2015)
78

(0.01 mi2), and they are probably only a few meters 

deep. Because of the large volume of water in Mount 

Katmai’s crater lake, and because of repeated silicic and 

fragmental eruptions from that volcano, an eruption 

through the Katmai crater lake is considered both likely 

and quite dangerous. Although the volume of water in 

the Martin and Mageik crater lakes is small, it would 

likely add intensity to any crater-derived eruption. 

The disruption of such acidic lakes also increases the 

possibility of local acid rainfall and of sending acid 

water-rich lahars and debris flows downhill from those 

summits. Floods of acidic volcanic lake water can have 

catastrophic effects on riverine and lake ecosystems. For 

example, during winter 2004–2005, a small acidic crater 

lake on Chiginagak volcano, near Aniakchak National 

Monument and Preserve, broke through a glacial dam 

and flooded the streams that run into Mother Goose 

Lake (Figure 1) and the King Salmon River. The event 

killed all aquatic life in a stream below the mountain, 

Mother Goose Lake, and the King Salmon River, 

preventing the annual salmon run. Severe vegetation 

damage and die-offs occurred around the streams as 

high as 150 m (500 ft) above the stream level (Schaefer 

et al. 2008). The crater lakes on Mounts Mageik, Martin, 

Katmai, and Douglas are extremely acidic, with pH 

levels between 1 and 3. Such acidic water, released 

during an eruption or breach, would cause severe 

damage to stream and lake ecosystems.

Windstorms and Resuspension of 1912 Ash

Air quality is affected periodically by resuspension of 

1912 ash during strong northwesterly wind events (e.g. 

Hanlon 2015). The strong wind events usually occur 

in spring and fall during times of low snow. A handful 

of events occur nearly every year and commonly cause 

Figure 99. Satellite (MODIS) image of ash being resuspended from the Valley of Ten Thousand Smokes and 

creating an ash cloud over Shelikof Strait. NASA image (taken 29 November 2010) courtesy of USGS-AVO.
79

flight cancellations. Climate change may increase the 

frequency of these events due to warmer temperatures 

leading to lower snow cover during the spring and 

fall. Cloud heights have been estimated between 

1,000–3,500 m (4,000–11,000 ft) above sea level, and 

distances up to 250 km (150 mi) to Kodiak Island and 

beyond (Figure 99). These resuspension events are not 

caused by an active volcanic eruption but have led to 

many spurious reports of eruptions (Hadley et al. 2004; 

McGimsey et al. 2005; Hanlon 2015)

Air quality during these events is often a concern 

of residents of Kodiak Island, so in 2015 the Alaska 

Volcano Observatory initiated a monitoring campaign 

to test the frequency and severity of airborne ash 

from these events (see https://www.avo.alaska.edu/

news.php?id=991 for information about resuspended 

ash). Particulate monitoring stations were installed 

on Kodiak Island at Kodiak and Larsen Bays during 

summer 2015 (Kristi L. Wallace, USGS-AVO, research 

geologist, telephone communication, 30 October 2015). 

When a strong wind event is forecast, cooperators put 

out measuring buckets to capture airborne particulates. 

A meteorological station was installed and co-located 

with a seismic station in the Valley of Ten Thousand 

Smokes. The project is run in cooperation with the 

Alaska Department of Environmental Conservation, 

Division of Air Quality. Official warnings about these 

ash resuspension events (volcanic ash advisories and 

forecasts of ash fall) are issued by the National Weather 

Service (http://www.weather.gov/afc/, http://aawu.

arh.noaa.gov). Air quality hazards and guidance are 

provided by the Alaska Department of Environmental 

Conservation, Division of Air Quality (http://dec.alaska.

gov/Applications/Air/airtoolsweb/Advisories/Index).

Landslides and Rockfall

Map Units: Qls, Qc (in part)

Landslides (Qls) and rockfall (Qc in part) occur on steep 

slopes, particularly those greater than 40°. Landslide 

events are generally triggered by high-rainfall, seismic, 

or volcanic events. Plate 1 shows where large landslides 

(Qls) have occurred in the past, some of which slid for 

many kilometers down valleys below high mountains 

during the 1912 eruption (Riehle and Detterman 1993; 

Hildreth and Fierstein 2003). Landslides can dam river 

drainages and impound water. Subsequent breaches 

of the dam and floods have occurred, including on 

the Katmai River a few years after the 1912 eruption 

(Griggs 1922). Rockfall occurs below steep slopes and 

their deposits are mapped as part of the colluvium 

map unit (Qc on Plate 1). A summary map of landslide 

and rockfall deposits is presented in Figure 100. No 

comprehensive hazard map for the park unit or areas 

of interest have yet been compiled. In the Geological 

Monitoring chapter about slope movements, Wieczorek 

and Snyder (2009) described five vital signs for 

understanding and monitoring slope movements: 

(1) types of landslide, (2) landslide causes and triggers,

(3) geologic materials in landslides, (4) measurement

of landslide movement, and (5) assessment of landslide

hazards and risks.

Seismic Activity

Earthquakes are common in the Katmai area because 

it lies over the Aleutian megathrust (Figure 4) and 

contains numerous volcanoes. Tectonic earthquakes are 

associated with movements of plates of Earth’s crust. 

Volcanic earthquakes are associated with movement 

of magma beneath the surface or eruptions onto the 

surface. Volcanic earthquakes are generally moderate 

strength whereas subduction megathrusts generate the 

largest earthquakes of any type of plate boundary. The 

1964 Great Alaskan, or Good Friday, earthquake was a 

subduction earthquake and registered a magnitude 

9.2, the most powerful earthquake in recorded North 

American history. According to the USGS 2009 

probabilistic seismic hazard analysis model (Figure 

101), the probability for a moderate earthquake, greater 

than magnitude 5.5, in the next 20 years is between 0.20 

and 0.50 or a 20% to 50% “chance.”

The direct effect of shaking from an earthquake may 

make a person fall down, but it is the indirect effects of 

an earthquake, such as rockfall and landslides, that pose 

the highest risk to park resources and visitors. However, 

the lack of major infrastructure within the area limits 

the risk to human development. The Brooks Camp 

area and the park headquarters at King Salmon have a 

low probability of having a larger earthquake directly 

underneath in the next 20 years (0.10–0.25), but being 

built on unconsolidated lacustrine and glacial deposits 

makes the areas vulnerable to shaking from adjacent 

high probability earthquake areas.

The AVO seismic stations provide seismic monitoring 

capability for the Katmai area. Earthquake hazards 

are actively monitored by the US Geological Survey in 

conjunction with the Alaska Earthquake Information 
80

Center (http://www.aeic.alaska.edu/). Zanon et al. 

(2015) identifies seismic activity as a “key resource” 

and provides a summary of seismic activity, measures, 

and causes in the Katmai area. Additional information 

is available in the Geological Monitoring chapter where 

Braile (2009) described the following methods and vital 

signs for understanding earthquakes and monitoring 

seismic activity: (1) monitoring earthquakes,

(2) analysis and statistics of earthquake activity,

(3) analysis of historical and prehistoric earthquake 

activity, (4) earthquake risk estimation, (5) geodetic 

monitoring and ground deformation, and

(6) geomorphic and geologic indications of active 

tectonics.

Figure 100. Cursory hazard map showing volcanic rocks, volcanic ash, pyroclastic flow deposits, landslide deposits, 

colluvial deposits, and slopes susceptible to rockfall or landslides (compilation of map units from Plate 1). Slopes 

greater than 40o have a high potential for producing rockfall. Slope map was derived from the National Elevation 

Dataset 30 m grid digital elevation model.
81

Tsunami Hazards

No known historic tsunami studies have been 

conducted for the Katmai area, but studies around 

Cook Inlet, on Kodiak Island, on the Alaska Peninsula, 

and islands across Shelikof Strait indicate that the region 

is susceptible to potentially large tsunamis. Tsunamis 

affecting Katmai could be caused by landslides 

associated with tectonic or volcanic earthquakes. 

Movement along the Aleutian megathrust can cause 

the sea floor to rise or fall significantly, so the area has 

a high potential for earthquake generated tsunamis, 

as illustrated by the 1964 Alaska “Good Friday” 

earthquake and tsunamis (more information about 

this earthquake is available at http://earthquake.usgs.

gov/earthquakes/events/alaska1964/), the 2004 Indian 

Ocean earthquake and tsunami, and the 2011 Tōhoku 

earthquake and tsunami in Japan. Large earthquakes 

anywhere along the circum-north Pacific can generate 

tsunamis that may hit the Katmai coast. The Katmai 

coast may be partially protected from distant circumPacific earthquake generated tsunamis by Kodiak 

Island, but the wrap-around effect (increase in height 

behind an island) could be significant. Preliminary 

models indicate that a very large earthquake (magnitude 

9.0) on the Aleutian megathrust near Kodiak Island has 

the potential to produce a run-up height of 20 m (66 

ft) along the coast of Katmai (Dmtry Nicolsky, UAFAlaska Earthquake Center, Tsunami Modeler, written 

communication, 29 October 2015).

Ash flows from volcanoes can also be a major tsunami 

generator. In particular, the northern Katmai coast lies 

only 30 km (20 mi) from Augustine Volcano, which is 

Figure 101. Map showing the probability of earthquake of magnitude 5.5 or greater over the next 20 years in the 

Katmai area. Map generated using the USGS earthquake probability mapping program (http://geohazards.usgs.gov/

eqprob/2009/index.php).
82

the most historically active volcano in Cook Inlet. The 

island contains evidence of numerous ash flows that 

reached the shoreline, as many as 14 in the last 2,000 

years (Waythomas et al. 2006). Evidence of tsunamis 

generated from these mass flows is preserved in oral 

and written history, and by tsunami deposits around 

Cook Inlet (Beget and Kowalik 2006; Beget et al. 2008). 

Models show that a tsunami generated from an ash flow 

on Augustine Volcano will reach the northern shores of 

Katmai within 30–40 minutes, leaving little warning and 

response time for people on the shores of Kamishak Bay 

(Beget and Kowalik 2006; Waythomas et al. 2006).

The NOAA Pacific Tsunami Warning Center (based 

in Palmer, Alaska) monitors global earthquakes and 

tsunami potential for the coast of North America and 

publishes real-time watches, warnings, and advisories 

on its website (http://ptwc.weather.gov/). 

Geothermal Features Inventory and 

Monitoring

Katmai National Park and Preserve is one of 16 units in 

the National Park System, nine of which are in Alaska, 

with significant thermal features as designated by the 

Geothermal Steam Act of 1970 (amended in 1988). As 

documented on 3 August 1987 in the Federal Register (v. 

52, no. 148, p. 28790–28800), Novarupta and vicinity is 

a significant thermal feature within the park. The actual 

extent of the feature covers more than 1,500 km2 (600 

mi2) and includes the following volcanoes: Novarupta, 

Mount Martin, Mount Mageik, Trident, Griggs, Kukak, 

and Katmai. Smaller scale geothermal features within 

and near these volcanoes, and elsewhere in the park, 

include fumaroles, warm springs, warm ground, and 

crater lakes. Geothermal features are described in 

the “Geothermal Features” section and mapped on 

Plate 4. Geothermal features are subject to monitoring 

as required by the Geothermal Steam Act. The act 

prohibits geothermal leasing in parks, and authorizes 

the Secretary of the Interior to mitigate or not issue 

geothermal leases outside parks that would have a 

significant adverse impact on notable thermal features 

within the park. The act also requires inventorying and 

monitoring significant geothermal features of the park. 

In the Geological Monitoring chapter about geothermal 

systems and hydrothermal features, Heasler et al. (2009) 

described the following methods and vital signs for 

understanding geothermal systems and monitoring 

hydrothermal features: (1) thermal feature location,

(2) thermal feature extent, (3) temperature and 

heat flow, (4) thermal water discharge, and (5) fluid 

chemistry.

Coastal Issues

Map units: Qmt, Qb, Qa (in part), Qaf (in part),

Qd (in part)

The rugged Katmai coast, encompassing 737 km (458 

mi) of shoreline, is constantly changing (see “Coastal 

Features” section). Dynamic geological processes have 

shaped and continue to shape the coast. Raised marine 

terraces (Qmt) and stranded sea caves provide evidence 

of uplift in the last few thousand years (Riehle and 

Detterman 1993; Harper and Morris 2005). The 1964 

earthquake caused the area to subside 20 cm (0.5 ft) 

(Plafker 1969). Sediment input after the 1912 eruption 

increased in many of the rivers flowing to the coast 

(Griggs 1922). This increase of sediment dramatically 

reshaped the coastline by forming large alluvial fans 

(Qaf) and filling in previously large bays (e.g., Katmai 

Bay). Large glaciers near the coast produce sediment 

laden rivers that form alluvial fans (Qaf) and wide 

beaches (Qb). Wind transportation and deposition 

of the glacial silt forms extensive dune fields (Qd). 

Extensive beach ridge complexes are present in most 

protected bays with large river systems. The Katmai 

coast is a geomorphically dynamic place, but little work 

has been done to understand the processes that shape 

the coast.

Relative and eustatic sea level along the Katmai coast is 

changing in response to a number of factors, including 

isostatic rebound (land level rise) and climate change. 

Climate change may lead to sea level rise, increased 

storm strength, and ocean acidification, which could 

alter the current coastal geomorphic processes and 

coastal ecosystem (Winfree et al. 2014). Raised marine 

terraces indicate that the relative sea level has decreased 

over the last several thousand years due to isostatic 

rebound and plate tectonic movement. Sea level 

fluctuated as the Pleistocene glaciers melted, which 

increased global water levels (Crowell and Mann 1996). 

This interplay between land levels and water levels 

explains why tide gauge records from the nearest tide 

station in Seldovia, Alaska, show relative sea level has 

decreased by around 0.04 mm/yr since 1964 (NOAA: 

http://tidesandcurrents.noaa.gov/sltrends/sltrends.

html). For the Katmai area, the Intergovernmental Panel 

on Climate Change (IPCC) models predict that absolute 

sea level in the region will increase about 37 cm (1.2 ft) 
83

by the end of the century (Intergovernmental Panel on 

Climate Change 2013), which is a rate of about 4 mm/

yr (0.16 in/yr). However, given the faster rate of land 

level uplift along the Katmai coast (8 mm/yr; 0.3 in/yr; 

Freymueller et al. 2008), the rate of absolute sea level 

will not keep pace with the rate of land level changes, 

and relative sea level is likely to decrease over the 

next few decades. Uplift has preserved archeological 

sites from inundation and erosion along the coastline 

(Crowell and Mann 1996). However, increased erosion 

from increasing storm frequency should also be 

expected in the future. Storms are predicted to become 

stronger as waters become warmer. Warmer waters 

will likely alter storm tracks and provide more water 

vapor to fuel and intensify the storms. Conditions are 

becoming more conducive for storms to travel farther 

north in the Northern Hemisphere.

A simple classification of shore zone morphology was 

published by Harper and Morris (2005); the study 

provided a line dataset depicting coasts that are made of 

rock, sediment, wetland, or channel. This classification 

does not fully describe the complex, and in some 

places, very wide shore zone of the Katmai coast. A 

more detailed shore zone geomorphic map could 

help with modeling potential effects of climate change 

or sudden tectonic subsidence on the Katmai coast. 

Such a map could be used for understanding dynamic 

coastal geomorphic systems, and integrating these 

systems with shore zone biological and archeological 

inventories. Understanding the physical morphology 

of the coast was listed as highly desirable objectives for 

the inventory and monitoring plan for all parks in the 

Southwest Alaska Network (Bennett et al. 2006). 

The NPS Coastal Adaptation Handbook (RM 39-3; 

in review, expected 2016) will provide climate change 

adaptation guidance to coastal park managers in the 

118 parks, including Katmai, that have been identified 

by their regional offices as potentially vulnerable to sea 

level change. Focus topics will include NPS policies 

relevant to climate change, guidance on evaluating 

appropriate adaptation actions, and adaptation 

opportunities for planning, incident response, cultural 

resources, natural resources, and infrastructure. The 

handbook will also provide guidance on developing 

communication and education materials about climate 

change impacts. Case studies of the many ways that 

park managers are implementing adaptation strategies 

for threatened resources, including Alaska parks, are 

available in Schupp et al. (2015). Additional reference 

manuals that guide coastal resource management 

include NPS Reference Manual #39-1: Ocean and 

Coastal Park Jurisdiction, which can provide insight 

for managers in parks with boundaries that may shift 

with changing shorelines (available at http://www. 

nps.gov/applications/npspolicy/DOrders.cfm); and 

NPS Reference Manual #39-2: Beach Nourishment 

Guidance (Dallas et al. 2012) for planning and managing 

nourishment projects. The National Park Service is 

also developing a climate change response strategy that 

connects climate science with historic preservation 

planning. The summary report from the Preserving 

Coastal Heritage workshop in 2014 identified and 

described six climate change adaptation options for 

cultural resources and cultural landscapes: (1) no active 

intervention, (2) offset stressors, (3) improve resilience, 

(4) manage change, (5) relocate or facilitate movement, 

and (6) document and release. Additional information 

about the workshop, and associated presentations 

and reports, are available at https://sites.google.com/

site/democlimcult/. In the Geological Monitoring

chapter on coastal resources, Bush and Young (2009) 

listed the following vital signs for inventorying and 

monitoring coasts: (1) shoreline change, (2) coastal 

dune geomorphology, (3) coastal vegetation cover, 

(4) topography/elevation, (5) composition of beach 

material, (6) wetland position/acreage, and (7) coastal 

wetland accretion. The NPS Water Resources Division, 

Ocean and Coastal Resources Branch website (http://

www.nature.nps.gov/water/oceancoastal/) has 

additional information about servicewide programs and 

the resources and management programs at the coastal 

parks. 

Fluvial Erosion

Fluvial erosion along steep river banks is a threat to 

archeological sites, especially along the Brooks and 

Alagnak Rivers. Extreme erosion along the Brooks River 

has exposed artifacts at the aptly named “Cutbank” 

site. This site was recognized in the 1950s as potentially 

threatened by river erosion. In 2002, NPS personnel 

found that the river had removed approximately 6 m 

(20 ft) of a terrace. Bundy et al. (2005) conducted an 

emergency site investigation and concluded that erosion 

at the site is a chronic problem and developed an annual 

monitoring plan.

The Alagnak Wild River corridor protects the river’s 

scenic landscape, natural characteristics, cultural 
84

heritage, and recreational and subsistence activities. 

Cultural sites along the river are generally within 50 

m (160 ft) of the river banks, so river bank erosion 

threatens the cultural resources (Curran 2003). The 

river is both meandering and braided and changes 

course over time. By comparing air photos and satellite 

imagery over the last 50 years, Curran (2003) found that 

the river’s upper and lower reaches have been relatively 

stable, with only minor meander migrations; whereas, 

the middle, braided portion has had substantial 

changes. That investigation monitored bank erosion 

at numerous sites over two years and found that 

motorized boat traffic increased bank erosion rates, but 

that the traffic did not appear to have altered the natural 

mechanisms of channel change. 

In the Geological Monitoring chapter about fluvial 

geomorphology, Lord et al. (2009) described methods 

for inventorying and monitoring geomorphologyrelated vital signs, including: (1) watershed landscape 

(vegetation, land use, surficial geology, slopes, and 

hydrology), (2) hydrology (frequency, magnitude, and 

duration of stream flow rates), (3) sediment transport 

(rates, modes, sources, and types of sediment),

(4) channel cross section, (5) channel planform, and

(6) channel longitudinal profile.

Glacier Changes

The area covered by glaciers has decreased from 1,060 

km2 to 915 km2 (410 mi2 to 350 mi2) since 1950. This 

equates to a loss of 14% (Loso et al. 2014). Most glaciers 

in the Katmai area are receding, like most glaciers in 

Alaska, but glaciers that were covered by thick deposits 

of 1912 ash are not receding and some have advanced 

(Figure 73). Terminus retreat was the response seen in 

most individual glaciers, including notable retreats by 

glaciers on Fourpeaked Mountain and Mount Douglas 

in the northeast section of the park, and Hallo Glacier 

and others on the Kukak Volcano edifice. 

Alaska-wide, Loso et al. (2014) noted that the trend 

of warmer summers and wetter winters will continue 

for at least the next 50 years, and warming will 

accelerate. Recent glacier trends of negative mass 

balance, diminished ice cover, and reduced ice volume 

are predicted to intensify as climate changes (Loso et 

al. 2014). Glacial extent is considered a key natural 

resource condition for the Katmai area and information 

on glaciers, measures, stressors, and reference condition 

is summarized by Zanon et al. (2015). Four parameters 

were identified by Karpilo (2009) to monitor glacial 

changes: (1) mass balance, (2) terminus, (3) area, and 

(4) surface velocity. Understanding the changes due to 

retreat of Pleistocene and modern glaciers was listed as 

an essential objective of the Southwest Alaska Network 

inventory and monitoring plan (Bennett et al. 2006).

Paleontological Resource Inventory, 

Monitoring, and Protection

Map units: Tc, Th, Khe, Kk, Jni, Jns

The Katmai area contains approximately 550 fossil 

localities. The Alaska Regional Office maintains a 

database of all known fossil localities for Katmai 

National Park and Preserve. No known fossil localities 

or resources occur in Alagnak Wild River. Blodgett 

et al. (2016) provided a review of paleontological 

resources from Katmai National Park and Preserve. 

Their inventory was based primarily on literature 

review, review of unpublished internal USGS E&R 

“Evaluate and Report” documents, and brief site visits. 

The Mesozoic sedimentary units contain abundant 

invertebrate and a few vertebrate marine fossils, and 

the Tertiary units contain well-preserved plant fossils, 

including petrified wood (see “Mesozoic Bedrock” and 

“Tertiary Sedimentary Rocks” sections). The units with 

the most abundant fossils are the Ketavik Formation 

(not mapped), Copper Lake Formation (Tc), Hemlock 

Conglomerate (Th), Herendeen Formation (Khe), 

Kaguyak Formation (Kk), and the Naknek Formation, 

namely the Indecision Creek (Jni) and Snug Harbor 

Siltstone (Jns) Members. 

Most places in the park are relatively inaccessible, but 

plant fossils are easily accessed from Brooks Camp, 

and invertebrate fossils are present near the popular 

bear viewing area at Hallo Bay. Furthermore, unusual 

fossils like the large ammonites (Figure 88) found in the 

Kaguyak Formation (Kk) may attract non-permitted 

collecting and are a priority for protection.

Although a park-specific survey has not yet been 

completed for the park and preserve, a cursory 

paleontological summary was completed for the 

Southwest Alaska Network by Kenworthy and Santucci 

(2003), and a more in-depth review was provided by 

Blodgett et al. (2016). A detailed inventory and fieldbased paleontological resource survey of interesting 

or sensitive fossil sites can provide detailed, sitespecific descriptions and resource management 

recommendations. Katmai National Park and 
85

Preserve has diverse and abundant fossil resources 

and would benefit from a baseline field inventory 

of paleontological resources in order to develop 

monitoring and interpretive programs. 

Fossils in NPS areas occur in rocks or unconsolidated 

deposits, museum collections, and cultural contexts 

such as archeological sites. All paleontological resources 

are nonrenewable and subject to science-informed 

inventory, monitoring, protection, and interpretation 

as outlined by the 2009 Paleontological Resources 

Preservation Act (see Appendix C). All fossils are 

protected from collection by the 2009 Paleontological 

Resources Preservation Act. Fossils collected under 

research permits are accessioned by the NPS curatorial 

staff and held in NPS curation centers or at research 

institutions for ongoing research projects. As of August 

2016, Department of the Interior regulations associated 

with the act were being developed. In the Geological 

Monitoring chapter about paleontological resources, 

Santucci et al. (2009) described the following methods 

and vital signs for monitoring in situ paleontological 

resources: (1) erosion (geologic factors), (2) erosion 

(climatic factors), (3) catastrophic geohazards,

(4) hydrology/bathymetry, and (4) human access/

public use. All of these are potential vital signs at 

Katmai. Fossils along NPS coastlines present additional 

management challenges and considerations as 

outlined by Brunner et al. (2009). The NPS Fossils and 

Paleontology website, http://go.nps.gov/fossils_and_

paleo, provides more information.

Abandoned Mineral Lands (AML)

The USGS Alaska Resource Data File (ARDF; http://

ardf.wr.usgs.gov/) lists 18 metaliferous mineral 

occurrences or deposits in Katmai National Park and 

Preserve. None are listed for Alagnak Wild River. Smallscale mining and prospecting historically occurred in 

the Katmai area at 11 sites between the early 1900s and 

the 1980s. Mineral occurrences and prospected mineral 

resources included pumicite from the Novarupta 

eruption (Moxham 1952), placer gold, coal, and copper. 

Most of the sites have not been relocated in the field 

by NPS staff, but are unlikely to pose any resource 

or safety-related issues based on knowledge of the 

historic operations. No known safety issues exist at 

any AML sites within Katmai. One mine site, Pfaff 

copper prospect, is considered “medium” priority for 

mitigation (Burghardt et al. 2014). Diesel-contaminated 

soil at the Pfaff copper prospect is the only documented 

resource issue that has been associated with AML in 

Katmai. After several years of soil treatment, the Alaska 

Department of Environmental Conservation declared 

the site to be adequately cleaned up in 2011. The 

abandoned mine structures are unsightly but pose no 

known safety or environmental threat.

Potential Petroleum Development

The Katmai area is surrounded by oil and gas reservoirs. 

The Cook Inlet area contains reserves that supply 

natural gas to much of south-central Alaska and crude 

oil to a refinery on the Kenai Peninsula. The Iniskin 

Peninsula area of the Alaska Peninsula, 60 km (40 mi) 

north of Katmai, has been explored for oil since the 

1800s. Offshore exploration wells have been drilled 

less than 25 km from the northeastern coast (Figure 

102). State tax credits for Cook Inlet exploration over 

the last few years has increased exploration, although 

most of it has been in the northern portions of the inlet. 

The Bureau of Ocean Energy Management (BOEM) 

is preparing an environmental impact statement for a 

potential lower Cook Inlet lease sale (Bureau of Ocean 

Energy Management 2014). The notice of intent states 

that the proposed area “reduces potential effects to 

parks, preserves, and wildlife refuges by placing a 

buffer between the area considered for leasing and 

the Katmai National Park and Preserve, the Kodiak 

National Wildlife Refuge, and the Alaska Maritime 

National Wildlife Refuge” (Bureau of Ocean Energy 

Management 2014, p. 63437). 

Oil spills from exploration or production activity 

in Cook Inlet have the potential to severely harm 

the coastal ecosystems of Katmai. The Katmai coast 

supports a complex ecosystem that was impacted 

by the Exxon Valdez oil spill in 1989. Crude oil was 

stranded along the entire length of the coastline. Future 

petroleum exploration and development is possible, if 

economic conditions warrant, on state oil lease tracts 

west of Katmai National Park and Preserve (Figure 

102). Native corporation and state lands within the 

authorized boundary can be developed; however, NPS 

regulations limit the impact that development would 

have on the park resources. Potential impacts include 

groundwater and surface water contamination, erosion 

and siltation, introduction of exotic plant species, 

reduction of wildlife habitat, impairment of view sheds 

and night skies, excessive noise, and diminished air 

quality. Visitor safety and overall degradation of the 

visitor experience are particular concerns. The NPS 
86

Geologic Resources Division Energy and Minerals 

website, http://go.nps.gov/grd_energyminerals, provides 

additional information about external exploration and 

development.

Soils and Permafrost

Map unit: Qsf

The soils changed dramatically after the 1912 eruption 

(see the “Landscape Changes Caused By the 1912 

Eruption” section). The eruption deposited a layer 

of ash over the entire Katmai area, and areas near the 

eruption were buried so deeply that it formed a sterile 

landscape. A primary purpose of preserving the Katmai 

area was to study the regeneration of vegetation after 

the 1912 eruption, but such an investigation is limited 

without a soils map, which has not yet been completed. 

A park specific soils map is planned to be completed by 

the Inventory and Monitoring Program in 2018. 

Soil temperature and permafrost were listed as 

important physical elements of the Southwest Alaska 

Network Vital Signs Monitoring Plan (Bennett et al. 

2006). Climate scenarios indicate a rise in average 

annual temperature of 2.6°C (4.7°F) by 2040 in the 

Katmai area, and permafrost melting was identified as 

a potential major change to the park in the Southwest 

Parks Climate Change Scenarios Report (Winfree et al. 

2014) and the Natural Resource Condition Assessment 

(Zanon et al. 2015). Other than the general permafrost 

map of the King Salmon area by Abrahamson (1950) 

and the Jorgenson et al. (2008) permafrost map of 

Alaska (Figure 77), no detailed permafrost map has 

been produced for the Katmai area. Furthermore, no 

permafrost or soil temperature monitoring plan has 

been established. In the Geological Monitoring chapter 

about permafrost conditions and processes, Osterkamp 

and Jorgenson (2009) described two vital signs for 

monitoring permafrost conditions and processes: 

thermal state and physical conditions. Park managers 

may find this information useful in developing a 

monitoring plan for the Katmai area.

Figure 102. Map showing location of oil and gas wells near the Katmai area shown as black points (Wilson et al. 2012), 

proposed BOEM Cook Inlet Lease Sale 244 boundary shown in red (Orr and Brown 2013; Bureau of Ocean Energy 

Management 2014), and Alaska State oil lease tracts on the west side of Katmai shown as gray squares. Relief derived 

from National Elevation Dataset.
87

Geologic Map Data

This section summarizes the geologic map data available for Katmai National Park and Preserve and 

Alagnak Wild River. A poster (Plate 1, in pocket) displays the map data draped over a hillshade of the 

National Elevation Dataset of the park and surrounding area. Complete GIS data are available at the 

GRI publications website: http://go.nps.gov/gripubs.

Geologic Maps

Geologic maps facilitate an understanding of an area’s 

geologic framework and the evolution of its present 

landscape. Using designated colors and symbols, these 

maps portray the spatial distribution and temporal 

relationships of rocks and unconsolidated deposits. The 

American Geosciences Institute website, http://www.

americangeosciences.org/environment/publications/

mapping, provides more information about geologic 

maps and their uses.

Source Maps

The source of digital geologic map data for National 

Park System units in Alaska is the Alaska digital geologic 

map database, which is compiled and maintained under 

the direction of Fredric H. Wilson of the USGS Alaska 

Science Center. Wilson has been compiling geologic 

data for the state of Alaska for more than two decades 

and has produced numerous regional geologic maps as 

part of this project with support from the NPS Geologic 

Resources Inventory (see http://mrdata.usgs.gov/

geology/state/state.php?state=AK).

The source of the digital geologic map data for Katmai 

National Park and Preserve and Alagnak Wild River 

is an updated version of the statewide database. The 

most recent digital data sets for the Katmai area were 

published as regional geologic maps of the area:

Wilson, F. H., R. B. Blodgett, C. D. Blomé, S. Mohadjer, C. 

C. Preller, E. P. Klimasauskas, B. M. Gamble, and W. L. 

Coonrad. 2006. Preliminary reconnaissance bedrock 

geologic map for the northern Alaska Peninsula area, 

southwest Alaska. Open-File Report 2006-1303 (1:250,000). 

US Geological Survey, Reston, Virginia.

http://pubs.usgs.gov/of/2006/1303/.

Wilson, F. H., R. L. Detterman, and G. D. Dubois. 1999. 

Preliminary geologic framework of the Alaska Peninsula, 

southwest Alaska, and the Alaska Peninsula terrane. OpenFile Report 99-317 (1:500,000). US Geological Survey, 

Reston, Virginia.

http://geopubs.wr.usgs.gov/open-file/of99-317/.

Wilson, F. H., C. P. Hults, H. R. Schmoll, P. J. Haeussler, J. M. 

Schmidt, L. A. Yehle, and K. A. Labay. 2009. Preliminary 

geologic map of the Cook Inlet region, Alaska; including 

parts of the Talkeetna, Talkeetna Mountains, Tyonek, 

Anchorage, Lake Clark, Kenai, Seward, Iliamna, Seldovia, 

Mount Katmai, and Afognak 1:250,000-scale quadrangles. 

Open-File Report 1108 (1:250,000). US Geological Survey, 

Reston, Virginia. http://pubs.usgs.gov/of/2009/1108/.

For the Katmai area, the Wilson et al. (1999) 

compilation was based on the following geologic maps:

Detterman, R. L., J. E. Case, F. H. Wilson, and M. E. Yount. 

1987a. Geologic map of the Ugashik, Bristol Bay, and 

western part of Karluk quadrangles, Alaska. Miscellaneous 

Investigations Series Map 1685 (1:250,000). US Geological 

Survey, Reston, Virginia.

Detterman, R. L., and B. L. Reed. 1973. Surficial deposits of 

the Iliamna quadrangle, Alaska. Bulletin 1368-A (1:250,000). 

US Geological Survey, Reston, Virginia.

Detterman, R. L., and B. L. Reed. 1980. Stratigraphy, structure, 

and economic geology of the Iliamna quadrangle, Alaska. 

Bulletin 1368-B (1:250,000). US Geological Survey, Reston, 

Virginia.

Detterman, R. L., F. H. Wilson, M. E. Yount, and T. P. Miller. 

1987b. Quaternary geologic map of the Ugashik, Bristol 

Bay, and western part of Karluk quadrangles, Alaska. 

Miscellaneous Investigations Series Map 1801 (1:250,000). 

US Geological Survey, Reston, Virginia.

Riehle, J. R., and R. L. Detterman. 1993. Quaternary geologic 

map of the Mount Katmai quadrangle and adjacent 

parts of the Naknek and Afognak quadrangles, Alaska. 

Miscellaneous Investigations Series Map 2032 (1:250,000). 

US Geological Survey, Reston, Virginia.

Riehle, J. R., R. L. Detterman, M. E. Yount, and J. W. Miller. 

1993. Geologic map of the Mount Katmai quadrangle and 

adjacent parts of the Naknek and Afognak quadrangles, 

Alaska. Miscellaneous Investigations Series Map I-2204 

(1:250,000). US Geological Survey, Reston, Virginia.

Wilson, F. H., R. B. Blodgett, C. D. Blomé, S. Mohadjer, C. 

C. Preller, E. P. Klimasauskas, B. M. Gamble, and W. L. 

Coonrad. 2006. Preliminary reconnaissance bedrock 

geologic map for the northern Alaska Peninsula area, 

southwest Alaska. Open-File Report 2006-1303 (1:250,000). 

US Geological Survey, Reston, Virginia.

http://pubs.usgs.gov/of/2006/1303/.
88

Wilson, F. H., R. L. Detterman, and G. D. Dubois. 1999. 

Preliminary geologic framework of the Alaska Peninsula, 

southwest Alaska, and the Alaska Peninsula terrane. OpenFile Report 99-317 (1:500,000). US Geological Survey, 

Reston, Virginia.

http://geopubs.wr.usgs.gov/open-file/of99-317/.

Wilson, F. H., C. P. Hults, H. R. Schmoll, P. J. Haeussler, J. M. 

Schmidt, L. A. Yehle, and K. A. Labay. 2009. Preliminary 

geologic map of the Cook Inlet region, Alaska; including 

parts of the Talkeetna, Talkeetna Mountains, Tyonek, 

Anchorage, Lake Clark, Kenai, Seward, Iliamna, Seldovia, 

Mount Katmai, and Afognak 1:250,000-scale quadrangles. 

Open-File Report 1108 (1:250,000). US Geological Survey, 

Reston, Virginia. http://pubs.usgs.gov/of/2009/1108/.

Surficial Geologic Mapping of Alagnak Wild River 

in Dillingham Quadrangle

At the start of this project, the area around the Alagnak 

River was mapped as unconsolidated deposits, 

undifferentiated. The surficial geology was clear in the 

detailed imagery available through Google Earth, so 

Chad Hults, lead author, digitized the geology in Google 

Earth. This dataset was merged into the GRI GIS dataset 

as the “Geologic Units (Dillingham Quadrangle)” and 

“Geologic Contacts (Dillingham Quadrangle)” layers. 

These data are visible on Plate 1.

Geologic Map of the Katmai Volcanic Cluster

The following map is a more detailed map of the Katmai 

volcanic cluster. It is not part of the GRI GIS data but is 

available to NPS employees via the GIS Theme Manager 

(downloadable at https://irma.nps.gov/DataStore/

Reference/Profile/2188597).

Hildreth, W., and J. Fierstein. 2003. Geologic map of the 

Katmai volcanic cluster, Katmai National Park, Alaska. 

Geologic Investigations Series I-2778 (1:63,360 scale). US 

Geological Survey, Reston, Virginia.

http://pubs.usgs.gov/imap/i2778/.

GRI GIS Data

The GRI team implements a GIS data model that 

standardizes map deliverables. The data model is 

available at http://go.nps.gov/gridatamodel. This data 

model dictates GIS data structure, including layer 

architecture, feature attribution, and relationships 

within ESRI ArcGIS software. The GRI team digitized 

the data for the park using data model version 2.2. 

The GRI Geologic Maps website, http://go.nps.gov/

geomaps, provides more information about GRI map 

products. 

GRI GIS data are publically available through the NPS 

Integrated Resource Management Applications (IRMA) 

portal (https://irma.nps.gov/App/Portal/Home). Enter 

“GRI” as the search text and select a park from the unit 

list.

The following components are part of the GRI GIS 

data:

● A GIS readme file (katm_gis_readme.pdf) 

that describes the GRI data formats, naming 

conventions, extraction instructions, use 

constraints, and contact information.

● Data in ESRI geodatabase GIS format.

● Layer files with feature symbology (Table 5).

● Federal Geographic Data Committee (FGDC)–

compliant metadata.

● An ancillary map information document (katm_

geology.pdf) that contains information captured 

from source maps such as map unit descriptions, 

geologic unit correlation tables, legends, cross 

sections, and figures.

● An ESRI map document (katm_geology.mxd) that 

displays the GRI GIS data; and

● A version of the map data viewable in Google Earth 

(katm_geology.kmz).

Use Constraints

Graphic and written information provided in this 

report is not a substitute for site-specific investigations. 

Ground-disturbing activities should neither be 

permitted nor denied based upon the information 

provided here. Please contact GRI with any questions.

Minor inaccuracies may exist regarding the locations 

of geologic features relative to other geologic or 

geographic features on Plate 1.
89

Table 5. GRI GIS data layers for the Katmai area.

Data Layer On Poster? Google Earth 

Layer?

Age-Date Sample 

Localities No No

Volcanic Point Features Yes No

Caldera Boundary Line 

Features Yes Yes

Glacial Feature Lines 

(moraine, ice limit, and 

kame-terrace scarp)

Yes No

Geologic Line Features 

(lineaments and 

escarpments)

Yes No

Folds Yes Yes

Faults Yes Yes

Linear Dikes Yes Yes

Alteration and 

Metamorphic Area 

Boundaries

Yes No

Alteration and 

Metamorphic Areas

(areas of contact 

metamorphism or 

hydrothermal alteration)

Yes Yes

Geologic Contacts 

(Dillingham Quadrangle) Yes Yes

Geologic Units 

(Dillingham Quadrangle) Yes Yes

Geologic Contacts Yes Yes

Geologic Units Yes Yes

91

Literature Cited

These references are cited in this report. Contact the Geologic Resources Division for assistance in 

obtaining them.

Abe, K. 1992. Seismicity of the caldera-making eruption of Mount Katmai, Alaska. Bulletin of the Seismological Society of America 

82:175–191.

Abrahamson, S. R. 1950. Geography of the Naknek Region, Alaska. Dissertation. Clark University, Worcester, Massachusetts.

Adams, N. K., B. F. Houghton, S. A. Fagents, and W. Hildreth. 2006. The transition from explosive to effusive eruptive regime: The 

example of the 1912 Novarupta eruption, Alaska. Geological Society of America Bulletin 118:620–634.

Albanese, M. D., and K. M. Goff. 1987. Petrified wood occurrences in Alaska. Public Data File 87-26. Alaska Division of Geological 

& Geophysical Surveys, Fairbanks, Alaska.

Antón, M., J. M. Vaquero, and A. J. P. Aparicio. 2014. The controversial early brightening in the first half of 20th century: A 

contribution from pyrheliometer measurements in Madrid (Spain). Global and Planetary Change 115:71–75.

http://www.sciencedirect.com/science/article/pii/S0921818114000368.

Arendt, A., and J. Rich. 2013. Randolf glacier inventory. Geospatial Dataset-2221653. University of Alaska Fairbanks, Fairbanks, 

Alaska. https://irma.nps.gov/App/Reference/Profile/2221653.

Atwood, W. W. 1911. Geology and mineral resources of parts of the Alaska Peninsula. Bulletin 467. US Geological Survey, Reston, 

Virginia.

Beget, J. E., C. Gardner, and K. Davis. 2008. Volcanic tsunamis and prehistoric cultural transitions in Cook Inlet, Alaska. Journal of 

Volcanology and Geothermal Research 176:377–386.

Beget, J. E., and Z. Kowalik. 2006. Confirmation and calibration of computer modeling of tsunamis produced by Augustine Volcano, 

Alaska. Science of Tsunami Hazards 24(4):257–267. http://www.sthjournal.org/244/beget.pdf.

Bennett, A. J., W. L. Thompson, and D. C. Mortenson. 2006. Vital signs monitoring plan: Southwest Alaska Network. National Park 

Service, Anchorage, Alaska.

Blodgett, R. B., V. L. Santucci, and J. S. Tweet. 2016. An inventory of paleontological resources from Katmai National Park and 

Preserve, southwest Alaska. Pages 41–50 in R. M. Sullivan and S. G. Lucas, editors. Fossil record 5. New Mexico Museum of 

Natural History and Science, Albuquerque, New Mexico. Bulletin 74. 

Braile, L. W. 2009. Seismic monitoring. Pages 229–244 in R. Young and L. Norby, editors. Geological monitoring. Geological Society 

of America, Boulder, Colorado. http://go.nps.gov/geomonitoring.

Brubaker, L. B., P. M. Anderson, and F. S. Hu. 2001. Vegetation ecotone dynamics in southwest Alaska during the late Quaternary. 

Quaternary Science Reviews 20(1–3):175–188. http://www.sciencedirect.com/science/article/pii/S0277379100001244.

Brunner, J., J. Kenworthy, and V. L. Santucci. 2009. Unauthorized fossil collecting from National Park Service shorelines: 

Servicewide policy and perspectives. Pages 319–323 in S. Weber, editor. Rethinking protected areas in a changing world: 

Proceedings of the 2009 George Wright Society biennial conference on parks, protected areas, and cultural sites. George Wright 

Society, Hancock, Michigan. http://www.georgewright.org/0956brunner.pdf.

Bundy, B. E., D. M. Vinson, and D. E. Dumond. 2005. Brooks River cutbank: An archeological data recovery project in Katmai 

National Park. Anthropological Papers 64. University of Oregon Department of Anthropology and the Museum of Natural and 

Cultural History, Eugene, Oregon.

Bureau of Ocean Energy Management. 2014. Outer continental shelf, Alaska region, Cook Inlet program area, proposed oil and gas 

lease sale 244. Federal Register 79:63437–63438. https://federalregister.gov/a/2014-25255.

Burghardt, J. E., E. S. Norby, and H. S. Pranger II. 2014. Abandoned mineral lands in the National Park System—comprehensive 

inventory and assessment. National Park Service, Fort Collins, Colorado. https://irma.nps.gov/App/Reference/Profile/2215804.

Burk, C. A. 1965. Geology of the Alaska Peninsula Island Arc and Continental Margin (part 1). Geological Society of America 

Memoir 99 (1:250,000, 1:500,000).
92

Bush, D. M., and R. Young. 2009. Coastal features and processes. Pages 47–68 in E. S. Norby and R. Young, editors. Geological 

monitoring. Geological Society of America, Boulder, Colorado. http://go.nps.gov/geomonitoring.

Cahalane, V. H. 1959. A biological survey of Katmai National Monument. Smithsonian Miscellaneous Collections 138(5).

Cameron, C. E., and C. J. Nye. 2014. Preliminary database of Quaternary vents in Alaska. Miscellaneous Publication 153 (digital 

dataset). Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska. http://www.dggs.alaska.gov/pubs/id/27357.

Cas, R. A. F., and J. V. Wright. 1988. Volcanic successions: Modern and ancient. Unwin Hyman, London.

Clynne, M. A., and L. J. P. Muffler. 2010. Geologic map of Lassen Volcanic National Park and vicinity, California. Scientific 

Investigations Map 2899 (1:50,000). US Geological Survey, Reston, Virginia. http://pubs.usgs.gov/sim/2899/.

Coombs, M. L., J. C. Eichelberger, and M. J. Rutherford. 2000. Magma storage and mixing conditions for the 1953–1974 eruptions of 

Southwest Trident volcano, Katmai National Park, Alaska. Contributions to Mineralogy and Petrology 140(1):99–118.

http://link.springer.com/article/10.1007/s004100000166.

Cowan, D. S., M. T. Brandon, and J. I. Garver. 1997. Geological tests of hypotheses for large coastwise displacements: A critique 

illustrated by the Baja British Columbia controversy. American Journal of Science 297(2):117–173.

Crowell, A. L., and D. H. Mann. 1996. Sea level dynamics, glaciers, and archaeology along the central Gulf of Alaska coast. Arctic 

Anthropology 33(2).

Curdts, T. 2011. Shoreline Length and Water Area in the Ocean, Coastal and Great Lakes Parks: Updated Statistics for Shoreline 

Miles and Water Acres. National Park Service Natural Resource Report NPS/WASO/NRR—2011/282, rev1a.

https://irma.nps.gov/DataStore/Reference/Profile/2180595.

Curran, J. H. 2003. Channel stability and water quality of the Alagnak River, southwestern Alaska. Water-Resources Investigations 

Report 2002-4184. US Geological Survey, Reston, Virginia. http://pubs.usgs.gov/wri/wri024184/.

Curtis, G. H. 1968. The stratigraphy of the ejecta from the 1912 eruption of Mount Katmai and Novarupta, Alaska. Pages 153–210 in

R. R. Coats, R. L. Hay, and C. A. Anderson, editors. Studies in Volcanology. Geological Society of America Memoir 116.

Dallas, K., J. Eshleman, and R. Beavers. 2012. National Park Service beach nourishment guidance. Natural Resource Technical 

Report NPS/NRSS/GRD/NRTR—2012/581. National Park Service, Fort Collins, Colorado.

https://irma.nps.gov/DataStore/Reference/Profile/2185115.

Detterman, R. L. 1986. Glaciation of the Alaska Peninsula. Pages 151–170 in T. D. Hamilton, K. M. Reed, and R. M. Thorson, 

editors. Glaciation in Alaska: The geologic record. Alaska Geological Society, Anchorage, Alaska.

Detterman, R. L., J. E. Case, J. W. Miller, F. H. Wilson, and M. E. Yount. 1996. Stratigraphic framework of the Alaska Peninsula. 

Bulletin 1969-A. US Geological Survey, Reston, Virginia.

Detterman, R. L., J. E. Case, F. H. Wilson, and M. E. Yount. 1987a. Geologic map of the Ugashik, Bristol Bay, and western part of 

Karluk quadrangles, Alaska. Miscellaneous Investigations Series Map 1685 (1:250,000). US Geological Survey, Reston, Virginia.

Detterman, R. L., and J. K. Hartsock. 1966. Geology of the Iniskin-Tuxedni region, Alaska. Professional Paper 512 (1:63,360). US 

Geological Survey, Reston, Virginia.

Detterman, R. L., J. W. Miller, and J. E. Case. 1985. Megafossil locality map, checklists, and pre-Quaternary stratigraphic sections of 

Ugashik, Bristol Bay, and part of Karluk quadrangles, Alaska. Miscellaneous Field Studies Map 1539-B (1:250,000). US Geological 

Survey, Reston, Virginia.

Detterman, R. L., and B. L. Reed. 1973. Surficial deposits of the Iliamna Quadrangle, Alaska. Bulletin 1368-A:A1–A64 (1:250,000). 

US Geological Survey, Reston, Virginia.

Detterman, R. L., and B. L. Reed. 1980. Stratigraphy, structure, and economic geology of the Iliamna quadrangle, Alaska. Bulletin 

1368-B (1:250,000). US Geological Survey, Reston, Virginia.

Detterman, R. L., F. H. Wilson, M. E. Yount, and T. P. Miller. 1987b. Quaternary geologic map of the Ugashik, Bristol Bay, and 

western part of Karluk quadrangles, Alaska. Miscellaneous Investigations Series Map 1801 (1:250,000). US Geological Survey, 

Reston, Virginia.
93

Detterman, R. L., M. E. Yount, and J. E. Case. 1981. Megafossil sample locality map, check lists, and stratigraphic sections of the 

Chignik and Sutwik Island quadrangles, Alaska. Miscellaneous Field Studies Map 1053-N (1:250,000). US Geological Survey, 

Reston, Virginia.

Dixon, J. P., and J. A. Power. 2009. The January 2006 volcanic-tectonic earthquake swarm at Mount Martin, Alaska. Page 17 in P. 

J. Haeussler and J. P. Galloway, editors. Studies by the US Geological Survey in Alaska, 2007. Professional Paper 1760-D. US 

Geological Survey, Reston, Virginia.

Druckenmiller, P. S., K. C. May, R. B. Blodgett, P. J. McCarthy, and S. J. Fowell. 2011. First record of Jurassic dinosaurs in Alaska 

from the Naknek Formation (Kimmeridgian-Tithonian), Peninsular terrane. Pages 46–47 in D. B. Stone, J. G. Clough, and D. K. 

Thurston, editors. Geophysical Institute Report UAG-R-335. University of Alaska, Fairbanks, Alaska.

Dumond, D. E. 1981. Archaeology on the Alaska Peninsula: The Naknek Region, 1960-1975. Anthropological Papers 21, University 

of Oregon Department of Anthropology and the Museum of Natural and Cultural History, Eugene, Oregon.

Eichelberger, J. C., W. Hildreth, and J. J. Papike. 1991. The Katmai Scientific Drilling Project, surface phase: Investigation of an 

exceptional igneous system. Geophysical Research Letters 18(8):1513–1516.

Elder, W. P., and J. W. Miller. 1993. Mesozoic macrofossil locality information for the Mount Katmai and part of the Afognak 

quadrangles, Alaska. Open-File Report 93-713 (1:250,000). US Geological Survey, Reston, Virginia.

Erskine, W. F. 1962. Katmai: The true narrative of a volcanic eruption which suddenly turned a pioneer Alaskan community into a 

prison of ashes and terror. Abelard-Schuman, London, United Kingdom.

Ewert, J. W., M. Guffanti, and T. L. Murray. 2005. An assessment of volcanic threat and monitoring capabilities in the United States: 

Framework for a National Volcano Early Warning System. Open-File Report 2005-1164. US Geological Survey, Reston, Virginia. 

http://pubs.usgs.gov/of/2005/1164/.

Fenner, C. N. 1930. Mount Katmai and Mount Mageik. Zeitschrift für Vulkanologie 13:1–24.

Fierstein, J. 2007. Explosive eruptive record in the Katmai region, Alaska Peninsula: An overview. Bulletin of Volcanology 

69(5):469–509.

Fierstein, J. 2012a. The great eruption of 1912. Alaska Park Science 11(1):7–13.

https://www.nps.gov/akso/nature/science/ak_park_science/volume_11_issue_1.cfm.

Fierstein, J. 2012b. Katmai National Park volcanoes. Alaska Park Science 11(1):15–21.

https://www.nps.gov/akso/nature/science/ak_park_science/volume_11_issue_1.cfm.

Fierstein, J. 2012c. Concluding thoughts. Can another great volcanic eruption happen in Alaska? Alaska Park Science 11(1):89–93. 

https://www.nps.gov/akso/nature/science/ak_park_science/volume_11_issue_1.cfm.

Fierstein, J., and W. Hildreth. 1992. The Plinian eruptions of 1912 at Novarupta, Katmai National Park, Alaska. Bulletin of 

Volcanology 54(8):646–684.

Fierstein, J., and W. Hildreth. 2001. Preliminary volcano-hazard assessment for the Katmai volcanic cluster, Alaska. Open-File 

Report 2000-489. US Geological Survey, Reston, Virginia. http://pubs.er.usgs.gov/publication/ofr00489.

Fierstein, J., and W. Hildreth. 2008. Kaguyak dome field and its Holocene caldera, Alaska Peninsula. Journal of Volcanology and 

Geothermal Research 177(2):340–366.

Fierstein, J., B. F. Houghton, C. J. N. Wilson, and W. Hildreth. 1997. Complexities of Plinian fall deposition at vent: An example from 

the 1912 Novarupta eruption. Journal of Volcanology and Geothermal Research 76:215–227.

Fierstein, J., and M. Nathenson. 1992. Another look at the calculation of fallout tephra volumes. Bulletin of Volcanology 

54(2):156–167.

Fierstein, J., and C. J. N. Wilson. 2005. Assembling an ignimbrite: Compositionally defined eruptive packages in the 1912 Valley of 

Ten Thousand Smokes, Alaska. Geological Society of America Bulletin 117:1094–1107.

Fiorillo, A. R., R. Kucinski, and T. Hamon. 2004. New frontiers, old fossils: Recent dinosaur discoveries in Alaska National Parks. 

Alaska Park Science 3(2):4–9. http://www.nps.gov/akso/nature/science/ak_park_science/volume_3_issue_2.cfm.

Forbes, R. B. 1965. New volcanic activity on Mount Griggs (Knife Peak). Memorandum. NPS Alaska Regional Curatorial Center 

KATM 41414-00283.
94

French, B. M., E. H. Muller, and P. L. Ward. 1972. Savonoski crater, Alaska: A possible meteorite impact structure. Meteoritics 

7(2):97–107.

Freymueller, J. T., H. Woodard, S. C. Cohen, R. Cross, J. Elliott, C. F. Larsen, S. Hreinsdóttir, and C. Zweck. 2008. Active 

deformation processes in Alaska, based on 15 years of GPS measurements (data set revised 11 March 2009). Pages 1–42 in J. T. 

Freymueller, P. J. Haeussler, R. L. Wesson, and G. Ekström, editors. Active Tectonics and Seismic Potential of Alaska. Geophysical 

Monograph 179. American Geophysical Union, Washington, DC. http://gps.alaska.edu/jeff/Chapman_GPS_velocities.html.

Gillis, R. J., R. F. Swenson, M. A. Wartes, and R. A. Frohman. 2013. Reconnaissance investigations of the Bruin Bay fault system 

along the western margin of lower Cook Inlet and upper Alaska Peninsula. Pages 33–37 in R. J. Gillis, editor. Overview of 2012 

field studies: Upper Alaska Peninsula and west side of lower Cook Inlet, Alaska. Preliminary Interpretive Report 2013-1G. Alaska 

Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

Graham, J. 2005. Southwest Alaska Network (SWAN) geologic resources management issues scoping summary. Geologic Resources 

Inventory Scoping Report, Colorado State University, Fort Collins, Colorado. http://go.nps.gov/gripubs.

Griggs, R. F. 1917. Valley of Ten Thousand Smokes: The National Geographic Society explorations in the Katmai District of Alaska. 

National Geographic Magazine 31(1):13–68.

Griggs, R. F. 1918a. The recovery of vegetation at Kodiak. Ohio Journal of Science 19(1):1–57.

Griggs, R. F. 1918b. The eruption of Katmai. Nature 101(2547):497–499.

Griggs, R. F. 1918c. The Valley of Ten Thousand Smokes: an account of the discovery and exploration of the most wonderful 

volcanic region in the world. National Geographic Magazine 33(2):115–169.

Griggs, R. F. 1918d. The great hot mud flow of the Valley of Ten Thousand Smokes. Ohio Journal of Science 19(2):117–142.

Griggs, R. F. 1918e. Are the Ten Thousand Smokes real volcanoes? Ohio Journal of Science 19(2):97–116.

Griggs, R. F. 1919. The character of the eruption as indicated by its effects on vegetation. Ohio Journal of Science 19(3):173–209.

Griggs, R. F. 1920. The great Mageik Landslide. Ohio Journal of Science 20(8):325–354.

Griggs, R. F. 1922. The Valley of Ten Thousand Smokes. National Geographic Society, Washington, DC.

Griggs, R. F. 1933. The colonization of the Katmai ash, a new and inorganic “soil.” American Journal of Botany 20(2):92–113.

Guffanti, M., S. R. Brantley, and L. McClelland, editors. 2001. Volcanism in national parks: Summary of the Workshop Convened by 

the US Geological Survey and National Park Service, 26-29 September 2000, Redding, California. Open-File Report 01-435. US 

Geological Survey, Reston, Virginia. http://pubs.usgs.gov/of/2001/0435/.

Hadley, D., G. L. Hufford, and J. J. Simpson. 2004. Resuspension of relic volcanic ash and dust from Katmai: Still an aviation hazard. 

Weather and Forecasting 19(5):829–840. http://dx.doi.org/10.1175/1520-0434(2004)019%3C0829:RORVAA%3E2.0.CO;2.

Haeussler, P. J., and G. Plafker. 2004. Earthquakes in Alaska. Open-File Report 95-624. US Geological Survey, Reston, Virginia. 

http://pubs.usgs.gov/of/1995/0624/.

Hamilton, T. D. 1973. Geomorphic role of snow and ice during the Katmai 1912 eruption. Geological Society of America Abstracts 

with Programs 5(1):48–49.

Hanlon, T. 2015, March 12. Ash, dust from 1912 Novarupta eruption cancels Kodiak flights. Alaska Dispatch News, Anchorage, 

Alaska. http://www.adn.com/article/20150312/ash-dust-1912-novarupta-eruption-cancels-kodiak-flights.

Harper, J., and M. Morris. 2005. The Katmai coast: A guide to coastal biophysical features and ecological processes. National Park 

Service, Anchorage, Alaska. https://irma.nps.gov/DataStore/Reference/Profile/590695.

Heasler, H. P., C. Jaworowski, and D. Foley. 2009. Geothermal systems and monitoring hydrothermal features. Pages 105–140 in R. 

Young and L. Norby, editors. Geological monitoring. Geological Society of America, Boulder, Colorado.

http://go.nps.gov/geomonitoring.

Herriott, T. M., M. A. Wartes, and P. L. Decker. 2015. Deep-water canyons in the Snug Harbor Siltstone and Pomeroy Arkose 

Members, Naknek Formation, Alaska: New insights into the sequence stratigraphy of the Late Jurassic Cook Inlet forearc basin. 

Slides presented at Geological Society of America, Cordilleran Section Annual Meeting, 11-13 May 2015. Alaska Division of 

Geological and Geophysical Surveys, Fairbanks, Alaska. http://www.dggs.alaska.gov/pubs/id/29443.
95

Hildreth, W. 1983. The compositionally zoned eruption of 1912 in the Valley of Ten Thousand Smokes, Katmai National Park, 

Alaska. Journal of Volcanology and Geothermal Research 18:1–55.

Hildreth, W. 1987. New perspectives on the eruption of 1912 in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska. 

Bulletin of Volcanology 49:680–693.

Hildreth, W. 1991. The timing of caldera collapse at Mount Katmai in response to magma withdrawal toward Novarupta. 

Geophysical Research Letters 18:1541–1544.

Hildreth, W., and J. Fierstein. 2000. Katmai volcanic cluster and the great eruption of 1912. Geological Society of America Bulletin 

112(10):1594–1620. http://gsabulletin.gsapubs.org/content/112/10/1594.

Hildreth, W., and J. Fierstein. 2003. Geologic map of the Katmai volcanic cluster, Katmai National Park, Alaska. Geologic 

Investigations Series I-2778 (1:63,360). US Geological Survey, Reston, Virginia. http://pubs.usgs.gov/imap/i2778/.

Hildreth, W., and J. Fierstein. 2012. The Novarupta-Katmai eruption of 1912—Largest eruption of the twentieth century: Centennial 

perspectives. Professional Paper 1791. US Geological Survey, Reston, Virginia. http://pubs.usgs.gov/pp/1791/.

Hildreth, W., J. Fierstein, M. A. Lanphere, and D. F. Siems. 1999. Alagogshak volcano: a Pleistocene andesite-dacite stratovolcano 

in Katmai National Park. Pages 105–113 in K. D. Kelley, editor. Geologic studies in Alaska by the US Geological Survey, 1997. 

Professional Paper 1614. US Geological Survey, Reston, Virginia.

Hildreth, W., J. Fierstein, M. A. Lanphere, and D. F. Siems. 2000. Mount Mageik; a compound stratovolcano in Katmai National 

Park. Pages 23–41 in K. D. Kelley and L. P. Gough, editors. Geologic studies in Alaska by the US Geological Survey, 1998. 

Professional Paper 1615. US Geological Survey, Reston, Virginia.

Hildreth, W., J. Fierstein, M. A. Lanphere, and D. F. Siems. 2001. Snowy Mountain: a pair of small andesite-dacite stratovolcanoes 

in Katmai National Park. Pages 13–34 in L. P. Gough and F. H. Wilson, editors. Geologic studies in Alaska by the US Geological 

Survey, 1999. Professional Paper 1633. US Geological Survey, Reston, Virginia.

Hildreth, W., J. Fierstein, M. A. Lanphere, and D. F. Siems. 2002. Mount Griggs: A compositionally distinctive Quaternary 

stratovolcano behind the main volcanic line in Katmai National Park. Pages 87–112 in F. H. Wilson and J. P. Galloway, editors. 

Studies by the US Geological Survey in Alaska, 2000. Professional Paper 1662. US Geological Survey, Reston, Virginia.

Hildreth, W., J. Fierstein, M. A. Lanphere, and D. F. Siems. 2003a. Trident Volcano: Four contiguous stratocones adjacent to Katmai 

Pass, Alaska Peninsula. Pages 1–28 in J. P. Galloway, editor. Studies by the US Geological Survey in Alaska, 2001. Professional 

Paper 1678. US Geological Survey, Reston, Virginia.

Hildreth, W., J. Fierstein, D. F. Siems, J. R. Budahn, and J. Ruíz. 2004. Rear-arc vs. arc-front volcanoes in the Katmai reach of 

the Alaska Peninsula: A critical appraisal of across-arc compositional variation. Contributions to Mineralogy and Petrology 

147:243–275.

Hildreth, W., M. A. Lanphere, and J. Fierstein. 2003b. Geochronology and eruptive history of the Katmai volcanic cluster, Alaska 

Peninsula. Earth and Planetary Science Letters 214(1–2):93–114.

Hillhouse, J. W. 1977. Paleomagnetism of the Triassic Nikolai Greenstone, McCarthy quadrangle, Alaska. Canadian Journal of Earth 

Sciences 14:2578–2592.

Hillhouse, J. W., and R. S. Coe. 1994. Paleomagnetic data from Alaska. Pages 797–812 in G. Plafker and H. C. Berg, editors. The 

geology of Alaska. The geology of North America, Decade of North American geology (DNAG), Geological Society of America, 

Boulder, Colorado.

Hillhouse, J. W., and C. S. Gromme. 1984. Northward displacement and accretion of Wrangellia: New paleomagnetic evidence from 

Alaska. Journal of Geophysical Research 89(B6):4461–4477.

Hollick, A. 1936. The Tertiary floras of Alaska. Professional Paper 182 (1:5,000,000). US Geological Survey, Reston, Virginia.

Houghton, B. F., C. J. N. Wilson, J. Fierstein, and W. Hildreth. 2004. Complex proximal deposition during the Plinian eruptions of 

1912 at Novarupta, Alaska. Bulletin of Volcanology 66(2):95–133.

Houston, W. S. 1994. Lower Tertiary stratigraphy in Katmai National Park, Alaska: A lithologic and petrographic study. Thesis. 

Colorado State University, Fort Collins, Colorado.

Hubbard, B. R. 1932. Mush, You Malamutes! The America Press, New York.
96

Hubbard, B. R. 1935. Cradle of the Storms. Dodd, Mead and Co., New York.

Hults, C. P., F. H. Wilson, R. A. Donelick, and P. B. O’Sullivan. 2013. Two flysch belts having distinctly different provenance suggest 

no stratigraphic link between the Wrangellia composite terrane and the paleo-Alaskan margin. Lithosphere 5(6):575–594.

http://lithosphere.gsapubs.org/content/early/2013/11/15/L310.1.abstract.

Intergovernmental Panel on Climate Change. 2013. Climate change 2013: The physical science basis. Contribution of working 

group I to the fifth assessment report of the Intergovernmental Panel on Climate Change. (T. F. Stocker, D. Qin, G. K. Plattner, M. 

Tignor, S. K. Allen, J. Boschung, A. Nauels, Y. Xia, V. Bex, and P. M. Midgley, Eds.)Cambridge University Press, Cambridge, United 

Kingdom and New York, New York, USA:1535. http://www.ipcc.ch/report/ar5/wg1/.

Jorgenson, M. T., G. V. Frost, and W. E. Lentz. 2007. Photographic monitoring of landscape change in the Southwest Alaska Network 

of National Parklands, 2004-2006. Natural Resource Technical Report NPS/SWAN/NRTR-2006-03, National Park Service, 

Southwest Alaska Network, Anchorage, AK. https://irma.nps.gov/App/Reference/Profile/649852.

Jorgenson, M. T., K. Yoshikawa, M. Kanevskiy, Y. Shur, V. Romanovsky, S. Marchenko, G. Grosse, J. Brown, and B. Jones. 2008. 

Permafrost characteristics of Alaska (1:7,200,000). University of Alaska Fairbanks, Institute of Northern Engineering, Fairbanks, 

Alaska. http://permafrost.gi.alaska.edu.

Karpilo, R. D. 2009. Glacier monitoring techniques. Pages 141–162 in R. Young and L. Norby, editors. Geological monitoring. 

Geological Society of America, Boulder, Colorado. http://go.nps.gov/geomonitoring.

Kaufman, D. S., and K. B. Stilwell. 1997. Preliminary evaluation of emergent postglacial shorelines, Naknek and Iliamna lakes, 

southwestern Alaska. Pages 73–81 in J. A. Dumoulin and J. E. Gray, editors. Geologic studies in Alaska by the US Geological 

Survey, 1995. Professional Paper 1574. US Geological Survey, Reston, Virginia.

Keith, T. E. C. 1991. Fossil and active fumaroles in the 1912 eruptive deposits, Valley of Ten Thousand Smokes, Alaska. Journal of 

Volcanology and Geothermal Research 45(3):227–254.

Keith, T. E. C., J. M. Thompson, R. A. Hutchinson, and L. D. White. 1992. Geochemistry of waters in the Valley of Ten Thousand 

Smokes region, Alaska. Journal of Volcanology and Geothermal Research 49:209–231.

Keller, A. S., and H. N. Reiser. 1958. Geology of the Mount Katmai area, Alaska. Mineral resources of Alaska, 1956:G261–G298.

KellerLynn, K. 2013. Crater Lake National Park: Geologic resources inventory report. National Park Service, Fort Collins, 

Colorado:70, 3 sheets, tables. http://go.nps.gov/gripubs.

Kent, D. V., and E. Irving. 2010. Influence of inclination error in sedimentary rocks on the Triassic and Jurassic apparent pole 

wander path for North America and implications for Cordilleran tectonics. Journal of Geophysical Research 115(B10).

Kenworthy, J. P., and V. L. Santucci. 2003. Paleontological resource inventory and monitoring: Southwest Alaska Network. National 

Park Service, Fort Collins, Colorado.

Kienle, J. 1991. Depth of the ash flow deposit in the Valley of Ten Thousand Smokes, Katmai National Park, Alaska. Geophysical 

Research Letters 18(8):1533–1536. http://onlinelibrary.wiley.com.arlis.idm.oclc.org/doi/10.1029/91GL01186/abstract.

Kienle, J., and S. E. Swanson. 1983. Volcanism in the eastern Aleutian arc: Late Quaternary and Holocene centers, tectonic setting 

and petrology. Journal of Volcanology and Geothermal Research 17:393–432.

Kienle, J., S. E. Swanson, and H. Palpan. 1983. Magmatism and subduction in the eastern Aleutian arc. Pages 191–224 in D. 

Shimozuru and I. Yokoyama, editors. Arc volcanism: physics and tectonics. Terra Scientific Publishing Company, Tokyo Japan.

Kimball, H. H. 1918. Volcanic eruptions and solar radiation intensities. Pages 355–356 in H. H. Kimball, editor. Monthly Weather 

Review. US Department of Agriculture - Weather Bureau.

Knowlton, F. H. 1904. Fossil plants from Kukak Bay. Pages 149–186 in B. K. Emerson, C. Palache, W. H. Dall, E. O. Ulrich, and F. 

H. Knowlton, editors. Harriman Alaska Expedition. Doubleday, Page & Company with cooperation of Washington Academy of 

Sciences, New York.

Lord, M. L., D. Germanoski, and N. E. Allmendinger. 2009. Fluvial geomorphology: Monitoring stream systems in response to a 

changing environment. Pages 69–103 in R. Young and L. Norby, editors. Geological monitoring. Geological Society of America, 

Boulder, Colorado. http://go.nps.gov/geomonitoring.

Loso, M., A. Arendt, C. F. Larsen, J. Rich, and N. Murphy. 2014. Alaskan national park glaciers - Status and Trends. National Park 

Service, Fort Collins, Colorado. https://irma.nps.gov/App/Reference/Profile/2217472.
97

Lowell, R. P., and T. E. C. Keith. 1991. Chemical and thermal constraints on models of Thermal Springs Valley of Ten Thousand 

Smokes, Alaska. Geophysical Research Letters 18(8):1553–1556.

http://onlinelibrary.wiley.com.arlis.idm.oclc.org/doi/10.1029/91GL01758/abstract.

Madden, J. W., J. Power, K. W. VanPeursem, G. Holt, A. Devaris, J. Brennell, and L. Hartig (Signatories). 2014. Alaska interagency 

operating plan for volcanic ash episodes. Alaska Volcano Observatory, Anchorage, Alaska.

https://www.avo.alaska.edu/pdfs/cit3996_2014.pdf.

Mann, D. H., and D. M. Peteet. 1994. Extent and timing of the last glacial maximum in southwestern Alaska. Quaternary Research 

42:136–148.

Martin, G. C. 1913. The recent eruption of Katmai volcano in Alaska. National Geographic Magazine 24:131–181.

McGimsey, R. G., C. A. Neal, and O. Girina. 2005. 2003 volcanic activity in Alaska and Kamchatka: Summary of events and response 

of the Alaska Volcano Observatory. Open-File Report 2005-1310. US Geological Survey, Reston, Virginia.

http://pubs.usgs.gov/of/2005/1310/.

Miller, J. W., W. P. Elder, and R. L. Detterman. 1995. Mesozoic macrofossil locality map, checklists, and pre-Quaternary stratigraphic 

section of the Mt. Katmai and adjacent parts of the Afognak and Naknek quadrangles, Alaska Peninsula, Alaska. Miscellaneous 

Field Studies Map 2021-G (1:250,000). US Geological Survey, Reston, Virginia.

Moran, S. C. 2003. Multiple Seismogenic Processes for High-Frequency Earthquakes at Katmai National Park, Alaska: Evidence 

from Stress Tensor Inversions of Fault-Plane Solutions. Bulletin of the Seismological Society of America 93(1):94–108.

Motyka, R. J. 1977. Katmai Caldera: Glacier growth, lake rise and geothermal activity. Pages 17–21 in Alaska Division of Geological 

& Geophysical Surveys, Short Notes on Alaskan Geology - 1977. Geologic Report 55. Alaska Division of Geological & 

Geophysical Surveys, Fairbanks, Alaska.

Motyka, R. J. 1978. Surveillance of Katmai caldera and crater lake, Alaska: 1977. Final Report on NPS purchase order PX 9100-7-

1009. University of Alaska Fairbanks, Geophysical Institute, Fairbanks, Alaska.

Motyka, R. J., S. A. Liss, C. J. Nye, and M. A. Moorman. 1994. Geothermal resources of the Aleutian arc. Professional Report 114 

(1:1,000,000). Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

Moxham, R. M. 1952. Pumice deposits in the Alaska Peninsula-Cook Inlet region, Alaska. Open-File Report 52-103. US Geological 

Survey, Reston, Virginia.

Muller, E. H. 1952. The glacial geology of the Naknek District, the Bristol Bay region, Alaska. Dissertation. University of Illinois, 

Urbana, Illinois.

Muller, E. H. 1953. Northern Alaska Peninsula and eastern Kilbuck Mountains, Alaska. Pages 2–5 in T. L. Péwé, editor. Multiple 

Glaciation in Alaska - A progress report. Circular 289. US Geological Survey, Reston, Virginia.

Muller, E. H. 1963. Geology of the Brooks River archaeological sites: A preliminary report. Unpublished, on file at the NPS Alaska 

Region Curation Center.

Muller, E. H., and H. W. Coulter. 1957. Incipient glacier development within Katmai Caldera, Alaska. Journal of Glaciology 3:13–17.

Myers, B., and C. Driedger. 2008. Geologic hazards at volcanoes. General Information Product 64 version1.0. US Geological Survey, 

Reston, Virginia. http://pubs.usgs.gov/gip/64/.

NASA. 2012. Stratospheric aerosol optical thickness. NASA, Goddard Institute for Space Studies.

http://data.giss.nasa.gov/modelforce/strataer/.

NASA. 2015. Surface temperature analysis. NASA, Goddard Institute for Space Studies. http://data.giss.nasa.gov/gistemp/.

National Research Council. 1989. Volcanic studies at Katmai. National Academy Press, Washington, DC.

Neal, C. A., R. G. McGimsey, J. P. Dixon, A. Manevich, and A. Rybin. 2009. 2006 volcanic activity in Alaska, Kamchatka, and the 

Kurile Islands: Summary of events and response of the Alaska Volcano Observatory. Scientific Investigations Report 2008–5214. 

US Geological Survey, Reston, Virginia.

Newhall, C. G., and S. Self. 1982. The Volcanic Explosivity Index (VEI): An Estimate of Explosive Magnitude for Historical 

Volcanism. Journal of Geophysical Research 87(C2):1231–1238.
98

NOAA. 2012. Atmospheric transmission of direct solar radiation at Mauna Loa, Hawaii - Version C (12 March 2012 data set). 

NOAA Earth System Research Laboratory, Global Monitoring Division, Global Radiation Group.

http://www.esrl.noaa.gov/gmd/grad/mloapt.html.

Nokleberg, W. J., E. J. Moll-Stalcup, T. P. Miller, D. A. Brew, A. Grantz, J. C. Reed, G. Plafker, T. E. Moore, S. R. Silva, and W. W. 

Patton. 1994. Tectonostratigraphic terrane and overlap assemblage map of Alaska. Open-File Report 94-194 (1:2,500,000). US 

Geological Survey, Reston, Virginia.

NPS. 2009a. Katmai National Park and Preserve foundation statement. National Park Service, Anchorage, Alaska.

NPS. 2009b. Katmai National Park and Preserve, Aniakchak National Monument and Preserve, Alagnak Wild River long-range 

interpretive plan. Department of the Interior, National Park Service, Harpers Ferry Center, Harpers Ferry, West Virginia.

Nye, C. J. 1998. Volcanoes of Alaska. Information Circular 38. Alaska Division of Geological & Geophysical Surveys, Fairbanks, 

Alaska.

Orr, L. R., and W. Y. Brown. 2013. Additional recommendations for proposed Cook Inlet oil and gas lease sale 244 area identification 

(includes map). Memorandum to T. P. Beaudreau, director, Bureau of Ocean Energy Management.

http://www.boem.gov/uploadedFiles/BOEM/About_BOEM/BOEM_Regions/Alaska_Region/Leasing_and_Plans/Leasing/

Lease_Sales/Sale_244_-_Cook_Inlet/Sale_244_Area_ID.pdf.

Osterkamp, T. E., and M. T. Jorgenson. 2009. Permafrost conditions and processes. Pages 205–227 in R. Young and E. S. Norby, 

editors. Geological monitoring. Geological Society of America, Boulder, Colorado. http://go.nps.gov/geomonitoring.

Page, R. A., N. N. Biswas, J. C. Lahr, and H. Pulpan. 1991. Seismicity of continental Alaska. Pages 47–68 in D. B. Slemmons, E. 

R. Engdahl, M. D. Zoback, and D. D. Blackwell, editors. Neotectonics of North America. The Geology of North America, 

Continent-Scale Maps Series, Decade of North American Geology (DNAG), Geological Society of America, Boulder, Colorado.

Parrish, J. T., A. R. Fiorillo, B. F. Jacobs, E. D. Currano, and E. A. Wheeler. 2010. The Ketavik Formation: A new stratigraphic unit and 

its implications for the Paleogene paleogeography and paleoclimate of southwestern Alaska. Palaeogeography, Palaeoclimatology, 

Palaeoecology 295(3–4):348–362.

Petit, J. R., J. Jouzel, D. Raynaud, N. I. Barkov, J. M. Barnola, I. Basile, M. Bender, J. Chappellaz, M. Davis, G. Delaygue, and others. 

1999. Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica. Nature 399(6735):429–436.

Pinney, D. S. 1993. Late Quaternary glacial and volcanic stratigraphy near Windy Creek, Katmai National Park, Alaska. Thesis. 

University of Alaska, Fairbanks, Alaska.

Pinney, D. S., and J. E. Begét. 1991a. Late Pleistocene volcanic deposits near the Valley of Ten Thousand Smokes, Katmai National 

Park, Alaska. Pages 45–53 in R. D. Reger, editor. Short Notes on Alaskan Geology 1991. Professional Report 111F. Alaska Division 

of Geological & Geophysical Surveys, Fairbanks, Alaska.

Pinney, D. S., and J. E. Begét. 1991b. Deglaciation and latest Pleistocene and early Holocene glacier readvances on the Alaska 

Peninsula: Records of rapid climate change due to transient changes in solar intensity and atmospheric C02

 content? Pages 634–

640 in G. Weller, C. L. Wilson, and B. A. B. Severlin, editors. International Conference on the Role of the Polar Regions in Global 

Change: Proceedings of a Conference Held June 11-15, 1990 at the University of Alaska Fairbanks. University of Alaska Fairbanks, 

Geophysical Institute and Center for Global Change and Arctic System Research, Fairbanks, Alaska.

Plafker, G. 1969. The Alaska Earthquake: March 27, 1964: Regional effects. Professional Paper 543-I (1:500,000, 1:2,000,000). US 

Geological Survey, Reston, Virginia.

Plafker, G., J. C. Moore, and G. R. Winkler. 1994. Geology of the southern Alaska margin. Pages 389–449 in G. Plafker and H. C. 

Berg, editors. The Geology of Alaska. The geology of North America, Decade of North American geology (DNAG), Geological 

Society of America, Boulder, Colorado.

Plafker, G., W. J. Nokleberg, and J. S. Lull. 1989. Bedrock geology and tectonic evolution of the Wrangellia, Peninsular, and Chugach 

terranes along the Trans-Alaska Crustal Transect in the Chugach Mountains and southern Copper River basin, Alaska. Journal of 

Geophysical Research 94(B4):4255–4295.

Reading, H. G., and M. T. Richards. 1994. Turbidite systems in deep-water basin margins classified by grain size and feeder system. 

American Association of Petroleum Geologists Bulletin 78:792–822.
99

Reger, R. D., D. S. Pinney, R. M. Burke, and M. A. Wiltse. 1996. Catalog and initial analyses of geologic data related to middle to 

late Quaternary deposits, Cook Inlet region, Alaska. Report of Investigations 95-6. Alaska Division of Geological & Geophysical 

Surveys, Fairbanks, Alaska.

Riehle, J. R., and R. L. Detterman. 1993. Quaternary geologic map of the Mount Katmai Quadrangle and adjacent parts of the 

Naknek and Afognak quadrangles, Alaska. Miscellaneous Investigations Series Map 2032 (1:250,000). US Geological Survey, 

Reston, Virginia.

Riehle, J. R., R. L. Detterman, M. E. Yount, and J. W. Miller. 1993. Geologic map of the Mount Katmai quadrangle and adjacent parts 

of the Naknek and Afognak quadrangles, Alaska. Miscellaneous Investigations Series Map I-2204 (1:250,000). US Geological 

Survey, Reston, Virginia.

Rioux, M., J. Mattinson, B. Hacker, P. Kelemen, J. Blusztajn, K. Hanghoj, and G. E. Gehrels. 2010. Intermediate to felsic middle 

crust in the accreted Talkeetna arc, the Alaska Peninsula and Kodiak Island, Alaska: an analogue for low-velocity middle crust in 

modern arcs. Tectonics 29(3).

Santucci, V. L., J. P. Kenworthy, and A. L. Mims. 2009. Monitoring in situ paleontological resources. Pages 189–204 in R. Young and 

L. Norby, editors. Geological monitoring. Geological Society of America, Boulder, Colorado. http://go.nps.gov/geomonitoring.

Sattler, A. R. 1990. Operations plan for the Katmai drilling project. Sandia National Laboratories, Albuquerque, New Mexico.

Schaber, G. G. 2005. The US Geological Survey, Branch of Astrogeology—A chronology of activities from conception through the 

end of project Apollo (1960-1973). Open-File Report 2005-1190. US Geological Survey, Reston, Virginia.

http://www.hq.nasa.gov/alsj/Schaber.html.

Schaefer, J. R., W. E. Scott, W. C. Evans, J. Jorgenson, R. G. McGimsey, and B. Wang. 2008. The 2005 catastrophic acid crater lake 

drainage, lahar, and acidic aerosol formation at Mount Chiginagak volcano, Alaska, USA: Field observations and preliminary 

water and vegetation chemistry results. Geochemistry, Geophysics, Geosystems 9(7).

http://onlinelibrary.wiley.com/doi/10.1029/2007GC001900/abstract.

Scholl, D. W. 2007. Viewing the tectonic evolution of the Kamchatka-Aleutian (KAT) connection with an Alaska crustal extrusion 

perspective. Pages 3–35 in J. Eichelberger, E. Gordeev, P. Izbekov, M. Kasahara, and J. Lees, editors. Volcanism and Subduction: 

The Kamchatka Region. American Geophysical Union.

Scholl, D. W., W. J. Nokleberg, J. W. H. Monger, T. K. Bundtzen, R. A. Price, and D. B. Stone. 2015. The oceanic crust of the Aleutian 

Basin is a large, tectonostratigraphic terrane accreted to the North America plate - Evidence and IODP drilling to test this 

hypothesis. Geological Society of America Abstracts with Programs 47(4).

Scholl, D. W., T. L. Vallier, and A. J. Stevenson. 1986. Terrane accretion, production, and continental growth: A perspective based on 

the origin and tectonic fate of the Aleutian–Bering Sea region. Geology 14(1):43–47.

Schupp, C. A., R. L. Beavers, and M. A. Caffrey, editors. 2015. Coastal Adaptation Strategies: Case Studies. NPS 999/129700, 

National Park Service, Fort Collins, Colorado. http://www.nps.gov/subjects/climatechange/coastaladaptationstrategies.htm.

Sheppard, D. S., C. J. Janik, and T. E. C. Keith. 1992. A comparison of gas geochemistry of fumaroles in the 1912 ash-flow sheet and 

on active stratovolcanoes, Katmai National Park, Alaska. Journal of Volcanology and Geothermal Research 53:185–197.

Shew, N. B., and M. A. Lanphere. 1992. Map showing potassium-argon ages from the Mount Katmai and adjacent parts of the 

Naknek and Afognak quadrangles, Alaska Peninsula, Alaska. Miscellaneous Field Studies Map 2021-E (1:250,000). US Geological 

Survey, Reston, Virginia.

Sigl, M., M. Winstrup, J. R. McConnell, K. C. Welten, G. Plunkett, F. Ludlow, U. Büntgen, M. Caffee, N. Chellman, D. Dahl-Jensen, 

H. Fischer, S. Kipfstuhl, C. Kostick, O. J. Maselli, F. Mekhaldi, R. Mulvaney, R. Muscheler, D. R. Pasteris, J. R. Pilcher, M. Salzer, S. 

Schüpbach, J. P. Steffensen, B. M. Vinther, and T. E. Woodruff. 2015. Timing and climate forcing of volcanic eruptions for the past 

2,500 years. Nature 523:543–549.

Simkin, L., and T. Siebert. 1994. Volcanoes of the world. Geoscience Press, Tucson, AZ.

Smith, J. G., J. Dehn, A. L. Mims, R. P. Hoblitt, R. G. LaHusen, J. B. Lowenstern, S. C. Moran, L. McClelland, K. A. McGee, M. 

Nathenson, P. G. Okubo, J. S. Pallister, M. P. Poland, J. A. Power, D. J. Schneider, and T. W. Sisson. 2009. Volcano Monitoring. 

Pages 273–305 in R. Young and L. Norby, editors. Geological monitoring. Geological Society of America, Boulder, Colorado. 

http://go.nps.gov/geomonitoring.
100

Smith, W. R. 1925. The Cold Bay-Katmai district. Pages 183–207 in Mineral resources of Alaska, report on progress of investigations 

in 1923. Bulletin 773 (1:250,000). US Geological Survey, Reston, Virginia.

Smithsonian Institution. 2015. Smithsonian Institution - Global Volcanism Program: Worldwide Holocene Volcano and Eruption 

Information. Smithsonian Institution - National Museum of Natural History: Global Volcanism Program. http://volcano.si.edu/.

Spurr, J. E. 1900. A reconnaissance in southwestern Alaska. Pages 31–264, 17 plates in C. D. Walcott, editor. Twentieth annual 

report of the United States Geological Survey, 1898-1899: Part VII - explorations in Alaska in 1898. Annual Report 20-VII. US 

Geological Survey, Reston, Virginia.

Stamatakos, J. A., J. M. Trop, and K. D. Ridgway. 2001. Late Cretaceous paleogeography of Wrangellia: paleomagnetism of the 

MacColl Ridge Formation, southern Alaska, revisited. Geology 29(10):947–950.

Stevens, D. A. S. P. 2012. Pre-1912 Glacial and Volcanic History near Windy Creek, Katmai National Park and Preserve, Alaska. 

Alaska Park Science 11(1):47–51. https://www.nps.gov/akso/nature/science/ak_park_science/volume_11_issue_1.cfm.

Stevens, D. A. S. P., and P. A. Craw. 2003. Geologic hazards in and near the northern portion of the Bristol Bay Basin. Miscellaneous 

Publication 132. Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

Stilwell, K. B., and D. S. Kaufman. 1996. Late Wisconsin glacial history of the Northern Alaska Peninsula, southwestern Alaska, USA. 

Arctic and Alpine Research 28(4):475–487.

Stone, D. B., and D. R. Packer. 1977. Tectonic implications of Alaska Peninsula paleomagnetic data. Tectonophysics 37(1–3):183–201.

Stone, D. B., and D. R. Packer. 1979. Paleomagnetic data from the Alaska Peninsula. Bulletin of the Geological Society of America 

90(6):545–560.

Thompson, W. F. 1954. Katmai geographic studies. Pages 26–49 in R. S. Luntey, editor. Katmai project interim report, Katmai 

National Monument, Alaska. National Park Service, Washington, DC.

Thrupp, G. A., and R. S. Coe. 1986. Early Tertiary paleomagnetic evidence and the displacement of southern Alaska. Geology 

14(3):213–217.

Trop, J. M., D. A. Szuch, M. Rioux, and R. B. Blodgett. 2005. Sedimentology and provenance of the Upper Jurassic Naknek 

Formation, Talkeetna Mountains, Alaska: Bearings on the accretionary tectonic history of the Wrangellia composite terrane. 

Geological Society of America Bulletin 117(5–6):570–588.

Ward, P. L., A. M. Pitt, and E. Endo. 1991. Seismic evidence for magma in the vicinity of Mt. Katmai, Alaska. Geophysical Research 

Letters 18(8):1537–1540. http://onlinelibrary.wiley.com.arlis.idm.oclc.org/doi/10.1029/91GL01906/abstract.

Wartes, M. A., and P. L. Decker. 2015. Late Jurassic glaciers during the Mesozoic greenhouse: Evidence from the lower Naknek 

Formation, southern Alaska. Geological Society of America Abstracts with Programs 47(4):8.

Wartes, M. A., T. M. Herriott, K. P. Helmold, and R. J. Gillis. 2013. Preliminary stratigraphic interpretation of the Naknek 

Formation: Evidence for Late Jurassic activity on the Bruin Bay fault, Iniskin Peninsula, lower Cook Inlet. Pages 39–46 in R. J. 

Gillis, editor. Overview of 2012 field studies: Upper Alaska Peninsula and west side of lower Cook Inlet, Alaska. Preliminary 

Interpretive Report 2013-1H. Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska.

Waythomas, C. F. 2015. Geomorphic consequences of volcanic eruptions in Alaska: A review. Geomorphology 246:123–145.

http://www.sciencedirect.com/science/article/pii/S0169555X15300234.

Waythomas, C. F., P. Watts, and J. S. Walder. 2006. Numerical simulation of tsunami generation by cold volcanic mass flows at 

Augustine Volcano, Alaska. Natural Hazards and Earth System Sciences 6:671–685.

http://www.nat-hazards-earth-syst-sci.net/6/671/2006/.

Weems, R. E., and R. B. Blodgett. 1996. The pliosaurid Megalneusaurus; a newly recognized occurrence in the Upper Jurassic 

Naknek Formation of the Alaska Peninsula. Pages 169–176 in T. E. Moore and J. A. Dumoulin, editors. Geologic studies in Alaska 

by the US Geological Survey, 1994. Bulletin 2152. US Geological Survey, Reston, Virginia.

Wieczorek, G. F., and J. B. Snyder. 2009. Monitoring slope movements. Pages 245–271 in R. Young and E. S. Norby, editors. 

Geological monitoring. Geological Society of America, Boulder, Colorado. http://go.nps.gov/geomonitoring.

Wilson, F. H. 1985. The Meshik arc - An Eocene to earliest Miocene magmatic arc on the Alaska Peninsula. Professional Report 88. 

Alaska Division of Geological & Geophysical Surveys, Fairbanks, Alaska.
101

Wilson, F. H., R. B. Blodgett, C. D. Blomé, S. Mohadjer, C. C. Preller, E. P. Klimasauskas, B. M. Gamble, and W. L. Coonrad. 2006. 

Preliminary reconnaissance bedrock geologic map for the northern Alaska Peninsula area, southwest Alaska. Open-File Report 

2006-1303 (1:250,000). US Geological Survey, Reston, Virginia. http://pubs.usgs.gov/of/2006/1303/.

Wilson, F. H., R. L. Detterman, and G. D. Dubois. 1999. Preliminary geologic framework of the Alaska Peninsula, southwest Alaska, 

and the Alaska Peninsula terrane. Open-File Report 99-317 (1:500,000). US Geological Survey, Reston, Virginia.

http://geopubs.wr.usgs.gov/open-file/of99-317/.

Wilson, F. H., R. L. Detterman, and G. D. Dubois. 2015. Geologic Framework of the Alaska Peninsula, southwest Alaska, and the 

Alaska Peninsula Terrane. Bulletin 1969-B (1:500,000). US Geological Survey, Reston, Virginia.

Wilson, F. H., J. H. Dover, D. C. Bradley, F. R. Weber, T. K. Bundtzen, and P. J. Haeussler. 1998. Geologic map of Central (Interior) 

Alaska. Open-File Report 133a (1:500,000). US Geological Survey, Reston, Virginia. http://pubs.usgs.gov/of/1998/of98-133-a/.

Wilson, F. H., C. P. Hults, S. Mohadjer, and W. L. Coonrad. 2013. Reconnaissance geologic map of the Kuskokwim Bay region, 

southwest Alaska. Scientific Investigations Map 3100 (1:500,000, 1:300,000, 1:250,000). US Geological Survey, Reston, Virginia. 

http://pubs.usgs.gov/sim/3100/.

Wilson, F. H., C. P. Hults, H. R. Schmoll, P. J. Haeussler, J. M. Schmidt, L. A. Yehle, and K. A. Labay. 2012. Geologic map of the 

Cook Inlet region, Alaska, including parts of the Talkeetna, Talkeetna Mountains, Tyonek, Anchorage, Lake Clark, Kenai, Seward, 

Iliamna, Seldovia, Mount Katmai, and Afognak 1:250,000-scale quadrangles. Scientific Investigations Map 3153 (1:250,000). US 

Geological Survey, Reston, Virginia. http://pubs.usgs.gov/sim/3153/.

Winfree, R., B. Rice, J. Morris, D. Callaway, N. Swanton, D. Weeks, J. Mow, N. Fresco, and L. Krutikov. 2014. Climate change 

scenario planning for southwest Alaska parks. National Park Service, Fort Collins, Colorado.

https://irma.nps.gov/App/Reference/Profile/2212383.

Wood, C. A., and J. Kienle, editors. 1990. Volcanoes of North America: United States and Canada. Cambridge University Press, New 

York.

Young, R., and L. Norby, editors. 2009. Geological monitoring. Geological Society of America, Boulder, Colorado.

http://go.nps.gov/geomonitoring.

Zanon, J., M. R. Komp, J. Sopcak, K. M. Benck, K. Allen, K. J. Stark, L. J. Meinke, A. Robertson, and B. Drazkowski. 2015. Katmai 

National Park and Preserve and Alagnak Wild River: Natural resource condition assessment. Natural Resource Report NPS/

SWAN/NRR—2015/1095, National Park Service, Fort Collins, Colorado.

https://irma.nps.gov/DataStore/Reference/Profile/2225350. 

103

Additional References

This section lists additional references, resources, and websites that may be of use to resource managers. 

Web addresses are valid as of September 2016. Refer to Appendix C for laws, regulations, and policies 

that apply to NPS geologic resources.

Geology of Alaska

● Geologic Map of Alaska:

http://dx.doi.org/10.3133/sim3340

● Alaska Digital Geologic Map and Geologic Data 

Online Viewer: http://mrdata.usgs.gov/geology/

state/alaska.html

● Alaska (Minerals) Resource Data File:

http://ardf.wr.usgs.gov/

● Alaska Paleontology Database:

http://www.alaskafossil.org/

● Alaska Division of Geological and Geophysical 

Surveys (and Alaska USGS) publications:

http://dggs.alaska.gov/pubs/pubs.jsp

Geology of National Park Service Areas

● NPS Geologic Resources Division—Energy 

and Minerals, Active Processes and Hazards, and 

Geologic Heritage: http://go.nps.gov/geology/

● NPS Geologic Resources Inventory:

http://go.nps.gov/gri

● NPS Geoscientist-In-the-Parks (GIP) internship 

and guest scientist program: http://go.nps.gov/gip

● NPS Views program (geology-themed modules are 

available for Geologic Time, Paleontology, Glaciers,

Caves and Karst, Coastal Geology, Volcanoes, and a 

variety of geologic parks): http://go.nps.gov/views

NPS Resource Management Guidance and 

Documents

● 1998 National Parks Omnibus Management Act: 

http://www.gpo.gov/fdsys/pkg/PLAW-105publ391/

pdf/PLAW-105publ391.pdf

● Geologic monitoring manual:

http://go.nps.gov/geomonitoring

● Management Policies 2006 (Chapter 4: Natural 

resource management):

http://www.nps.gov/policy/mp/policies.html

● NPS-75: Natural resource inventory and 

monitoring guideline:

http://www.nature.nps.gov/nps75/nps75.pdf

● NPS Natural resource management reference 

manual #77: http://www.nature.nps.gov/Rm77/

● NPS Technical Information Center (TIC) (Denver, 

Colorado; repository for technical documents): 

http://www.nps.gov/dsc/technicalinfocenter.htm

http://etic.nps.gov/

Climate Change Resources

● NPS Climate Change Response Program Resources: 

http://www.nps.gov/subjects/climatechange/

resources.htm

● US Global Change Research Program:

http://globalchange.gov/home

● Intergovernmental Panel on Climate Change:

http://www.ipcc.ch/

Geological Surveys and Societies

● Alaska Division of Geological and Geophysical 

Surveys: http://dggs.alaska.gov/

● US Geological Survey: http://www.usgs.gov/

● USGS Publications: http://pubs.er.usgs.gov/

● Geological Society of America:

http://www.geosociety.org/

● American Geophysical Union: http://sites.agu.org/

● American Geosciences Institute:

http://www.americangeosciences.org/

● Association of American State Geologists:

http://www.stategeologists.org/

US Geological Survey Reference Tools

● Geologic glossary (simplified definitions):

http://geomaps.wr.usgs.gov/parks/misc/glossarya.

html

● Geologic names lexicon (Geolex; geologic unit 

nomenclature and summary):

http://ngmdb.usgs.gov/Geolex/geolex_home.html

● Geographic names information system (GNIS; 

official listing of place names and geographic 

features): http://gnis.usgs.gov/

● GeoPDFs (download searchable PDFs of any 

topographic map in the United States):

http://store.usgs.gov (click on “Map Locator”)
104

● National geologic map database (NGMDB):

http://ngmdb.usgs.gov/

● Publications warehouse (many publications 

available online): http://pubs.er.usgs.gov
105

Appendix A: History of Exploration

A thorough history of geologic exploration of the Katmai area was compiled by Hildreth and Fierstein 

(2012, Chapter 4). This appendix provides a concise chronology of historic geologic exploration and 

provides references to published reports.

1898—Josiah E. Spurr led a USGS party through 

southwest Alaska and passed through Naknek Lake and 

Katmai Pass (Spurr 1900).

1912—George C. Martin (USGS geologist) conducted 

a survey of the surrounding communities gathering 

information about the 1912 eruption (Martin 1913).

1913—George B. Rigg (US Bureau of Soils) conducted 

a coastal survey examining the eruption’s impact on 

kelp and intertidal algae with the assistance of Robert F. 

Griggs (Griggs 1918a, 1919).

1915–1930—Robert F. Griggs led numerous National 

Geographic expeditions to the site of the eruption 

and discovered the Valley of Ten Thousand Smokes 

(Griggs 1917, 1918b, 1918c, 1918d, 1918e, 1933). 

Griggs’ seminal book (Griggs 1922) was published, 

which covered the 1912 eruption and its effects on 

the surrounding area, and is a synthesis of all of the 

expeditions prior to 1922.

1923—Clarence N. Fenner and Charles Yori explored 

the Katmai area, and Walter R. Smith led a USGS party 

that explored and mapped the area from Katmai to 

Savonoski (Smith 1925).

Figure A1. Griggs expedition, Baked Mountain Camp in 1919. Mount Martin in the background. National Geographic 

Society photograph by Emery C. Kolb (Griggs 1922, p. 264).
106

1929–1934—Bernard R. Hubbard explored the Katmai 

area (Hubbard 1932, 1935).

1953—Katmai Project. A comprehensive, multi-agency 

geologic and biologic investigation of the monument 

sponsored by the National Park Service in cooperation 

with the US Geological Survey, US Navy, Public Health 

Service, and various universities.

1954—Garniss H. Curtis and Jack Sheehan examined 

the deposits and postulated that the ignimbrite was 

sourced from the Novarupta vent and not from Mount 

Katmai (Curtis 1968).

1963—Robert W. Decker and Peter L. Ward, supported 

by the University of Alaska Fairbanks (UAF)-

Geophysical Institute, began a geophysical study of 

the Valley of Ten Thousand Smokes, which included 

installing seismic monitoring stations and measuring 

gravity.

1965—The Baked Mountain Huts (see cover 

photograph) were built by the UAF-Geophysical 

Institute with assistance of the US Air Force. 

Ed Berg and Jürgen Kienle continued the seismic and 

geophysical studies of the Valley of Ten Thousand 

Smokes and Katmai Pass.

NASA and USGS Apollo moon landing field training 

mission to Katmai to study rocks and landscapes 

similar to those that may be encountered on the moon. 

Astronauts included Buzz Aldrin, William Anders, 

Charles Bassett, Eugene Cernan, Roger Chaffee, Walt 

Cunningham, Rusty Schweikart, Dave Scott, and C. C. 

Williams (Schaber 2005).

1969—Robert Forbes initiated a multi-year geophysical 

study of the Katmai area, the results of which were 

never published. Draft manuscripts are available in the 

Alaska NPS curation center, and the UAF-Geophysical 

Institute.

Figure A2. Bernard Hubbard inspecting a bread-crust bomb adjacent to the steaming Novarupta dome in 1935. Image 

provided by Archives and Special Collections, Santa Clara University Library; The Bernard R. Hubbard, S. J. Alaskan 

Photographs, 1927–1961, VTS-35-330.
107

1975—Roman J. Motyka accessed the Mount Katmai 

crater lake using an inflatable raft to make water quality 

measurements (Motyka 1977).

1976—Wes Hildreth begins studying the Katmai area 

and spends much of next 40 years studying the Katmai 

volcanoes.

1980—Judy Fierstein first steps foot in the Katmai area 

as an assistant to Wes Hildreth, which was the start 

of a fruitful research collaboration that resulted in 

numerous publications and culminated in the capstone 

centennial report of the eruption and volcanoes of 

Katmai (Hildreth and Fierstein 2012).

1983–1987—James R. Riehle and Robert L. Detterman 

of the US Geological Survey conducted an Alaska 

Mineral Resources Assessment Project, which 

produced the primary geologic maps used for the GRI 

compilation in Plate 1 (Riehle and Detterman 1993; 

Riehle et al. 1993).

1985—John Eichelberger proposes a scientific project 

to drill into the Novarupta vent and adjacent areas to 

understand the inner workings of the volcano. Although 

the project was eventually not permitted by the National 

Park Service, many research projects were conducted 

during the preparations for the project.

1987–1988—Judy Fierstein initiated a tephra study 

along both shores of Shelikof Strait to measure 

thicknesses of the 1912 ash fall layers (Fierstein and 

Hildreth 1992; Fierstein and Nathenson 1992).

1989–1990—Geophysical expeditions were carried out 

by numerous researchers in support of the proposed 

drilling project (Eichelberger et al. 1991).

1992—Fierstein and Hildreth (1992) publish a detailed 

analysis and stratigraphy of the eruption sequence.

1996—Hildreth and Fierstein begin work on a detailed 

geologic map of the Katmai cluster volcanoes (Hildreth 

and Fierstein 2003).

1994–2010—Fierstein, Wilson, Houghton, and Hildreth 

characterized 1912 near-vent deposits in unprecedented 

detail, elucidating eruption processes for large explosive 

events.

109

Appendix B: Potential Geologic Research, Inventory, and 

Monitoring Projects

This section provides some suggestions for future geologic studies of the Katmai area. This list was 

compiled by the authors after meetings with park staff, review of the foundation statements and 

founding documents, the GRI scoping report, and reviewing available geologic literature for the area. 

This list is not an exhaustive list of research, nor is it a list of the highest priority research to support 

park management. Some of the studies suggested have clear ties to park management issues; other 

studies have broader interests and applications. In addition to USGS, Alaska Geological Survey, and 

NPS Alaska Region Office, the Geoscientists-in-the-Parks (GIP; http://go.nps.gov/gip) and Mosaics In 

Science (http://go.nps.gov/mosaics) internship programs are potential sources to recruit assistance for 

these projects.

In general, the volcanic features formed during the 1912 

eruption have been the focus of most geologic research 

in the park. The other volcanoes of the park have only 

been studied at the reconnaissance level. The surficial 

geology and glacial geology of the Brooks Camp area 

have been a focus for understanding the archeological 

resources of the area, but outside of that area, little 

research has been conducted. The bedrock geology has 

been mapped at the 1:250,000 scale, which is considered 

a reconnaissance level of detail. The bedrock units 

contain a great abundance of paleontological resources, 

so more detailed study of these rocks is warranted. 

The coastal morphology has not been studied in detail. 

Volcanic hazards have been addressed by the Alaska 

Volcano Observatory (AVO), but many other hazards 

exist that could cause harm. No detailed systematic 

study or monitoring of the volume changes of the 

numerous glaciers has been conducted.

● Conduct detailed study of the eruptive history 

of the 24 Quaternary (up to 2.6 MYA) volcanoes. 

Most of the Quaternary volcanoes have only 

been studied at a reconnaissance level. A more 

detailed study of these volcanoes will form a better 

understanding of their eruptive histories and lead 

to better assessment of their eruption potential. 

For example, the eruption of Trident Volcano was 

out of heavily eroded peaks that would have been 

considered an old and dead volcano. Fourpeaked 

Volcano was listed as a low concern according to 

the USGS volcanic threat assessment (Ewert et 

al. 2005), but the 2006 eruption surprised AVO 

staff, and now rates as a higher threat. Very little 

is known about the eruptive histories of most 

of the Quaternary volcanoes, so a complete 

understanding of their eruptive potential is not 

known. The volcanoes north of Kaguyak are 

remote and ice covered, so have not been studied 

in detail. However, the eruption of Fourpeaked 

and the active fumaroles on many of the volcanoes 

suggest that they are active.

● Study the Pliocene (5.3–2.6 MYA) volcanic 

centers. Pliocene volcanic centers have been little 

studied. For example, the dissected Pleistocene 

(2.6–0.01 MYA) or Pliocene (5.36–2.6 MYA) 

volcanic rocks make up the Kejulik Mountains, but 

little effort has been made to study these volcanic 

rocks, which lie on strike with the main Aleutian 

volcanic arc front, are well-exposed, and close to 

King Salmon.

● Understand the landscape geomorphic 

changes in response to the 1912 eruption. 

Detailed geomorphic mapping and analysis of 

the 1912 eruption features and its effects have 

only been side notes to the volcanic research. An 

understanding of the geomorphic changes caused 

by the eruption would provide a framework for 

better understanding the response of ecosystems 

to volcanic disturbances. Methods could include 

review of old photos and repeat photographs, 

aerial photography, and satellite imagery such as 

Landsat to measure stream erosion, aggregation, 

delta growth, and revegetation of thick volcanic 

deposits. Of particular interest would be the study 

of the aggradation and stream avulsion of the 

Ukak, Savonoski, and Katmai Rivers. Examples 

of geomorphic effects of volcanic eruptions, 

including connections to ecology, were outlined in 

Waythomas (2015).
110

● Map fissures using IKONOS imagery. The 

fissure and fracture geometry may be useful for 

interpreting the cooling history of the ignimbrite; 

modeling water flow within the ignimbrite; 

modeling differential erosion of the ignimbrite; 

and modeling differential contraction/compaction/

welding of the ignimbrite. 

● Monitor the crater lakes. The crater lakes have 

evidence of active volcanic inputs in the form of 

high sulfur, acid, and temperature levels, so the 

monitoring of these lakes’ hydrochemistry may 

lead to a better understanding of these geothermal 

features. Also monitor the rising lake level in Katmai 

Crater.

● Search for dinosaur tracks and bone in the 

Naknek Formation. Dinosaur tracks were found in 

the Naknek Formation farther south on the Alaska 

Peninsula (Druckenmiller et al. 2011), and bone 

fragments have been found (Fiorillo et al. 2004). 

The type section of Naknek Formation is in the 

park, and the unit is extensive through the park, so 

there is a high potential for finding dinosaur tracks 

or bones.

● Conduct detailed geomorphic mapping. The 

available geomorphic maps of the Katmai area were 

compiled at the 1:250,000 scale from air photos. 

New InSAR derived digital elevation models 

provided through the Alaska Statewide Mapping 

Initiative (http://www.alaskamapped.org/sdmi) 

could be used to make more detailed surficial 

maps and landform maps. Geomorphic mapping 

would provide a better understanding of surficial 

processes such as landslides, floods, and glaciation, 

which impact human use and management of 

rugged landscapes. The materials and landforms 

produced by these geomorphic processes influence 

soils and vegetation patterns, and provide 

indications of geohazards, prehistoric use, and 

ecological disturbances.

● Conduct detailed coastal geomorphology 

mapping. The coast is a dynamic place that is 

constantly changed by the addition of sediment 

from glacially fed rivers and eroded by storm 

waves. The coast is tectonically uplifting and sea 

levels and storm frequency are forecast to rise, so 

understanding the coastal geomorphic processes 

would provide park managers with a better 

framework for predicting ecological changes and 

protecting or preserving infrastructure and cultural 

resources. Methods could include interpretation 

using remote sensing, photogrammetry, or LiDAR.

● Conduct detailed bedrock geology and surficial 

geology map of Brooks River area. Brooks Camp 

and the Brooks River National Historic Landmark 

is the most visited area of the Katmai area, so a 

detailed bedrock and surficial geology map would 

be useful for interpretation and integration with 

cultural studies.

● Create a comprehensive geohazards map. AVO 

staff members have produced a volcanic hazard 

assessment for the Katmai cluster, but as described 

in the “Geologic Resource Management Issues” 

section of this report, many other geohazards 

can occur in areas away from the volcanoes. A 

cursory hazard map showing potential rockfall and 

landslide areas map is provided in Figure 100. A 

comprehensive geohazards map and analysis could 

help managers identify areas of high potential. 

Particular areas of interest could be mapped or 

modeled in more detail where infrastructure may be 

damaged and where staff or visitors spend extended 

periods of time.

● Date glacial moraines. Surface dating of glacial 

moraines would help better constrain their ages 

and test correlation hypotheses. Plate 1 shows 

the deposits from the various glaciations, and 

Figure 64 shows a glacial extent map for the region 

surrounding Katmai. The Katmai area holds a wellexposed record of past glaciations, but the dating 

of the glacier deposits is still reconnaissance level 

at best. An understanding of past climate could be 

improved with better control on the ages of the 

glaciations, which could lead to significant revisions 

to the glacial history of the Alaska Peninsula. 

The results of such as study could initiate a new 

generation of moraine and outwash investigations 

in the Katmai area.

● Cosmogenic and radiometric dating of the lake 

terraces. Dating of the lake terraces will better 

constrain the timing of draining Naknek Lake in 

relation to the timing of glacial retreat. These lake 

terraces formed the foundations for the ancient 

dwellings and the draining of the lake allowed the 

Brooks River to form, creating a good fishing site.

● Date raised marine terraces. The uplift rates of 

the coast are provided from only two sources: a 

single modern GPS survey marker (Freymueller 

et al. 2008) and limited radiocarbon ages on 

organic material on a few raised marine terraces 

(Detterman and Reed 1973; Crowell and 

Mann 1996). A study focused on surveying and 

inventorying marine terraces and relict sea caves, 
111

inventorying marine terraces and relict sea caves, 

and better dating these features, would improve 

the constraints for the uplift rate of the coast and 

understanding of earthquake effects on the coastal 

ecology and landforms. 

● Conduct a reconnaissance study of tsunami

deposits along the coast. No tsunami deposits

have yet been identified along the coast, but

preliminary modeling of an earthquake generated

tsunami indicates that the run-up heights of a

tsunami may be on the order of tens of meters. The

probability is good that a tsunami has hit the coast

in prehistoric times, so deposits may be hidden in

the uplands of the many bays.

● Model the possible effects of volcanic activity

on the glaciers and downstream hydrologic

effects. Many volcanoes in the Katmai area have

substantially sized glaciers. The effects of volcanic

activity on the overlying glaciers could cause

catastrophic changes to downstream ecosystems

and geomorphology. Types of effects could be

described, areas of potentially affected areas could

be mapped, and baseline data could be collected

prior to eruptions.

● Map “interesting geologic features.” The GRI 

scoping report (Graham 2005) identified the need

for a map showing “interesting geologic features”

such as those indicative of the 1912 eruption,

volcanoes, geothermal activity, crater lakes, beach

berms, beach ridges, terminal moraines, ancient

glacial lakes, the 1964 earthquake, and raised

terraces.

● Prepare geologic fact sheets, website content,

and other interpretive products:

□ Brooks Camp area geology. The Brooks Camp

area is the most visited area in the park, so

geologic information about the immediate area

would be useful for visitors.

□ Ukak Falls geology. The Ukak Falls area is

the most visited area outside of Brooks Camp,

so geology information about the Naknek

Formation, its fossils, and the ignimbrite would

be useful.

□ 1912 Novarupta eruption and Valley of Ten

Thousand Smokes. Many park information

newsletters and interpretive products contain

information about the 1912 eruption and its

deposits, but a simplified fact sheet describing

the features is not available.

□ Glacial history of Naknek Lake area. Most

visitors to Katmai fly over the spectacularly 

exposed glacial moraines and other glacial

features of the area. A fact sheet describing

these features with a map pointing out the main

features seen from the air along common flight

paths would provide visitors with an aerial

guide to the geomorphic features of the park.

113

Appendix C: Geologic Resource Laws, Regulations, and Policies

The NPS Geologic Resources Division developed this table to summarize laws, regulations, and policies 

that specifically apply to National Park Service minerals and geologic resources. The table does not 

include laws of general application (e.g., Endangered Species Act, Clean Water Act, Wilderness Act, 

National Environmental Policy Act, or National Historic Preservation Act). The table does include the 

NPS Organic Act when it serves as the main authority for protection of a particular resource or when 

other, more specific laws are not available. Information is current as of August 2016. Contact the NPS 

Geologic Resources Division for detailed guidance.

Resource Resource-specific Laws Resource-specific Regulations 2006 Management Policies Paleontology

National Parks Omnibus Management 

Act of 1998, 16 USC § 5937 protects the 

confidentiality of the nature and specific 

location of paleontological resources and 

objects.

Paleontological Resources Preservation 

Act of 2009, 16 USC § 470aaa et 

seq. provides for the management and 

protection of paleontological resources on 

federal lands.

36 CFR § 2.1(a)(1)(iii) prohibits destroying, 

injuring, defacing, removing, digging or 

disturbing paleontological specimens or 

parts thereof.

Prohibition in 36 CFR § 13.35 applies 

even in Alaska parks, where the surface 

collection of other geologic resources is 

permitted.

Regulations in association with 2009 PRPA 

are being finalized (August 2016).

Section 4.8.2 requires NPS to protect 

geologic features from adverse effects of 

human activity.

Section 4.8.2.1 emphasizes Inventory and 

Monitoring, encourages scientific research, 

directs parks to maintain confidentiality of 

paleontological information, and allows 

parks to buy fossils only in accordance with 

certain criteria.

Rocks and Minerals

NPS Organic Act, 16 USC § 1 et seq.

directs the NPS to conserve all resources 

in parks (including rock and mineral 

resources), unless otherwise authorized by 

law.

36 CFR § 2.1 prohibits possessing, 

destroying, disturbing mineral resources...

in park units.

Exception: 36 CFR § 13.35 allows some 

surface collection of rocks and minerals 

in some Alaska parks (not Klondike 

Gold Rush, Sitka, Denali, Glacier Bay, 

or Katmai) by non-disturbing methods 

(e.g., no pickaxes), which can be stopped 

by superintendent if collection causes 

significant adverse effects on park 

resources and visitor enjoyment.

Section 4.8.2 requires NPS to protect 

geologic features from adverse effects of 

human activity.

Park Use of Sand and Gravel

Materials Act of 1947, 30 USC § 601

does not authorize the NPS to dispose of 

mineral materials outside of park units.

None applicable.

Section 9.1.3.3 clarifies that only the 

NPS or its agent can extract park-owned 

common variety minerals (e.g., sand and 

gravel), and:

-only for park administrative uses;

-after compliance with NEPA and other 

federal, state, and local laws, and a 

finding of non-impairment;

-after finding the use is park’s most 

reasonable alternative based on 

environment and economics;

-parks should use existing pits and create 

new pits only in accordance with parkwide borrow management plan;

-spoil areas must comply with Part 6 

standards; and

-NPS must evaluate use of external 

quarries.

Any deviation from this policy requires a 

written waiver from the Secretary, Assistant 

Secretary, or Director.
114

Resource Resource-specific Laws Resource-specific Regulations 2006 Management Policies Upland and Fluvial Processes

Rivers and Harbors Appropriation 

Act of 1899, 33 USC § 403 prohibits the 

construction of any obstruction on the 

waters of the United States not authorized 

by Congress or approved by the USACE.

Clean Water Act 33 USC § 1342 requires 

a permit from the USACE prior to any 

discharge of dredged or fill material 

into navigable waters (waters of the US 

[including streams]). 

Executive Order 11988 requires federal 

agencies to avoid adverse impacts to 

floodplains. (see also D.O. 77-2)

Executive Order 11990 requires plans for 

potentially affected wetlands (including 

riparian wetlands). (see also D.O. 77-1)

None applicable.

Section 4.1 requires NPS to manage 

natural resources to preserve fundamental 

physical and biological processes, as well 

as individual species, features, and plant 

and animal communities; maintain all 

components and processes of naturally 

evolving park ecosystems.

Section 4.1.5 directs the NPS to reestablish natural functions and processes 

in human-disturbed components of natural 

systems in parks, unless directed otherwise 

by Congress.

Section 4.4.2.4 directs the NPS to allow 

natural recovery of landscapes disturbed by 

natural phenomena, unless manipulation of 

the landscape is necessary to protect park 

development or human safety. 

Section 4.6.4 directs the NPS to (1) 

manage for the preservation of floodplain 

values; [and] (2) minimize potentially 

hazardous conditions associated with 

flooding.

Section 4.6.6 directs the NPS to manage 

watersheds as complete hydrologic systems 

and minimize human-caused disturbance 

to the natural upland processes that deliver 

water, sediment, and woody debris to 

streams.

Section 4.8.1 directs the NPS to allow 

natural geologic processes to proceed 

unimpeded. Geologic processes...include...

erosion and sedimentation...processes. 

Section 4.8.2 directs the NPS to protect 

geologic features from the unacceptable 

impacts of human activity while allowing 

natural processes to continue.

Caves and Karst Systems

Federal Cave Resources Protection Act 

of 1988, 16 USC §§ 4301 – 4309 requires 

Interior/Agriculture to identify “significant 

caves” on Federal lands, regulate/

restrict use of those caves as appropriate, 

and include significant caves in land 

management planning efforts. Imposes 

civil and criminal penalties for harming 

a cave or cave resources. Authorizes 

Secretaries to withhold information about 

specific location of a significant cave from 

a Freedom of Information Act (FOIA) 

requester. 

National Parks Omnibus Management 

Act of 1998, 16 USC § 5937 protects the 

confidentiality of the nature and specific 

location of cave and karst resources.

36 CFR § 2.1 prohibits possessing/ 

destroying/disturbing...cave resources...in 

park units.

43 CFR Part 37 states that all NPS caves 

are “significant” and sets forth procedures 

for determining/releasing confidential 

information about specific cave locations to 

a FOIA requester.

Section 4.8.1.2 requires NPS to maintain 

karst integrity, minimize impacts.

Section 4.8.2 requires NPS to protect 

geologic features from adverse effects of 

human activity.

Section 4.8.2.2 requires NPS to protect 

caves, allow new development in or on 

caves if it will not impact cave environment, 

and to remove existing developments if 

they impair caves.

Section 6.3.11.2 explains how to manage 

caves in/adjacent to wilderness.
115

Resource Resource-specific Laws Resource-specific Regulations 2006 Management Policies Soils

Soil and Water Resources Conservation 

Act, 16 USC §§ 2011–2009 provides for 

the collection and analysis of soil and 

related resource data and the appraisal of 

the status, condition, and trends for these 

resources.

Farmland Protection Policy Act, 7 USC 

§ 4201 et. seq. requires NPS to identify 

and take into account the adverse effects 

of Federal programs on the preservation 

of farmland; consider alternative actions, 

and assure that such Federal programs 

are compatible with State, unit of local 

government, and private programs and 

policies to protect farmland. NPS actions 

are subject to the FPPA if they may 

irreversibly convert farmland (directly 

or indirectly) to nonagricultural use and 

are completed by a Federal agency or 

with assistance from a Federal agency. 

Applicable projects require coordination 

with the Department of Agriculture’s 

Natural Resources Conservation Service 

(NRCS).

7 CFR Parts 610 and 611 are the US 

Department of Agriculture regulations 

for the Natural Resources Conservation 

Service. Part 610 governs the NRCS 

technical assistance program, soil erosion 

predictions, and the conservation of private 

grazing land. Part 611 governs soil surveys 

and cartographic operations. The NRCS 

works with the NPS through cooperative 

arrangements.

Section 4.8.2.4 requires NPS to

-prevent unnatural erosion, removal, and 

contamination;

-conduct soil surveys;

-minimize unavoidable excavation; and

-develop/follow written prescriptions 

(instructions).

Coastal Features and Processes

NPS Organic Act, 16 USC § 1 et. 

seq. authorizes the NPS to promulgate 

regulations to protect park resources and 

values (from, for example, the exercise of 

mining and mineral rights).

Coastal Zone Management Act, 16 USC 

§ 1451 et. seq. requires Federal agencies 

to prepare a consistency determination for 

every Federal agency activity in or outside 

of the coastal zone that affects land or 

water use of the coastal zone.

Clean Water Act, 33 USC § 1342/Rivers 

and Harbors Act, 33 USC 403 require that 

dredge and fill actions comply with a Corps 

of Engineers Section 404 permit.

Executive Order 13089 (coral reefs) 

(1998) calls for reduction of impacts to 

coral reefs.

Executive Order 13158 (marine 

protected areas) (2000) requires every 

federal agency, to the extent permitted by 

law and the maximum extent practicable, 

to avoid harming marine protected areas.

36 CFR § 1.2(a)(3) applies NPS regulations 

to activities occurring within waters subject 

to the jurisdiction of the US located 

within the boundaries of a unit, including 

navigable water and areas within their 

ordinary reach, below the mean high water 

mark (or OHW line) without regard to 

ownership of submerged lands, tidelands, 

or lowlands.

36 CFR § 5.7 requires NPS authorization 

prior to constructing a building or other 

structure (including boat docks) upon, 

across, over, through, or under any park 

area.

Section 4.1.5 directs the NPS to reestablish natural functions and processes 

in human-disturbed components of natural 

systems in parks unless directed otherwise 

by Congress.

Section 4.4.2.4 directs the NPS to allow 

natural recovery of landscapes disturbed by 

natural phenomena, unless manipulation of 

the landscape is necessary to protect park 

development or human safety.

Section 4.8.1 requires NPS to allow natural 

geologic processes to proceed unimpeded. 

NPS can intervene in these processes 

only when required by Congress, when 

necessary for saving human lives, or when 

there is no other feasible way to protect 

other natural resources/ park facilities/

historic properties.

Section 4.8.1.1 requires NPS to:

-Allow natural processes to continue 

without interference,

-Investigate alternatives for mitigating the 

effects of human alterations of natural 

processes and restoring natural conditions, 

-Study impacts of cultural resource 

protection proposals on natural resources, 

-Use the most effective and natural-looking 

erosion control methods available, and 

-Avoid putting new developments in areas 

subject to natural shoreline processes 

unless certain factors are present.
116

Resource Resource-specific Laws Resource-specific Regulations 2006 Management Policies Climate Change

Secretarial Order 3289 (Addressing 

the Impacts of Climate Change on 

America’s Water, Land, and Other Natural 

and Cultural Resources) (2009) requires 

DOI bureaus and offices to incorporate 

climate change impacts into long-range 

planning; and establishes DOI regional 

climate change response centers and 

Landscape Conservation Cooperatives to 

better integrate science and management 

to address climate change and other 

landscape scale issues.

Executive Order 13653 (Preparing the 

United States for the Impacts of Climate 

Change) (2013) outlines Federal agency 

responsibilities in the areas of supporting 

climate resilient investment; managing 

lands and waters for climate preparedness 

and resilience; providing information, data 

and tools for climate change preparedness 

and resilience; and planning.

Executive Order 13693 (Planning for 

Federal Sustainability in the Next Decade) 

(2015) established to maintain Federal 

leadership in sustainability and greenhouse 

gas emission reductions.

President’s Climate Action Plan (2013), 

http://www.whitehouse.gov/sites/default/

files/image/president27sclimateactionplan.

pdf

None applicable.

Section 4.1 requires NPS to investigate 

the possibility to restore natural ecosystem 

functioning that has been disrupted by past 

or ongoing human activities. This would 

include climate change, as put forth by 

Beavers et al. (in review).

NPS Climate Change Response Strategy

(2010) describes goals and objectives to 

guide NPS actions under four integrated 

components: science, adaptation, 

mitigation, and communication.

Policy Memo 12-02 (Applying National 

Park Service Management Policies in the 

Context of Climate Change) (2012) applies 

considerations of climate change to the 

impairment prohibition and to maintaining 

“natural conditions”.

Policy Memo 14-02 (Climate Change and 

Stewardship of Cultural Resources) (2014) 

provides guidance and direction regarding 

the stewardship of cultural resources in 

relation to climate change.

Policy Memo 15-01 (Climate Change 

and Natural Hazards for Facilities) (2015) 

provides guidance on the design of facilities 

to incorporate impacts of climate change 

adaptation and natural hazards when 

making decisions in national parks.

DOI Manual Part 523,

Chapter 1 establishes policy and provides 

guidance for addressing climate change 

impacts upon the Department’s mission, 

programs, operations, and personnel.

Revisiting Leopold: Resource 

Stewardship in the National Parks

(2012) will guide US National Park natural 

and cultural resource management into 

a second century of continuous change, 

including climate change.

Climate Change Action Plan (2012) 

articulates a set of high-priority no-regrets 

actions the NPS will undertake over the 

next few years

Green Parks Plan (2013) is a long-term 

strategic plan for sustainable management 

of NPS operations.
117

Resource Resource-specific Laws Resource-specific Regulations 2006 Management Policies Mining Claims

Mining in the Parks Act of 1976, 16 

USC § 1901 et seq. authorizes NPS 

to regulate all activities resulting from 

exercise of mineral rights, on patented and 

unpatented mining claims in all areas of the 

System, in order to preserve and manage 

those areas.

General Mining Law of 1872, 30 USC 

§ 21 et seq. allows US citizens to locate 

mining claims on Federal lands. Imposes 

administrative and economic validity 

requirements for “unpatented” claims (the 

right to extract Federally-owned locatable 

minerals). Imposes additional requirements 

for the processing of “patenting” claims 

(claimant owns surface and subsurface). 

Use of patented mining claims may be 

limited in Wild and Scenic Rivers and 

OLYM, GLBA, CORO, ORPI, and DEVA. 

Surface Uses Resources Act of 1955, 

30 USC § 612 restricts surface use of 

unpatented mining claims to mineral 

activities.

36 CFR § 5.14 prohibits prospecting, 

mining, and the location of mining claims 

under the general mining laws in park 

areas except as authorized by law.

36 CFR Part 6 regulates solid waste 

disposal sites in park units.

36 CFR Part 9, Subpart A requires the 

owners/operators of mining claims to 

demonstrate bona fide title to mining 

claim; submit a plan of operations to NPS 

describing where, when, and how; prepare/

submit a reclamation plan; and submit a 

bond to cover reclamation and potential 

liability.

Section 6.4.9 requires NPS to seek to 

remove or extinguish valid mining claims in 

wilderness through authorized processes, 

including purchasing valid rights. Where 

rights are left outstanding, NPS policy is 

to manage mineral-related activities in 

NPS wilderness in accordance with the 

regulations at 36 CFR Parts 6 and 9A.

Section 8.7.1 prohibits location of new 

mining claims in parks; requires validity 

examination prior to operations on 

unpatented claims; and confines operations 

to claim boundaries.

Nonfederal Oil and Gas

NPS Organic Act, 16 USC § 1 et seq.

authorizes the NPS to promulgate 

regulations to protect park resources and 

values (from, for example, the exercise of 

mining and mineral rights).

36 CFR Part 6 regulates solid waste 

disposal sites in park units.

36 CFR Part 9, Subpart B requires the 

owners/operators of nonfederally owned 

oil and gas rights to

-demonstrate bona fide title to mineral 

rights;

-submit a plan of operations to NPS 

describing where, when, how they intend 

to conduct operations;

-prepare/submit a reclamation plan; and 

-submit a bond to cover reclamation and 

potential liability.

Section 8.7.3 requires operators to comply 

with 9B regulations.
118

Resource Resource-specific Laws Resource-specific Regulations 2006 Management Policies Nonfederal minerals other than oil and gas

NPS Organic Act, 16 USC §§ 1 and 3

Surface Mining Control and 

Reclamation Act of 1977, 30 USC 

§ 1201 et. seq. prohibits surface coal 

mining operations on any lands within the 

boundaries of a NPS unit, subject to valid 

existing rights.

NPS regulations at 36 CFR Parts 1, 5, 

and 6 require the owners/operators of 

other types of mineral rights to obtain 

a special use permit from the NPS as a 

§ 5.3 business operation, and § 5.7 – 

Construction of buildings or other facilities, 

and to comply with the solid waste 

regulations at Part 6.

SMCRA Regulations at 30 CFR Chapter 

VII govern surface mining operations on 

Federal lands and Indian lands by requiring 

permits, bonding, insurance, reclamation, 

and employee protection. Part 7 of the 

regulations states that National Park System 

lands are unsuitable for surface mining.

Section 8.7.3 states that operators 

exercising rights in a park unit must comply 

with 36 CFR Parts 1 and 5.

Geothermal

Geothermal Steam Act of 1970, 30 USC 

§ 1001 et seq. as amended in 1988, 

states that

-no geothermal leasing is allowed in parks;

-“significant” thermal features exist in 16 

park units (features listed by the NPS at 52 

Fed. Reg. 28793-28800 [August 3, 1987], 

and thermal features in Crater Lake, Big 

Bend, and Lake Mead);

-NPS is required to monitor those features; 

and

-based on scientific evidence, Secretary 

of Interior must protect significant NPS 

thermal features from leasing effects.

Geothermal Steam Act Amendments 

of 1988, Public Law 100--443 prohibits 

geothermal leasing in the Island Park 

known geothermal resource area near 

Yellowstone and outside 16 designated 

NPS units if subsequent geothermal 

development would significantly adversely 

affect identified thermal features.

None applicable

Section 4.8.2.3 requires NPS to

-preserve/maintain integrity of all thermal 

resources in parks.

-work closely with outside agencies, and

-monitor significant thermal features.
119

Resource Resource-specific Laws Resource-specific Regulations 2006 Management Policies Federal Mineral Leasing (Oil and Gas, Salable Minerals, and Non-locatable Minerals)

The Mineral Leasing Act, 30 USC § 181 

et seq., and the Mineral Leasing Act for 

Acquired Lands, 30 USC § 351 et seq. 

do not authorize the BLM to lease federally 

owned minerals in NPS units. 

Exceptions: Native American Lands Within 

NPS Boundaries Under the Indian Allottee 

Leasing Act of 1909, (25 USC § 396), 

and the Indian Leasing Act of 1938 (25 

USC §§ 396a, 398 and 399) and Indian 

Mineral Development Act of 1982 

(25 USC §§ 2101-2108), all minerals 

are subject to lease and apply to Native 

American trust lands within NPS units.

Federal Coal Leasing Amendments Act 

of 1975, 30 USC § 201 does not authorize 

the BLM to issue leases for coal mining on 

any area of the national park system.

36 CFR § 5.14 states prospecting, mining, 

and...leasing under the mineral leasing 

laws [is] prohibited in park areas except as 

authorized by law.

BLM regulations at 43 CFR Parts 3100, 

3400, and 3500 govern Federal mineral 

leasing.

Regulations re: Native American Lands 

within NPS Units:

25 CFR Part 211 governs leasing of tribal 

lands for mineral development. 

25 CFR Part 212 governs leasing of 

allotted lands for mineral development. 

25 CFR Part 216 governs surface 

exploration, mining, and reclamation of 

lands during mineral development. 

25 CFR Part 224 governs tribal energy 

resource agreements.

25 CFR Part 225 governs mineral 

agreements for the development of Indianowned minerals entered into pursuant to 

the Indian Mineral Development Act of 

1982, Pub. L. No. 97-382, 96 Stat. 1938 

(codified at 25 USC §§ 2101-2108).

30 CFR §§ 1202.100-1202.101 governs 

royalties on oil produced from Indian 

leases. 

30 CFR §§ 1202.550-1202.558 governs 

royalties on gas production from Indian 

leases. 

30 CFR §§ 1206.50-1206.62 and §§ 

1206.170-1206.176 governs product 

valuation for mineral resources produced 

from Indian oil and gas leases. 

30 CFR § 1206.450 governs the valuation 

coal from Indian Tribal and Allotted leases.

43 CFR Part 3160 governs onshore oil and 

gas operations, which are overseen by the 

BLM.

Section 8.7.2 states that all NPS units 

are closed to new federal mineral leasing 

except Glen Canyon, Lake Mead and 

Whiskeytown-Shasta-Trinity NRAs.

121

Appendix D: Scoping Participants

The following people attended the GRI scoping meeting for the Southwest Alaska Network, held on 14–

18 February 2005 or a follow-up report writing kick-off meeting held on 27 January 2015. Discussions 

during these meetings supplied a foundation for this GRI report. The scoping summary document is 

available on the GRI publications website: http://go.nps.gov/gripubs.

2005 Scoping Meeting Participants

Name Affiliation Position

Beavers, Rebecca NPS-Geologic Resources Division Coastal geologist

Bennett, Alan NPS-Southwest Alaska Network Network coordinator

Bundtzen, Tom Pacific Rim Geological Consulting Geologist

Connors, Tim NPS-Geologic Resources Division Geologist

Covington, Sid NPS-Geologic Resources Division Geologist

Cusick, Joel NPS-Alaska Regional Office GIS specialist

Dickson, George NPS-Alaska Regional Office GIS team manager

Fiorillo, Tony Dallas Museum of Natural History Curator

Giffen, Bruce NPS-Alaska Regional Office Geologist

Graham, John Colorado State University Geologist

Griffiths, Lynn NPS-Alaska Regional Office Geological engineer

Haeussler, Peter USGS-Alaska Science Center Geologist

Hall, Shelley Kenai Fjords National Park Resource management chief

Halloran, Jim NPS-Alaska Regional Office Geologist

Heiser, Patricia University of Alaska, Anchorage Assistant professor - Geology

Kozlowski, Janis Alaska Regional Office Resource management specialist

Matt, Colleen Lake Clark National Park and Preserve Natural Resources chief

Miller, Amy NPS-Southwest Alaska Network Ecologist

Miller, Joe NPS-Southwest Alaska Network Fishery biologist

Mortenson, Dorothy NPS-Southwest Alaska Network Data manager

Mow, Jeff Kenai Fjords National Park Superintendent

Neal, Tina USGS-AVO Geologist

Piercy, Joni NPS-Alaska Regional Office GIS specialist

Pinamont, John NPS-Alaska Regional Office GIS specialist

Rice, Bud NPS-Alaska Regional Office Environmental protection. specialist

Schaefer, Janet Alaska Division of Geological & Geophysical Surveys/AVO Geologist

Stromquist, Linda NPS-Alaska Regional Office Geologist

Tetreau, Mike Kenai Fjords National Park Resource Management Specialist

VanderHoek, Richard DNR/Parks/Office of History & Archaeology/U. of Illinois Archaeologist

Wesser, Sara NPS-Alaska Regional Office Inventory and Monitoring coordinator

Wilson, Frederic (Ric) USGS Geologist
122

2015 Report Kick-off Participants

Name Affiliation Position

Michelle Coombs USGS Alaska Volcano Observatory Research Geologist

Judy Fierstein USGS California Volcano Observatory Research Geologist

Mike Fitz NPS Katmai/Aniakchak Visual Information Specialist

Troy Hamon NPS Katmai/Aniakchak Natural Resources Manager

Chad Hults NPS Alaska Region/Geologic Resources Inventory Geologist

Peter Kirchner NPS Southwest Alaska Network Physical Scientist

Katie Myers NPS Lake Clark/Katmai/Aniakchak Museum Curator

Dale Vinson NPS Katmai/Aniakchak Cultural Resources Specialist

Roy Wood NPS Katmai/Aniakchak Chief of Interpretation
The Department of the Interior protects and manages the nation’s natural resources and cultural heritage; provides scientific and 

other information about those resources; and honors its special responsibilities to American Indians, Alaska Natives, and affiliated 

Island Communities.

NPS 127/134578, September 2016
Natural Resource Stewardship and Science 

1201 Oak Ridge Drive, Suite 150 

Fort Collins, Colorado 80525

www.nature.nps.gov

National Park Service

U.S. Department of the Interior

EXPERIENCE YOUR AMERICATM

Jnn - Northeast Creek Sandstone Member 

Jns - Snug Harbor Siltstone Member 

Jni - Indecision Creek Sandstone Member 

Kst - Staniukovich Formation 

Khe - Herendeen Formation 

Kk - Kaguyak Formation 

Tc - Copper Lake Formation (and Ketavik Fm) 

Tm - Meshik Volcanics 

Tgl - Gibraltar Lake Tuff and 

Tab - Volcanic rocks of the Barrier Range 

Qv, Qs - Volcanic rocks and surficial deposits 

Extensive 

Unconformity 

Jtk - Talkeetna Formation 

TRk - Kamishak Formation 

TRc - Cottonwood Bay Greenstone 

Jnc - Chisik Conglomerate Member 

Jnk - Katolinat Conglomerate Member 

JPk - Kakhonak Complex 

Js - Shelikof Formation 

Kp - Pedmar Formation Naknek Fm 

Th - Hemlock Conglomerate 

Tiu - Intrusive rocks, undivided 

Togq - Granodiorite and quartz diorite 

TKgd - Granodiorite 

Kqm - Quartz monzonite 

Jgr - Granite and granodiorite 

Jqd - Tonalite and quartz diorite 

Jgb - Diorite and gabbro 

Oxfordian 

Kimmeridgian 

Tithonian 

Berriasian 

Valanginian 

Hauterivian 

Barremian 

Aptian 

Albian 

Cenomanian 

Turonian 

Coniacian 

Santonian 

Campanian 

Maastrichtian 

160 

150 

140 

130 

120 

110 

100 

90 

80 

70 

Late 

Early 

Late 

CRETACEOUS JURASSIC 

60 

50 

40 

30 

20 

10 

0 

Paleocene 

Eocene 

Oligocene 

Miocene 

Pliocene 

Pleistocene Quaternary Holocene TERTIARY Paleogene Neogene 

170 

180 

190 

200 

210 

TRIASSIC

Late 

Middle 

Early 

Callovian 

Bathonian 

Bajocian 

Aalenian 

Toarcian 

Pliensbachian 

Sinemurian 

Hettangian 

Rhaetian 

Norian 

220 

230 

Carnian 

Million Years Ago (MYA) 

Sandstone and conglomerate 

Sandstone 

Sandstone with shale 

Cross-bedded calcareous sandstone 

Shale and siltstone 

Tuff 

Basalt flows 

Rhyolite 

Andesite and dacite 

Mafic plutonic 

Calcareous siltstone 

Shale 

Intermediate plutonic 

Felsic plutonic 

Plants 

Marine invertebrate 

Plant debris 

Coal 

Vertebrate 

Fossils 

Plate 2. Stratigraphic chart of the bedrock units of the Katmai area. Colors of geologic units correspond to those used in Plate 1. 

Red unit labels and names signify plutonic (intrusive) rocks. Blank areas without sedimentary units are generally time periods of 

uplift or quiescence, which create unconformities in the stratigraphic record.