The Alaska Earthquake 

March 27, 1964 

Regional Effects 

Kodiak and 

Nearby Islands 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 543-D 

THE ALASKA EARTHQUAKE, MARCH 27, 1964: 

RE:GIONAL EFFECT'S 

Geologic Effects of the 

March 1964 Earthquake 

And Associated Seismic 

Sea Waves on Kodiak 

And Nearby Islands 

Alaska 

By GEORGE PLAFKER and REUBEN KACHADOORIAN 

GEOLOGICAL SURVEY PROFESSIONAL PAPER 543-D 
UNITED STATES DEPARTMENT OF THE INTERIOR 

STEW ART L. UDALL, Secretary 

GEOLOGICAL SURVEY 

William T. Pecora, Director 

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON: 1966 

For sale by the Superintendent of Documents, U.S. Government Printing Office 

Washington, D. C. 20402 - Price 60 cents 
THE 

ALASKA EARTHQUAKE 

SERIES 

The U.S. Geological Survey is publishing theresults of investigations of the earthquake in a series 

of six Professional Papers. Professional Paper 543 

describes the regional effects of the earthquake. 

Other Professional Papers describe the effects of 

the earthquake on communities; the effects on hydrology; the effects on transportation, communications, and utilities; and the history of the field investigations and reconstruction effort. 

Page 

Abstract .......................................... D1 

Introduction .................................... 2 

Purpose and scope of investigation .......................................... 2 

Acknowledgements .................... 3 

Geographic setting .................... 3 

Geologic setting .......................... 6 

The earthquake and its aftershocks ...................................... 7 

Location and magnitude........ 7 

Ground motion in the initial 

shock .................................... 7 

Surface waves ............................ 12 

Aftershocks ................................ 12 

Sounds .......................................... 13 

Surficial subsidence and associated ground cracks ................ 14 

Beach deposits ............................ 15 

CONTENTS 

Surficial subsidence and associated ground cracks-Con. 

All uvial and lacustrine 

Page 

deposits .................................... D15 

Artificial fills and embankments ........................................ 15 

Causes of surficial subsidence.. 15 

Landslides ...................................... 18 

Distribution and nature .......... 18 

Causes .......................................... 22 

Effects on ground and surface 

water ........................................ 23 

Observations .............................. 23 

Causes of fluctuations .............. 24 

Vertical tectoniC' deformation...... 25 

Distribution ................................ 25 

Effects on shorelines ................ 27 

ILLUSTRATIONS 

PLATES 

Page 

Vertical tectonic deformation-Con. 

Regional setting of the changes D28 

Seismic sea waves .......................... 30 

Chronology .................................. 30 

Crest heights .............................. 33 

Runup heights ............................ 34 

Periods ........................................ 35 

Effects on shorelines and sea 

bottoms .................................... 37 

Origin .......................................... 37 

Damage and casualties ............ 39 

Highways .................................... 39 

Fishing industry ........................ 42 

Cattle ranches ............................ 43 

Logging industry ...................... 44 

Casualties .................................... 45 

References cited ............................ 45 

Facing page 

1. Drowned stream estuary at Eagle Harbor along south of U gak Bay ........................................... D10 

2. Debris avalanche on the peninsula between Ugak and Kiliuda Bays.......................................... 11 

3. Subsidenc·e at Middle Bay...................................................................................................................... 30 

4. Undermined trees on barrier beach in Izhut Bay, Afognak Island................................................ 31 

Page 

1. PhY,siographic map of southcentral Alaska.................... D4 

2. Physiographic map of Kodiak and nearby islands ...... 5 

3. Geologic sketch map .............. 8 

4. Map showing aftershock distribution .............................. 9 

5. Map showing reported 

ground motion, sounds, 

and assigned Mercalli intensities .............................. 10 

6. Kadiak Fisheries cannery 

site ........................................ 11 

7. Piling at Kadiak Fisheries 

cannery site ........................ 13 

FIGURES 

Page 

8. Submerged road at Lake 

Rose Tead Lake ................ D14 

9. Cracks and slumped delta at 

Terror Lake ........................ 16 

10. Sectioned extension c'rack .... 17 

11. Map showing landslide distribution .............................. 19 

12. Rockslides ................................ 20 

13. Reactivated debris slide on 

Sitkinak Island .................. 20 

14. Earthfiow on Sitinak Island.. 2.1 

15. Main scarp at head of Narrow Cape landslipe ............ 21 

16. Isobase map ............................ 26 

Page 

17. Map showing regional tectonic deformation .............. D29 

18. Map showing wave damage 

and heights .......................... 31 

19. Initial wave crest, Womens 

Bay ...................................... 32 

20. Breached barrier beach ........ 36 

21. Wave-damaged trees ............ 37 

22. Map of highway damage ...... 40 

23. Bridge damage ...................... 41 

24. Bridge destroyed by seismic 

sea waves ............................ 41 

25. Roadway damage .................. 42 

26. Ground vessels at Kodiak...... 43 

27. Wave-deposited debris at 

Beaty Ranch ...................... 44 

v 
TABLES 

Page 

1. Estimated property losses on Kodiak and nearby islands .......... ·-··--···------·--·--------···------------·-----------------------···-------·---------·········-- D3 

2. Tidal constants at selected stations along the coasts of Kodiak and nearby islands -----------····---··--·---··························· 6 

3. Tidal inundation resulting from tectonic and surficial subsidence ---·-·········----··------·····-----·-···----····--·-····----···············--··············· 27 

4. Heights and arrival times of seismic sea-wave crests at Womens Bay, Myrtle Creek, Terror River, and Uganik 

River on Kodiak Island ---------------------------------------------·----------------------·---------·-----··-----·-····--·--·-···-----·------·--·-····--······--··············--········· 34 

Vl 
THE ALASKA EARTHQUAKE, MARCH 27, 1964: REGIONAL EFFECTS 

GEOLOGIC EFFECTS OF THE MARCH 1964 'EARTHQUAKE AND 

ASSOCIATED SEISMIC SEA WAVES ON 

KODIAK AND NE.ARBY ISLANDS, ALASKA 

By George Plafker and Reuben Kachadoorian 

Kodiak Island and the nearby islands 

constitute a mountainous landmass 

with an aggregate area of 4,900 square 

miles that lies at the western border of 

the Gulf of Alaska and from 20 to 40 

miles off the Alaskan mainland. Igneous and metamorphic rocks underlie 

most of the area except for a narrow 

belt of moderately to poorly indurated 

rocks bordering the Gulf of Alaska 

coast and local ac·cumulations of unconsolidated alluvial and marine deposits 

along the streams and coast. The area 

is relatively undeveloped and is sparsely inhabited. About 4,800 of the 5,700 

permanent residents in the area live in 

the city of Kodiak or at the Kodiak 

Naval Station. 

The great earthquake, which occurred on March 27, 1964, at 5:36 p.m. 

Alaska standard time (March 28,1964, 

0336 Greenwich mean time), and had a 

Richter magnitude of 8.4-8.5, was the 

most severe earthquake felt on Kodiak 

Island and its nearby islands in modern 

times. Although the epicenter lies in 

Prince William Sound 250 miles northeast of Kodiak-the principal city of 

the area, the areal distribution of the 

thousands of aftershocks that followed 

it, the local tectonic deformation, and 

the estimated source area of the subsequent seismic sea wave, all suggest 

that the Kodiak group of islands lay 

immediately adjacent to, and northwest 

of, the focal region from which the 

elastic seismic energy was radiated. 

The duration of strong ground motion 

in the area was estimated at 21h-7 

minutes. Locally, the tremors were preceded by sounds audible to the human 

ABSTRACT 

ear and were reportedly accompanied 

in several places by visible ground 

waves. 

Intensity and felt duration of the 

shocks during the main earthquake and 

aftershock sequence varied markedly 

within the area and were strongly influenced by the local geologic environment. Estimated Mercalli intensities in 

most areas underlain by unconsolidated 

Quaternary deposi~s ranged from VIII 

to as high as IX. In contrast, intensities 

in areas of upper Tertiary rock ranged 

from VII to VIII, and in areas of relatively well indurated lower Tertiary 

and Mesozoic rocks, from VI to VII. 

Local subsidence of as much as 10 

feet was widespread in noncohesive 

granular deposits through compa.ction, 

flow, and sliding that resulted from vibratory loading during the earthquake. 

This phenomenon, which was largely 

restricted to saturated beach and alluvial deposits or artificial fill, was 

locally accompanied by extensive 

cracking of the ground and attendant 

ejection of water and water-sediment 

mixtures. 

Numerous landslides, including a 

wide variety of rockfalls, rockslides, 

and flows along steep slopes, were triggered by the long-duration horizontal 

and vertical accelerations during the 

earthquake. The landslides are most 

numerous in a narrow belt along the 

southeast coast of Kodiak Island and 

the nearby offshore islands. Their 

abundance appears to be related to an 

area underlain predominantly by Tertiary rocks. 

Temporary and permanent changes 

of level occurred after the earthquake 

in some wells, lakes, and streams 

throughout the area; ice was cracked, 

and the salinity of a few wells increased. Permanent change of water level at 

some localities appears to be related to 

readjustments of fracture porosity by 

earthquake-induced movements of bedrock blocks. Increased salinity of wells 

in coastal areas resulted from encroachment of sea water into aquifiers 

after subsidence during the earthquake, and to flooding of watersheds 

by seismic sea waves. 

Vertical displacements, both downward and upward, occurred throughout 

the area as a result of crustal warping 

along a northeast-trending axis. Most 

of Kodiak and all of Afognak, Shuyak, 

and adjacent islands are within a regional zone of subsidence whose trough 

plunges gently northeastward and approximately coincides with the mountainous backbone of Kodiak Island. 

Subsidence in excess of 6 feet occurred 

throughout the northern part of the 

zone-a maximum subsidence of 61h-7 

feet having occurred on Marmot and, 

eastern Afognak Islands. Southeast of 

the axis of tectonic tilting, uplift of at 

least 2lh feet occurred in a narrow 

zone that includes most of the southeasterly capes of Kodiak Island, the 

southeastern half of Sitkalidak Island, 

and Sitkinak Island. The uplift is inferred to extend offshore over much or 

all of the continental shelf adjacent to 

the Kodiak group of islands. Within the 

affected area, tectonic subsidence, 

which was locally augmented by surficial subsidence of unconsolidated. 

Dl 
D2 

deposits, caused widespread inundation of shorelines and attendant damage to intertidal organisms, nearshore terrestrial vegetation, and 

salmon -spawning areas. 

The most devastating effect of the 

earthquake on Kodiak Island and nearby i,slands resulted from seismic sea 

waves that probably originated along 

a linear zone of differential uplift in 

the Gulf of Alaska. A train of at least 

seven seismic sea waves, having initial 

periods of 50-55 minutes, struck along 

all the southeast coast of the island 

group from 38 to 63 minutes after the 

earthquake. The southeast shores were 

repeatedly washed by destructive 

waves having runup heights along exposed coasts of perhaps as much as 40 

feet above existing tide level, and of 

8-20 feet along protected shores. Runup heights of the waves were much less 

on the northwest and southwest sides 

of the islands, and no wave damage 

was incurred there. Locally, highvelocity currents that accompanied the 

waves caused intense erosion and redistribution of unconsolidated natural 

The great earthquake of March 

27, 1964 was strongly felt 

throughout Kodiak Island and the 

nearby islands. Earth tremors 

triggered numerous landslides 

and avalanches, caused the ground 

to crack and subside in some areas 

of unconsolidated deposits, and 

affected water levels of streams, 

lakes, and wells. The earthquake 

was accompanied by regional tectonic warping that resulted in 

both extensive subsidence and 

local uplift of the land relative 

to sea level. It was followed 

after about half an hour by a 

train of at least seven destructive large-amplitude seismic sea 

waves that repeatedly inundated 

low-lying segments of the shore. 

The loss of 18 lives and most of 

the property damage were due to 

seismic sea waves that battered 

the southeastern coast of the 

islands. Additional heavy losses 

ALASKA EARTHQUAKE, MARCH 27, 1964 

and artificial shore deposits and of 

shallow sea-floor deposits. 

The Alaska earthquake was the 

greatest natural catastrophe to befall 

the Kodiak Island area in historic time. 

The combination of seismic shock and 

the earthquake-related tectonic deformation and seismic sea waves took 

18 lives, destroyed property worth 

about $45 million, and resulted in estimated losses of income to the fishing 

industry of an additional $5 million. 

Most of the damage and all of the 

loss of life were directly attributable 

to the seismic sea waves that crippled 

the city of Kodiak, wiped out the village of Kaguyak, and destroyed most 

of the village of Old Harbor and parts 

of the villages of Afognak and U zinki. 

Bridges and segments of the highways 

in the vicinity of the city of Kodiak 

were washed out, and parts of the Kodiak Naval Station were inundated 

and damaged. Especially serious to all 

the damaged communities was the loss 

of fishing boats, seafood processing 

plants, and other waterfront installations, which had been the mainstay of 

the economy. 

INTRODUCTION 

resulted from inundation of 

coastal lowlands and waterfront 

installations as a result of the 

combined tectonic and local subsidence. Structural damage directly attributable to seismic 

shock during the earthquake was 

light and was largely due to foundation failure of varying degrees. 

Total earthquake-related property damage in the area is estimated at about $45 million (table 

1), and income losses to the fishing industry amount to an additional $5 million. 

PURPOSE AND SCOPE OF 

INVESTIGATION 

This report presents the results of a reconnaissance study of 

the earthquake effects over the 

vast uninhabited parts of the 

islands. The regional setting of 

the islands, and the effects of the 

earthquake at localities other than 

Additional heavy losses resulted 

from the combined regional tectonic 

and local surficial subsidence that occurred during the earthquake. Widespread shoreline flooding by high tides 

necessitated raising, protecting, or removing many installations otherwise 

undamaged by the earthquake or 

waves. 

Structural damage attributable to 

seismic shock during the earthquake 

was relatively light and was restricted 

to areas underlain by saturated unconsolidated deposits. The chief structural 

failure in the area as a result of shaking was the collapse of part of a cannery built on saturated beach deposits 

that were partially liquefied during the 

earthquake. Minor structural damage 

resulted from differential settlement 

and cracking of the ground on natural 

granular deposits and artificial fills. 

The overwhelming majority of structures are constructed on indurated bedrock; none of these sustained damage 

other than small losses resulting from 

shifting about and breakage of their 

contents. 

the urban areas are described. 

Detailed accounts of specific damage at the communities will be 

given in a separate volume of this 

series on earthquake effects on 

Kodiak and other communities on 

the Kodiak Islands. 

An effort was made to evaluate 

the local geologic factors that control the distribution and character of the shock-induced effects 

because these factors have potential significance in the design and 

construction of engineering works 

in seismically active areas. A reconnaissance of the tectonic 

changes in land level was made to 

delineate the areal extent and nature of these movements on the 

islands, and their relationship to 

the deformation that occurred 

elsewhere in south-central Alaska. These data are pertinent to 

any critical interpretation of the 

mechanics of the earthquake and 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D3 

TABLE 1.- Estimated property losses on Kodiak and nearby islands 

Location I 

Kodiak City ............ 

Afognak; village 

site abandoned. 

Nature of damage 

Losses of private, 

commercial, and 

public property. 

Losses of private 

and public 

property. 

Station. 

Old Harbor 

Kaguyak; village 

site abandoned. 

Uzinki ...................................... 

Entire area except dty of 

Kodiak. 

Entire area ............ 

Kodiak Island 

exclusive of 

Kodiak Naval 

Station. 

Kodiak Naval 

equipment including bridges and 

highway. 

.............................. do ................ 

.................. do ................. 

do ................ 

Commercial .............. 

Vessels damaged 

and lost. 

Bridge and highway 

damage. 

Structures and 

Estimated 

replacement 

eost 

Source of data 

Tudor (1964). 

Bur. Indian Affairs (written 

commun., Sept. 

25,1964). 

Do. 

Do. 

Do. 

Alaska Dept. Fish 

and Game 

(1965). 

Do. 

Alaska Dept. Highways (written 

commun., April 

1, 1964). 

Tudor (1964). 

to the origin of the seismic sea was obtained from the numerous 

waves that followed. Incidental to individuals and organizations listthe geologic studies enumerated ed in the acknowledgments. Kachabove, information was also ob- adoorian wrote the section on 

tained on the arrival times, runup damage to the highways ; the reheights, and characteristics of the mainder of the report was written 

seismic sea waves and the damage by Plafker. 

caused by them. 

The present report is based 

largely on studies made by Plafker from float-equipped fixedwing aircraft and helicopter during the periods July 14-20, 1964, 

and July 15-21, 1965; on studies 

made by Kachadoorian at Kodiak 

and vicinity July 14-18, 1964; 

and on observations on earthquake effects made by G. W. 

Moore May 13-21, 1964. Moore 

also provided unpublished data on 

the geology of the islands. These 

observations were supplemented 

with studies of U.S. Coast and 

Geodetic Survey vertical aerial 

photography by the writers and 

W. H. Condon. Additional data 

We are greatly indebted to numerous individuals who provided 

us, in interviews and on form 

questionnaires, with eyewitness 

accounts of their experiences during and immediately after the 

earthquake. 

Personnel of the Fleet Weather 

Central, Kodiak Naval Station 

(Comdr. A. L. Dodson, Cornrnanding Officer), obtained critical data 

on the seismic sea-wave sequence 

and the change in tide levels at the 

Naval base in Womens Bay and 

furnished helicopter transportation to an otherwise inaccessible 

area of Narrow Cape. Dexter Lall 

and other biologists of the Alaska 

Department of Fish and Game 

provided unpublished data and numerous photographs of the earthquake effects on coastal lakes and 

streams. June Brevdy of the U.S. 

Navy Radiological Laboratory 

furnished photographs, newspaper clippings, and published 

data on structural damage from 

seismic sea waves in the Kodiak 

area. Lt. Comdr. W. D. Barbee, 

of the U.S. Coast and Geodetic 

Survey, provided tide records and 

data on changes in land level at 

tide-gage stations on Kodiak 

Island. The U.S. Coast and Geodetic Survey and the U.S. Army 

furnished postearthquake aerial 

photographs. Pierre St. Amand, 

of the U.S. Naval Ordnance Test 

Station, made available data obtained during an aerial reconnaissance of the area irnrnediately after the earthquake. Fred 0. 

Jones, consulting geologist, provided photographs and data on 

earthquake effects in the 'Terror 

River drainage basin. 

Pilots Bob Leonard and A1 

Cratty flew Plafker around the 

islands and freely shared with 

him their intimate knowledge of 

the Kodiak Islands area and of 

earthquake-induced changes that 

had occurred there. 

GEOGRAPHIC SETTING 

The group of islands described 

in this report, of which Kodiak 

lsland is the largest, lies at the 

western border of the Gulf of 

Alaska in the north Pacific Ocean 

between lat 56O30' and 58O40' N. 

and long 150°40' and 154'50'W. 

(fig. 1). The group has an aggregate land area of 4,900 square 

rniles, extends for a distance of 

177 miles in a northeast direction, 

and is 67 miles wide at its greatest width. The largest islands of 

the group are shown on figure 2. 
D4 ALASKA EARTHQUAKE, MARCH 27, 1964 

1. -Physiographic map of south-central Alaska showing location of the Kodiak group of islands with respect to the epicenter of the March 27 earthquake and its zone of major aftershocks (lined pattern). Submarine contours in meters. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA 

/---l Shuyak Strait X , / 

Marmot 

Island 

Cattle ranch 

Government communications 

facility 

0 10 20 30 MILES IIIIIII 

2. - Physiographic map of Kodiak and nearby islands. 
D6 ALASKA EARTHQUAKE, MARCH 27, 1964 

The population of the Kodiak 

group of islands is sparse, only 

about 3,600 permanent residents 

being reported in the 1960 census, in addition to 2,160 personnel at the Kodiak Naval Station. 

The city of Kodiak and nearby 

Kodiak Naval Station have the 

only large concentrations of population on the islands. The remaining settlements are small 

fishing villages. Permanent population of these settlements in 

1960 was as follows: 

Community 

A f agnak ................ 

Akhio'k .................. 

Kaguyak ................ 

Karluk .................... 

Kodiak .................... 

Larsen Bay ............ 

Old Harbor ............ 

Uzinki .................... 

Population 

190 

72-75 

36 

129 

2,628 

72 

193 

214 

Of the total of some 5,700 persons living on these islands, more 

than 5,300 live within 20 miles 

of the city of Kodiak. Throughout 

the rest of the area the population is concentrated in the villages with the exception of a few 

remote cattle ranches and Government communications facilities. Several large canneries on 

the island employ numerous workers during the summer; at the 

time of the earthquake none of 

the canneries were in operation 

and their only occupants were the 

winter watchmen. 

Kodiak and the nearby islands 

are the structural extension of 

the Kenai-Chugach Mountains 

(fig. 1). This group of islands, 

and the Barren Islands that lie 

between the group and the Kenai 

Mountains, have been named the 

Kodiak Mountains section of the 

Pacific Border Ranges province 

(Wahrhaftig, 1965, p. 39). As 

a whole, the islands are mountainous, being lowest on the islands 

at the extreme north and south 

and highest in the middle (fig. 2). 

TABLE 2. - Tidal constants at selected stations along the 

coasts of Kodiak and nearby islands 

Istation: A, on the Gulf of Alaska; B, on Shelikof Strait. Predicted time and height 

of tides from U.S. Coast and Geodetic Survey (1964a). Local (Alaska standard) 

time; tide measurements in feet above lower low water] 

I Annual tide 1 Predicted tide, March 27-28.1964 

Perenosa Bay (A) 

Izhut Bay (A) .................... 

Kizhuyak Bay (A) ........... 

Kodiak Harbor (A) ........ 

Ugak Bay (A) .................... 

Sitkalidak Island (A). 

Alitak Bay (AB) .............. 

Uyak Bay (B) .................. Uganik Bay (B) ................. 

Malina Bay (B) ................. 

Station 

(fig. 2) 

I 

The western part of Kodiak 

Island has many broad alluviated valleys and coastal lowlands that are underlain by thick 

glacial deposits. Sitkinak Island, 

at the south end of the group, has 

a maximum altitude of 1,470 feet. 

The surface of nearby Tugidak 

Island is a marine terrace that 

rises only about 100 feet above 

sea level. Shuyak Island and the 

northern part of Afognak Island 

are hilly lowlands. 

The coastline is extremely steep 

and irregular and is characterized by many deep narrow fiords 

and rocky islets. Narrow marine 

terraces occur at intervals on the 

oi~ter capes along the southeast 

coast of Kodiak and Sitkalidak 

Islands. Bars and spits have 

formed across the mouth of many 

of the bays and inlets. Numerous 

shallow lagoons and lakes occur 

behind low barrier beaches along 

the shore. 

There is a marked difference 

in the range of tides on the ocean 

side and on the Shelikof Straits 

side of the islands. Mean annual 

tide range is 13 to 14% feet along 

Shelikof Strait in contrast to 8.2 

to 11.3 feet at most places on the 

ocean coast. Furthermore, the 

difference in maximum annual 

tide height on the two sides of 

the island may be as much as 7 

feet. These differences are significant to this study because they 

strongly influenced the amount 

and distribution of the damage 

caused by seismic sea waves and 

by tectonic subsidence along the 

coast. Table 2 shows the tidal 

constants at selected localities, 

and the time and height of high 

and low tide during the period 

when seismic sea waves struck 

the coast on the night of March 

27. 

On March 27, 1964, the weather was mild; highest and lowest 

reported temperatures were 37" 

F. and 20" F. ; there was little or 

no snow on the ground at sea 

level, but traces of snow fell during the day at Kodiak Naval Station and Larsen Bay (U.S. 

Weather Bureau, 1964). Winds 

were light with scattered high 

overcast. All the lakes were frozen over. 

Mean Highest D'''''l 1 1 --- 

GEOLOGIC SETTING 

The oldest rocks in the area lie 

along the northwest coast of KOdiak Island and consist chiefly 

of metavolcanic and marine sedimentary rocks of Triassic and 

Jurassic age that are cut by mafic 

intrusives. Younger Mesozoic 

Low, evening, 

March 27 

Time 1 Height 

High, morning, 

March 28 

Time 1 Height 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D7 

marine sedimentary rocks of probable Cretaceous age, complexly 

deformed and extensively intruded by granitic rocks, underlie the 

axial part of the Kodiak Mountains. Northeast-trending belts of 

downfaulted lower Tertiary rocks 

make up the southeast side of 

Kodiak Island, Sitkalidak, Tugidak, and Sitkinak Islands. These 

belts are composed of a sequence 

of highly inclined and intensely 

folded sandstone, shale, conglomerate, and altered volcanic rocks 

that are locally cut by felsic intrusives. Overlying the older 

rocks are poorly consolidated upper Tertiary marine sedimentary 

rocks that have been gently to 

moderately folded. Fold axes and 

major faults strike northeast, the 

northwest blocks of the faults 

generally being upthrown. Distribution of the major lithologic 

units is shown in figure 3 (next 

page). 

On Kodiak and the nearby islands, unconsolidated deposits as 

a rule are thin and discontinuous. 

They consist mainly of glacial 

debris, alluvial and delta deposits, 

and beach deposits. Local thick 

accumulations of colluvium occur 

along the bases of the steeper 

slopes, particularly in areas underlain by Tertiary rocks. Most 

of the coast consists of rugged 

rocky bluffs; extensive and welldeveloped beaches are uncommon. 

A significant proportion of the 

alluvial deposits in an east-west 

belt across the central part of the 

islands consists of virtually uncompacted volcanic ash and pumice deposited in the spring of 

1912 during the eruption of Katmai Volcano, on the Alaska Peninsula to the west (Capps, 1937, 

p. 170- 171). 

The thickest and most extensive alluvial and glacial deposits 

are delineated on figure 3. Areas 

where bedrock is covered by thin 

deposits of soil, colluvium, glacial 

debris, stream gravel, marine 

beach deposits, or artificial fill 

are not shown. 

THE EARTHQUAKE AND ITS AFTERSHOCKS 

LOCATION AND MAGNITUDE 

The earthquake began at 

5:35 :12.15± 0.25 p.m. Alaska 

standard time (S. T. Algermissen, U.S. Coast and Geodetic Survey, oral commun., April 22, 

1965) ; its hypocenter is 12- 31 

miles deep (20- 50 km) ; and the 

epicenter is located at lat 61.1 o 

N., long 147.7° W. in northern 

Prince William Sound, 250 miles 

northeast of the Kodiak group of 

islands (fig. 1). Estimates of 

Richter magnitude, based upon 

surface wave amplitudes (M., ) 

are in the range of 8.4 to 8.5 

according to the U.S. Coast and 

Geodetic Survey. The focal region, or zone of probable fault 

breakage during the earthquake, 

is approximately outlined by the 

spatial distribution of aftershocks. As shown by figure 1, this 

zone extends 400 miles southwestward from the epicenter in 

a broad belt that includes much 

of the continental shelf and southeastern margin of the Kodiak 

group of islands. 

Perhaps related to the earthquake was an apparent instantaneous increase in the magnetic 

field by about 100 gamma on a 

continuously recording magnetometer in the city of Kodiak 

(Moore, 1964, p. 508). It is possible, however, that the anomaly, 

which occurred 1 hour and 4 minutes before the tremors were first 

felt, was caused by a local surface disturbance unrelated to the 

earthquake. 

During the first month after 

the earthquake, more than 7,500 

aftershocks were recorded at 

seismograph stations in the focal 

region (S. T. Algermissen, oral 

commun., April 22, 1965). Locations of the larger aftershocks 

(magnitudes of 5.0 or greater) 

with epicenters in the vicinity of 

the Kodiak group of islands are 

indicated on figure 4. Except for 

two aftershocks centered in the 

western part of the islands ( p. 

D9) they all lie along the southeast coast of Kodiak, Sitkalidak, 

and Sitinak Islands and on the 

adjacent continental shelf. The 

largest aftershock recorded in the 

mapped area had a magnitude of 

6.1. Focal depths range from 

about 9 to 19 miles (15-30 km). 

GROUND MOTION IN THE 

INITIAL SHOCK 

Strong ground motion that 

lasted from 2% to 7 minutes was 

experienced throughout the study 

area. However, marked variations 

in the duration, intensity, and nature of the shaking were reported 

in different parts of the islands. 

According to most observers, the 

earthquake started with a gentle 

rolling motion for a period of 20 

seconds to 1 minute, shook hard 

for about 21/ 2 minutes, and then 

gradually subsided. The ground 

motion was generally described 

as rolling like sea waves, or as a 

strong horizontal oscillation. The 

jarring motion that was felt in 
D8 ALASKA EARTHQUAKE, MARCH 27, 1964 

3. - Geologic sketch map of Kodiak and nearby islands. Geology generalized after Capps (1937) and from unpublished data 

by G. W. Moore. 

Dl0 ALASKA EARTHQUAKE, MARCH 27, 1964 

5. - Reported ground motion, sounds, ground waves, and assigned Mercalli intensities on Kodiak and nearby islands. The 

directions of reported ground motion are shown by arrows; localities at which sound was reported are shown by solid circles, 

localities at which ground waves were reported by open circles, and assigned Mercalli intensities by Roman numerals. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 543- D PLATE 1 

DROWNED STREAM ESTUARY AT EAGLE HARBOR ALONG SOUTH SHORE OF UGAK BAY 

Extensive brown area of terrestrial vegetation has been killed by salt·water immersion after 4 feet of tectonic subsidence and an unknown amount of surficial Bubsidence. 

The gray ridge of beach gravel in the l eft part of view (arrows) has been eroded back and built up in adjustment to the new higher base level of deposition. The fact that 

the effects of inundati on are scarcely visible along the steep bedrock shore in the backgrou nd suggests that much of th e subsidence at the estuary deposits was surficial 

rather than tectonic. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 1$43- D PLATE 2 

DEBRIS AVALANCHE ON THE PENINSULA BETWEEN UGAK AND KILIUDA BAYS 

A slide of Tertiary rocks (rom the 1,500-foot-high peak at upper right flowed into the uninhabited valley below at about 300-foot altitude where it spread out as a debris 

lobe roughl y 1,500 feet across. The narrow streak of light-colored debris in the lower right corner is part of the slide mass that overflowed the near flank of the landslide scar. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA Dll 

6.- The Kadiak Fisheries canner y site in Sheanvater Bay along the north shore of Kiliuda Bay. Canner y buildings in the 

foreground were split during the earthquake and the sea ward parts of the structures were later washed away by seismic 

sea waves. The form er locations of the buildings and dock are outlined by timber pile foundations in the beach and water. 

The entire beach is now inundated at high tide as a result of about 4 feet of tectonic subsidence and 2-10 feet of surficial 

subsidence of the beach deposits. The barge behind the cusp is a floating cannery that replaces the destroyed facility on 

land. Location of canner y shown on figure 5. 

some areas closer to the epicenter 

was not experienced on Kodiak or 

the nearby islands during the initial shock, although it was reported in some of the larger aftershocks. A local resident, Mr. 

Rudy Lorensen, timed the duration of the strongest ground motion as 2% minutes on a bedrock 

site near the city of Kodiak. 

Reports of the directions of 

vibrations show a wide variation. 

The apparent variations may be 

in part due to the difficulty in 

determining the direction from 

which a shock comes during such 

a distressing experience. In part 

they may result from a change 

in the source of the vibrations as 

the rupture propagated southwestward from its epicenter ir: 

Prince William Sound or to local 

vanations in ground conditions. 

Figure 5 shows that the reported 

vibration directions were mostly 

northeast-southwest to northsouth, although in a few instances 

they were northwest-southeast. 

The intensity, or the destructive potential, of the vibrations 

in the area varied markedly from 

place to place and appeared to be 

closely controlled by the local geologic environment. The generalization that both the intensity and 

duration of earthquake vibrations 

are enhanced in unconsolidated 

ground, particularly on watersoaked unconsolidated deposits 

(Gutenberg, 1957), is strikingly 

borne out by the distribution of 

vibration-induced damage in the 

area. 

The most severe shaking occurred in areas of thick saturated 

unconsolidated Quaternary deposits throughout the islands. In 

these areas, structural damage 

resulted mainly from foundation 

failure attributable to partial 

liquefaction, differential settlement, and cracking of unconsolidated deposits and artificial fill. 

The sole structural failure reported in the area was the partial 

coilapse of the main building of 

the Kadiak Fisheries cannery located on a beach cusp on Shearwater Bay along the north shore 

of Kiliuda Bay. The structure 

split in half when it was shifted 

off its piling foundation according to the cannery watchman, Mr. 

Sergei Pestrikoff. The piling was 

driven into beach gravel that was 

partially liquefied during the 

earthquake (fig. 6). The fallen 

section was later washed away 

by the seismic sea waves. 
D12 

SURF ACE WAVES 

Reliable data on the amplitude 

and period of the ground waves 

that accompanied the earthquake 

in the area are unavailable. Longperiod surface waves set bodies 

of surface water, trees, radio antennas, and hanging objects such 

as lighting fixtures and wall pictures into violent oscillation 

throughout the islands but caused 

only minor damage to manmade 

structures. The period of an oscillating antenna pole about 50 feet 

high on a bedrock site was timed 

by one observer as "slightly less 

than one second." 

Visible traveling undulations of 

the ground surface in areas underlain by unconsolidated deposits were reported at the villages 

of Uzinki and Afognak. The 

wavelength at Uzinki was described as 30 feet; estimates of 

amplitude could not be made. 

Similar progressive linear earth 

waves having estimated amplitudes as great as 3 feet were observed at numerous localities underlain by unconsolidated deposits 

in the part of south-central Alaska where the earthquake was 

strongly felt. Such waves have 

been frequently noted in comparable geologic environments during other great earthquakes 

throughout the world. The waves 

may correspond to the large amplitude "hydrodynamic" waves 

discovered by Leet (1946, p. 209-

211) on seismograph recordings 

of underground explosions. It is 

conceivable that such waves, 

which have particle orbits comparable to those of water waves, 

may be propagated in ground 

that has become semifluid as a 

result of ground vibration. 

Elsewhere in areas underlain 

by consolidated deposits and in 

areas of poorly consolidated TerALASKA EARTHQUAKE, MARCH 27, 1964 

tiary rock, there was minor 

cracking of interior plaster, concrete and concrete-block walls 

and floors, and a few concreteblock chimneys, and rupture of 

buried pipelines. In some of these 

areas slight damage was incurred when heavy objects such as 

generators, appliances, and furniture were shifted about or overturned. In areas underlain by unconsolidated deposits it was generally difficult or impossible for 

people to stand or walk during 

the earthquake. 

Ground motion in areas of preTertiary bedrock or bedrock mantled by thin unconsolidated deposits-areas where most communities and canneries of Kodiak 

and the adjacent islands are located-was not strong enough 

to cause structural damage. Some 

small light objects or heavier objects in precarious positions were 

thrown down, although in most 

places inanimate objects were not 

disturbed. People report that, although difficult, it was possible 

to stand and move about during 

the earthquake. 

Estimates of the Mercalli intensity of ground shaking in the 

area, based on the reported effects on people and inanimate objects, are shown on figure 5. 

Ground-water effects, landsliding, 

and avalanching, which were 

widely distributed and bore no 

clearcut relationship to structural 

damage, were not considered as 

suitable criteria for intensity estimates. Except as noted, assigned 

intensity ratings are according to 

the abridged Modified Mercalli 

Intensity scale of 1931, in which 

the violence of ground motion is 

separated into 12 categories of 

increasing destructiveness from I 

to XII (Hodgson, 1964, p.58-59). 

With one exception, assigned 

Mercalli intensities range from 

VI to VIII throughout the area. 

They are lowest in areas of preTertiary bedrock or bedrock mantled with thin well-drained unconsolidated deposits and highest 

in areas of poorly consolidated 

'Tertiary rocks and thick unconsolidated deposits. Significantly, 

the highest intensity experienced, 

which is estimated as VIII to IX 

on the scale, was at the Kadiak 

Fisheries cannery-the only large 

structure in the entire area that 

is founded wholly on unconsolidated, saturated, granular deposits. 

AFTERSHOCKS 

Many of the numerous aftershocks that followed the main 

shock were felt as short, sharp, 

jarring shakes. They reportedly 

occurred at intervals of a few 

minutes to an hour throughout 

the night of the earthquake and 

at increasingly longer intervals 

for a period of several weeks 

thereafter. One aftershock, at 

12 :55 p.m. on April 14th, was 

especially noted throughout the 

islands. Its epicenter was about 

20 miles northwest of the city of 

Kodiak (fig. 4), the magnitude 

is given as 5.4, and the focal 

depth as about 19 miles (30 km). 

Oddly enough, although this aftershock was the strongest one 

felt in the area, its magnitude 

was less than many of the other 

nearby aftershocks. It reportedly 

hit with a short jarring motion 

equal to the intensity of the main 

shock, after which it quickly subsided. Although it caused major 

consternation, it resulted in no 

noteworthy damage on Kodiak 

Island except for three broken 

pipelines at one cannery on the 

northwest coast of Kodiak Island, 

and a cracked roof at another 

cannery in Alitak Bay on the 

southwest coast of the island. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D13 

SOUNDS 

The initial shock was heard as 

a low-pitched rumble by two individuals in the area. One of them 

reportedly heard the rumbling 

an estimated 5 seconds before the 

tremors were felt. During the 

weeks after the earthquake, many 

people heard aftershocks as deep 

rumbles a second or so before 

they were felt. Some individuals, 

both in the area and elsewhere in 

south-central Alaska, said they 

heard warning rumbling sounds 

before every felt aftershock. 

Richter (1958, p. 128) postulated 

that such noise may be produced 

during passage of the body waves, 

but that the shaking is felt only 

upon arrival of the slower moving surface waves. 

SURFICIAL SUBSIDENCE AND ASSOCIATED GROUND CRACKS 

Vibratory loading of noncohesive granular deposits during the 

earthquake resulted in local surficial subsidence through compaction, flow, and sliding. Areas of 

greatest subsidence were in thick, 

unconsolidated, saturated marine 

or lacustrine deposits and uncompacted manmade fills. Subsidence 

in some of these areas was accompanied by cracking of the 

ground and ejection of water or 

water-sediment mixtures. By the 

time this reconnaissance study 

was initiated 4 months after the 

earthquake, however, much of the 

evidence of ground cracking was 

obliterated. 

Surficial subsidence of unconsolidated beach and delta deposits 

along the coast was most clearly 

manifested in the relatively greater amount of inundation of shoreline areas as compared to nearby 

rock outcrops. Virtually all areas 

underlain by such deposits, both 

in the zone of tectonic subsidence 

and slight uplift, show some indication of salt water immersion in 

the form of dead brown terrestrial vegetation (pl. 1) . 

BEACH DEPOSITS 

At the Kadiak Fisheries cannery along the north shore of 

Kiliuda Bay, local subsidence of 

beach deposits was 2-10 feet 

more than that of the adjacent 

bedrock areas. The cannery is 

on a broad, roughly triangular 

cusp that juts out into Shearwater Bay-a small bay on the 

north side of Kiliuda Bay (figs. 

5, 6). Before the earthquake, the 

buildings shown in the foreground 

of figure 6 extended on piling 

slightly beyond the water's edge, 

as shown in the photograph. Beyond this was a pier 170 feet 

long. The piling had been driven 

to refusal, that is, 10- 15 feet into 

the beach deposits. The piles were 

originally vertical and the tops 

were level. 

After the earthquake, measured subsidence was 5% feet at 

the shipway piling to the right 

(north) of the cannery buildings. 

This subsidence, 2 feet more than 

that at a bedrock site 1 mile to 

the south, indicates surficial settlement of about 2 feet relative 

to bedrock. Furthermore, measurement of the difference in 

height of the tops of the piling 

that previously supported the destroyed part of the cannery indicates that an additional 7.8 feet 

of surficial settlement occurred 

towards the tip of the cusp (fig. 7). 

7. -Timber pile foun dation at Kadiak Fisheries cannery site. Pronounced tilting 

of unbroken piling is indicative of lateral motion of the piling through 10-15 

feet of beach gravel. Piling tops formerly level are now 7.8 feet lower at the 

seaward end of the cannery site than in the foreground owing to local settlement of the distal part of the beach cusp. Bent drift pins in the piling tops 

indicate t hat the cannery moved southward (away from the observer) off the 

piling. 
ALASKA EARTHQUAKE, MARCH 27, 1964 

8. -Road near the head of Lake Rose Tead submerged by about 6 feet of surficial subsidence of inlet-stream deltaic 

deposits. Ugak Bay is visible in the background. Photograph by Alaska Department of Fish and Game. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D15 

The site is now submerged at 

high tides, and the facilities have 

been replaced by a floating cannery. Ground cracks as much as 

a foot wide reportedly crisscrossed the cusp after the earthquake. Mr. Edward Pestrikoff, 

the cannery watchman, saw 

cracks form in the ground during 

the earthquake and saw water 

ejected as high as 6 feet. Reduction of shear strength of the unconsolidated deposits through partial liquefaction is suggested by 

the manner in which the foundation pilings shown in figure 7 

were tilted without being broken 

when the cannery building collapsed. 

Elsewhere, local differential 

subsidence of unconsolidated beach 

deposits relative to nearby bedrock amounted to an estimated 

1-2 feet at Old Harbor and perhaps 5 feet near the McCord cattle ranch on Sitkalidak Island. 

ALLUVIAL AND 

LACUSTRINE DEPOSITS 

Mr. Joe Beaty, a long-time 

cattle rancher at Narrow Cape, 

observed that during the earthquake his truck and other heavy 

machinery settled as much as 2 

inches into alluvial deposits on 

the flood plain of a small stream 

on the cape. He also noted much 

cracking at a bog between two 

lakes near the tip of the cape, 

and extrusion of gravel that had 

been buried beneath 20 feet of 

fine-grained surficial alluvial deposits; thus the cracks evidently 

extended to at least that depth. 

Local subsidence of lacustrine 

delta deposits was noted at three 

localities by personnel of the 

Alaska Department of Fish and 

Game who carried out studies of 

the earthquake's effects on salmon spawning and sport fishing 

(Alaska Dept. Fish and Game, 

1965, p. 3- 21). Several feet of 

subsidence occurred on deltas of 

three streams that enter Buskin 

Lake near the city of Kodiak 

and at the inlet stream deltas of 

two large lakes-Lake Rose Tead 

and Saltery Lake-along the 

north shore of Ugak Bay. Surficial subsidence has resulted in local flooding of shoreline vegetation of these lakes and inundation 

of a segment of road along the 

shore of Lake Rose Tead (fig. 8). 

Mr. Ron Hurst, a rancher at 

Saltery Lake, reports that several 

acres along the lakeshore sank as 

much as 3 feet, and large amounts 

of subsurface pumice was pumped up into Saltery Lake and 

caused excessive turbidity early 

in the summer of 1964. 

Slumped lake deltas, ground 

cracks, and spectacular sand-vent 

deposits were examined and photographed by F. 0. Jones, consultant geologist to the Chugach 

Electric Association, in the upper Terror River drainage, on 

Kodiak Island between U gak and 

Viekoda Bays at about 1,250-

1,400 feet altitude. The inlet delta of Terror River at the head of 

Terror Lake slumped and subsided during the earthquake; 

near-shore vegetation there was 

put under 2- 3 feet of water (fig. 

9, next page). Lateral extension 

of the slumped delta margin 

caused it to be cut by a system 

of rectilinear cracks as much as 

1 foot wide (fig. 9). Large volumes of light-colored fine- to medium-grained pumice were ejected to the surface from many of 

these cracks, and the pumice 

forms clastic dikes that fill the 

cracks below the surface (fig. 

10 p. D17). Jones noted similar 

slumped and cracked deltas elsewhere along the margin of Terror 

Lake and saw from the air an 

extensive area of reticulate cracks 

and sand-vent deposits in a partially filled lake basin 3 miles upstream from Terror Lake. 

Drowning of shoreline vegetation was noted from the air along 

the margins of numerous lakes 

throughout the area. Undoubtedly 

shoreline subsidence, cracking of 

the ground, and extrusion of sediment similar to that noted above 

also occurred in comparable geologic environments at the numerous other lakes on the island that 

were not examined in detail. 

ARTIFICIAL FILLS AND 

EMBANKMENTS 

In addition to the subsidence of 

natural unconsolidated deposits, 

damage was caused to engineering works by surficial subsidence 

and cracking of filled ground and 

by settling of engineered fills and 

breakwaters into underlying unconsolidated natural deposits. 

Most of these effects, which occurred in the Kodiak area and 

along the highway east of Kodiak, 

will be discussed separately in 

the section of this report that describes effects on highways and 

in the companion report on damage to communities. The only 

other noteworthy examples of 

subsidence of artificial fill occurred at the U.S. Coast Guard 

Loran facility on Sitkinak Island 

where measured differential settlement of 4% inches occurred at 

one corner of a reinforced-concrete structure that was reportedly built on a 12-foot-thick fill. 

At Narrow Cape the approach fill 

of a ranch road on alluvial deposits sank about 2 feet below the 

level of a bridge deck. 

CAUSES OF SURFICIAL 

SUBSIDENCE 

From the foregoing descriptions it should be apparent that 

surficial subsidence of unconsoli-
Dl6 ALASKA EARTHQUAKE, MARCH 27, 1964 

9. -Inlet delta at the head of Terror Lake showing inundation of slumped and cracked delta margin and linear c~acks 

defined by light-colored pumiceous ejecta. Photograph by F. 0. Jones. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA Dl7 

lO.-Sectioned extension crack 1 foot wide at head of Terror Lake showing light-colored fine- to medium-grained 

pumiceous sand ejecta at surface and subsurface dastic dike. Photograph by F. 0. Jones. 
D18 

dated deposits and attendant 

ground cracking occurred under 

a variety of geologic conditions 

over a vast area. Causes of the 

subsidence are probably diverse 

and are related to the physical 

properties of the materials composing each deposit, as well as to 

the configuration of the deposit. 

Subsidence of natural granular 

materials and uncompacted fills 

under vibratory loading may result from: ( 1) compaction, or 

volume reduction due to closer 

packing of the grains that compose the deposit; ( 2) varying 

Long-duration horizontal and 

vertical accelerations during the 

earthquake triggered numerous 

landslides and avalanches on the 

slopes of Kodiak and the adjacent islands. The landslides included a wide variety of falls, 

slides, and flows involving bedrock, unconsolidated deposits, and 

snow in varying proportion.1 

Landslides of rock and soil presumably loosened by shaking during the initial shock were unusually abundant in the months 

after the earthquake. Some of 

them may have been triggered by 

the larger aftershocks or by summer thaw of frozen ground. None 

of the landslides or avalanches in 

the area caused property damage 

or human casualties. 

The following general descriptions of the distribution and nature of the landslides and avalanches are based almost entirely 

on aerial observation, interpretation of postearthquake aerial photographs, and accounts by local 

1 The classification and nomenclature for 

landslides used herein correspond · to those of 

Varnes ( 1958). 

ALASKA EARTHQUAKE, MARCH 27, 1964 

degrees of liquefaction of saturated incoherent material with 

resultant lateral spreading 

through flow or sliding; ( 3) shear 

failure causing downward and 

outward movement of the slide 

mass; and ( 4) combinations of 

(1 ) , ( 2 ) , and ( 3) . 

Details of the physical properties and configuration of the affected materials before and after 

the earthquake are unavailable so 

that the specific cause, or causes, 

of subsidence are generally not 

known. Compaction of some of 

the deposits is suggested by surLANDSLIDES 

residents. Only a few of these 

features were examined on the 

ground. 

DISTRIBUTION AND NATURE 

Most of the landslides occurred 

along the southeast coast of Kodiak Island and on the islands 

offshore from Kodiak Island. A 

few other landslides-mainly 

large rockfa lls-occurred at 

widely scattered sites on Kodiak 

Island and on Afognak and Marmot Islands. The generalized areal distribution of the larger landslides that occurred during or 

after the earthquake and before 

August 1964 is shown in figure 

11. Many of these slides were reactivated older slides. In some 

places-most notably along steep 

coastal bluffs-rockfalls are so 

closely spaced that a single symbol on figure 11 necessarily represents several slides. No attempt 

was made to map the smaller 

rockfalls and soil slips, although, 

as might be expected, their frequency is roughly proportional to 

that of the large slides. 

face ejection of water and watersediment mixtures. Reduced shear 

strength through liquefaction is 

indicated at the Kadiak Fisheries cannery, where piling embedded 10-15 feet in beach deposits 

was dragged laterally and tilted 

to angles of as much as 20° without failure. Reduced bearing 

strength and compaction of some 

ground is suggested by the mass 

sinking of compacted fills, breakwaters, structures, and heavy objects into underlying alluvial deposits and artificially filled 

ground. 

Numerous snow avalanches and 

debris avalanches of snow-rock 

mixtures are visible on aerial 

photographs of the steep slopes 

at higher altitudes along the rugged backbone of Kodiak Island. 

They are not shown on figure 11 

because the postearthquake aerial 

coverage was inadequate to permit photogeologic mapping of 

their distribution. Furthermore, 

most of the avalanches at high 

altitudes were obscured by new 

snowfall by the time this study 

was initiated 3% months after 

the earthquake. 

In approximate order of abundance, the landslides in the area 

may be divided into the following 

general categories: (1) rockslides and rockfalls in areas of 

consolidated rock, (2) debris 

slides and avalanches of Tertiary 

and Quaternary deposits, (3) 

earthflows and soil slips of unconsolidated surficial materials, 

and ( 4) rotational slumps in both 

consolidated rock and soil. Many 

of the landslides observed are 

complex features that probably 
1 • 

( 

•::::::-::::. 

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' ' 

r;•'l l 

-. J.: '{1'31 

f,J. 

~- ~-

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:; ? .' / 

• 

V,_,).! .. lhK fS1. .. 1'N:> 

GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA 

or· 

')f 

/ '~ f 

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('' <. 

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.. ~:::::: :::::: -::::::·:::J;:::· .. " .. 

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SPRLC SL-ANO 

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D19 

<' e ~ t• ~(!\/lOT 1: l.lJ..NrJ 

11. -Generalized distribution of the larger landslides and soil slips triggered by the March 27, 1964, earthquake on 

Kodiak and nearby islands. Areas underlain by rocks of Tertiary or probable Tertiary age are shaded. 
D20 ALASKA EARTHQUAKE, MARCH 27, 1964 

12.- Rockslides in tightly folded blocky sandstone along north shore of Ugak 

Bay, Kodiak Island. Bluff is about 1,000 feet high and is exposed to surf from 

Gulf of Alaska. 

13.- Reactivated large debris slide in sedimentary rocks of middle Tertiary age 

along the south shore of Sitkinak Island. Note the characteristic· steplike transverse scarps, displacing surface vegetation at head of the slide. A small rockfall 

covers part of the beach in lower left of photograph. Vertical height of slide 

mass is approximately 300 feet. 

involve varying combinations of 

falling, sliding, and flowage, but 

in the descriptions that follow 

they have been classified on the 

basis of their most characteristic 

features as interpreted mainly 

from the aerial photographs and 

from aerial observation. 

Rockfalls and rockslides are 

locally very numerous along steep 

coastal bluffs (fig. 12). Commonly, the bluffs are partially undercut by wave erosion and have 

surf-cut sea caves near the hightide line that iead to precipitous 

failures of large rock masses. 

The rock falls and slides are particularly numerous where blocky 

massive sandstone and basalt of 

Tertiary age, or older igneous 

intrusive rocks, form the steep 

bluffs along the shore. They are 

relatively rare in areas underlain 

by the well-indurated bedded and 

slaty rocks of pre-Tertiary age 

that compose the central part of 

Kodiak Island and most of Afognak and Shuyak Islands (fig. 3). 

Many rockfalls, too small to be 

plotted on the landslide distribution map, were seen in areas . underlain by the blocky granitic 

rocks that compose much of the 

rugged drainage divide on Kodiak 

Island. · 

Debris slides and debris avalanches were sporadically distributed along the southeastern coast 

of Kodiak Island, on Sitkalidak 

Island, and on Sitkinak Island. 

They apparently occurred mostly 

in areas underlain by bedded 

rocks of Tertiary age or by 

Quaternary deposits. Such slides 

are especially numerous on deeply 

weathered, moderately steep 

slopes underlain by rocks of middle to late Tertiary age. The debris slide shown in figure 13 is 

typical of many throughout the 

area. 

The slide illustrated on plate 

2 is probably the largest that occurred in the area and is anomalous in that it spread as a relatively thin sheet over the valley 

below the slide source. The areal 

distribution and irregular surface 

characteristics of the slide debris 

suggest that it was emplaced by 

high-velocity viscous flow. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D21 

Earthflows and soil slips of unconsolidated materials occurred 

throughout the area, but were especially common along the moderately steep slopes that were deeply weathered and mantled with 

thick deposits of one or more of 

the following: ( 1) glacial till, 

(2) volcanic ash, (3) colluvium. 

Typically, the flows and slips are 

manifested at the head as a series 

of transverse "wrinkles" or scarps 

stepped downslope, below which is 

a subtle bulge of debris (fig. 14). 

All gradations occur between the 

earthflows and soil slips that involve thin surficial layers of unconsolidated debris and the debris 

slides that are characterized by 

relatively coherent slide units. 

Rotational slumps were rather 

rare in the study area. This type 

of landslide was recognized only 

at Narrow Cape on Kodiak Island 

and along the southeast cape of 

Sitkalidak Island. Pierre St. 

Amand of the U.S. Naval Ordnance Test Station and George 

W. Moore of the U.S. Geological 

Survey directed our attention to 

these features, which were studied with special care because their 

long linear scarps bore a superficial resemblance to fault breaks. 

The Narrow Cape landslide involved moderately dipping, poorly indurated sedimentary rocks of 

late Tertiary age. It occurred on 

slopes of 15 °-35° along a structurally controlled northeast-trending linear valley that is incised 

125- 150 feet into a flat-lying ero-

:;ion surface. 'The main scarp of 

the slide (fig. 15) broke at the 

top of the southeast valley wall 

along a distance of roughly 1,400 

feet. The slide mass slumped 

down on the northwest side as 

much as 15 feet with headward 

tilting along a surface of rupture 

that intersected the surface on 

the valley floor 125-150 feet be14. - Earthfiow resulting from soil slip or slump in deeply weathered Tertiary 

sedimentary deposits along the north shore of Sitkinak Island. The head of the 

slide is marked by numerous small scarps; the foot is the hummocky bulbous 

mass in the lower left corner. 

15.- Main sc'arp at the head of a large r otational slump in Tertiary deposits 

on Narrow Cape, Kodiak Island. The landslide is approximately 1,400 feet long 

and 125-150 f~et high. The rock mass at the left slid 8-15 feet downslope along 

a surfac·e of rupture, the main scarp of which trends diagonally across the 

photograph. Note the headward tilt of the original surface on the upper part 

of the slide mass and draping of the vegetation mat over the crown of the 

main slide. 
D22 

low. Open tension cracks and 

shallow grabens are abundant on 

the erosion surface headward 

from the main scarp. The slide 

toe is characterized by transverse 

pressure ridges and small overthrusts in the surface mat of 

muskeg vegetation. The brushcovered hummocky topography of 

the lower part of the slide surface and the chaotic internal 

structure suggest that earlier 

gravity movement has taken 

place. 

At the southeast end of Sitkalidak Island, a discontinuous 

zone of landslides occurs along 

the base of a moderately steep 

southeast-facing ridge that fronts 

on a broad, gently sloping terrace. 

The landslides have exposed a 

series of southeast-facing scarps 

that can be traced along the base 

of the ridge for about 1112 miles. 

They die out both to the northeast and the southwest. As seen 

from the air, the freshly exposed 

scarps are estimated to be as 

much as 15 feet high and appear 

to be largely in unconsolidated deposits. The slide masses consist of 

both headward-tilted blocks and 

irregular hummocky earthflows 

along the downslope sides of the 

scarps. 

The relatively straight and 

abrupt break in slope along which 

the sliding occurred on Sitkalidak 

Island strongly suggests the possibility that the topographic feature is controlled by a preexisting 

fault and that the line of slumps 

may have been related to renewed 

displacement along this inferred 

fault during the earthquake. Fortunately, it was feasible to check 

this possibility by measuring vertical displacement of the shore 

relative to sea level both to the 

northeast and southwest of the 

line of landslides. No changes indicative of vertical fault displaceALASKA EARTHQUAKE, MARCH 27, 1964 

ment during the earthquake were 

detected within the limits of precision of the method (estimated 

to be ± 1% ft in this area). On 

the contrary, the measurements 

showed a slight northwest tilting 

of the island which is opposite in 

sense to the down-to-the-southeast movement along the landslide 

scarps. 

CAUSES 

Elastic ground vibrations during the 1964 earthquake triggered most of the fresh landslides (and avalanches), or so 

loosened large masses of rock that 

they slid shortly thereafter. A 

contributory factor may have 

been ground accelerations related 

to the observed permanent vertical displacements, together with 

possible horizontal displacements, 

that occurred during the earthquake. The effect of transitory 

horizontal accelerations is to increase temporarily the shear 

stress on slope-forming materials; this increase may result in 

failure (Varnes, 1958, p. 43). In 

some instances slope failure may 

have occurred because of loss of 

shear strength through partial 

liquefaction of saturated granular 

materials below the layer of seasonal frost. 

Although the earthquake was 

clearly the trigger, it was not the 

ultimate cause of the slides. In 

a topographically rugged and geologically complex area such as 

Kodiak and the nearby islands, 

many rock masses are in a state 

of unstable equilibrium as a result of local topography, lithology, structure, weathering, and 

water saturation. Even without 

earth shocks to act as a trigger, 

numerous landslides continually 

occur. 

Of particular interest is the 

concentration of earthquakeinduced slides along the southeast 

coast of Kodiak Island and the 

nearby offshore islands (fig. 11) , 

in contrast to their relative scarcity elsewhere. This distribution 

appears to be controlled primarily by local lithology and structure but may also be related to 

proximity to the earthquake focal 

region. Steepness of slope probably is not an important factor in 

controlling the overall distribution, inasmuch as maximum slope 

angles in the area of few slides 

are, in general, equal to, or greater than, those in the zone of many 

landslides. 

The strong coincidence of maximum landslide frequency and 

outcrop areas of bedded Tertiary 

rock is shown in figure 11. It is 

also noteworthy that the landslides in Tertiary rock are exceedingly diverse and complex in 

character and include all the 

types that were described above, 

whereas those in pre-Tertiary 

outcrop areas are almost exclusively rockfalls. 

The predominance of landsliding in areas underlain by Tertiary rock seems to be largely controlled by the physical properties 

of the rocks in at least five ways : 

( 1) The Tertiary sequence locally 

contains inherently weak materials such as clay, siltstone, and 

tuff along which sliding may occur. ( (2) The rocks, as a rule, 

are complexly folded and are 

broken by numerous discontinuities such as faults, joints, and 

bedding planes, which reduce 

shear strength. ( 3) The relative 

ease of weathering has resulted 

in local thick accumulations of 

landslide-prone soil and colluvium. ( 4) More rapid erosion has 

produced numerous steep-sided 

stream valleys and wave-cut 

cliffs, and attendant slope instability has resulted from removal 

of lateral support. ( 5) Intensity 

of the tremors during the earth-
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D23 

quake (fig. 5) suggests that the 

horizontal ground accelerations 

and amplitudes in some areas underlain by Tertiary rock were 

greater than in areas underlain 

by pre-Tertiary rock. Such differences in intensity would result in proportionately larger 

transient increases in shear stress 

and attendant reductions in shear 

strength of slope-forming materials in the Tertiary outcrop belt 

during the earthquake. 

In summary, the distribution 

of landsliding shown in figure 11 

appears to be closely related to 

local geologic conditions, the slides 

being most abundant in areas 

underlain by the least competent 

Tertiary rocks, and relatively few 

and widely scattered throughout 

the remainder of the region. The 

five factors enumerated above 

apply especially to units of middle and late Tertiary age. Rocks 

of early Tertiary age, as a rule, 

are well indurated, can be distinguished from pre-1

Tertiary bedded rocks only with difficulty, and 

probably have physical properties 

and susceptibility to sliding that 

are intermediate between those of 

the late Tertiary and pre-Tertiary sequences. 

Although it appears that landslide frequency is largely controlled by the underlying rock 

units, the possibility must also 

be considered that proximity of 

the southeastern coast to known 

faults (fig. 3) or to the focal region (as defined by aftershock 

distribution shown on figs. 1 and 

4) may have resulted in a higher 

intensity of ground motion and 

attendant susceptibility to sliding. The limited available data, 

however, do not indicate that 

either proximity to faults or to 

the focal region had a discernible 

influence on landslide distribution. Geologic study of the deformation in the area of highest 

landslide frequency failed to reveal active faults having significant surface displacement along 

which landslides might be concentrated. Furthermore, if the 

landsliding were controlled mainly by proximity to the focal region rather than by lithology and 

structure, there should be a progressive decrease in landslide frequency northwestward, away 

from the focal region, instead of 

the abrupt change that occurs between the belt of Tertiary rocks 

and the remainder of the area 

studied. 

EFFECTS ON GROUND AND SURFACE WATER 

Earthquake-induced fluctuations in level and (or) flow of 

some wells, lakes, and streams 

occurred at numerous localities 

throughout Kodiak and the adjacent islands. Temporary and permanent fluctuations of water 

level and flow that were recorded 

after the earthquake throughout 

much of Alaska, Canada, and conterminous United States, Hawaii, 

and Puerto Rico (Waller and 

others, 1965) are to be detailed in 

a separate volume of this series 

of reports that deals with earthquake-induced changes in the hydrologic regime and, consequently, will be described only briefly 

in the following paragraphs. 

OBSERV A'TIONS 

Reported effects of the earthquake on the few water-supply 

wells on the islands varied markedly. Some wells went dry or decreased yield and a few had increased yield, but most reportedly 

had no perceptible change. Many 

wells were muddied, and some 

along the coast became saline. Because none of the wells on the 

islands were equipped with water-level recorders, all the available data on earthquake-induced 

changes are, of necessity, based 

on observations by local residents 

reported in questionnaires and 

personal interviews. 

The only wells in the area 

known to have gone completely 

dry during the earthquake were 

shallow hand-dug wells on a small 

island near the Port Bailey cannery on the south side of Kupreanof Strait (fig. 2). A cannery 

worker, Mr. Rudy Lorenson, reported that after the earthquake 

the wells were dug 2 feet deeper 

without finding water. The wells 

were still dry 4 months later. 

Ranch wells at Narrow Cape (fig. 

2) became muddy immediately 

after the earthquake. Although 

the yield of some wells reportedly 

increased, it is not known whether this increase was accompanied 

by a permanent change of level. 

Wells along the shore at Afognak 

village were also muddied after 

the earthquake. These wells, and 

the school well at Old Harbor, 

became salty and unusable. There 

was no change in quality or level 

of water at the Coast Guard station near Cape Chiniak on Kodiak Island, or at the Federal A viation Agency radio station at the 

north end of Shuyak Island. 

Observers throughout the area 

report that ice on virtually all 

lakes and reservoirs at low altitudes was cracked during the 
D24 

earthquake-particularly around 

the margins. At higher altitudes 

pilots noted cracking of ice on 

some large lakes, but many of the 

smaller lakes showed no perceptible changes. A small cabin along 

the shore of a pond near Cape 

Chiniak was destroyed when 

seiching drove the ice cake 

over the bank and into the structure. According to eyewitnesses 

at Afognak village, ice on the 

lakes began cracking as soon as 

the earthquake was felt. Marginal 

cracking of lake ice probably can 

be attributed to the inertial effect 

of the water and ice cakes in resisting horizontal ground oscillations during the earthquake. In 

other parts of south-central Alaska it was noted that pressure 

ridges built up in the ice and 

snow along the shorelines in response to repeated pounding of 

the ground against the ice cakes. 

Although similar pressure ridges 

undoubtedly formed along lakeshores in the area, they were not 

specifically noted by local residents. 

In general, lake levels were 

either unaffected by the earthquake or were lowered. R. M. 

Waller has pointed out that erroneous reports of lowered lake 

levels may have been made in 

places where earthquake-induced 

seiching stranded cracked ice 

along the shore, or where the 

tremors have caused collapse of 

peripheral ice and snow bridges 

that commonly form by normal 

lowering of lake levels during 

the winter. Two shallow lakes 

between 3 and 3 }'i feet deep on 

Shuyak Island reportedly went 

dry during the earthquake. One 

filled up soon afterward but the 

other remained dry. Numerous 

shallow lakes on Kodiak Island 

that had gone dry during the 

earthquake were still dry or had 

lower water levels 4 months 

ALASKA EARTHQUAKE, MARCH 27, 1964 

afterward. A cirque lake 2,000 

feet long by 1,000 feet wide, at 

an altitude of 500 feet 5 miles 

northwest of Narrow Cape, reportedly was lowered 20 feet during the earthquake, although 

nearby lakes showed no perceptible change of level. 

A few local changes in streamflow-involving both decreases 

and increases in volume~were 

reported in the area after the 

earthquake. Abnormally reduced 

water flow at two important salmon-rearing streams was noted 

by Dexter Lall of the Alaska Department of Fish and Game. 

A particularly interesting sequence of changes was noted by 

Mr. Rudy Lorensen in a small 

stream that flows across Mesozoic bedrock near the Port Bailey 

cannery on n o r t h e r n Kodiak 

Island. According to Mr. Lorenson, the creek flow was reduced 

to about half its normal volume 

after the earthquake. The remaining flow was cut off entirely 

during the jarring aftershock of 

April 14th, the epicenter of which 

was located within 10 miles of the 

cannery (fig. 4). The stream remained dry for two months until 

another sharp aftershock in June 

started the normal volume of flow 

once again. 

The flow of streams at Afognak village and springs at a ranch 

on the north shore of U gak Bay 

on Kodiak Island reportedly increased for a period of one week 

after the earthquake. Four larger 

streams on which U.S. Geological 

Survey water-level recording 

gages were installed showed no 

significant flow changes following 

the earthquake. 

CAUSES OF FLUCTUATIONS 

Lack of detailed data on the 

pre- and postearthquake flow 

records of wells, streams, and 

springs for which earthquake-induced changes are reported precludes analysis of the origin of 

these changes. 

!Elsewhere in the part of Alaska strongly affected by the earthquake, where adequate data are 

available, the widespread lowered 

well and lake levels and reduced 

streamflow in granular materials 

has been attributed by H. E. 

Thomas of the U.S. Geological 

Survey to temporary increases in 

the porosity of saturated materials (in Grantz and others, 1964, 

p. 10). 'This mechanism could be 

the reason for lowered well levels 

in the islands, and, in conjunction 

with increased opportunity for 

water seepage from lakes and 

streams into earthquake-cracked 

frozen banks, and through cracked ice darns at lake outlets, could 

also explain some of the lowered 

lake and stream levels. 

In many places, however, lowered water levels in wells, 

streams, and lakes appear to be 

permanent. The reported sequence of abrupt changes in discharge of the small stream near 

Port Bailey suggests that, in 

areas underlain by bedrock, fracture porosity may be abruptly increased or decreased by slight 

shock-induced adjustments of 

bedrock blocks. Similar changes 

may have resulted from tectonic 

deformation within the area, especially if significant horizontal 

extension accompanied the vertical subsidence. Retriangulation 

within the zone of subsidence 

near Anchorage has revealed horizontal extension roughly normal 

to the trend of the zone amounting to as much as 8 X 10-5 or 

roughly one-half foot per mile 

(U.S. Coast and Geodetic Survey, 

1965, p. 17). If comparable extension occurred on Kodiak and 

the nearby islands, where subsidence is equal to or greater than 

that of the Anchorage area, near-
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D25 

surface fracture porosity may 

have increased sufficiently to 

cause some of the reported 

changes in water regimen, and 

particularly in areas of fracture 

porosity. 

The permanently increased salinity of a few wells in highly 

permeable beach and alluvial deposits at Afognak and the school 

well at Old Harbor probably was 

the result of encroachment of sea 

water into aquifers after tectonic 

subsidence. Temporarily increased salinity of most of the shallow 

dug wells, however, resulted from 

flooding of watershed areas by 

the seismic sea waves. 

VERTICAL TECTONIC DEFORMA'TION 

The March 27 earthquake was 

accompanied by tectonic deformation that resulted in vertical 

crustal movements, both upward 

and downward throughout the 

report area. Anomalous tide levels soon after the earthquake 

made coastal residents aware of 

the vertical displacement of the 

land. 

The isobase contours of figure 

16 (next page) show the amount 

and direction of vertical displacement that accompanied the earthquake. Directions and relative 

amounts of change were determined at four localities from 

coupled pre- and postearthquake 

tide-gage readings, at about 25 

localities from estimates made by 

local residents, and at 95 localities from measurements of the 

displacement of the upper growth 

limit of sessile intertidal organisms along the seashore. Datapoint locations are shown on 

figure 16. 

Determinations of vertical displacement at tide gages is probably accurate to within a few 

tenths of a foot. Most of the estimates made by fishermen, mariners, and other coastal residents 

who have had long experience 

with the local tides are probably 

correct to within a foot. The technique used for estimating vertical 

displacements from the height of 

the upper growth limit of marine 

organisms above tidal datum 

planes has been outlined elsewhere (Plafker, 1965, p. 1675-

1679.) It will also be described in 

detail in a forthcoming volume on 

tectonic deformation, to be prepared for this series of publications on the earthquake. Such 

measurements were carried out 

in 1964 and 1965 on a reconnaissance basis in the area. Those 

based on difference in pre- and 

postearthquake altitudes of upper growth limits of barnacles 

and algae are thought to be generally accurate to about 1 foot. 

Most of the measurements, however, are based only on the postearthquake altitude of these organisms above sea level; they 

contain inherent errors due to 

(1) deviation of sea level from 

predicted heights and (2) local 

variations in the growth limits of 

the organisms resulting from local factors of exposure, rock type, 

and water characteristics. 'They 

are estimated to be accurate to 

within 1 :Y2 feet in sheltered bays 

on the eastern side of the islands. 

Along segments of the coast exposed to heavy surf or swells, and 

especially in areas of high and erratic tides such as the Shelikof 

Strait side of the islands (see 

table 2), the measurements may 

be in error by as much as 2 :Y2 

feet. In these areas, more reliance 

was placed on estimates made by 

coastal residents and on the 

measured difference in upper 

growth limits of pre- and postearthquake organisms than on 

those measurements that require 

use of tide level as a datum. 

DISTRIBUTION 

Almost all of Kodiak Island, 

and all of Afognak, Shuyak, and 

Marmot Islands have undergone 

tectonic subsidence (fig. 16). The 

zone of subsidence consists of a 

broad trough that plunges gently 

northeastward along an axis that 

approximately coincides with the 

axis of the Kenai Mountains between Alitak Bay and the city of 

Kodiak. The limbs of the trough 

are strongly asymmetric, the 

steepest limb being southeast of 

the axis. Subsidence in excess of 

6 feet has occurred in the vicinity 

of northern Kodiak Island, on 

Afognak Island, and on Shuyak 

Island. Maximum subsidence of 

6:Y2-7 feet was measured on 

eastern Afognak Island and on 

Marmot Island. 

Uplift has occurred in a narrow 

zone that includes Narrow Cape 

on Kodiak Island, the southeastern half of Si tkalidak Island, all 

or part of Sitkinak Island, and 

some small islands off the southeastern coast of Kodiak Island. 

Maximum uplift of 21/2 feet was 

measured on Sitkalidak Island. 

Mr. Joe Beaty (seep. D15)reports 

that at the tip of Narrow Cape on 

Kodiak Island a surf-cut platform 

about 200 feet wide is now exposed at stages of tide that completely inundated the platform 

before the earthquake. Uplift of 

at least 2 feet, and possibly in excess of 3 feet, is suggested near 

this locality by postearthquake 
16.-Areas affected by tectonic deformation on Kodiak and nearby islands. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D27 

incision of streams and the consequent partial draining of two 

small beach-ban·ed lakes. However, the outlet streams may 

have become incised through 

scouring action of the seismic sea 

waves that entered the lakes 

after the earthquake. At Sitkinak 

Island, another rancher, Mr. Hal 

Nelson, noted 1-2 feet of shoaling at the entrance to a lagoon 

immediately after the earthquake-probably the result of a 

slight crustal uplift. Evidence of 

as much as 2 feet of uplift in the 

coastal area and small offshore 

islands between Narrow Cape, 

Sitkalidak Island, and Sitkinak 

Island suggests that the zone of 

uplift is probably continuous beneath intervening water-covered 

areas. 

As far as could be determined 

during the brief reconnaissance 

of the area, changes of land level 

associated with the earthquake 

resulted from regional warping 

rather than faulting. A diligent 

search was made for surface 

faults, particularly in the vicinity 

of the zero isobase between the 

areas of uplift and subsidence, a 

zone roughly paralleling numer--

ous known faults (fig. 3). No evidence of significant surface 

faulting was found, nor were 

there any anomalous abrupt 

changes in amounts of uplift or 

subsidence along the coast suggestive of measurable displacement along concealed faults. 

Past movements on the major 

faults in this zone have been 

mainly dip slip with the northwest blocks upthrown (fig. 3). 

Consequently, if any of these 

faults were reactivated during 

the earthquake only a reverse 

displacement could produce the 

observed pattern of deformation 

along the southeast coast of the 

islands. 

EFFECTS ON SHORELINES 

Tectonic· subsidence, augmented locally by surficial subsidence 

of unconsolidated deposits, has 

had a profound effect on shoreline 

morphology, intertidal marine organisms, and terrestrial vegetation. Virtually all shorelines that 

subsided more than 3 feet show 

clear physical evidence of the 

change, and the changes were l~­

cally noticeable where the subsidence was as little as 1 foot. 

The effects were most pronounced in areas of lowest mean 

annual tidal range (table 2) , inasmuch as both the frequency and 

duration of shoreline immersion 

for a given amount of subsidence 

vary inversely with the tidal 

range. 1

The conspicuous effect of 

subsidence is the fringe of dead 

brown terrestrial vegetation 

along the shore that has been 

killed by salt-water inundation at 

periods of high tides (pls. 1, 3). 

Beach berms and stream deltas 

in subsided areas are shifted 

landward and are building up to 

the new higher sea levels. The 

lower reaches of streams are now 

Stream Location 

(fig. 2) 

inundated by tides for distances 

of as much as 4,500 feet inland 

(table 3). The striking effect of 

subsidence in the estuarine part 

of Olds River at Kalsin Bay is illustrated by plate .3. Many former 

beach-barred lakes at stream 

mouths or bay heads have become 

tidal lagoons. Wave action at the 

higher sea levels is rapidly eroding shorelines composed of poorly 

consolidated deposits that are 

now brought within reach of the 

tides (pl. 4). An irreparable loss 

resulting from accelerated erosion of such deposits is the destruction of many coastal archaeological sites situated on them. 

Former reefs and low-lying 

islands along the coast are now 

submerged, and some tombolotied points or capes have become 

islands. 

Effects of the small and localized uplift along the shore are 

minor compared to those due to 

subsidence. At Narrow Cape a 

new surf-cut rock terrace 200 

feet wide reportedly is exposed at 

zero tide, and nearby beachbarred lakes have been partially 

drained by incision of the outlet 

Length of 

Approximate stream 

tectonic newly inunsubsidence dated by 

(feet) tides 

(feet)l 

Danger Bay Creeks ------

Afognak Island 

14 miles northeast of 

Afognak. 

5% 865 

Marka Creek ------------···· 

Back Ba.y Creeks ----------

Afognak River -----------·--

5 miles northeast of 

Afognak. 

5 miles north of Afognak .... 

4;.2 miles north-northeast 

of Afognak. 

Kodiak Island 

Kiliuda Creeks -------------- Kiliuda Bay -----------------------···· 

Eagle Harbor Creek.... U gak Bay -------------------------------

Saltery Cove Creek ...... ------------------------ do --------------------··· 

Olds River---------------·-···-- Kalsin Bay ---------------------·-·· ... 

1 Alaska Depa.rtment of Fish and Game l1965, p. 5) • 

4-5 

3%-5 

3%-5 

4-5 

4 

5 

4% 

2,600 

605 

825 

1,900 

850 

570 

4,500 
D28 

streams. Elsewhere a few new 

reefs are exposed at stages of tide 

when they formerly were under 

water. Lowered tide levels in lagoons in the area with attendant 

reduced volume and velocity of 

diurnal flow through the outlets 

may eventually result in the barring of the lagoon outlets and 

subsequent conversion of the lagoons to fresh-water lakes. 

REGIONAL SETTING OF 

THE CHANGES 

The 4,900-square-mile land 

area of Kodiak and the nearby 

islands within which vertical displacements were measured is but 

a part of a re.gional zone of tectonic deformation associated with 

the earthquake. An area of at 

least 70,000 square miles, and 

possibly 110,000 square miles or 

more of south-central Alaska, is 

involved (Plafker, 1965). The 

zone, which is more than 500 

miles long and as much as 200 

miles wide, is roughly parallel 

to the Gulf of Alaska coast from 

the Kodiak group of islands 

northeastward to Prince William 

Sound and thence eastward to 

about long 143 ° W. It consists of 

a major seaward zone of uplift 

bordered on the northwest and 

north by a major zone of subsidence (fig. 17). These two zones 

are separated by a line of zero 

land-level change that trends 

northeastward from Sitkinak Island along the seaward sides of 

Sitkalidak and Kodiak Islands 

(fig. 16). From Kodiak Island, 

the line trends northeastward to 

intersect the mainland between 

Seward and Prince William 

Sound. It then curves eastward 

ALASKA EARTHQUAKE, MARCH 27, 1964 

through the western part of 

Prince William Sound to the vicinity of Valdez and crosses the 

Copper River valley about 50 

miles above the mouth. 

In addition to most of the Kodiak group of islands, the zone 

of subsidence includes most of 

Cook Inlet, the Kenai Mountains, 

and the Chugach Mountains. The 

axis of maximum subsidence 

within this zone trends roughly 

northeastward along the crest of 

the Kodiak and Kenai Mountains 

and then bends eastward in the 

Chugach Mountains. Maximum 

recorded downwarping along this 

axis is 7 :Y2 feet. 

In the northern part of the deformed area, uplift in excess of 

6 feet occurred over a wide area 

including part of Prince William 

Sound, the mainland east of the 

sound, and offshore islands on the 

continental shelf as far southwest 

as Middleton Island. Along surface faults on Montague Island, 

the uplift locally exceeded 30 feet 

(Plafker, 1965, fig. 7). Southwest of Montague Island the sea 

bottom may have been uplifted 

more than 50 feet (Malloy, 1964, 

p. 1248), where pre- and postearthquake bottom soundings 

show seaward continuations of 

new fault scarps along preexisting fault lines. Large-seale uplift 

of the continental shelf and slope 

southwest of Montague Island is 

inferred from the trend of isobase contours in the northeastern 

part of the deformed area, and 

from the presence of the fringe 

of uplift along the outer coast of 

the Kodiak Island area (fig. 16) . 

The minimum extent of this inferred offshore zone of uplift is 

thought to be roughly outlined by 

the earthquake focal region, or 

belt of major aftershocks, shown 

on figure 1. 

The major zones of vertical 

tectonic displacement and the belt 

of aftershocks, which lie within 

and parallel to the Aleutian 

Trench and the Aleutian volcanic 

arc, are inferred to have resulted 

from displacement along a fault 

or zone of faulting that dips at a 

moderate angle northward from 

the Aleutian Trench beneath the 

continent (Grantz and others, 

1964, p. 2). Neither the orientation nor the sense of movement 

on the primary fault (or faults), 

along which the earthquake presumably occurred, is certain, inasmuch as the primary fault or 

zone of faulting is not known to 

intersect the surface on land. 

The two known surface breaks, 

which occurred on preexisting 

faults on Montague Island along 

the axis of maximum uplift, are 

clearly within and subsidiary to 

the zone of regional uplift. The 

faulting on Montague Island is 

known to extend offshore southwestward at least 15 miles, and 

comparable fault displacements 

probably occurred along this 

trend or elsewhere on the sea 

floor of the continental shelf within the focal region of the earthquake. Indeed, the dir,eetion of 

travel and reported arrival times 

of the initial wave crest in the 

area (p. D30-D39) suggest that 

the axis of maximum uplift (fig. 

17), along which faulting occurred on Montague Island, may extend southwestward perhaps to 

the latitude of Sitkalidak Island 

(Plafker, 1965, p. 6; Plafker and 

Mayo, 1965, fig. 12). 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 543-D PLATE 3 

SUBSIDENCE AT MIDDLE BAY 

Extensive inundation at the head of Middle Bay resulting from 5 feet of tectonic subsidence and an unknown but substantial amount of surficial subsidence. Arrows 

indicate the app roximate location of remnants of the Kodiak-Chiniak highway. Dashed line shows the approximate preearthquake mean high-water shoreline which has been 

shifted about half a mile landward. 
GEOLOGICAL SURVEY PROFESSIONAL PAPER 543-D PLATE 4 

UNDERMINED TREES ON BARRIER BEACH IN IZHUT BAY, AFOGNAK ISLAND 

Accelerated wave erosion in an area of about 5 feet of tectonic subsidence caused this damage. Foliage of trees along shore has turned brown from salt-water immersion of 

the roots. 
0 

I 

0 

50 

I 

I 

50 

100 

I 

GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D29 

I 

100 

150 

I 

I 

200 KILOMETERS 

I 

150 Ml LES 

EXPLANATION 

GJJ) 

Area of uplift or probable uplift 

Dashed where inferrnl 

Area of subsidence 

Axis of uplift 

Dashed where inferred 

Axis ~ of subsidence 

Volcano * 

Outer edge of continental shelf 

(600 feet) 

17.- Setting of the observed and inferred vertical displacements of the Kodiak group of islands with respect to regional 

tectonic deformation in south-central Alaska. 
D30 

By far the most catastrophic 

effect of the 1964 earthquake on 

Kodiak and the adjacent islands 

was the train of destructive seismic sea waves that first struck 

the coast about 38 minutes after 

the start of the earth tremors. 

The waves, repeatedly inundating 

low-lying coastal areas, caused 18 

fatalities and extensive property 

damage along the southeast coast 

of the islands. This train of seismic sea waves resulted in the 

worst natural disaster to befall 

the islands in historic times. 

There is no authenticated record 

of previous destructive seismic 

sea waves along this same segment of the Alaskan coast. 

Ac.cording to a widely quoted 

account in the historical novel 

"Lord of Alaska" ( Chevigny, 

1942, p. 63), the original Russian 

settlement on Kodiak Island at 

the site of a native village in 

Three Saints Bay was wiped out 

by a "tidal wave" during a violent earthquake in 1792 after 

which it was moved to the present location of Kodiak. The historian, Bancroft ( 1886, p. 324) , 

states, however, that the decision 

to move the settlement was based 

solely on sound tactical and economic reasons. The original site 

continued to be inhabited by natives at least until 1805, at which 

time the Russian naval captain 

Lisiansky called at 1

Three Saints 

Bay in the ship Neva (Bancroft, 

1886, p. 434-435) . 

CHRONOLOGY 

For a period of about half an 

hour after the earthquake, most 

residents were busily assessing 

the relatively light earthquakeinduced damage and discussing 

ALASKA EARTHQUAKE, MARCH 27, 1964 

SEISMIC SEA WAVES 

the terrifying shaking they had 

so recently endured. Few people 

recall having noticed any unusual 

movements of the sea in that interval of time. The tide was ebbing and nearly at low stage (table 

2) , the wind was calm, and there 

was ample daylight for reliable 

visual observations for about 2 

hours after the earthquake, or 

until about 7:30 p.m. 

The only reported noteworthy 

fluctuation of water level prior 

to arrival of the first seismic sea 

wave was a gradual rise and subsequent withdrawal of the sea. 

This fluctuation was noted by a 

fisherman, Mr. Jerry Tilley, who 

was aboard the 75-foot shrimpfishing boat Fortress tied up at 

the city dock in Kodiak. Mr. 

Tilley states that the water level 

rose calmly from about 0 to 13 

feet within 10 minutes after the 

earthquake was initially felt. Water level then receded gradually 

for an estimated 25 minutes to 

about -10 feet, after which the 

first wave moved in from the 

south as a large swell. This first, 

calm rise of water level has not 

been reported elsewhere, and it 

caused no damage whatever. The 

origin of this reported sea-level 

rise at Kodiak is uncertain. It 

could have been a local seiche 

generated largely by the tectonic 

tilting and possible horizontal displacement that occurred during 

the earthquake. However, the fact 

that it was not noticed at the 

nearby Naval station, which underwent approximately the same 

amount of subsidence, argues 

against this possibility. In any 

event, the limited data available 

on this initial sea-level rise suggest that it was a local phenomenon, rather than part of the train 

of long-period seismic sea waves 

that followed. 

At 6:14p.m., 38 minutes after 

the start of the earthquake, Fleet 

Weather Central, Kodiak Naval 

Station, received an ominous report of a "30-foot tsunami" at the 

Cape Chiniak station of the U.S. 

Coast Guard 15 miles to the 

southeast (fig. 18). An immediate "tidal-wave" warning, broadcast over the Armed Forces Radio, resulted in the timely evacuation to high ground of most base 

and city personnel in the Kodiak 

area. Many individuals began immediately trying to fly amphibious 

aircraft from the harbor area, to 

pilot fishing boats to the relative 

safety of deep water, or to remove vehicles and other valuable 

belongings to high ground, but 

with varying degrees of success. 

At about the time that the 

wave was observed at Cape Chiniak, Mr. Joe Beaty (see p. D15) 

was on the roof of his ranch home 

at Narrow Cape repairing a radio antenna broken during the 

earthquake. Lo.oking seaward, he 

was astonished to see the sea 

withdraw a long distance from 

the shore ; the withdrawal was 

immediately followed by a "wall 

of water" that moved in from 

the east and broke off shore. A 

wave then surged over low-lying 

parts of the ranch as much as 

three-quarters of a mile inland 

from the beach; it deposited vast 

quantities of driftwood but it 

stopped just short of the house 

and outbuildings. Seven head of 

cattle were drowned, contrary to 

one journalist's account which 

claimed that the animals somehow sensed the oncoming wave in 

time to move to the safety of high 

ground, 
'c 

' 7 

1.5+ 0 

C.l' ;1, I"· I.. N 

• 1 

1 (>1}" .. 

GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA 

4.2 

,:_,1 

0 

~"'; 

r • y 

';o! 

j·\r-' 

> v 

') 

' J 

V I 

0 

s: 

'' 

/Nav1gation buoy in Shuyak 

X Strait shifted westward 

i ::.: '/ 

5+ 0 

X 

~~: -i 1 \i <\ ! 

~ l <\f· [ 

<' 

X ' <~ X 

X, X ' 

. 10.8 

, • ~Afognak 

X 

9+ 

' ' { 

X 

X X 

I Lf'-ND 

~-.,,) 

'\ )( 

\; .41, 

·' X s' e12.8 

.;:womens Bay~ 111 ,, ~- ,./ ,~1' 

Midcj·le Baye · X 30? 

X X ~ cJKalsm Bay_ a. X 

") ' • 1 Myrtle Si;lltery •' '· t5 1 Ck y: '/ .. / 

Cov; X 31.5+ · 20 ± 2 

X ~ X 

Shearwater Bay 

.- .14!5 ' 

,, ', Old ·Harbor ··. X 

.- X ._12 /Port Hobro.n " 

/ 

' 

"'- N"' iS:./"..;) 

_....... No wave damage 

/ ' 

14+ . 

'\.. ·L CAt<: 

JSLAND 

]'). 

D31 

18. - Localities on Kodiak an d nearby islands at which waves caused ma jor property damage (black ~ircles), shorelines 

showing physical evidence of wave damage (x), shorelines reportedly inundated by run up (open circles), and U.S. Geological Survey streamflow gages on which waves were recol'ded (triangles). Numbers indicate approximate highest runup 

in feet above existing tide level; plus sign following numeral indicates that tide stage is unknown and maximum run up 

shuwn is minimum value assuming coincidence of wave with high tide. Lined pattem offshore indicates inferred position of the northwest and southwest margins of the wave-::rest source. 
D32 ALASKA EARTHQUAKE, MARCH 27, 1964 

'~. 

19.- Seaplane ramp at Kodiak Naval Station along shore of Womens Bay showing approximate high-water level reached 

by first wave. Note calm water surface. Aircraft parked in front of hangar at left center were later moved to high 

ground and saved. Photograph by U.S. Navy. 

Shortly after the initial wave 

struck the outer coast from Cape 

Chiniak to Narrow Cape, inhabitants elsewhere along the southeast coast between Kaguyak and 

Afognak noticed rapid rises of 

the sea, accompanied in some 

places by dull rumbling sounds. 

By 6 :35 p.m., 63 minutes after 

the start of the earthquake, the 

initial wave was cresting at the 

city of Kodiak, nearby Kodiak 

Naval Station, and other points 

along the shore of Chiniak Bay, 

and was inundating low-lying 

coastal areas. Everywhere except 

at Cape Chiniak and Narrow 

Cape, the first waves were described as a gentle gradual flood 

with swirls resembling riverflow 

that rose at estimated rates of as 

much as 3 feet per second. Figure 

19 shows part of the airport at 

Kodiak Naval Station as the first 

wave crested. At Kodiak and Old 

Harbor, gradual withdrawals of 

about 10 feet reportedly preceded 

the initial wave, but no withdrawal in Womens Bay was observed at the Kodiak Naval 

Station. 

The initial wave was followed 

everywhere by a turbulent swirling retreat of water from the 

shore, during which segments of 

the sea floor were bared far below 

the level of the extreme low tides. 

Much of the fishing fleet at Kodiak was left grounded, but some 

boats were swept offshore and 

caught in whirlpool-like eddies or 

high-velocity currents that accompanied the withdrawal. The 

water withdrew to about 10 feet 

below the postearthquake mean 

lower low water at the Kodiak 

Electric Association powerhouse 

in Kodiak. At the Kodiak Naval 

Station, the water withdrew to 

about 11% feet below the postearthquake mean lower low 

water. 

Approximately at 7:40 p.m., 

as darkness was falling and the 

tide beginning to flood, a second 

wave that was the largest and 

most destructive of the train in 

the Chiniak Bay area struck the 

coast. It swept away docks, 

houses, and vehicles along the 

shore and drove flotsam and fishing vessels inland as battering 

rams, causing much destruction 

of property previously undamaged by the high water. 

The withdrawal that followed 

the second wave was extremely 

turbulent and rapid. Swirling 

currents with velocities variously 

estimated at 20- 25 knots flowed 

through the straits near Kodiak. 

The water was choked with debris, and vessels that were unable to steer against the swirling 

erratic currents were carried on 

its flood. 

The third wave, which struck 

the southeast coast of the area 

between 8:30 and 9:30p.m., was 

slightly lower than the second 

wave in Chiniak Bay, but because 
GEOLOGIC EFF'ECTS ON THE KODIAK ISLAND ARE,A D33 

it came in on a rising tide it 

reached almost the same altitude 

along the shore as the previous 

wave, adding substantially to the 

damage. It was the highest and 

most destructive wave witnessed 

at the villages of Afognak, Old 

Harbor, and Uzinki; numerous 

homes and other structures were 

washed to sea, and fishing vessels 

were sunk or beached. At the 

widely spaced villages of Afognak and Old Harbor, the arrival 

time of the wave crest was recorded on clocks that were stopped by the inundation almost simultaneously-at 9 :27 p.m. and 

9 :28 p.m., respectively. By this 

time virtually everyone along the 

southeast coast except those 

aboard boats and personnel at 

Fleet Weather Central had evacuated to higher ground, and it 

was too dark in most places to 

permit reliable observations on 

the nature and sequence of waves. 

The instrumental records and 

the record kept at the Kodiak 

Naval Station show that waves 

continued to inundate the shoreline with progressively decreasing amplitude until early the next 

morning. However, the highest 

runup in some localities, including W omens Bay near Kodiak 

Harbor, coincided with high tide 

shortly after midnight (table 2). 

The greatest observed withdrawal of water occurred at the 

Kodiak Naval Station a few minutes after midnight. At that time, 

water level fell some 24 feet from 

a plus 8-foot tide to 16 feet below 

mean lower low water. 

Along the Shelikof Strait side 

of the group of islands, no wave 

action or water motions were 

noted, aside from minor local turbulence, until about 90 minutes 

after the earthquake. Water fluctuations there consisted of rapid 

low -amplitude tide changes accompanied by swift and erratic 

currents. The shoreline was inundated a few feet above normal 

preearthquake highest tide levels 

only by the waves that occurred 

between 11 :30 p.m. and 1 :00 

a.m., within an hour of high tide 

(table 2) . The last recorded anomalous tide rise on the Shelikof 

Strait side of the island that 

could be attributed to wave action 

was at about 5:00 a.m. on the 

morning after the earthquake. 

CREST HEIGHTS 

Locations of coastal areas on 

Kodiak and nearby islands that 

were affected by the seismic sea 

waves are shown on figure 18. 

Also shown are maximum runup 

heights recorded at shore stations 

and the inferred source area of 

the waves. 

The sole operative tide gage on 

Kodiak and the nearby islands 

was at the Kodiak Naval Station 

in W omens Bay. It was put out 

of action by the earthquake tremors and was subsequently inundated by the waves; the marigram for March was lost. Observations of water-level changes at 

the Naval Station were made by 

Fleet Weather Central personnel 

throughout the night of March 27 

and the early hours of March 28. 

It is the most complete record 

available of the seismic sea waves 

in the area or elsewhere along the 

Gulf of Alaska coast in the region 

strongly affected by the earthquake. 

Unique instrumental records of 

arrival times and maximum runup heights of the higher waves 

were obtained from three U.S. 

Geological Survey streamflow 

gages at localities shown on figure 18. The three gages were situated at sites near stream mouths 

that subsided sufficiently during 

the earthquake to bring them 

within reach of the highest seismic sea waves; the two gages on 

the Shelikof Strait side of the 

island are low enough to record 

the higher astronomical tides 

since the earthquake. Arrival 

times, crest heights, and run up altitudes of the waves at Womens 

Bay and at the three streamflow 

gages are given in table 4 (next 

page). 

With the exception of the four 

localities enumerated above, all 

data on wave-arrival times were 

obtained through conversations 

or written communications with 

eyewitnesses. Most are little 

more than rough estimates of 

elapsed time beween start of the 

tremors and the wave-crest arrivals. Few observers had the opportunity or presence of mind under the prevailing conditions to 

record the time at which the 

waves struck, and in any given 

locality opinions varied considerably. 

The maximum heights to which 

the waves rose along the shore at 

localities other than W omens Bay 

and the sites of the streamflow 

gages could be readily ascertained from the strand lines of seaweed and driftwood, waterstains 

on buildings, and abraded bark or 

broken branches in trees and 

brush along the shore. Heights 

were measured by hand level and 

stadia rod above prevailing sea 

level and later reduced to mean 

lower low water. At most localities measured heights were substantially lower than those indicated by eyewitnesses or estimated by some investigators who visited the area after the earthquake. 

Because much of the land area 

had been lowered or uplifted by 

the tectonic deformation that presumably occurred during the 

earthquake (Plafker, 1965, p. 

1680) and because the wave train 

struck the coast at stages of tide 

ranging from low to high, appro-
D34 ALASKA EARTHQUAKE, MARCH 27, 1964 

TABLE 4.- Heights (in feet) and arrival times of seismic sea-wave C'r!ests at Womens Bay, Myrtle Creek, 

Terror River, and U ganik River on Kodiak Island 

[Local (Alaska standard) time. MLLW, postearthquake mean lower low water] 

Womens Bayl Myrtle Creek2 Terror River3 U ganik River4 (Kodiak Naval Station) 

Wave Crest height Crest height Crest height Crest height 

Time Above 

i 

Above Time Above I Above 

Time Above Above Time Above 

I 

Above tide MLLW tide MLLW tide MLLW tide MLLW level level level level 

March 27 

1 ....... 6:35p.m. 10.8 10.6 6:45p.m. 15.2 15.0 11:15 p.m. 8.0 I 18.2 I 11:00 p.m. 6.2 I 15.2 

March 28 

2 7:40p.m. 12.8 12.8 7:40p.m. 18.6 18.8 1:15 a.m. 1.8 17.0 1:15 a.m. 0.9 16.0 

3 8:30-

8:44p.m. 8.6 9.7 8:30p.m. 17.2 18.4 1:50 a.m. 2.6 17.7 2:32a.m. 4.9 18.5 

4 10:00 p.m. 9.4 13.7 9:45p.m. 14.3 18.4 3:00p.m. 8.6 21.1 ----·---------· 5 11:16-

11:34 p.m. 11.6 18.8 11:15 p.m. 13.2 20.3 4:20a.m. 9.2 18.2 ............................. 

--------------· 

March 28 

6 0:47a.m. 3.2 11.6 2:40a.m. 7.3 13.9 ............................. 

7 1:54a.m. 6.4 13.8 ·-------------· --------------- 8 2:20a.m. 3.0 10.0 ·-------------· --------------· ·-------------- 9 2:58a.m. 2.2 7.2 ·-------------· ·-------------· ............................. 

10 3:20a.m. 1.6 5.6 --------------· ·-------------· ·--------------

1 Data from Fleet Weather Station, U.S. Navy, Kodiak. 

2 Data recorded on U.S. Geological Survey streamflow gage about 1 mile above preeartbquake stream mouth. 

3 Data recorded on U.S. Geological Survey streamflow gage 0.7 mile above preearthquake stream mouth. 4 Data recorded on U.S. Geological Survey streamflow gage 0.5 mile above preearthquake stream mouth. 

priate corrections for vertical 

displacement and tide stage had 

to be made at each locality to 

obtain the actual runup heights 

shown in figure 18 and table 4. 

Where wave-crest arrival times 

were known, corrections were 

made by subtracting from the 

measured runup heights (1) the 

amount of subsidence, if any, at 

the shore station, and ( 2) the 

predicted tide height above lower 

low water at the time the wave 

crested. Where runup heights 

were measured from swash 

marks or other evidence left along 

the shore at unknown stages of 

tide, corrections could be made 

for vertical displacement but not 

for tide stage. In these localities, 

the height indicated on figure 18 

is a minimum value (indicated by 

a plus sign following the numeral) 

that assumes coincidence of the 

highest wave with high tide on 

the morning of March 28 (table 

2) . Along the ocean side of the 

islands the highest waves apparently occurred between low and 

half tide, so the runup heights of 

the highest waves most probably 

were 4-8 feet higher than those 

shown on figure 18. 

RUNUP HEIGHTS 

In general, the waves were 

high and destructive only along 

the exposed ocean coast. They 

barely inundated shorelines above 

normal highest tide levels along 

the Shelikof Strait side of the 

islands and the straits between 

the larger islands. The waves 

were too low to flood above the 

shoreline along the southwest 

shore of Kodiak Island or at Sitkinak Island. 

As indicated by figure 18, maximum runup heights of the waves 

around the islands ranged from a 

minimum of 5 feet or less to at 

least 31 lf2 feet. Large local variations in runup heights occurred 

around the islands-apparently 

controlled by the highly irregular 

configuration of the coastline, differences in offshore bottom topography, and length of wave travel 

path. 'The highest recorded runups were along exposed beaches 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D35 

and bluffs on southeastward-facing shores of Kodiak and Sitkalidak Islands, whereas runup 

heights in adjacent sheltered embayments and segments of coast 

protected by offshore reefs were 

substantially lower. 

The highest measured runup 

was at an uninhabited locality between Cape Chiniak and Narrow 

Cape, where trees were damaged 

31% feet above predicted astronomical high tide on the night of 

the earthquake; however, the 

highest wave probably coincided 

with the first large wave at low 

tide that was witnessed at Narrow Cape and Cape Chiniak. If it 

did, runup above existing tide 

level would have been almost 40 

feet. Runup of 24% feet above 

the March 28 high-tide level was 

measured on an eastward-facing 

beach at Sitkalidak Island, and 

driftwood deposited on a terrace 

at the south end of the island is 

estimated to be at least 15 feet 

higher. Wave-deposited driftwood 

was also seen from the air at 

high altitudes on bluffs along the 

north coast of Marmot Island. 

In sheltered embayments along 

the ocean coast, runup heights 

ranged from 12 to 17 feet. The 

highest run up of 17 + feet occurred at Kaguyak which is situated 

at the head of a large, deep bay 

that opens into the Gulf of Alaska. The rather low measured 

runup of 8 feet at Afognak village and at other localities on 

Afognak Island that face the 

open ocean are suggestive of 

rapid dissipation of wave energy 

with distance from the inferred 

offshore-source area, especially in 

areas of shoal waters and shallow 

reefs such as extend several miles 

offshore from Afognak village. 

On the Shelikof Strait side of 

the islands, maximum runup 

heights generally range from 5 to 

6 feet. A lone exception is at the 

Terror River streamflow gage 

site, where, as described in the 

following section, seiching caused 

anomalous water-level rises of as 

much as 10 feet above tide level 

at 3:00a.m. and 4:00a.m. on the 

morning of March 28. 

Other than at the Terror River 

gage site, maximum recorded 

runups above tide level occurred 

during the first three waves. The 

highest runups above predicted 

postearthquake astronomical 

tides recorded at Kodiak Naval 

Station and at the Myrtle Creek 

streamflow gage ( 12.8 and 18.4 

ft, respectively) occurred during the second wave. At Cape 

Chiniak and Narrow Cape the 

first wave (at least 31% and possibly 40 ft) reportedly was the 

highest. At Afognak and Old 

Harbor the third wave (8 and 13 

ft above tide level, respectively) 

was the highest. The maximum 

runup altitude in these areas, 

however, did not necessarily coincide with the highest wave, inasmuch as the maximum was the 

resultant of both wave height and 

the stage of postearthquake astronomical tide at any given locality. As shown by table 2, the 

tides on which the seismic sea 

waves were superimposed ranged 

from slightly less than 0 to 16.0 

feet. Consequently, the highest 

recorded runup at many localities, including those stations indicated on table 4, coincided with 

wave arrivals close to midnight 

at about high tide, rather than 

with the larger early waves that 

arrived at lower tide stages. 

PERIODS 

'The first three seismic sea 

waves as recorded at W omens 

Bay and the stream gage at 

Myrtle Creek had periods of 

50-55 minutes (table 4). This 

period probably most nearly approximates that of the waves at 

their source. Later irregularities 

in the interval between successive 

waves at these places and at the 

two stream gages on the Shelikof 

Strait side of the islands may reflect superposition of local seiches 

upon the wave train. Such superposition may in part explain the 

inconsistencies in the reports by 

eyewitnesses at different localities on the number and arrival 

times of wave crests. 

The anomalous increase in 

wave height recorded at the 'Terror Bay streamflow gage (table 

4) is suggestive of a longitudinal 

seiche excited in Terror Bay 

through approximate coincidence 

between the natural oscillation 

period of the bay and that of the 

seismic seawave train. That the 

anomalous high waves in the bay 

were purely of local origin is 

clearly demonstrated by the record of successive waves of declining amplitude during the same 

period on the Uganik River gage 

and at inhabited areas nearby. 

'The Terror River gage is at the 

head of a nearly rectangular fiord 

about 14 miles long, less than 1 

mile wide, and with an average 

depth of roughly 270 feet. The 

natural period of oscillation for 

the fundamental mode of opensided bays, such as Terror Bay, is 

given by the formula: 

4l Tn=-= v gd 

where Tn is the natural period in 

seconds, l is the length of the bay 

in feet, g is the gravitational constant, and d is the water depth in 

feet (Ruttner, 1953, p. 43). The 

fundamental mode of oscillation 

is that in which the first node is 

situated at the mouth of the bay. 

By use of this formula and the 

dimensions and depth indicated 

above, the period for the fundamental mode of water in the fiord 

is about 53 minutes, which coin-
D36 ALASKA EARTHQUAKE, MARCH 27, 1964 

20. -- Openlng torn by selsmlc sea 71 aves In the bar1 1c.1 beach of a 1tt1 ge lake along the shore of Izhut Bay on Afognalr 

Island. Channel scour and subsidence of at least G feet pelmit sea water to enter the basin at all stages of tide. Note 

partially submerged trees along inner margins of the beacb spits, and small new rockslide along bluff in background. 

Photograph by Alaska Department of Fish and Game. 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D37 

cides almost too closely with the 

period of 50- 55 minutes indicated 

for the initial waves. Consequently, the anomalously high wave 

recorded at the stream gage may 

have resulted from resonant amplification of a longitudinal seiche 

that was excited by the train of 

seismic sea waves. 

EFFECTS ON SHORE:LINES 

AND SEA BOTTOMS 

High-velocity currents associated with the repeated ebb and 

flood of the waves resulted in extensive damage through erosion 

of artificial fills and unconsolidated deposits along the coast. The 

effect of the surges may be compared to erosion during extreme 

flood conditions of rivers. At several places, barrier beaches damming coastal lakes were breached 

by the waves, and the lakes were 

thereby converted to lagoons, as 

illustrated in figure 20. 

Stream gravel was removed 

from the bed and banks of Olds 

River at the head of Kalsin Bay 

along a length of at least 400 feet 

of the estuary (Alaska Dept. Fish 

and Game, 1965, p. 6). Mud was 

eroded from tidal flats along the 

shore at Kodiak to a depth of 10 

feet. Bottom changes off shore 

from Kodiak at a depth of 75 feet 

were reported by a scuba diver, 

Mr. J erry Tilley, who noted that 

the channel had been scoured 

clean of mud and that thousands 

of clams were thereby exposed on 

the sea floor. 

The combination of swift currents and the buoyant effect of 

large-amplitude waves moved 

several navigation and mooring 

buoys in the Chiniak Bay area, 

and dragged the navigation buoy 

in Shuyak Strait off station. Undoubtedly the 20- to 25-knot currents associated with the waves 

caused intensive scouring of sediment from shorelines and narrow 

21.- Shoreline damage between Narrow Cape and Cape Chiniak caused by 

driftwood-laden seismi c sea wave. Spruce trees as much as 8 inches in diameter 

were broken off at about 30 feet altitude. Limbs were broken and trunks scarred 

to a measured altitude of 42 feet above lower low water. Crowns of downed 

trees point in direction of water movement. 

straits and deposition of the 

eroded material in deeper quieter 

water. Few such effects, however, 

have been documented along the 

shores of Kodiak and the nearby 

islands because of the general 

scarcity of preearthquake reference marks in coastal areas and 

the complicating factor of widespread postearthquake subsidence. 

At uninhabited capes and embayments along the ocean coast, 

wave inundation was evidenced 

by newly deposited driftwood and 

seaweed above the level of highest tides and by broken and scarred shoreline vegetation in timbered areas. Figure 21 illustrates 

the effects on a stand of spruce 

trees near Narrow Cape of a 

driftwood-laden surge of water 

that ran up to an altitude of 42 

feet above lower low water. 

ORIGIN 

The seismic sea waves clearly 

were generated off shore from 

the Kodiak group of islands within the Gulf of Alaska, as shown 

by the arrival times of the initial 

waves, the distribution of wave 

damage, and the orientation of 

damaged shorelines. The distance 

traveled by the waves can be determined where wave velocity 

along the propagation path and 

travel time are known. Because 

the wave lengths are long, seismic 

sea waves move as shallow water 

waves even in the deepest ocean. 

As such, their velocity is controlled by the depth and conforms 

closely to LaGrange's equation 

(in Lamb, 1932, p. 257) : 

V=v gh 

where g is the gravitational constant, and h is the water depth 
D38 

along the travel path (as determined from nautical charts). The 

travel time is taken as the elapsed time between arrival of the 

first wave crest at shore stations 

and the inferred time at which 

the waves were generated. 

Calculations of the distance 

travelled by the first waves to 

the few stations where reliable 

data are available on arrival 

times defines a source area that 

trends northeastward at a minimum distance of 28 miles off 

Cape Chiniak and 17 miles offshore from Sitkalidak Islandassuming that the waves were 

generated at the time of the 

earthquake or shortly thereafter 

(fig. 18). A time delay between 

the beginning of the earthquake 

and generation of the waves 

would modify the position of the 

inferred source by shifting it 

shoreward. Thus, if as much as 5 

minutes elapsed between the beginning of the earthquake in 

Prince William Sound and the 

generation of the waves offshore 

from the Kodiak area, the inferred source area would be 4-6 

miles shoreward from the position shown on figure 18. The absence of large waves at Sitkinak 

Island and in Alitak Bay suggests 

that the wave source did not extend southwest of the general latitude of southern Sitkalidak 

Island. The anomalous lack of 

wave effects along the low-lying 

northeast shore of Sitkinak 

Island, which is ideally situated 

to receive heavy damage from 

northeasterly waves, further suggests that the waves were strongly directional-as might be expected from a linear northeasttrending source area. 

Initial upward motion in the 

source area is suggested by (1) 

the distribution of measured 

land-level change along the adjacent coast and offshore islands, 

ALASKA EARTHQUAKE, MARCH 27, 1964 

(2) the initial rise recorded on 

tide gages outside the immediate 

area affected by the earthquake 

(Van Dorn, 1964, p. 11), and 

(3) possibly by the unique atmospheric waves ("seismic air 

waves") recorded shortly after 

the earthquakes on microbaragraphs at both the University of 

California at Berkeley and the 

Scripps Institution of Oceanography at La Jolla (Van Dorn, 

1964, p. 7; Bolt, 1964, p. 1096). 

The initial direction of water 

movement within the Kodiak 

islands area is less clear, however, because there were no operative tide gages, and in many 

localities water movement during 

and after the earthquake was 

complicated by land-level changes 

along the coast, and perhaps also 

by local waves generated by the 

ground tremors or by subaerial 

and submarine landslides. With a 

few notable exceptions, however, 

most observers along the coast of 

the Kodiak group of islands and 

elsewhere along the coast of the 

Kenai Peninsula and Prince William Sound area reported that 

the first strong surge of waves 

from the Gulf of Alaska was upward; this report tends to support the inference of vertical displacement in the source area. 

The waves recorded on Kodiak 

and the nearby islands and those 

that struck the outer coast of the 

Kenai Peninsula (fig. 17; Plafker and Mayo, 1965, p. 10, fig. 

12) appear to have originated 

along a linear axis of maximum 

uplift that extends about 350 

miles between Sitkalidak Island 

in the Kodiak group and Montague Island in Prince William 

Sound. The discrepancy in the 

position of the inferred axis of 

maximum uplift offshore from 

the Kodiak Island area between 

figure 21 and that of a preliminary report ( Plafker and Mayo, 

1965, fig. 12) results from a previous error in calculating propagation velocities of the waves. 

The axis of the inferred wave 

source as shown in figure 17 and 

as computed independently by 

VanDorn (1964, figs. 8, 10) are 

in close agreement. At the north 

end of this axis near Montague 

Island there is clear evidence for 

significant upward displacement 

in a 6-mile-wide segment of the 

sea floor. Both extreme crustal 

warping and large fault dislocation must have taken place. The 

southwest tip of Montague Island 

was elevated as much as 33 feet 

relative to sea level; there was 

at least 18 feet of vertical offset 

on land along the Patton Bay 

fault (Plafker, 1965, p. 1132; 

Plafker and Mayo, 1965, p. 7). 

Furthermore, the fault has been 

traced as a prominent scarp in 

the ocean floor for at least 15 

miles southwest of Montague Island towards the Kodiak group of 

islands. As much as 50 feet of net 

uplift of the sea floor along this 

line has been inferred from comparison of pre- and postearthquake bathymetric surveys made 

by the U.S. Coast and Geodetic 

Surveys southwest of Montague 

Island (Malloy, 1964). 

The inferred source area shown 

on figure 18, from which destructive waves radiated northwestward to batter the coast of the 

Kodiak group of islands could be 

a southwestern extension of the 

axis of uplift and faulting in the 

Montague Island area. As in that 

area, it may represent a relatively narrow strip of extreme differential uplift and (or) faulting 

that is superimposed on the broad 

regional zone of uplift. The position of the inferred wave source 

is largely in an area of fiat slopes 

and shoal water on the continental shelf; the possibility is thus 

virtually precluded that the 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D39 

waves result either from massive 

submarine landslides along the 

continental slope or from special 

resonant oscillations of water in 

the adjacent Aleutian Trench. 

The low-amplitude dipole-type 

wave that Van Dorn ( 1964) considered to have been formed by 

tectonic warping of the broad 

zones of uplift and subsidence 

shown on figure 17 apparently 

did not adversely affect Kodiak or 

the nearby islands, although it 

may have contained much of the 

wave energy radiated out into the 

Pacific Ocean. No negative wave 

phase was recorded within the 

zone of subsidence along the 

shores of the islands, nor was a 

positive phase reported at any 

The earthquake and attendant 

subsidence and seismic sea waves 

severed the main coastal highways on Kodiak Island and caused 

extensive damage to the fishing, 

cattle ranching, and logging industries on Kodiak and the nearby islands. These industries constitute the main economic base 

for the region. The city of Kodiak 

also receives substantial revenue 

from the operation and maintenance of the Kodiak Naval Station that is about 6 miles south 

of the city. 

The effects of the earthquake 

on the . highway routes and on 

the various industries throughout 

the Kodiak Island region are described in the following section. 

The nature and cause of the extensive damage to public, private, 

commereial, and military property at population centers in the 

Kodiak region is discussed in a 

separate volume of this series 

of reports on earthquake effects 

locality other than the city of Kodiak prior to the arrival of the 

initial wave crest. The tectonic 

warping did result, however, in 

almost immediate withdrawal of 

water from some tilted uplifted 

areas and in complementary rises 

of water level in depressed areas. 

The reported initial calm rise of 

water observed at Kodiak immediately after the earthquake may 

have been associated with this 

regional crustal tilting about the 

axis of zero land-level change. 

The amount of uplift at the 

inferred wave source offshore 

from the Kodiak group of islands 

is not known and probably cannot be determined because the 

area had not been covered by deDAMAGE AND CASUALTIES 

on Alaskan communities. The 

estimated dollar value of damage 

by the earthquake is shown in 

table 1. 

HIGHWAYS 

There are approximately 125 

miles of highway on Kodiak and 

the nearby islands; about 115 

miles are on Kodiak Island-85 

miles of which are rural routes 

(fig. 22, next page). This report 

will consider only the 85 miles 

of rural highway on Kodiak 

Island, because the remainder are 

in communities and will be discussed in the companion chapter 

in Professional Paper 542. 

The earthquake caused approximately $5,036,000 worth of damage to the highway system on 

Kodiak Island-about $446,000 

in the city of Kodiak and $1,677,-

000 in the Kodiak Naval Station 

(Tudor, 1964, fig. 3). Chiniak 

highway on the Naval Station 

was damaged from the station 

tailed preearthquake bathymetric 

surveys. That the vertical seafloor displacements may be of the 

same order of magnitude as those 

in the Montague Island area is 

suggested by the similarity in the 

maximum runup heights of the 

seismic sea waves (35-40 ft) 

along physiographically comparable segments of coast both on 

the Kenai Peninsula opposite 

Montague Island (Plafker and 

Mayo, 1965, p. 10) and on Kodiak Island. Other factors, however, such as rate of uplift, initial 

slope at the wave source, and 

energy loss along the propagation 

path preclude direct correlation 

of runup heights with displacement at the source. 

complex to Middle Bay, the southern boundary of the station. 

Most of the damage occurred 

on the 47-mile route to Chiniak 

and Sequel Point. 1

The seismic 

sea waves destroyed two bridges 

at W omens Bay, four in Middle 

Bay, one across Mayflower Creek, 

one across the Kalsin River at 

Kalsin Bay, two on Twin Creek, 

and one at an unnamed creek at 

mile 33.7, about 0.8 mile east of 

Twin Creek. (Mile posts are 

reckoned north and south of the 

Buskin River-mile 0.0-which 

flows through the main complex 

of the Kodiak Naval Station.) 

Eyewitness accounts of the 

seismic sea waves indicate that 

the bridges were not destroyed 

by the incoming water of the 

first wave, but by the outgoing 

wave and by the more violent incoming and outgoing subsequent 

waves. Figures 23 and 24 (p. 

D41) show seismicsea-wavedamage to two bridges. 
D40 ALASKA EARTHQUAKE, MARCH 27, 1964 

58°00' ,-----------------------------------~--------------------------------------------------------, 

sr3o' 

Spruce 

Cape 

EXPLANATION 

Highway net 

Dashed line indicates road bed 

that required relocation or 

replacement 

• 

Bridge destroyed by seismic 

sea waves 

0 

Bridge replaced due to 

regional and local subsidence 

Boundary of Naval 

Reservation 

CHINIAK 

BAY 

Saltery Cove 

0 4 

22.- Earthquake damage to major highway routes on Kodiak Island. 

Cape 

Chiniak 

APPRO<IMATE MEAN 

DE(Lir>JATION, 1966 

8 MILES 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D41 

23. - Bridge at Womens Bay destroyed by seismic sea waves. Deck of bridge collapsed owing to destruction of piles. 

Compare with fig. 24. Photograph by U.S. Navy, March 30, 1964. 

24. - Deck of h~ghway bi~tige at il-omens Bay \\aslied arny by seismic sea waves. \ Photograph by U.S. Navy, March 30, 1964. 
ALASKA EARTHQUAKE, MARCH 27, 1964 

25. -Section of roadway along Chirl~ak 111gh\vay at IVomells Bay destroyed by seismic sea waves. 

Photograph by U.S. Navy, March 30, 1964. 

In addition to those that were 

destroyed, five bridges on the 

Chiniak highway had to be replaced either because they were 

underwater during high tide or 

because their approaches needed 

realinement. The bridges that required replacement (indicated by 

open circles on fig. 22) are at 

Womens Bay, Middle Bay, and 

Kalsin Bay. 

The seismic sea waves destroyed at least 13 miles of roadway 

on the highway to Chiniak. About 

3 miles of road was destroyed at 

Womens Bay (figs. 22 and 25), 

3 miles at Middle Bay (pl. 3), 1 

mile at Mayflower Creek, and 4 

miles at Kalsin Bay. The roads 

in these areas were not only destroyed but had to be realined 

because regional and local subsidence was so great that the preearthquake alinement left the 

roadway under water during high 

tides. 

The Anton Larson highway 

spur, 9 miles long, starts near 

Buskin Lake on the Naval Reservation and runs west and then 

north to Anton Larson Bay. Damage occurred near the terminus 

of the road at the bay. One mile 

of roadway was destroyed and 

required replacing. I11 addition, 

two bridges near the bay required 

replacing. 

The Saltery Cove spur road 

originates at the Chiniak highway at Middle Bay. It heads generally southeastward for 14 miles 

to Saltery Cove on Ugak Bay. 

Damage on this spur occurred 

near its point of origin at Middle 

Bay and at the divide between the 

Saltery Cove and Middle Bay 

drainage basins. Two miles of 

roadway were destroyed and one 

bridge had to be replaced. 

The Narrow Cape spur road is 

15 miles long; it originates at 

I<alsin Bay and heads south, 

where it skirts the east edge of 

Lake Rose Tead, then runs on to 

Pasagshak Bay. At the head of 

Pasagshak Bay, the road forks. 

One spur continues south about 

2 miles to Pasagshak Point; the 

other spur heads east for about 

5 miles to Narrow Cape. 

Two miles of roadway of the 

Narrow Cape spur was damaged 

by the earthquake and attendant 

subsidence. At Kalsin Bay 1 mile 

of roadway had to be replaced. 

Another mile of roadway re- I 

quired replacement at Lake Rose 

Tead (fig. 8). In addition to 2 

miles of roadway that was de- I 

stroyed, three bridges had to be 

replaced on the Narrow Cape 

spur road. 'Two bridges at Lake 

Rose Tead and one on a small i 

I 

creek that flows into the head of 

Pasagshak Bay required replacement. I 

Along the 85 miles of rural I 

highway on Kodiak Island, 18 I 

miles of roadway, 22 bridges, and 1 

1 culvert were either destroyed 

by seismic sea waves or had to be 

replaced because of regional and 

local subsidence. No bridges were 

destroyed by seismic shock even 

though some were on foundations 

of unconsolidated deposits. 

FISHING INDUSTRY 

The salmon, king crab, halibut, \ 

dungeness crab, shrimp, and clam 

fishing industry, upon which the 

economy of the area is almost en- I 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D43 

26. - Chaotic condition of the commercial section of the city of Kodiah following inundation by seismic sea waves. The I 

t- small-boat harbor, which was in the left background, contained an estimated 160 crab and salmon fishing boats when the 

I waves struck. Photograph by U.S. Navy, March 30, 1964. 

I 

1 -/ 

tirely dependent, suffered devasI tating losses of processing facilities, vessels, and gear. Three canneries at Kodiak and one at 

Uzinki were destroyed by seismic 

sea waves, and one other cannery 

and a cold-storage plant at KOdiak were severely damaged. The 

Kadiak Fisheries cannery at 

Shearwater Bay was damaged by 

seismic shock during the earthquake, after which it was virtu- 

) ally destroyed by the waves. Estii 

i 

mated value of the structures and 

the finished products they contained is $2,610,000. 

The total number of lost or 

damaged fishing boats is not 

known. In the vicinity of Kodiak 

alone, 13 vessels were lost and 

19 others were swamped or run 

aground (fig. 26). Vessels underway in deep water were not damaged by the waves. One boat, a 

38-foot seiner, went down with 

its crew of six when it either 

struck a wave-propelled log or 

mas grounded between waves in 

shallow water near Spruce Cape, 

8 miles northeast of Kodiak. Two 

other lives were lost on two fishing boats that sank in the Kodiak 

small-boat harbor. Replacement 

cost of vessels that were sunk, 

grounded, or otherwise damaged 

throughout the area has been estimated at $2,466,500. 

As a result of regional tectonic 

subsidence, three canneries and 

their facilities were made unusable by inundation, and four 

others sustained costly damage. 

The lost and damaged cannery facilities were valued at $1.3 million (Alaska Dept. Fish and 

Game, 1965, p. 21). 

Studies of salmon habitat by 

the Alaska Department of Fish 
D44 ALASKA EARTHQUAKE, MARCH 27, 1964 

and Game (1965, p. 3) indicate 

that, because of subsidence, tides 

have made many previous intertidal salmon spawning areas 

nearly useless and have engulfed 

former fresh-water stream rearing areas. As shown by table 3, 

tidal inundation of streams extends as much as 4,500 feet 

farther inland than before the 

earthquake. According to the Department of Fish and Game, at 

least two important salmon fishing areas did not produce in 1964, 

even though it was a bumper salmon year elsewhere. Studies have 

been initiated to determine whether the poor catch was due to normal seasonal variations in salmoli 

runs, or was in some way related 

to the earthquake. 

Significant changes in currents 

and the time of tide changes have 

been reported by fishermen on 

the Shelikof Strait side of the 

islands since the earthquake. 

These changes are probably related to changes in water depth 

resulting from the tectonic deformation. The difference in tides 

and currents has required modification of fishing techniques and 

could have a detrimental longterm effect on the migration pattern of the salmon. 

In Sitkalidak and Raspberry 

Straits (fig. 2) where subsidence 

amounted to about 1 and 3y' feet, 

respectively, local residents report not only higher high tides 

since the earthquake but also 

lower low tides. In these areas, 

clamming is reportedly better on 

minus tides than it was prior to 

the earthquake. These reports 

have not been confirmed or explained by the fisheries authorities. 

Tectonic uplift and subsidence 

has changed the appearance of 

landmarks used by vessel operators along the treacherous rocky 

coast and has altered water 

27. - Part of Reaty Ranch showing extent of m7ave inundation, as indicated by 

light-colored debris. Ranch buildings are a quarter of a mile from the shoreline. 

depths. These changes have reportedly caused several vessels to 

be damaged or sunk since the 

earthquake by collision with submerged objects. 

CATTLE RANCHES 

The earthquake was a neardisaster to several of the small 

cattle ranchers in the area who 

were struggling to develop sound 

and profitable operations. 

Inundation by seismic sea 

waves caused extensive property 

damage at all the isolated cattle 

ranches along the southeast coast 

of Kocliak Island and on Sitkalidak Island. According to a U.S. 

Department of Agriculture report (Oliver, 1964), 175 cattle 

were drowned, 3 ranch houses 

and 20-25 outbuildings with their 

contents were swept away, and 

25 miles of corral and range fencing was lost. In addition, several 

hundred acres of land used for 

hay production was littered with 

wave-borne debris (fig. 27). 

Numerous beaches and deltas 

along the southeast coast of KOdiak and Sitkalidak Islands are 

now inundated by tides, and salt 

water has ruined several hundred 

acres of the best beach rye lands 

which were used for winter grazing. 

LOGGING INDUSTRY 

Logging in the area is carried 

on by small operators and is almost entirely for local consumption. One of the sawmills near 

Afognak village on southern 

Afognak Island was abandoned 
GEOLOGIC EFFECTS ON THE KODIAK ISLAND AREA D45 

because seismic sea waves washed 

away most of the docking facilities and caused extensive damage 

to the mill. A second small mill 

near Uzinki sustained an unknown amount of wave damage 

to the dock. 

CASUALTIES 

In the Kodiak Island area the 

earthquake caused the loss of 18 

lives through drowning, but the 

extent of wave damage and attendant loss of life would undoubtedly have been much greater had not the largest waves coincided with low, rather than 

high, stages of tide. Furthermore, 

the disaster would have been 

worse had the earthquake occurred during the summer when the 

population of the islands is substantially increased by large numbers of fishermen and cannery 

workers, many of whom normally 

live and fish along shores. 

The toll of 18 dead, although 

relatively light, was to a considerable extent needless and was 

caused largely by public ignorance concerning the nature and 

destructive force of seismic sea 

Alaska Department of Fish and Game, 

1965, Post-earthquake fisheries 

evaluation; an interim report on 

the March 1964 earthquake effects 

on Alaska's fishery resources: 

Juneau, Alaska, 72 p. 

Alaska Department of Health and 

Welfare, 1964, Preliminary report 

of earthquake damage to environmental health facilities and services in Alaska: Juneau, Alaska 

Dept. Health and Welfare, Environmental Health Br., 46 p. 

:bancroft, H. H., 1886, The history 

of Alaska: San Francisco, Calif., 

A. L. Bancroft and Co., 775 p. 

from the great 1964 Alaskan 

Bolt, B. A., 1964, Seismic air waves 

waves. Especially serious is the 

prevailing mistaken belief that 

the first wave is necessarily the 

highest. As a consequence some 

individuals made the disastrous 

error of returning to low -lying 

coastal areas after the initial 

wave, and 10 of them were trapped and drowned by subsequent 

waves. Furthermore, the first 

wave did not reach any of the 

boat harbors until about an hour 

after the earthquake, and a local 

warning broadcast was issued 

half an hour earlier advising of 

the impending wave, yet few 

manned vessels were piloted to 

the safety of nearby deep water. 

All the vessels that were sunk, 

including three in which eight 

lives were lost, went down In 

shallow water. 

Clearly, a better method of 

disseminating information is required as the key to minimizing 

loss of life from future seismic 

sea waves in coastal areas of the 

Kodiak group of islands, as well 

as elsewhere along coastal segments of the Gulf of Alaska that 

may be threatened by similar 

waves in the future. Evacuation 

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should be made clear that the 

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are generated by distant earthquakes in the Pacific Ocean basin. 

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D46 

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*U.S. GOVERNMENT PRINTING OFFICE: 1966-0 216-706