MAGNETIC 

 NORTH 

11°

G 

G 

G 

G 

G 

G 

G 

G 

G 

s9g1 

f9d6 

s9d1 

f9g1 

1963 

1961 f9d1 

U.S. DEPARTMENT OF THE INTERIOR 

U.S. GEOLOGICAL SURVEY 

155°02′30′′

19°27′30′′ 19°27′30′′ 1984 f8d4 f9d3 

GEOLOGIC INVESTIGATIONS SERIES I–2614 

Version 1.0 

CORRELATION OF MAP UNITS f8d11 Pähoehoe flow at western boundary of the mapped area between the 1986 

Undated flows are correlated to dated flows using superposition; surface exposure; color change due to solar radiation; extent of weathering; tree Küpaianaha pähoehoe and 1977 Pu‘u Kiai ‘aÿä flows—Basalt contains 

height, size, and girth; diversity of native plant species; and soil and ash accumulation. Units that are stacked show direct superposition relations 1–2 percent plagioclase phenocrysts (young over old flows). Question mark indicates that the base of the flow is concealed. Vertical dashed lines indicate units that are in contact with 

each other. UNITS 400–750 YEARS OLD 

AGE f7g4 Pähoehoe flow in central part of mapped area at distal end of 1984 Pu‘u 

GROUP ÿÖ‘ö ‘aÿä—Basalt contains less than 1 percent olivine phenocrysts and 0–1 

percent plagioclase phenocrysts 1986 f9d2 s7d19 f7d19 Spatter deposits, cinder-fall deposits, and pähoehoe flows extruded from 

cinder cone near western boundary of the mapped area between two 

lobes of 1984 Puÿu ‘Öö ‘aÿä—Basalt with 1–2 percent olivine phenocrysts 

1983 f9d4 and microphenocrysts and 2–3 percent plagioclase phenocrysts in a 

feldspathic, gray groundmass 

f9d5 0–200 years old 1977 s9d5 9 s7d20 f7d20 Spatter deposits and pähoehoe flow near boundary of the 1984 Puÿu ‘Öö ‘aÿä (1790 and younger) and 1977 flow field—Basalt contains 1–3 percent plagioclase phenocrysts 

and less than 1 percent olivine phenocrysts and microphenocrysts 1968 f9e4 f7b1 Extensive ‘aÿä and pähoehoe flow—At northeastern part of mapped area. Basalt 

contains 10–20 percent olivine and less than 1 percent plagioclase 

phenocrysts 

f7c6 Pähoehoe flow—At eastern edge of mapped area. Basalt contains 3–6 percent 

olivine phenocrysts 

f7b1 s7d15 Spatter deposits surrounded by Heiheiahulu flows at the southeastern 1790 

f8g6 boundary of the mapped area—Basalt contains 3–5 percent olivine

phenocrysts and 1–2 percent plagioclase phenocrysts and microphenocrysts 

f7b5 Pähoehoe flow in east-central part of the mapped area—Basalt contains 10–15 

percent olivine phenocrysts and microphenocrysts and less than 1 percent 

plagioclase phenocrysts 

f8g1 About 1750 f7d22 Pähoehoe flow in east-central part of the mapped area—Basalt contains 1–2 s8d8 f8d8 f8d4 

f8g3 percent olivine phenocrysts and microphenocrysts and less than 1 percent 

plagioclase phenocrysts f8d4 329 ± 53 years B.P. 

f7c13 Extensive pähoehoe flow in central part of the mapped area—Basalt

 contains 3–7 percent olivine phenocrysts and microphenocrysts and less 

f8g6 f7c6 

f9d1 than 1 percent plagioclase phenocrysts s9d1 s8c1 f8c1 

f8d4 UNITS 750–1500 YEARS OLD

s8g3 f8g3 s8g8 f8g8 f7b5 s9d1 

f8d11 s8g5 f8g5 s8g4 f8g4 f6g3 Minor spatter deposits, cinder-fall deposits, and pähoehoe flows extruded 329 f7d22 1961 200–400 years old 8 f9d4 from cinder cone in southwestern part of mapped area at the north 1983 f9d1 edge of the 1977 Pu‘u Kiai flow field—Basalt contains less than 1 percent 

f8d4 f6d14 s8c2 plagioclase laths f8c2 f7c13 f7c13 s6d14 f8d10 s6d14 f6d14 Spatter deposits, cinder-fall deposits, and pähoehoe flows extruded from

cinder cone southwest of 1961 flow—Basalt contains 2–4 percent olivine 

f9g1 phenocrysts and less than 1 percent plagioclase laths 1790 s6g4 f6g4 Spatter deposits, cinder-fall deposits, and ‘aÿä flows extruded from spatter f9d4 

1983 f8g3 f8d9 f8g6 f8g7 ramparts in south-central part of mapped area—Unit is a kïpuka within s9d5 

s8d1 the larger 1977 flow field. Basalt contains less than 1 percent each of f8d1 s9g1 olivine and plagioclase phenocrysts f8d4 f9e4 f7c13

1968 

s9g1 ? ? ? UNITS 1500–3000 YEARS OLD s9g1 s9g1 ? ? ? 

Holocene QUATERNARY f5g2 ‘A‘ä and pähoehoe flows in southeastern part of mapped area south of the s8g3 

f7g4 f8d9 s9d5 easternmost 1977 Pu‘u Kiai flow field—Basalt contains less than 1 

f9g1 s9g1 f9e4 f8c1 s8g8 percent plagioclase and olivine phenocrysts 1790 

f8g8 G f9d3 f7d19 

1984 f8d10 f8g7 s9d5 Graben f8d4 f8g1 f7g4 f9d2 s6g4 f6g4 Ground crack s8c1 f9d6 f6g3 f7c6 f8d9 f9d6 f8c1 f9d6 Fissure vent 

Sample locality for radiocarbon-dated sample 

f8d10 1963 f8d8 s6g4 f9d5 

329 1977 f9g1 f9d6 f7d20 s7d15 f9d3 f8g5 1790 s9d5 s8c2 1984 f8g7 19°25′00′′ 1977 f8d8 f7c13 

f8g4 f8g4 s8d1 f8c2 19°25′00′′ s7d19 s7d15 400–750 years old 7 s8d8 s7d20 f5g2 f9d2 ACKNOWLEDGMENTS
 f9d3 f9d5 f8g4 f8d1 f7d19 s8g5 f7d20 1986 f8d11 s8g4 f8g4 f8c2 

s9d5 

f9d5 f5g2 

f7b5 f8d1 

f7b1 

f7d22 

155°02′30′′ 155°00′ ? ? ? ? ?

SCALE 1:24 000 Geology mapped in 1990–94 

Meyer Rubin (U.S. Geological Survey) determined radiocarbon ages. Lisa Morgan and 

Edward Wolfe reviewed the map. 

REFERENCES 

Fornari, D.J., 1987, The geomorphic and structural development of Hawaiian submarine rift 

zones, in Decker, R.W., Wright, T.L., and Stauffer, P.H., eds., Volcanism in Hawaii: U.S. 

Geological Survey Professional Paper 1350, chap. 5, p. 125–132. 

Holcomb, R.T., 1987, Eruptive history and long-term behavior of Kilauea Volcano, in Decker, 

R.W., Wright, T.L., and Stauffer, P.H., eds., Volcanism in Hawaii: U.S. Geological Survey 

Professional Paper 1350, chap. 12, p. 261–350. 

Base from U.S. Geological Survey, Kalalua, 1982 Macdonald, G.A., 1944, The 1840 eruption and crystal differentiation in the Kilauean magma

Projection and 10,000-foot grid ticks: Hawaii coordinate 1 1/2 0 1 MILE Manuscript approved for publication, column: American Journal of Science, v. 242, p. 177–189. system, Zone 1 (Transverse Mercator). Clarke spheroid 1866 October 8, 1997 Macdonald, G.A., and Eaton, J.P., 1964, Hawaiian volcanoes during 1955: U.S. Geological 1000 0 1000 2000 3000 4000 5000 6000 7000 FEET HAWAIIAN 

ISLANDS Survey Bulletin 1171, 170 p.

TRUE NORTH 

1 .5 0 1 KILOMETER s6d14 f6g4 750–1,500 years old 6 Moore, J.G., and Koyanagi, R.Y., 1969, The October 1963 eruption of Kilauea Volcano, Hawaii: f6g3 s6g4 f6d14 U.S. Geological Survey Professional Paper 614–C, p. C1–C13. CONTOUR INTERVAL 20 FEET MAP LOCATION APPROXIMATE MEAN 

DECLINATION, 2005 Moore, R.B., 1981, Preliminary geologic map of the Kapoho quadrangle, Hawaii: U.S. DATUM IS MEAN SEA LEVEL 

Geological Survey Open-File Report 81–947. 

Moore, R.B., 1983, Distribution of differentiated tholeiitic basalts on the lower east rift zone of 

? ? ? Kilauea Volcano, Hawaii: A possible guide to geothermal exploration: Geology, v. 11, p. 

 INTRODUCTION Rocks of historic age (age group 9) cover an estimated 28 percent of the mapped area. 136–140. 

Eruptions occurred in 1790, 1961, 1963, 1968, 1983, 1984, and 1986. Soil cover is thin (<0.05 m) Moore, R.B., 1986, Preliminary geologic map of the Pahoa South quadrangle, Hawaii: U.S. Kïlauea is an active shield volcano in the southeastern part of the Island of Hawai‘i (see index Geological Survey Open-File Report 85–715. map). The middle east rift zone (MERZ) map includes about 27 km2 of the MERZ and shows the and surficial glass is common. 

Moore, R.B., Helz, R.T., Dzurisin, D., Eaton, G.P., Koyanagi, R.Y., Lipman, P.W., Lockwood, distribution of the products of 37 separate eruptions during late Holocene time. Lava flows erupted Small alluvial deposits are present in the MERZ but are not shown, since the underlying 

J.P., and Puniwai, G.S., 1980, The 1977 eruption of Kilauea Volcano, Hawaii: Journal of during 1983–96 have reached the mapped area. volcanic rocks can be recognized. f5g2 1,500–3,000 years old 5 Volcanology and Geothermal Research, v. 7, p. 189–210. The subaerial part of the MERZ is 3–4 km wide and about 18 km long. It is a constructional MAP UNIT SYMBOLS Moore, R.B., and Trusdell, F.A., 1991, Geologic map of Kilauea's Lower East Rift: U.S. ridge, 50–150 m above the adjoining terrain, marked by low spatter ramparts and cones as high as Each map unit is designated by a three-, four-, or five-part symbol: (1) a letter, either s for Geological Survey Miscellaneous Investigations Series Map I–2225, scale 1:24,000. 60 m. In contrast to the northern flank of the MERZ, the southern flank is unbuttressed by Mauna spatter or f for flow, (2) a numeral 5–9, indicating the age group; (3) a letter, a–g, designating the Peterson, D.W., and Moore, R.B., 1987, Geologic history and evolution of geologic concepts, Loa volcano; faulting that results from intrusion of magma into the east rift zone (Swanson and 

others, 1976) has resulted in a steeper topographic profile on the southern side. Normal faults petrographic type of tholeiitic basalt; and (4) a supplementary one- or two-digit numeral (sequential ? Island of Hawaii, in Decker, R.W., Wright, T.L., and Stauffer, P.H., eds., Volcanism in 

having cumulative displacements of as much as 10 m have the same N. 65° E. trend as eruptive within each age group), if necessary, that distinguishes units in the same age group having the same Hawaii: U.S. Geological Survey Professional Paper 1350, chap. 7, p. 149–189. 

fissures and cut vent deposits and flows in and near the rift zone. Grabens often form near active petrographic symbol (for example, f9d2, f9d3, f9d5). The year of historical eruption is indicated Richter, D.H., Ault, W.U., Eaton, J.P., and Moore, J.G., 1964, The 1961 eruption of Kilauea 

vents (Richter and others, 1964, 1970). Lava typically flowed either northeast or southeast, next to the symbol. Volcano, Hawaii: U.S. Geological Survey Professional Paper 474–D, 34 p. 

depending on vent location relative to the topographic crest of the rift zone. Richter, D.H., Eaton, J.P., Murata, K.J., Ault, W.U., and Krivoy, H.L., 1970, Chronological 

The northwestern one-third of the mapped area is underlain by extensive tube-fed pahoehoe AGE GROUPS narrative of the 1959–60 eruption of Kilauea Volcano, Hawaii: U.S. Geological Survey 

Professional Paper 537–E, 73 p. flows erupted from the Ailaau shield on the eastern summit of Kïlauea volcano (Holcomb, 1987). DESCRIPTION OF MAP UNITS [After Wolfe and Morris (1996). Numbers smaller than 5 refer to age groups recognized s8c2 f8c2 Spatter deposits, cinder-fall deposits, and pähoehoe flows of Kaimü-Mäkena Stearns, H.T., and Macdonald, G.A., 1946, Geology and ground-water resources of the Island of The MERZ receives more than 100 in. of rainfall annually and is covered by tropical rain elsewhere on the Island of Hawaii but not represented on this part of Kilauea volcano.] HISTORIC UNITS (1790 and younger) Homestead—Flows extruded from cinder cone in southeastern part of Hawaii: Hawaii Division of Hydrography Bulletin 9, 363 p. forest. Vegetation begins to grow on lava a few months after its eruption. Relative heights of trees 

can be a guide to relative ages of underlying lava flows, but proximity to faults, presence of easily 9 Historical (1790 and younger) f9d2 Pähoehoe flow of Küpaianaha eruption of 1986—Basalt contains 3–5 percent mapped area. Basalt contains 3–7 percent olivine phenocrysts and less than Swanson, D.A., Duffield, W.A., and Fiske, R.S., 1976, Displacement of the south flank of 

weathered cinders, and human acti 2–3 percent plagioclase phenocrysts Kilauea Volcano: The result of forceful intrusion of magma into the rift zones: U.S. vity also affect the rate of growth. 8 200–400 years old olivine phenocrysts and microphenocrysts and less than 1 percent 

The map is based on detailed f plagioclase phenocrysts and microphenocrysts s8d1 f8d1 Spatter deposits, cinder-fall deposits, and ‘aÿä flow of Kalapana—Unit found Geological Survey Professional Paper 963, 39 p. ield mapping conducted by Trusdell and Moore from 1990 to 7 400–750 years old

1994. Stearns and Macdonald (1946) presented a generalized geologic map of Kïlauea, showing 6 750–1,500 years old f9d3 ‘Aÿä flow of Pu‘u ‘Ö‘ö eruption of 1984—Basalt contains 3–5 percent olivine in southeastern part of mapped area. Basalt contains 3–5 percent plagioclase Wolfe, E.W., and Morris, J., 1996, Geologic map of the island of Hawaii: U.S. Geological 

phenocrysts Survey Miscellaneous Investigations Series Map I–2524–A, scale 1:24,000. 

photogeologic maps of Kïlauea and discussed its geologic history based mainly on paleomagnetic 

locations of historic flows and many prehistoric vent deposits. Holcomb (1987) presented 5 1,500–3,000 years old phenocrysts and microphenocrysts and less than 1 percent plagioclase 

phenocrysts and microphenocrysts f8g1 Heiheiahulu spatter and flows at the southeastern boundary of the mapped Wright, T.L., and Fiske, R.S., 1971, Origin of the differentiated and hybrid lavas of Kilauea 

secular-variation studies. PETROGRAPHIC CLASSIFICATION OF THOLEIITIC BASALT f9d4 Aÿä flow of Pu‘u ‘Ö‘ö eruption of 1983—Basalt contains 3–5 percent olivine area—Flows originate from a large shield complex just east of the mapped Volcano, Hawaii: Journal of Petrology, v. 12, pt. 1, p. 1–65. 

The rocks have been grouped into five basic age groups. The framework for the ages assigned phenocrysts and microphenocrysts and less than 1 percent plagioclase area. Basalt contains no phenocrysts of olivine or plagioclase. Oral All rocks in the mapped area are tholeiitic basalt. Rocks have been placed in one of seven phenocrysts and microphenocrysts Hawaiian legends suggest that Heiheiahulu erupted about 1750 (Stearns and is provided by eight radiocarbon ages from previous mapping (Moore and Trusdell, 1991) and a categories, a through g, based on respective abundances of olivine and plagioclase phenocrysts; s9d5 f9d5 Spatter deposits and cinder-fall deposits and extensive ‘aÿä of 1977 eruption Macdonald, 1946) 156° 155° single date from the current mapping effort. The numerical ages are supplemented by observations 

of stratigraphic relations, degree of weathering, soil development, and vegetative cover. most rocks have less than 1 percent pyroxene phenocrysts. The assignments were made in the field (Moore and others 1979)—Main vent is Pu‘u Kiai flow found along s8g3 f8g3 Spatter deposits and extensive pähoehoe and limited ÿa‘ä flows in central and represent megascopic estimates of the volume percentages of each kind of phenocryst. In a few southern boundary of mapped area. Lava was extruded along discontinuous Rocks 1,500–3,000 years old (age group 5) cover less than 1 percent of the mapped area. cases, noted in the individual descriptions of map units, abundances of olivine or plagioclase fissure systems eventually localizing at two central vents (Puu Kiai and vent parts of mapped area—Basalt contains less than 1 percent olivine and less 

Spatter and flows are deeply weathered, have 0.5–1 m of soil, and lack surficial glass. This age phenocrysts vary slightly from the following values. than 1 percent plagioclase laths. This unit is overlain by Pu‘u Kiai ÿa‘ä 

group is represented by a single flow. A). Lava contains 1–3 percent plagioclase phenocrysts and (f9d4) Kohala 

Rocks 750–1,500 years old (age group 6) cover less than 1 percent of the mapped area. Spatter a = picritic (> 15 percent olivine, <1 percent plagioclase) microphenocrysts and less than 1 percent olivine phenocrysts and s8g4 f8g4 Pahoehoe flows at south-southwestern boundary of mapped area—Lava microphenocrysts and flows are moderately weathered, have 0.2–0.5 m of soil, and have b = 10–15 percent olivine, <1–4 percent plagioclase extruded from spatter ramparts partially buried by 1977 flows. Basalt 

surficial glass preserved in flow creases. c = 5–10 percent olivine, <1–4 percent plagioclase f9e4 Pähoehoe flow of the eruption of 1968—Basalt contains 12 percent olivine contains less than 1 percent olivine microphenocrysts and less than 1 20°

Rocks 400–750 years old (age group 7) cover an estimated 15 percent of the mapped area. d = <1–4 percent olivine, <1–4 percent plagioclase phenocrysts and microphenocrysts and 7 percent plagioclase phenocrysts percent plagioclase laths
 Mauna Kea Spatter and flows have 0.1–0.2 m of soil, and surficial glass locally is preserved e = 5–10 percent plagioclase, variable (<1–12 percent) olivine and microphenocrysts. Unit is found at the distal end of the northernmost f8g5 Spatter deposits and limited pähoehoe flows partially buried by 1984 Puÿu 1984 Pu‘u ‘Ö‘ö ‘a‘ä s8g5 

Rocks 200–400 years old (age group 8), including summit-derived ‘Ailä‘au flows (Holcomb, f = >10 percent plagioclase, 1–3 percent olivine 

1987), cover 57 percent of the mapped area. Spatter and flows typically are slightly weathered and g = aphyric (<1 percent phenocrysts) f9d6 Extensive ‘a‘ä of 1963 eruption (Moore and Koyanagi, 1969)—Lava was ‘Ö‘ö ‘aÿä, Küpaianaha pähoehoe, and 1977 flows—Basalt contains 0–1 

extruded along discontinuous fissure systems eventually. Basalt contains percent olivine microphenocrysts and less than 1 percent plagioclase laths. have soil less than 0.1 m thick. Surficial glass commonly is present. The chemical composition of basalt in categories a, b, and c is controlled chiefly by 1–5 percent olivine phenocrysts and microphenocrysts. Unit is partially Microgabbroic xenoliths less than 1 cm in diameter occasionally found in Hualalai 

One flow in the MERZ has been dated by radiocarbon at 320 ± 70 years B.P.; radiocarbon Hilo fractionation and accumulation of olivine, and basalt of categories d, e, f, and g generally is hand sample buried by the southernmost 1984 Pu‘u ‘Ö‘ö ‘a‘ä ages of several ‘Ailä‘au flows outside the MERZ (Holcomb, 1987) have been determined. differentiated beyond olivine control (Wright and Fiske, 1971). s9d1 f9d1 Spatter deposits and extensive pähoehoe of 1961 eruption (Richter and f8g6 Extensive pähoehoe flows at northeastern margin of mapped area, north 

others, 1964)—Main vent and flow found near the eastern boundary of and east of 1961 flow—Basalt is aphyric 

mapped area. Basalt contains 0–5 percent olivine phenocrysts and f8g7 Pähoehoe flow extruded from a ground crack in west-central part of Mauna Loa 

microphenocrysts mapped area—Areal distribution very limited in extent; unit found as 

f9g1 Spatter deposits and extensive pähoehoe erupted about 1790—Lava was two separate flow fields. Uprift segment is a pähoehoe at eastern edge of 

extruded along discontinuous fissure systems in the east-central part of the 1984 Puÿu ‘Öÿö‘aÿä flows. The other segment is found between flow 

s9g1 

Location of the mapped area. Lava contains less than 1 percent olivine phenocrysts and units f8d8 and f7g4 in the center of the mapped area. Basalt contains 0–1 Kilauea middle east 

microphenocrysts percent olivine microphenocrysts and less than1 percent plagioclase laths 1983–94 rift 

flows Radiocarbon ages of samples from the middle east rift zone, Kïlauea volcano, Hawai‘i f8g8 Spatter deposits and ‘aÿä in south-central part of mapped area—Areal UNITS 200–400 YEARS OLD s8g8 

distribution very limited in extent. The unit is found as kïpuka in 1790 


twigs, vegetative litter, or unaltered wood (rarely). A variance is reported as one standard deviation in years.] f8d4 Extensive pähoehoe flows—In the northern part of the map, flows underlie (f9g1) deposits. Basalt contains 0–1 percent each of olivine and plagioclase 


[All ages are reported in radiocarbon years before present (yr B.P., before the calendar year datum of 1950). Materials dated include charcoal, roots, 

about 30 percent of mapped area. Source is the ‘Ailä‘au shield (Holcomb, 19° phenocrysts Unit Age Quality1 Field Lab Age2 S.D.2 Weighted S.D.3 Age Quadrangle Latitude Longitude Elev. Source 1987) at the eastern side of summit caldera of Kïlauea. Basalt contains f8d8 Spatter deposits and pähoehoe flows extruded from spatter cone almost label group no. no. yr B.P. yr avg. (yr B.P.) 3 yr range4 7.5 minute (degrees5

) (degrees5) (ft) variable amounts of olivine and plagioclase. Flow contains 1–7 percent s8d8 

f8d4 8 + FT-92-24b WW117 320 70 329 53 1438 to 1673 Kalalua 19.436667 -155.029333 1,411 ‘Ailä‘au shield olivine phenocrysts and microphenocrysts and 0–3 percent plagioclase completely buried by 1984 Pu‘u ‘Ö‘ö‘aÿä—Basalt contains 1–2 percent 0 5 10 15 20 25 30 MILES 

f8d4 8 + FT-92-24a WW117 340 80 329 53 1421 to 1676 Kalalua 19.436667 -155.029333 1,411 ‘Ailä‘au shield phenocrysts and microphenocrysts. Average age 329 ± 53 radiocarbon yr plagioclase laths and rare olivine phenocrysts and micropheno-crysts, all in 

1

Quality: + = age thought meaningful; 0 = age probably meaningful but accuracy may be poorer than indicated by the reported precision. Meaningless (large ana- B.P. a gray feldspathic groundmass 0 5 10 15 20 25 30 KILOMETERS 

tical error) or incorrect (using all age data and regional sratigraphic relationships) ages are not reported here. s8c1 f8c1 Spatter deposits and limited pähoehoe flows in the eastern part of the f8d9 Pähoehoe flow at center of the mapped area, near distal end of 1977 INDEX MAP OF THE ISLAND OF HAWAI‘I SHOWING ITS FIVE 2Each age was calibrated to calendar years using CALIB 4.0 Radiocarbon Calibration Program (Stuiver and others, 1998); calibrated ages are for two standard de- flow—Basalt contains 1 percent olivine phenocrysts VOLCANOES (AFTER PETERSON AND MOORE, 1987). STIPPLED 

vations. Samples were processed in 1998 at the U.S. Geological Survey, Reston, VA). intervening soil. Deposits formed early stages of eruption that became f8d10 Pähoehoe flow near the western boundary of the mapped area between the AREAS SHOW APPROXIMATE LOCATIONS OF HISTORIC ERUPmapped area—Unit underlies Heiheiahulu pähoehoe (f8g1) with no

3

Multiple ages are from multiple samples; weighted avg., each age is weighted by the inverse of its variance before averaging (for example, Taylor 1982). centralized at Heiheiahulu. Basalt contains 4–8 percent olivine and 3–5 1983 and 1984 Pu‘u ‘Ö‘ö‘aÿä flows—Basalt contains 1–2 percent TIONS OF KÏLAUEA, INCLUDING THE CONTINUING 1983–90 4 Entire range of calendar year ages possible for a given sample. percent plagioclase phenocrysts plagioclase phenocrysts ACTIVITY. AREA OF MAP IS OUTLINED 5 Datum, Old Hawaiian; projection, Transverse Mercator. 

GEOLOGIC MAP OF THE MIDDLE EAST RIFT GEOTHERMAL SUBZONE, KÏLAUEA VOLCANO, HAWAI‘I 

By Digital map layout by Norma J. Maes 

Any use of trade names in this publication is for 

descriptive purposes only and does not imply 

endorsement by the U.S. Geological Survey

Frank A. Trusdell and Richard B. Moore For sale by U.S. Geological Survey Information Services 

Box 25286, Federal Center, Denver, CO 80225 

Printed on recycled paper 2006 This map is also available online at http://cpg.cr.usgs.gov/pub/i-maps.html