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Digital files available at https://doi.org/10.3133/sim2932B

Suggested citation: Trusdell, F.A., and Lockwood, J.P., 2019, Geologic map of the central-southeast flank of Mauna Loa volcano, 

Island of Hawai‘i, Hawaii: Scientific Investigations Map 2932–B, pamphlet 23 p., 2 sheets, scale 1:50,000, 

https://doi.org/10.3133/sim2932B.

ISSN 2329-1311 (print)

ISSN 2329-132X (online)

https://doi.org/10.3133/sim2932B

Geologic Map of the Central-Southeast Flank of Mauna Loa Volcano, Island of Hawai‘i, Hawaii

By

Frank A. Trusdell and John P. Lockwood

2019

U.S. Department of the Interior

U.S. Geological Survey

Scientific Investigations Map 2932–B

Sheet 2 of 2

Pamphlet accompanies map

?

? ? ?

? ? ? ? ? ? ? ?

? ? ? ?

? ? ?

? ?

?

?

A.D. 1790

A.D.1984

A.D.1880–81

475±41

288±36

311±25

569±53

575±38

760±70

780±70

955±24

1,638±32

1,622±23

1,824±19

1,574±25

1,469±32

1,507±19

1,428±38

1,293±27

4,378±42

7,960±110

1,530±37

1,640±150

1,708±50

2,072±37

2,265±49

2,365±30

1,910±120

1,993±43

2,826±32

8,520±82

8,645±71

9,218±79

9,680±70

10,030±85

10,600±150

25,768±188

28,140±590

9,121±46

n

744

a13b2

384

a13f3

735

p11b3

386

a11a2

388

p11a1

390

p10a3

338

p10c2

742

p9g2

978

a9b5

944

m10b1

383

p9h1

395

p8e1

962

m5a1

399

p4a1

892

a4l7

882

p2b16

540

a2k11

864

p2b10

290

p2a4

297 p2i5

344

p2e8

346

p2b15

336

p2f9

288

p2c6

301

p1k2

801

a1g1

800

p1a3

274

a1k5

799

p1l6

833 a1b7

840

p1e8

837

a0b2

787

a0a1

783

p1g4, 802

a1i9

838

p2b2, 293 p2i3

298

a2k13

347

a2a12

841

p2j17

350

a2g1

300

a2a19

989

p2f7

289

p2e14, 343

p2b23

292

p2b24

294 p2c25

340

a3a1, 295

a3a2, 889

a3a3, 637

p3b10

296

p3a9

291

m3a7

554

a3l5

891

a3a6

357

p4l5

342

p4k4

339

p4c6

352

p4a11

844

p4g2

899

p4a3

401

p4a12

a4j8 895

890

p5h4

392

a5b3

379

p5f6

378

a5b7

870

p5a2

880

p5a5

397

s5a8

871

p3e4

345

a4a9

351

a4a10

348

a6c3

990

a6k2

398

a6d1

988

a6a4

986

p8b2

400

a8i4

979

m8k3

983

p8e5

385

p9b4

393

a9k3

402

m13b1

387 Pahala Ash pa

389

ts

959

m10k4

382

p10g6

942

a10i5

943

a11a4

391

a2k21

900

a2k20

893

p2g22, 883

a2a18

349

a3i8

884

Pleistocene

QUATERNARY

VOLCANIC DEPOSITS

LAVA FLOWS AND VENT DEPOSITS

Ka‘ū Basalts

DISTAL TEPHRA DEPOSITS

SEDIMENTARY DEPOSITS

Holocene

1

pre-A.D. 1843–1,000 yr B.P.

2

1,000–2,000 yr B.P.

3

2,000–3,000 yr B.P.

4

3,000–4,000 yr B.P.

5

4,000–5,000 yr B.P.

6

5,000–6,000 yr B.P.

7

6,000–7,000 yr B.P.

8

7,000–8,000 yr B.P.

9

8,000–9,000 yr B.P.

10

9,000–10,000 yr B.P.

11

10,000–15,000 yr B.P.

12

15,000–20,000 yr B.P.

13

20,000–30,000 yr B.P.

14 

30,000–100,000 yr B.P.

15

>100,000 yr B.P.

Age Group

0

A.D. 1843 and younger

Undivided tephra

9,500±140

Uwekahuna Ash

Member, Puna Basalt

2,110±120

2,265±50

2,770±70*

31,020±310

* Uwēkahuna Ash Member of the Puna Basalt: Two episodes between 2,110±120 and 2,770±70 (Dzurisin and 

others, 1995)

Undivided tephra

4,135±49

Kahuku Basalt

Nīnole Basalt

CORRELATION OF MAP UNITS

[Only the unit label for the most common flow type, listed first in the unit description (Description of Map units, pamphlet), is included in the Correlation of Map Units and table 2. See Description of Map Units for detailed unit age information. Uncalibrated radiocarbon 

ages are reported in years before present (yr B.P.). Undated flows are correlated with dated flows using superposition; surface exposure; color change due to solar radiation; extent of weathering; tree height, size, and girth; diversity of native plant species; and soil and ash 

accumulation. Equivalence of horizontal position of undated flows does not imply age equivalence and, vertical positioning of one unit over another applies only to the stratigraphic relations of the units that are superimposed (such as a4l7 and a4j8 or p3e4 and a4a9 and 

a4a10) in the correlation diagram. Queried dashed line at bottom of unit box shows base of flow is concealed. In addition to the map unit label, a unique, three-digit flow identification number (FID; for example, FID 831) is assigned to each mapped flow unit to facilitate 

use of the database (https://doi.org/10.3133/2932B); the FID is essential as a unique descriptor for unit identification in the database. FID numbers are included for the units shown]

1868

3,630±80

1,281±66

1,511±24

a0a1

a0b2

a1g1

p1k2, a1k2, m1k2

p1a3, a1a3, m1a3

p1g4

a1k5, p1k5, m1k5 

p1l6, a1l6

a1b7, p1b7

p1e8, a1e8

a1i9, p1i9

a2g1

p2i3 a2i3, m2i3

p2f9

p2f7

p2a4, a2a4

p2i5, a2i5

p2c6

p2e8, a2e8, m2e8

p2b10

a2k11, p2k11

a2a12, p2a12

a2k13, p2k13

p2e14, a2e14

p2b16

p2b15

p2j17, a2j17

a2a18, p2a18, m2a18

a2a19, p2a19

a2k21, p2k21

a2k20, p2k20

p2g22, a2g22

p2b23

p2b2

p2b24

p2c25

a3a1

ls

a3a2, p3a2

a3i3

p3e4, m3e4, a3e4

p4k4

p4l5

p4c6

a4l7

a4j8

a4a9, p4a9

p4a11, m4a11

p4a12

m5a1

p5a2, m5a2

a5b3

p5h4, a5h4

p5a5

p5f6

a5b7, p5b7, m5b7

s5a8

a6d1

a3l5, p3l5

a3a6

m3a7

a3i8, p3i8, m3i8

p3a9

p3b10

p4a1

p4g2, a4g2

p4a3, a4a3

a6k2

a6c3

a6a4

p8e1

p8b2, a8b2

m8k3,p8k3

a8i4, p8i4

p8e5

p9h1

p9g2, a9g2

a9k3

p9b4

a9b5, p9b6

m10b1, p10b1, a10b1

p10c2

p10a3

m10k4, p10k4, a10k4

a10i5

n

ts

pa

p10g6

p11a1

a11a2, p11a2

p11b3

a11a4

m13b1

a13b2

a13f3, p13f3

K

4790

8730

LIST OF MAP UNITS

[Some unit exposures on the printed or plotted map are not labeled to avoid obscuring data; 

use unit color or database (https://doi.org/10.3133/2932B) for unit identification. The 

simplified map unit label is not unique and provides quick access to flow morphology, flow 

age group, phenocryst mineralogy, and flow number in an age group (table 3, sheet 1); this 

non-unique unit label may be used for an entirely different unit on a different flank of 

Mauna Loa. We use the term "phenocryst" for any mineral ≥1 mm in maximum diameter. 

Pyroxene is not an abundant phenocryst in Mauna Loa lava flows; therefore, it is not 

included in phenocryst mineralogy. In addition to the map unit label, a unique, three-digit 

flow identification number (FID; for example, FID 831) is assigned to each mapped flow 

unit to facilitate use of the database for the entire Mauna Loa edifice; the FID is essential as 

a unique descriptor for unit identification in the database]

SEDIMENTARY DEPOSITS

Mudflow deposits of A.D. 1868 (Holocene)

Landslide deposits (Holocene)

VOLCANIC DEPOSITS

LAVA FLOWS AND VENT DEPOSITS

Ka‘ū Basalt

Age Group 0 (A.D. 1843 and younger; Holocene)

A.D. 1984 flow—FID 783

A.D. 1880–81 flow—FID 787

Age Group 1 (pre-A.D. 1843–1,000 yr B.P.; Holocene)

Ke‘āmuku Kīpukakēkake flow—FID 800

Kīpukamauna‘iu flow—FID 801

Ke A Po‘omoku Lava Flow—FID 274

Ke‘āmuku Kīpukakulalio flow—FID 802

Ke‘āmuku Kīpukakulalio east flow—FID 799

Keauhou Ranch flow—FID 833

Flow northeast of A.D. 1880 lobe—FID 840

Puʻuwahi picrite flow—FID 837

Ke‘āmuku Kīpukakulalio west flow—FID 838

Age Group 2 (1,000–2,000 yr B.P.; Holocene)

Flow 300—FID 300

West Wood Valley flow—FID 293

Pahuamimi flow—FID 298

Keakapulu Flat flow—FID 297

Kapāpala flow—FID 344

Kilohana flow—FID 301

Waimuku flow—FID 289

Pu‘u‘ele‘ele flow—FID 346

Ka‘ala‘ala Gulch flow—FID 288

Kapāpala Ranch flow—FID 290

Upper Waiākea flow—FID 864

Flow 841—FID 841

Nāpu‘ukūlua flow—FID 347

Kauhiuhi flow—FID 343

East Wood Valley flow—FID 336

Moa‘ula flow—FID 540

Flow 350—FID 350

Kauhiuhi Maluikeao flow—FID 349

Flow 989—FID 989

Kīpukalō‘ihi flow—FID 893

Flow 900—FID 900

Upper Strip Road flow—FID 883

Pi‘ikea flow—FID 292

Keaīwa Gulch flow—FID 294

Flow 340—FID 340

Age Group 3 (2,000–3,000 yr B.P.; Holocene)

Red Cone flow—FID 295

Eastern Ka‘ōiki Pali flow—FID 889

Nīnole flow—FID 637

Cow Pasture picrite flow—FID 345

Flow 891—FID 891

Flow 357—FID 357

‘Alili flow—FID 554

Flow 884—FID 884

Ka‘ala‘ala flow—FID 291

Flow 296—FID 296

Age Group 4 (3,000–4,000 yr B.P.; Holocene)

‘Ōhaikea flow—FID 892

Flow 899—FID 899

Flow 401—FID 401

Flow 339—FID 339

Wai‘akaloa Gulch flow—FID 342

Flow 352—FID 352

Flow 882—FID 882

Flow 890—FID 890

Flow 351—FID 351

Flow 348—FID 348

Flow 844—FID 844

Flow 895—FID 895

Age Group 5 (4,000–5,000 yr B.P.; Holocene)

Halfway House flow—FID 399

Flow 880—FID 880

‘Ahulili flow—FID 379

Age Group 5 (4,000–5,000 yr B.P.; Holocene)—Continued

Flow 392—FID 392

Ka‘ili‘ula flow—FID 397

Uēwale Gulch flow—FID 378

Kīpukakēkake flow—FID 870

Pu‘ukīpū cone—FID 871

Age Group 6 (5,000–6,000 yr B.P.; Holocene)

Flow 988—FID 988

Kīpukapakēkakē flow—FID 398

Flow 990—FID 990

Pu‘u 4274 flow—FID 986

Age Group 7 (6,000–7,000 yr B.P.; Pleistocene)

[No units of this age group are found at the surface in the map area]

Age Group 8 (7,000–8,000 yr B.P.; Holocene)

Palakea Flat flow—FID 962

Flow 400—FID 400

Flow 983—FID 983

Flow 979—FID 979

‘Ua‘u flow—FID 385

Age Group 9 (8,000–9,000 yr B.P.; Holocene)

Halfway House Kīpuka flow—FID 395

Pu‘u‘ula‘ula flow—FID 978

Flow 402—FID 402

Flow 393—FID 393

Flow 944—FID 944

Age Group 10 (9,000–10,000 yr B.P.; Holocene)

Ka‘ū High School flow—FID 383

Lae‘opuhili flow—FID 742

Flow 338—FID 338

‘Iliokōloa flow—FID 382

Flow 943—FID 943

Flow 942—FID 942

Age Group 11 (10,000–15,000 yr B.P.; Holocene and Pleistocene)

Kauhuhu‘ula flow—FID 390

Pā‘au‘au flow—FID 388

Meyer Camp flow—FID 386

Wailoa flow—FID 391

Age Group 12 (15,000–20,000 yr B.P.; Pleistocene)

[No units of this age group are found at the surface in the map area]

Age Group 13 (20,000–30,000 yr B.P.; Pleistocene)

Flow 387—FID 387

Flow 384—FID 384

Lava flow of Hi‘onamoa Gulch—FID 735

Kahuku Basalt

Age Group 14 (30,000–100,000 yr B.P.; Pleistocene)

[No units of this age group are found at the surface in the map area]

Nīnole Basalt

Age Group 15 ( >100,000 yr B.P.; Pleistocene)

Nīnole Basalt—FID 744

DISTAL TEPHRA DEPOSITS

Southern tephra—FID 959

Pāhala Ash—FID 389

EXPLANATION OF MAP SYMBOLS

Contact—Approximately located. Internal contact defines 

flows

Fault—Ball and bar on downthrown block. Dotted where 

concealed 

Fissure—Trace of fissure

Ground-crack zone

‘A‘ā and mixed flows

Spatter

Ash—Ash (unit ts) covering flows

Kīlauea Volcano deposits—Exposed in southern part of 

map area

Radiocarbon-dated sample locality—Age shown in yr 

B.P. See table 2 (pamphlet) for analytical data; note 

that not all age localities are in map area

Sample from surface flow—Charcoal

Sample from measured section—Does not date surface 

flow

mf mf

ls

a4a10

Photograph showing an upslope view of the A.D.1880–81 flow that originates from about 10,500 ft 

elevation. The different flow colors and the different vegetation provide geologists with clues of 

changing substrates (flows) with different ages. Photograph by Frank A. Trusdell, U.S. Geological 

Survey.

Photograph showing pasture land in the foreground that is composed of several lava flows mantled 

by undifferentiated ash (unit ts). The drainages carved into the ash also provide clues as to the age 

of the flows. The sharp boundary between the pasture and the forest is due to land use. The pasture 

consists of land used for cattle; the forest beyond is Hawaiʻi Volcanoes National Park. At one time 

the National Park land looked like the pasture; but, the forest returned after the cattle were removed. 

Photograph by Frank A. Trusdell, U.S. Geological Survey.

Photograph showing a view of the youngest prehistoric flows from Mauna Loa in Kilauea Crater 

quadrangle. Flow in the foreground is Ke‘āmuku Kīpukakulalio east flow (575 yr B.P.; FID 799); the 

forested region within the flow is vegetation that survived a forest fire. Right center, the region with 

the tall trees is unit ts or undifferentiated ash (FID 959). Left center, the flow with minimal trees, is 

the Ke‘āmuku Kīpukakēkake flow (288 yr B.P.; a1g1, FID 800). The mosaic of native vegetation types 

are an indirect indicator of substrate age. Photograph by Frank A. Trusdell, U.S. Geological Survey.

Photograph showing the stair-step land form that is the Ka‘ōiki fault system. The green pastures 

represent regions where undifferentiated ash (unit ts) mantles older lava flows. The young lava 

flows bisecting and surrounding the green grassy kīpuka all originate from the NERZ. In the 

background is the Pu‘ukīpū flow (left) and the Kūlani (right) cones. Photograph by Michael H. 

Zoeller, U.S. Geological Survey.

Photograph showing a section of undifferentiated ash near the Halfway house. The flow at the top of 

the section is the Halfway House Kīpuka flow dated at 8,520 yr B.P. Photograph by Frank A. Trusdell, 

U.S. Geological Survey.