Hawaiian Volcano Observatory

1956 Quarterly Administrative reports

Introductory Note By Thomas L. Wright and Jennifer S. Nakata

Compiled By Jennifer S. Nakata

Summary 1

January, February, and March 1956

By Gordon A. Macdonald and Jerry P. Eaton

Summary 2

April, May, and June 1956

By Gordon A. Macdonald and Jerry P. Eaton

Summary 3

July, August, and September 1956

By Jerry P. Eaton and George D. Fraser

 Summary 4

October, November, and December 1956

By Jerry P. Eaton and George D. Fraser

Open-File Report 2007-1316

U.S. Department of the Interior

U.S. Geological Survey
U.S. Department of the Interior

DIRK KEMPTHORNE, Secretary

U.S. Geological Survey

Mark D. Myers, Director

U.S. Geological Survey, Reston, Virginia 2007

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endorsement by the U.S. Government.

Although this report is in the public domain, permission must be secured from the individual 

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INTRODUCTORY NOTE

The Hawaiian Volcano Observatory Summaries have been published in the current format since 1956. The Quarterly 

Summaries (1956 through 1973) and the Annual Summaries (1974 through 1985) were originally published as Administrative Reports. These reports have been compiled and published as U.S. Geological Survey Open-File Reports. 

The quarterly reports have been combined and published as one annual summary. All the summaries from 1956 to 

the present are now available as .pdf files at http://www.usgs.gov/pubprod.

The earthquake summary data are presented as a listing of origin time, depth, magnitude, and other location parameters. Network instrumentation, field station sites, and location algorithms are described. Tilt and other deformation 

data are included until Summary 77, January to December 1977. From 1978, the seismic and deformation data are 

published separately, due to differing schedules of data reduction. 

There are eight quarters—from the fourth quarter of 1959 to the third quarter of 1961—that were never published. 

Two of these (4th quarter 1959, 1st quarter 1960) have now been published, using handwritten notes of Jerry Eaton 

(HVO seismologist at the time) and his colleagues. The seismic records for the remaining six summaries went back to 

California in 1961 with Jerry Eaton. Other responsibilities intervened, and the seismic summaries were never prepared.

Chronology

The following Kïlauea eruption chronology covers the two recent reports and the six missing quarters:

Location Beginning Date Ending Date Comment

Kïlauea Iki crater (Kïlauea’s summit) 11/14/1959 12/20/1959 19 eruptive episodes

Kapoho (lower east rift zone) 1/13/1960 2/18/1960 4 eruption stages

Halemaumau (Kïlauea’s summit) 2/24/1961 2/24/1961 Intermittent activity during 

uninterrupted inflation following the 1960 eruption

Halemaumau (Kïlauea’s summit) 3/22/1961 3/25/1961 Same as above.

Halemaumau (Kïlauea’s summit) 7/10/1961 7/17/1961 Same as above.

Heiheiahulu (middle east rift zone) 9/22/1961 9/25/1961 First historical east rift eruption at this location

The 1959-1960 eruptions were among two of the most spectacular Kïlauea eruptions. The HVO staff was kept busy 

with acquisition of unusually high quantities of instrumental data and observations of the two sequences, which 

were separated by less than one month. Even with a year’s interval before the beginning of the summit-east rift sequence in 1961, the staff never caught up, and the seismic records were set aside for later study. 

A total of 1,672 earthquakes—1,106 for 1960 and 566 for 1961—are part of HVO’s cataloged database. The annual 

listings have been appended to the 1st Quarter Report of 1960 and to the 4th Quarter Report for 1961. The number of 

earthquakes is probably low, biased toward the larger magnitudes. The entire HVO catalog, including 1960 and 1961, 

is accessible from the ANSS CATALOG SEARCH site at http://www.ncedc.org/anss/catalog-search.

 Thomas L. Wright and Jennifer S. Nakata 
(

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r\.ltl'rlvI (JI·"' 1'1".1 J{ I ().l{

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enr.lou, 1,000 ltel

Dcr'v,",s ".("Jff ""11 "1'.,,1

b, U :i Sur• .,

of the Island of I-Iawaii, showing location ot the Hawauun YolcanoUbs

tory, seisn10grnph stations oper:ltccl by the observatory, and localities ment.
,

Feb. 9, eP 14:39:56.1, 320 N. t 1160 W. Lower California.

iL 14:52:38, Magnitude

15:16:27,

Feb. 12, iP 12:01:31.8, 19° N., Off northwest coast of

Luzo.o, P. I. Magnitude 6Y..

Feb. 19, eL 02:37, 520 N. t 131Ylo W. Queen Charlotte Islands. :

Feb. 18, iP 07:43:52.2, 300 N., E. South of Honshu, Japan.

Depth about 450 km. Magnitude

MaT. 3, iP 00:12:58.2, 150 S., w. Samoa Islands region.

Magni tude 6Y2

'\Iar. 13, eP 13:24:43.8, 70 N., 82° W. Off south coast of Panama.

Mar. 22, iP 06:45:52.3, S., 7C)OW. Ecuador. Depth about 100 km

o

5
LOCAL EARTHQUAKES

following local earthquakes dctcrrnined

on the islands of llawaii and operated

lcano Observatory. Except for smaller earth

inter:st, classed as slight

10 the lIst. The Intensity ratings assign

he Bosch-On1ori seismograph at the U/hit;ey

ntensity scale has been extended empirically

ith the Loucks-Omori nnd Sprcngnerhcr

tries for a given earthquake are: time

nearest (J-Iawaiian standard tinle),

arest station, name of nearest station 

, 

ral remarks.

ight at Uwckahuna. Near Kilauea caldera. -

ight at,Uwekahuna. Kaoiki fault near Hnlfway

House. Felt at Hawaji Notional Park and

Pahala.

oderate at Uwekahuna. Kaoiki fault west of

Kilauea calder-a. Felt at Hawaii National

Park.

oderate at the Laboratory. Ten km south

of Kilauea caldera at a of (about 10 km.

Felt at Hawaii National Park, O!aa, and I1ilo.

ight at the Whito<oy Laboratory. rim

of Kilauea caldera. Felt at the Volcano House.

ight at Hilo. Off east const of Ilawaii about

20 km en$t northeast of Hilo at a depth of about

40 krn. Felt At Hilo and Glenwood.

odera te at Pahoa. E:lst rift of K,iJauea south of

Pahoa. Felt at Pahoa.

ISTANT EAR-rHQUAKES

thquakes of distant origin were recorded on

t the Volcano Ohscrvatory (190

1550 17.7 r W. longitude). Bel!,inninj;!=l of

n Greenwich civil time, which is 10 hours

n standard time. Locations of epicenters,

pths of focus are from the notices of Pre

ons of Epicenters published by the U. S.

Survey.

4, 25° S., 1.760 w. Tonga Islands region.

7, Depth about 200 kIn. 7 X.

2, 40 S., 152" E. New Ireland. Depth about

400 km. 7-7X·

1, 190 N., E. Marianns Islands. Depth

about 350 km. Magnitude 7.

4

PREFATORY NOTE

This sumfa1&:ry of observations made at the Hawaiian Volcano

Ob'servatory is published for the use of volcanological and seismological observatories and others interested in the data at intervals more

frequently than once a year. ° Heretofore this was

in The Volcano Leller, publtshed by the University of Haw3u, but

discontinued with issues number 529 and 530, July-December, 1955.

Those who wish to receive this summary should request inclusion on

the mailing list from the Director, U. S. Geological Survey, Washington 25, D. C.

1. 'Summary of volcanic conditions

January

l'he Hawaiian volcanoes were very quiet during January.

Only 12 earthquakes were recorded during the month on the

Bosch-Omori seismograph in the Whitney Laboratory of Seismology, on the northeastern rim of Kilauea caldera. Of these,

only 7 were larger than tremors. This is the smallest number

since October 1947, when only 11 quakes were recorded, and is

the same as the number recorded during February 1954. The

more sensitive Sprcngnether vertical seismograph at the Uwekahuna station recorded a total of 114 earthquakes during January,

but almost all of them were very small.

, The gradual subsidence of Kilauea caldera and the surround-

"ing that had continued through the last months of 1955,

following the end of the eruption in east Puna, finally stopped

during January, and during the last third of the month there was

ia small accumulation of northward tilting of the ground 'surface

at the Whitney Laboratory, suggesting the possibility of a small

rc inflation c;>f the volcano. '

February

Volcanic conditions in February were even quieter than in

January. The seismograph at the 1'hitney Laboratory of Seismology recorded only 9 earthquakes during the month, the smallest number for n.ore th3.n 15 years. The "Sprengnether vertical

seismograph at Uwekahuna recorded 81 earthquakes. The

Loucks-Onlori seismograph at the Mauna Loa station recorded

'28 nnd that at the Pahoa station recorded 26. Thus

there was more earthquake activity both on Loa and on

the east rift zone of Kilauea than in the Kilauea caldera region.

T Bting of the ground at the Whitney Laboratory was approxinormal in the east-west direction, but there was appre1

!

r.
3

3. Table of tilt at stations on the rim of Kilauea

caldera.

,2. Earthqual:es recorded on the Bosch-Omori seismograph in

....he Whi tncy Laboratory of Seismology, on the northeast

'rim of Kilauea caldera.

')

• I..oc;) i:; an value. Each local l'arrhql1akc is assioncd

a to Its strength. as follows: 0.25; very

feeble, 0 . .5; 1.0; 2.0; modcr<lte. srronc. 4.0. These value!';

?rl' to the weekly local Continuous volr.anic tremor is

Ignored tn the The assigned to the earthquake depends

on th.c amplitude oC the maximum oscillation it causes on the BoschOmora selsmogr3ph, 1,)llows: Tremor, less than 0.5 rTllD; very fceble, 0.5 to

4 rom; feeble, 4 to 11 rom; slight, 11 to 25 mm; moderate, 25 to 60 mm; strong,

than 60 mm.

, Week Urnitney station Uwekahuna station

beginning-

: (northeast rim) lwest rim)

Direction Amount, Direction Amount

: [(seconds c( arc) (seconds of arc)

Jan. 1 N t15°

E 0.7 S 0.3

8 S 39°

E 2.1

N 340

W 1.2

: 15 S 57°

E 0.4

N 45°

W 0.4

22

N 71 0 W 0.4 S 64°

W 0.7

29 N 0.1 S 14°

E 1.3

Feb. 5 S 710

W S 31°

E 1.9

12

N 71°

W '0.4 S 0.3

19 N 0.1 S 450 E 0.9

26 S 390 W- 0.8

W 0.6

'Mar. 4 S 45°

W 0.8 .....--_ ..... -.....---_ ... 0.0

11 S 34°

W 0.4

E 0.3

18

w 0.1 S 270 E 1.4

25

S 790 W 0.6

N 26°

W 0.7

,- Mihutes Week Very Moder- Local

I beginning vf feeble Feeble Slight Strong Total SClS- tremor ate micity •

Jan. 1 0 1 0 0 0 0 1 0.5

8 0 ,3 0 . 1 0 0 4 3.5

15 0 0 0 0 0 0 0 0,

22 2 2 0 0 0 0 4 1.5

29 2 0 0 0 0 0 2 0.5

Feb. 5 0 0 0 1 0 0 1 1.0

12 0 2 0 0 1 0 3 4.0

19 0 3 0 0 0 0 3 1.5

26 1 1 0 0 1 0 3 3.7.

'Mar. 4 4 3 1 1 0 0 9 5.5

11 0 2 0 0 0 0 2 1.0

18 10 4 0 0 0 0 14 4.5

25 1 3 2 0 0 0 6 3.7.

2

Afarch

Kilauea volcano increased markedly

to that during January and February.

Whitney Laboratory recorded 34 earth..

nsitive Sprengnether seismograph at

uakes. The Mauna Lou seisnlograph

hat at the Pahoa station recorded 22.

n activity, however, the number of

auea caldera region was onlYI slightly

y recorded during times of volcanic

s appear to have originated in the

severnl of them at a depth of about

ong the east: rift zone of Mauna Loa,

rift zone of Kilauea in east Puna.

arch 9, felt as a sharp short sh3ke in

Hawaii National Park, came from a

dera.

A quake at 1h 5H

m

on 10

o IIilo. It seems to have originated

of I-iilo at a depth of about km.

ccurred during the month on the walls

Most of them were on the southwest

re the rift zone intersects rhe crate,:

27 a higllly sensitive vertical

ph in n new station at the south edge

ed about 3 hours of continuous tremor

accolnpany the movernent of liquid

uits of tI,e volcano. The tremor was

visible on the from the other

y was caused by rnovemcnt of magma

lder(1. I-Iowevcr, because this new

er magnification than any instr\Jment

lauea, we do Got know whether oc not

this sort is

outhward tilting of the ground :tt the

much less than usual at that Season

icating a small increase of rnagmatic

ldera region. Westward was

nount.

ng than usual at that season Of the

ght turnescence of the volcano, ()I'ob

rease of magmatic pressure beneath
;, .

,i.

, .

I

UNlrl'EU S'!'Ar!'ES

DEPARTMENT OF THE INT.ERIOR

SURVEY

IIA'VAIIAN OBSEI{VATORY

2

April-Julle 1956

By

G. A. and J.·P. Eaton

N

J

• 5.;lmo9ro"" 'Iolion I. Hawoiion Volcano Obllrvotory

• Cil,. town, Of villoQe 2. Whitn., Loboratory of Sei,molo9Y

• LOCality 3 Uwellohuno lIi,/nooropfl ,to'ion

Ao4d " H.odquort.rt Hawaii Hollonol

Contour int.rvoll.OOO ftlt

OtJfu," S,tI ,",,,

TQtloorophy by U.S. GeoIOfieol Survey

Map of the Island of Hawaii, showing location ;'f the Hawaiian

Volcano Observatory, seismograph stations operated by the

observatory, and localities mentioned in text.
magnitudes, and depths of focus are from the notices of Preliminary .Determinations of Epicenters published by the u. s.

Coast and Geodetic Survey..

Apr. 18. eP 11:07:31.2,

Apr. 22. eP 17:29:17.8,

Apr. 2:3. e P 03: 41 :12.5,

May 6. e T 21:40:20.8,

May 23" i P 20:55:40.4,

is 21:00:35.4

May 26, eP 20:28:43.0,

MIY 28. eP 13:35:43.3,

M.y 30. eP 15:50:03.5,

]u'ne 4. eP

] me 13" e P 12: 19:45.1 ,

].ne28. eS 13:10:07,

eL 13:14:42

520 N., 1780 W. Andreanof Islands, Aleutian

Islands. Magnitude 6-6X.

54° N., 1620 W. South of Alaska

Magnitude 6.

E. Off east coast of Hokkaido.

Felt- Magnitude 6Yr6%.

N., w. Unimak Island region,

Alaska.. Magnitude sY:rS%.

S., 1790 W. Fiji Islands. Depth about

450 lern. Magnitude

19° S., W. Fiji Islands" Depth about

5 SO Ian. Magnitude 6X-6X.

10 N., 121XO E. Northern Celebes. Depth

abomt 100 km.

23° S.. , 178Xo W. Tonga Islands region.

Depth about 350 km.

52° N., 170Xo W. Fox Islands, Aleutian

Islands. Magnitude 6X.

XO S., 124Xo E. Near coast of Celebes.

Depth about 200 km.

49° N., w. Off coast of Vancouver

Island, British Columbia. Magnitude 6Xo

5
CAL EARTHQUAKES

wing local earthquakes were determined

he islands of Hawaii and Maui operated

o Observatory. Except for smaller earth

est,. only earthquakes classed as slight

n the list. The intensity ratings assigned

sch-Omori seismograph at the Whitney

sity scale has been extended empirically

he Loucks-Omori and Sprengnether seis

for a given earthquake are: date, time

rest station (Hawaiian standard time),

t station, name of the nearest station,

emarks.

at Uwekahuna. About 10 km south of

Kilauea caldera at a depth of about 15 km.

ht at Mauna Loa. Near the Mauna Loa

lope Observatory at a depth of about 10 km.

era te at Kamuela. About 20 km north

orthwest of Keahole Point at a depth of

bout 15 km. Felt at Honokaa.

erate at Kamuela. 200 17' N., 155 0 17' W.,

bout 75 km east of Hana, Maui and about

0 km north of Laupahoehoe, Hawaii. Depth

robably about 20 km. Felt from Hawaii

ational Park on Hawaii to Honolulu on Oahu.

ht at Kamuela. Fifteen km northwest of

amuela at a depth of about 30 km.

ng at Mauna Loa. Five km north of Ainapo

t a depth of about 5 km. Felt from Keala

ekua to Hilo, strongly at Kapapala.

derate at Kona. Near Kealakekua, probably

t a shallow depth. Felt at Kealakekua.

ng at Kona. Several km north of Kealakekua

t a depth of about 5 km. Felt throughout

ona and as far as the Hawaiian Volcano

bservatory.

ht at Mauna Loa. About 15 km deep near

he Mauna Loa seismograph station.

ht at Mauna Loa. About 15 km deep near

he Mauna Loa seismograph station.

ANT EARTHQUAKES

quakes of distant origin were recorded

at the Hawaiian Volcano Observatory

1550 17.7' W. longitude). Beginnings

Greenwich civil which is 10 hours

tandard time. LocatiOlls of epicenters,

4

'I

PREFATORY NOTE

This summary of observations made at the Hawaiian Volcano

Observatory is for the use of volcanological and se ismological observatories and others interested in the data at intervals more

frequently than once a year. Heretofore this material was available

in The Volcano Letter, published by the University of Hawaii, but

discontinued with issues number 529 and 530, July-December, 1955.

Those who wish to receive this summary should request inclusion on

the mailing list from the Director, U. S. Geological Survey, Washington 25, D. C.

1. Summary of volcanic conditions

April

Seismic actIVIty dropped to a very low level during April.

Only 8 earthquakes were recorded by the seismograph beneath

the Volcano House. The more sensitive seismograph at Uwekahuna recorded 120 earthquakes during the month, but most of

these were very small.

At 7:09 p.m. on April 15 an earthquake originating about

15 km deep 20 km north northwest of Keahole Point was felt

at Honokaa.

A small swarm of earthquakes about 45 km beneath

Kilauea caldera on April 18 and April 19 was followed by a

sequence of tiny, shallow earthquakes in or near Kilauea caldera

between April 24 and April 30.

Tilting of the ground surface at the northeast rim of Kilauea

caldera was negligible during April. Since the normal tilting

at this point during April was moderate in amount and directed

toward the southwest, the absence of tilt may reflect a slight

swelling of the top of Kilauea volcano.

May

Seismic actIVIty in Hawaii increased somewhat during May.

Nineteen earthquakes were reRistered by the seismograph bel
e, and the more sensItIve seismograph

bout 220 mostly very small earthquakes.

m Hawaii National Park on Hawaii to

:54 p.m. on May 13 originated about

aui, at a depth of about 20 km. This

ortheast margin of the Hawaiian Arch

been the site of several large earth

0 years.

7 an earthquake stemming from a focus

Ainapoand 5 km deep was felt from

he shaking was reported to be severe

surface at the Volcano House was to

in excess of the normal amount. The

o eastward in the east-west component

hree months earlier than usual. This

ve been caused by a tumescence of

ny fa:ctors, including temperature and

ecorded at the Volcano House that no

possible.

June

waii again dropped to a very low level

rthquakes were registered on the seis

ano House during the month. At Uweka

engnether seismograph recorded about

f these were very small, however.

7 a sharp earthquake originating within

was felt in central Kona.

A somewhat

he same region was felt from Kona to

3:09 p.m. on June 14.

ndred very tiny earthquakes from deep

were recorded at Mauna Loa and Uweka

earthquakes have stemmed from

ear for the last three years.

e earth's surface at the Volcano House

normal. The rate of eastward tilting

had been abnormally rapid for several

ed to normal during the last two weeks

2

2. Earthquakes recorded on the Bosch-Omori seismograph in

the Whitney Laboratory of Seismology, on the northeast

rim of Kilauea caldera.

Week Minutes Verr Moder- Local of Feeble Slight Strong Total seis- beginning feeb e ate tremor micity •

April 1 2 1 1 1 0 0 5 4.00

8 1 0 () 0 0 0 1 .25

15 0 2 0 1 0 0 3 3.. 00

22 0 0 0 0 0 0 0 0.00

29 2 5 0 0 0 0 7 3.. 00

May 6 0 1 0 0 '0 0 1 .50

13 1 2 0 1 0 0 4 3.25

20 0 1 0 0 0 0 1 .50

27 2 3 0 0 0 1 6 6.00

June 3 0 0 1 0 0 0 1 : 1.. 00

10 0 0 0 1 0 0 1 2.00

1.7 0 1 0 0 0 0 1 .50

24 0 2 0 0 0 0 2 1.00

• Local seismiCity is an arbitrary value. Each local earthquake

is assigned a seismicity value according to its strength, as follows:

tremor, 0.25; very feeble, 0.5; feeble, 1.0; slight, 2.0; moderate, 3.0;

strong, 4.0. These values are totaled to give the weekly local se ismicity. Continuous volcanic tremor is ignored in the calculation. The

strength assigned to the earthquake depends on the double amplitude

of the maximum oscillation it causes on the Bosch-Omori seismograph, as follows: tremor, less than 0.5 mm; very feeble, 0.5 to 4 mm;

feeble, 4 to 11 mm; slight, 11 to 25 mm; moderate, 25 to 60 mm; strong,

greater than 60 mm.

3. Table of tilt at seismograph stations on the rim of Kilauea

caldera.

Whitney station Uwekahuna station

Week rim) (WI! :t rim)

beginning Direction Amount Direction Amount I<seconds of arc) (seconds of arc)

April 1 S 63 0 w 0.3

W 0.3

8 N 570 W 0.4 S 180 E 1.0

15

N 720 E 0.8 S 630 E 0.7

22 S 220 W 0.7

N 45 0 W 0.5

29

N 0.5

W 0.3

May 6 N 0.8 S 45 0 E 0.5

13

E 0.5

E 0.3

20 .._-------------------- 0 w 0.3

27

N 63 0 E 0.5

N 270 W 1.4

June 3 N 18°

E 0.4

N 570 W 1.2

10

N 270 E 0.5

N 630 W 0.7

17

W 0.2 Record interrupted by

24

N ISO E 0.4 work in vault.

3
UNITED STATES

DEPARTMENT OF THE INTERIOR

GEOLOGICAL SURVEY

HAWAIIAN VOLCANO OBSERYATORY

SUMMARY 3

July-Septelllber 1956

By

J. P. Eaton and George D. Fraser

,,.

EXPLANATION

A SeislftOtrapfl Itof'Oll 1 Howeilon VoIcono ObwrYe'O',

• Cit,. ""'n.OI' ¥in. t Whtne, Labofo,ory of Seiamolo9Y

• Locality 5. uWufIuno Hi.",ot. "a,ion

Rood 4. .....,.,'.r. Hawaii NofioMi ,-,II

5 t!l '.IllS

Contour "".'wal 1,000 f••'

001_ i, INfIn ... -., •

Topo9,aph, ." U.S. '"'oIkoi Su,..,

Map of the Island of Hawaii, showing location of thei Hawaiian

Volcano Observatory, seismograph stations operated by the

observatory, and localities mentioned in text.
9, eP 10:08:00.7,

17, iP 07:45:43.4,

·July

I

I

Aug.

I

18, iP

23, eP

eS

eL

9, iP

is

eL

12,

eS

06:30:55.1,

19:36:10.7,

19:44:34

19:51:26

23:07:59.6,

13:13:46

13:16:57

17:09:46.7,

17:18:07

200 N.; 730 W. Near coast at Haiti. Moderate property damage of Port de Paix.

Depth about 100 km. Magnitude

70 S., 126W> E. Banda Sea. Depth about

450 km. Magnitude

50 S., 1300 E. Banda Sea. Magnitude

240 S., 1020 w. Easter Island region. Magnitude

150 S.1 790 w. Samoa)slands reJtion. Depth

about 2)0 km. Magnitude

340 N., 1380 E. Near south coast of

Honshu, Japan. Magnitude

South

Depth

Islands region,

Northern Celebes.

Prince Edward

Indian Ocean.

S., 1230 E.

about 150 km.

540 N., 1640 W. Unimak Island, Aleutian

Islands. Magnitude 6.

460 N., 1510 E. KorBe Islands. Magnitude

530 N., E. Near Islands, Aleutian

Islands. Magnitude

410 N., W. Off coast of northern

California. Magnitude

34 0 N., E. Magnitude

N., E. Near south coast of

Kamchatka. Magnitude

S., w. Samoa Islands. Magnitude 6.

220 S., 1750 E. Fiji Islands region.

II:03 :31.9,

11:13:44

11:25:19

13:28:41,

13:35:39

04:35:21.2,

04:41:40

04:46:24

04:31:15.1,

04:40:27

04:41 :53

05:31:26;

05:38:2506:04:42

Q2:52:50,

iP

is

eL

eS

eL

eP

eS

eL

eP

eS

eL

eP

eS

eT

eL S., E. Fiji Islands. Magnitude 6-

eP 21:12:41.7, N., 1550 E. Northern KurileIslands.

eS 21:19:51 Magnitude

eL 21:26:03

eL ,,09:28:25,

eP 22:00:38.4,

eS 22:07:37

eP 06:12:06.8,

eL 06:22:10

eP 07: 11 :16.0,

eL 07:23:05

iP 22:34:36.7,

14, eL 03:59:46,

15,

15,

24,

30,

30,

24,

11,

30 N., 1280 E. Off north coast of Halroahera. Depth about 60 km.

29, eP 23:30:48.9, N., 1400 E. Central Honshu, Japan.

One killed, several injured and minor

property damage in Tokyo. Depth about

60 km.. Magnitude

16,

20,

29,

Sept. 11,

o 0125
L EARTHQUAKES

ng local earthquakes were determined

islands of Hawaii and Maui operated

o Observatory. Except for smaller

terest, only earthquakes classed as

ded in the list. The intensity ratings

he Bosch-Omori seismograph at the

intensity scale has been extended

e with the Loucks-Omori and Spreng

entries for a given earthquake are:

e nearest station (Hawaiian standard

earest station, name of the nearest

eral remarks.

oderate at Naalehu. About five km south

ast of Puu 0 Keokeo on the southwest

ift of Mauna Loa. Felt in central Kona.

ght at Naalehu. Ten km north of Naalehu

at a depth of about fi ve km.

at Uw.ekahuna. Thirty km deep under

Kilauea Iki. .

ght at Naalehu. About 10 km northnorthwest of Naalehu at a depth of about five km.

ght at Uwekahuna. Kaoiki fault near

Halfway House at a depth of about 30 km.

ght at the Whitney Laboratory. Fifteen

m west southwest of Kalapana along

he south shore of Kilauea at a depth of

bout 10 km. Felt in Hilo.

EARTHQUAKES

es of distant origin were recorded

he Hawaiian Volcano Observatory

50 17.7' W. longitude). Beginnings

nwich civil time, which is 10 hours

ard time. Locations of epicenters,

focus are from the notices of Pre

Epicenters published by the U. S.

S., w. Fiji Islands. Depth

bout 450 km.

N., 260 E. Aegean Sea. 42 killed

nd many injured. Several towns de

royed on Thira and los Islands. Mag

tude

4

PREFATORY NOTE

This summary of observations made at the Hawaiian Volcano

Observatory is published for the use of volcanological and se ismological observatories and others interested in the data at intervals more

frequently than once a year. Heretofore this material was available

in the Volcano Letter, published by the University of Hawaii, but

discontinued with issues number 529 and 530, July-December, 1955.

Those who wish to receive this summary should request inclusion on

the mailing list from the Director, U. S. Geological Survey, Washington 25, D. C.

1. Summary of volcanic conditions

July

A flurry of tiny, shallow earthquakes orIgInating in or near

Kilauea caldera the last week of the month made July the most

seismic month for Hawaii since April, 1955. On the Sprengnether seismograph at Uwekahuna almost 1400, mostly very

small earthquakes were recorded. The Bosch-Omori seismograph

in the Whitney station recorded 206 disturbances, of which 51

were earthquakes larger than tremors.

These earthquakes were very similar in appearance to those

which accompanied the marked downwarping of the caldera and

surrounding area in March and April, 1955, during the Puna

eruption.

1
about five km southeast of Puu 0

ft of Mauna Loa at 1:41 a.m. on

na.

ng of the earth's surface at the

at less than normal during July.

roceeded at about twice the rate

ugust

emained at a moderate level during

quakes registered on the Bosch

hitney station. Almost all of the

c,?rded by the Sprengnether' seis

nated in or near Kilauea caldera

the month occurred at 3:36 p. m.

out 30 km deep under Kilauea lid

ldera and was reported felt by no

1 p. m. on August 23 was felt by

nonhward component of tilting of

mal for August, but the eastward

of the normal amount.

tember

n and near Kilauea caldera marked

waii's volcanoes. Twenty earth

Whitney station. The Sprengnether

gistered 344 earthquakes. Almost

nd originated in Kilauea caldera.

Kalalua Crater on the east rift

olcano area at 7:09 p. m. on Sep

earthquake originating southwest

out 10 km at 12:44 on Sep

e earth's surface at the Whitney

f the rate normal for

2

2. Earthquakes recorded on the Bosch-Omori seismograph in

the Whitney Laboratory of Seismology, on the northeast rim of

Kilauea caldera.

Week Minutes Very Moder- Local of Feeble Slight Strong Total seis- beginning tremor feeble ate micity •

July 1 1 ·1 0 0 0 0 2 0.75 8 8 2 0 0 0 0 10 3.00

15 30 2, 0 0 0 0 32 : 8.50

22 22 12 1 0 a 0 35 . 12.50

29 102 34 2 0 0 0 138 44.50

Aug. 5 1 0 0 0 0 0 1 ·25

12 2 0 0 0 0 0 2 .50

19 2 10 0 '0 0 0 ;12 5.50

26 2 2 0 0 0 0 4 1.50

Sept. 2 1 3 1 0 ·0 0 5 2.75 9 0 1 i 0 0 0 3 2.50

16 4 4 0 0 0 0 8 3.00

23 1 0 0 1 0 0 2 2.25

*Local seismicity is an arbitrary value. Each local is

assigned a seismicity value according to its strength, 'as follows:

tremor, 0.25; very feeble, 0.5; feeble, 1.0; slight, 2.0; moderate,.

3.0; strong, 4.0. These values ·aretotaled to give. the weekly local

seismicity. Continuous volcanic tremor is ignored in the cal¢ulationa The strength assigned to the earthquake depends on the double

amplitude of the maximum oscillation it causes on the Bosch-Omori

seismograph, as follows: Tremor, less than 0.5 mm; feeble,

0.5 to 4 mm; feeble, 4 to 11 mm; slight, 11 to 25 mm; moderate, 25 to

60 mm; strong, greater chan 60 mm.

3. Table of tilt at seismograph stations on the rim of

caldera.

Whitney station Uwekahuna station

Week (northeast rim) (west rim)

beginning Direction Amount Direction Amount (seconds of arc) (seconds qf arc)

July 1 N 220 E 0.7 I

8 N 230 W .9 Record interrupted by work in

15

N 370 E .6 vault.

22

N 220 E .7

W 330 S 0.5

29

N 370 E .6 S .5

Aug. 5 N 14° E .5

W .3

12

N 110 W .6

N .2

19

N 27<>' E .3

N 31 0 W .9

26

N 330 W .4 VI 370 N 1.5

Sept. 2 E 33°

N .4

W 60 S 1.5

9 N 450 E .5

N 330 VI 1.1

16 N .1 S 450 VI 1.1

23 E .2

W 8°

N 1.1

3
.

l

I

I

I

.....

UNITE'D STATES

DEPARTMENT OF THE INTERIOR

GEOLOGICAL SURVEY

HAWAIIAN VOLCANO OBSERVATORY

SUMMARY 4

October-December 1956

By

J. P. Eaton and George D. Fraser

156· 155·

N

l

20

Apuo Point

EXPLANATION

& Seisln09roph .totion I. Hawaiian Volcano Observatory

• City, town, or villoC)e 2. Whitney Loboratory of 5eismoloQy

• Locality 3. Uwekahuno seismograph .totion

Rood ". Headquarters Hawoii Notionol PQrk

Contour interval 1,000 feet

Oalum is Iw.1

Topography by U.S Geol09icoi Survey

Map of the Island of Hawaii, showing location of the lIawaiian

Volcano Observatory, seismograph stations operated by the

observatory, and localities mentioned in text.
'...

Oct. 26, eS 23 :06: 29,

eL 23:13:11

Oct. 28, iP 03:38:27.4,

is 03:46:23

eL 03:54:23

Nov. 4, eP 07:14:04.9,

Nov. 9, iP 13:15:53.9,

eS 13:23:44

Nov. 17, eP 20:35:03.8,

eL 20:43:29

eT 21:14:43

Nov. 28, eP 19:36:01,

eL 19:50:40

Nov. 29, eP 09:25:03.3,

Dec. 8, eP 16:17:53,

is 16:23:23

iL 16:27:21

Dec. 18, eP 02:44:39.3,

eS 02:56:49

iL 03:14:11

eT 04:27:54

Dec. 21, is 09:12:04,

eL 09:14:20

eT 09:44:58

Dec. 23, eP 08:47:03,Dec. 27, iP 00:22:27.0,

is 00:29:08

eL 00:33:13

Dec. 28" eP 14:34:56.1,

eS 14:45:42

eL 14:55:03

14° S., 167° E. New Hebrides Islands.

Magnitude

320 S., 1790 W. Kermades Islands. Magnitude

S., W. Tonga Islands. Depth

about 100 km. Magnitude

170 N., 940 W. Southern Mexico. Slight

damage In Oaxaca Province. Depth

about 150 kITh Magnitude 6.

N., 1340 W. Queen Charlotte Islands

region. Felt: Ketchikan, Alaska. Magnitude

N., 1550 E. Northern Kurile Islands.

Magnitude 7.

270 N., 1410 E. Bonin Islands. Magnitude 7.

510 N., W. Andreanof Islands,

Aleutian Islands. Magnitude

S., W. Chile-Argentina border.

Felt: Antofagasta and Copiapo. Magnitude

51 0 N., 1310 W. Queen Charlotte Islands.

Magnitude 6Yr6%.

220 N., E. Marianas Islands region.

Depth about 100 km. Magnitude

240 S., 1770 w. Islands region.

Depth about 300 km. Magnitude

380 S., E. Near coast of North

Island, New Zealand. Depth about

150 km. Magnitude 6Y4'6%.

5 lLt010
1. Summary of volcanic conditions.

This of observations made at the Hawaiian Volcano Observatory is published for the use of volcanological and seismological

observatories and others interested in the data at intervals more

frequently than once a year. Heretofore this material was available

in The Volcano Letter, published by the University of Hawaii, but

discontinued with issues number 529 and 530, July-December, 1955.

Those who wish to receive this summary should request inclusion on

the mailing list from the Director, U. S. Geological Survey, Wash-:

ington 25, D. C.

PREFATORY NOTE

October

The swarm of tiny earthquakes from the region of Kilauea

caldera that began near the end of July continued through October. At Uwekahuna the Sprengnether seismograph recorded

702 quakes. As in past months these earthquakes predominantly

were very small and originated in or near Kilauea caldera at

shallow depths.

At 12:45 a.m. on October 16, a strong earthquake from an

epicenter at sea about 45 km west of Kailua, Kona, was felt

over the entire island of Hawaii and as far north as Honolulu

on Oahu.

At the Whitney station on the northeast rim of Kilauea caldera,

northeastward tilting of the earth's surface continued at a rate

slightly less than normal for October.

November

During November the swarm of small earthquakes from Kilauea

caldera declined slightly. The Sprengnether seismograph at

Uwekahuna registered 562 quakes, most of which originated

within a few km of the station.

Near the Mauna Loa

at a depth of about

Pahoa. Near the south shore of

10 km southwest of Kalapana at a

about 5 km. Felt in Hilo.

Uwekahuna. Near Kilauea caldera at

of 30 km.

Uwekahuna. Near Kilauea caldera at

of about 10 km.

wekahuna. On the Kaoiki fault near

caldera at a depth of about 10 km.

he north rim of Kilauea caldera.

Mauna Loa.

aph station

Kona. Near the Kona seismograph

Felt in Kona.

N., E. Mindoro Island,

ilippine Islands. Depth about 100 km.

N., 87° W. Near coast of Nicaragua.

nor damage at Managua. Felt: South

n El Salvador. Magnitude 7-7X.

N., 870 W. Nicaragua aftershock.

elt: El Salvador and Nicaragua.

agnitude

ARTHQUAKES

of distant origin were recorded

awaiian Volcano Observatory (190

7' W. longitude). Beginnings of

ch civil time, which is 10 hours

d time. Locations of epicenters,

cus are from the notices of Pre

picenters published by the U. S.

N., E. Kurile Islands. Felt:

okkaido, Japan. Depth about 100 km.

agnitude

N., w. Off Cape Mendocino,

alif. Felt: Coastal area of northern

alifornia. Magnitude 6.

S., 1220 W. South Pacific Ocean.

agnitude

N., 1770 E. Rat Islands, Aleutian

ands. Magnitude

4 1
Oct. 11, 12:53:34,

Oct. 16, 00:44:55,

Oct. 16, 17:31:24,

Oct. 20, 20:23:04,

eporte<f felt during November. It

he 13th on the Kaoiki fault near

long the north rim of the caldera.

ormal eastward tilting continued

toward the north reversed sharply

rsal from northward to southward

th earlier than usual.

cember

lightly during December. Almost

ecorded by the Sprengnether se is

ated at Kilauea caldera and were

ted felt during the month shook

December 14.

on the northeast rim of Kilauea

the ground surface was slightly

l for December.

the Bosch-Omori seismograph in

of Seismology, on the northeast

Moder- Local 

Slight Strong Total selS- 

ate 

micity *

0 0 0 3 1.00

0 0 0 3 0.75

0 0 1 4 6.50

0 0 0 3 1.00

0 0 0 3 1.00

0 0 0 5 1.50

0 0 0 7 3.50

0 0 0 21 6.50

0 0 0 37 12.75

0 0 0 21 7.25

0 0 0 8 2.50

0 0 0 9 2.75

0 0 0 16 5.25

value. Each local earthquake is assigned

rength, as follows: tremor, 0.25; very fee

moderate, 3.0; strong, 4.0. These values

l seismicity. Continuous volcanic tremor

strength assigned to the earthquake de

he maximum oscillation it causes on the

s: tremor, less than 0.5 mm; very feeble,

ight, 11 to 25 mm; moderate, 25 to 60 mm;

2

3. Table of tilt at seismograph stations on the rIm of Kilauea

caldera.

Whitney station Uwekahuna station

Week (northeast rim) (west rim)

beginning Direction Amount Direction Amount (seconds of arc) (seconds of arc)

Sept. 30

E 18°

N 0.8

W18°

N 0.5

Oct. 7 N45°

E 0.2

W 0.5

14 E34°

N 0.9

W18° S 1.0

21

E 27° S 0.3

W 0.2

28 N45°

E 1.0 W34°

N 0.5

Nov. 4 E 11°

N 0.6 N27°

W 0.3

11 S 0.1

W18° S 0.5

18

E 0.7 W27°

N 0.3

25 S 18°

E 0.8 S 14°

E 0.6

Dec. 2 S 30°

w 1.0

E 22°

N 0.8

9 S 45 0 W 0.2

W11° S 0.8

16 0 W18°

N 0.5

23

E 18°

N 0.4 S 0.5

--

LOCAL EARTHQUAKES

The data for the following local earthquakes were determined

from seismographs on the islands of Hawaii and Maui operated

by the Hawaiian Volcano Observatory. Except for smaller earthquakes of special interest, only earthquakes classed as slight

or larger were included in the list. The intensity ratings

assigned are based the Bosch-Omori seismograph at the

Whitney Laboratory. This intensity scale has been extended

empirically to permit its use with the Loucks-Omori and Sprengnether seismographs. The entries for a given earthquake are:

date, time of arrival at the nearest station (Hawaiian standard

time), intensity at the neare st station, name of the neare st

station, epicenter, and general remarks.

slight at Kamuela. About 20 km northwest of

Kamuela at a depth of about 15 km. Felt

in Kamuela.

strong at Kona. At sea about 45 km west of

Kailua, Kona, at a shallow depth. Felt over

the entire island of Hawaii and as far as

Honolulu on Oahu.

slight at Kona. Aftershock of previous earthquake. Felt in Kona.

very feeble at Pahoa. Near the south shore of

Kilauea 10 km southwest of Kalapana at a

depth of about 5 km. Felt in Hilo.

3