U.S. DEPARTMENT OF THE INTERIOR

U.S. GEOLOGICAL SURVEY

China

Nepal

India

1934

Kathmandu

86°

86°

84°

84°

30° 30°

28° 28°

Pakistan

China

Nepal

Bhutan

Bangladesh

India

48

43

90°

90°

80°

80°

30° 30°

M7.8 Nepal Earthquake of 25 April 2015

Pakistan

China

Nepal

Bhutan

Bangladesh

India

90°

90°

80°

80°

30° 30°

20° 20°

0 250 500 1,000 1,500

Kilom eters

Prepared in cooperation with the

Global Seismographic Network

Tectonic Setting

Seismic Hazard

Epicentral Region

EXPLANATION

Main Shock

Earthquake Magnitude

4.0-4.5

4.51-5.0

5.01-6.0

6.01-7.0

>7.0

Earthquake Depth (km)

0-69

70-299

≥300

Aftershocks

Finite Fault Model

Slip (mm)

<50

50-100

100-150

150-250

250-280

>280

EXPLANATION

Main Shock

Mag >= 7.0

0-69km

70-299

300-600

Plate Bou ndary

Su b du c tion

Transform

Diverg ent

Oth ers

Volc anoes

0 250 500 1,000 1,500

Kilom eters

Peak Grou nd Ac c eleration in m /sec **2

.2 .4 .8 1.6 2.4 3.2 4.0 4.8

Epicentral Region

Epicentral Region

DATA SOURCES

EARTHQUAKES AND SEISMIC HAZARD

USGS, National Earthquake Information Center

NOAA, National Geophysical Data Center

IASPEI, Centennial Catalog (1900 - 1999) and

extensions (Engdahl and Villaseñor, 2002)

EHB catalog (Engdahl et al., 1998)

HDF (unpublished earthquake catalog, Engdahl, 2003)

Global Seismic Hazard Assessment Program

PLATE TECTONICS AND FAULT MODEL

PB2002 (Bird, 2003)

Hayes, G. P., Wald, D. J., and Johnson R. L., 2012, A

three-dimensional model of global

.

subduction zone

geometries: Journal of Geophysical Research, v. 117,

B01302,

.

doi:10.1029/2011JB008524.

DeMets, C., Gordon, R.G., Argus, D.F., 2010.

Geologically current plate motions, Geophys. J. Int. 181, 1-80.

BASE MAP

NIMA and ESRI, Digital Chart of the World

USGS, EROS Data Center

NOAA GEBCO and GLOBE Elevation Models

DISCLAIMER

Base map data, such as place names and political

boundaries, are the best available but may not be

current or may contain inaccuracies and therefore

should not be regarded as having official signifiance.

Map updated by U.S. Geological Survey National

Earthquake Information Center

27 April 2015

http://earthquake.usgs.gov/

Map not approved for release by Director USGS

REFERENCES

Bird, P., 2003, An updated digital model of plate

boundaries: Geochem. Geophys. Geosyst., v. 4,

no. 3, pp. 1027-80.

Engdahl, E.R., and Villasenor, A., 2002, Global

Seismicity: 1900-1999, chap. 41 of Lee, W.H.K.,

and others, eds., International Earthquake and

Engineering Seismology, Part A: New York, N.Y.,

Elsevier Academic Press, 932 p.

Engdahl, E.R., Van der Hilst, R.D., and Buland, R.P.,

1998, Global teleseismic earthquake relocation with

improved travel times and procedures for depth

determination;Bull. Seism. Soc. Amer., v. 88, p. 722-743.

M7.8 Nepal Earthquake of 25 April 2015

25 April 2015 6:11:26 UTC

28.147° N., 84.708° E.

Depth 15 km

Mw = 7.8 (USGS)

EARTHQUAKE SUMMARY MAP

PAGER

INDIA

PLATE

DYFI?

Th e April25,2015M 7.8Nepalearth qu ake oc c u rred as th e resu ltof th ru st

fau lting on ornearth e m ain frontalth ru stb etween th e su b du c ting Indiaplate

and th e overriding Eu rasiaplate to th e north .Atth e loc ation of th is earth qu ake,

approxim ately80km to th e north westof th e Nepalese c apitalof Kath m andu ,

th e Indiaplate is c onverg ing with Eu rasiaatarate of 45m m /yrtoward s th e

north -north east,d riving th e u pliftof th e Him alayan m ou ntain rang e.Th e

prelim inaryloc ation,size and foc alm ec h anism of th e April25earth qu ake are

c onsistentwith its oc c u rrenc e on th e m ain su b du c tion th ru stinterfac e b etween

th e Indiaand Eu rasiaplates.

Alth ou g h am ajorplate b ou ndarywith ah istoryof larg e-to-g reatsized

earth qu akes,larg e earth qu akes on th e Him alayan th ru stare rare in th e

d oc u m ented h istoric alera.Ju stfou revents of M 6orlarg erh ave oc c u rred

with in 250km of th e April25,2015earth qu ake overth e pastc entu ry.One,aM

6.9earth qu ake in Au g u st1988,240km to th e sou th eastof th e April25event,

c au sed c lose to 1500fatalities.Th e larg est,an M 8.0eventknown as th e 1934

Nepal-Bih arearth qu ake,oc c u rred in asim ilarloc ation to th e 1988event.It

severelydam ag ed Kath m andu ,and is th ou g h tto h ave c au sed arou nd 10,600

fatalities.

EURASIA

PLATE

0 40 80 120 160

Kilom eters

Finite Fault Model

Tectonic Summary Distrib u tion of th e am plitu d e and direc tion of slip forsu b fau ltelem ents of th e fau ltru ptu re m od elare d eterm ined from th e inversion of teleseism ic

b od ywaveform s and long period su rfac e waves.Arrows indic ate th e am plitu d e and direc tion of slip (of th e h ang ing wallwith respec tto th e footwall);

th e slip is also c olored b ym ag nitu d e.Th e viewof th e ru ptu re plane is from ab ove.Th e strike of th e fau ltru ptu re plane is 295°and th e dip is 10°NNE.

Th e dim ensions of th e su b fau ltelem ents are 20km in th e strike direc tion and 15km in th e dip direc tion.Th e ru ptu re su rfac e is approxim ately100km

along strike and 80km along d owndip.Th e seism ic m om entrelease b ased u pon th is plane is 8.1e+27d yne.c m .