The 2015 Gorkha, Nepal, Earthquake and Himalayan Studies: First Results
29°

Aftershock
M8
M7
M6

Main ShockEverest28°

Mw7.3
Kathmandu

1833(A)
1833(S)

30˚

27°

18

03

NE

PA
150

28˚

IN
26˚

DIA

200 kmrontal2015 (Mw7.8)
1833

82°

84°

Main F

L

5

86°

85°

Nepal

Thrus

t (MFT
)

~1100

1934

India

BAN
GLA

~3.5 cm/yr
84°

BHUTAN

88°

DES
H

50 km

86°

87°

Editorial Board (March 2017)
Editor-in-Chief
Yasuo Ogawa, Tokyo Institute of Technology, Japan

Vice Editors-in-Chief
Masato Furuya, Hokkaido University, Japan
Solid Earth Science

Nozomu Nishitani, Nagoya University, Japan
Space Science

Editors
Valerio Acocella
Ryosuke Ando
Yosuke Aoki
Kimiyuki Asano
Nanan Balan
Stephen Bannister
Paul Bedrosian
Phil Cummins
Koji Fukuma
Thomas Hobiger
Hauke Hussmann
Art Jolly
Attila Komjathy
Alexey Kuvshinov

Juanjo Ledo
Huixin Liu
Takuto Maeda
Koji Matsumoto
Yohei Miyake
Mitsuhiro Nakagawa
Junichi Nakajima
Haruhisa Nakamichi
Yasuhito Narita
Takuya Nishimura
Azusa Nishizawa
Takaaki Noguchi
Masahito Nose
Keiji Ohtsuki

Kyoko Okino
Makiko Ohtake
Taku Ozawa
Severine Rosat
Takeshi Sakanoi
David Shelly
Benoit Taisne
Hiroshi Takenaka
Sunny TamYoshiyuki Tanaka
Yanbin Wang
Yih-Min Wu
Takuji Yamada
Mare Yamamoto

Hiroo Kanamori
Jun'ichiro Kawaguchi
Takafumi Matsui
Hitoshi Mizutani

Toshitaka Tsuda
Zhongliang Wu
Kiyoshi Yomogida

Advisory Board
Benjamin Fong Chao
Bernard Chouet
Yoshimori Honkura
Toshihiko Iyemori

Journal Scope
Earth, Planets and Space (EPS) is the official journal of the Society of Geomagnetism and Earth, Planetary
and Space Sciences, The Seismological Society of Japan, The Volcanological Society of Japan, The
Geodetic Society of Japan, and The Japanese Society for Planetary Sciences.
EPS is a peer-reviewed, open-access journal published under SpringerOpen. It is an international journal
covering scientific articles in the entire field of earth and planetary sciences, particularly geomagnetism,aeronomy, space science, seismology, volcanology, geodesy, and planetary science. EPS also welcomesarticles in new and interdisciplinary subjects, and technical reports on instrumentation and software.
The journal was launched in 1998 and has since published over 3000 articles. All of them are available forfree on SpringerLink:
http://link.springer.com/journal/40623
More information about the journal, its article collections, and the submission process is available on thejournal homepage:
http://earth-planets-space.springeropen.com
Submit your next research article to Earth, Planets and Space via:
https://www.editorialmanager.com/epsp
Yours sincerely,
Prof. Yasuo Ogawa
Editor-in-Chief, Earth, Planets and Space
editor-in-chief@earth-planets-space.org

Earth, Planets and Space
Miyake et al. Earth, Planets and Space (2017) 69:12
DOI 10.1186/s40623-016-0597-8

Open Access

PREFACESpecial issue “The 2015 Gorkha, Nepal,
earthquake and Himalayan studies: First results”
Hiroe Miyake1*, Soma Nath Sapkota2, Bishal Nath Upreti3,4, Laurent Bollinger5, Tomokazu Kobayashi6and Hiroshi Takenaka7
Gorkha earthquake and estimated the site response in
and around the Kathmandu valley.
Unique interferometric synthetic aperture radar(InSAR) images and strong ground motion were recorded
during the 2015 Gorkha earthquake; high-rate Global
Navigation Satellite System (GNSS) observations werealso made. The detailed ground surface changes and fault
model are presented with InSAR images of ALOS-2 satellite. Natsuaki et al. (2016) performed InSAR analysis
and reported some technical problems and the solutions.
Kobayashi et al. (2015) revealed the geodetic slip distribution of the 2015 Gorkha earthquake using ScanSARbased interferograms and identified the remaining slip
region with Mw 7.0 between the mainshock and the largest aftershock. Based on satellite images, Sato and Une(2016) and Lacroix (2016) detected earthquake-induced
landslide in the Kathmandu and Langtang valleys,
respectively.
Field survey was conducted to the east of the epicentral area around the Kathmandu valley. Although theearthquake magnitude was large, no surface fault was
associated with the event (Kumahara et al. 2016). The
earthquake survey was not limited from the land andtoward the space field. Chum et al. (2016) captured theionospheric signatures of the 2015 Gorkha earthquake.
With respect to strong motion data, Takai et al.
(2016) observed clear differences in the ground motions
between the rock and sediment sites in the Kathmandu
valley. The rock site ground motion can be used to constrain the source characteristics. The nonlinear soil
behavior at the sediment site was investigated by Dhakal
et al. (2016). Yamada et al. (2016) performed a building
damage survey and carried out microtremor observations in the source region of the 2015 Gorkha earthquake.
Kobayashi et al. (2016) and Kubo et al. (2016) performed
joint source inversion to estimate the rupture processof the 2015 Gorkha earthquake using various sets ofobservational data. Ichiyanagi et al. (2016) analyzed the

A devastating earthquake with a moment magnitude of
7.9 struck Nepal on 25 April 2015, resulting in nearly
9000 fatalities. This earthquake, called the 2015 Gorkha
earthquake, was followed by large aftershocks to the west
and east of the mainshock rupture. The mainshock propagated toward the east, and a large slip occurred beneaththe capital city of Kathmandu. Contrary to the hugeseismic moment release, the seismic intensity was notas large as expected, except for long-period slip pulses
and basin resonance. This earthquake is seismologicallyremarkable in that the interplate earthquake occurredjust below the inland area, which offers an invaluable
opportunity to deepen our understanding of earthquakes
in the collision zone and disasters related to them. This
special issue focuses on multidisciplinary geoscientificresearch regarding the 2015 Gorkha earthquake and therelevant tectonics along the India–Eurasia plate collisionzone.
The special issue includes 17 papers demonstrating theprompt analyses of the 2015 Gorkha earthquake as well
as Himalayan studies conducted prior to the earthquake.
Overall, the research led to the improved understandingof the 2015 Gorkha earthquake and Himalayan studies.
The unique tectonic setting of the Himalayan region
has prompted extensive international scientific research.
Consequently, many Himalayan studies had been conducted before the 2015 Gorkha earthquake. Bollinger
et al. (2016) revealed the slip deficit and interpreted therepeatability of historical earthquakes. Sapkota et al.
(2016) discussed the fatality rates of the 1934 Bihar–
Nepal earthquake. Sakai et al. (2016) clarified the geological features of the Paleo-Kathmandu lake. Bhattarai
et al. (2016) observed ground motions before the 2015

*Correspondence: hiroe@eri.u‑tokyo.ac.jp
1
The University of Tokyo, Tokyo, Japan
Full list of author information is available at the end of the article© The Author(s) 2017. This article is distributed under the terms of the Creative Commons Attribution 4.0 International License(http://creativecommons.org/licenses/by/4.0/), which permits unrestricted use, distribution, and reproduction in any medium,provided you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons license,
and indicate if changes were made.

1

The 2015 Gorkha, Nepal, Earthquake and Himalayan Studies: First Results
Miyake et al. Earth, Planets and Space (2017) 69:12

Page 2 of 2

aftershock activity of the 2015 Gorkha earthquake basedon the local ground motion array. A statistical seismicity monitoring study on the 2015 Gorkha earthquake andaftershock sequence was performed by Ogata and Tsuruoka (2016).
The special issue demonstrates the scientific importance of Himalayan studies. Geospatial observations
that captured the earthquake sequence were highlighted.
The 2015 Gorkha earthquake ruptured beneath the capital city Kathmandu where urban strong motion data
were utilized. The geodetic, seismological, and geological interpretations indicate that the potential remains
for earthquakes in the region between the 2015 Gorkha
earthquake and the largest eastern aftershock and in
the Main Frontal Thrust. Therefore, further research isneeded regarding the Himalayan region, which has theworld’s fastest inland collision rate.

Dhakal YP, Kubo H, Suzuki W, Kunugi T, Aoi S, Fujiwara H (2016) Analysis ofstrong ground motions and site effects at Kantipath, Kathmandu, from2015 Mw 7.8 Gorkha, Nepal, earthquake and its aftershocks. Earth Planets
Space 68:58. doi:10.1186/s40623‑016‑0432‑2
Ichiyanagi M, Takai N, Shigefuji M, Bijukchhen S, Sasatani T, Rajaure S, Dhital
MR, Takahashi H (2016) Aftershock activity of the 2015 Gorkha, Nepal,
earthquake determined using the Kathmandu strong motion seismo‑graphic array. Earth Planets Space 68:25. doi:10.1186/s40623‑016‑0402‑8
Kobayashi T, Morishita Y, Yarai H (2015) Detailed crustal deformation and fault
rupture of the 2015 Gorkha earthquake, Nepal, revealed from ScanSAR‑
based interferograms of ALOS‑2. Earth Planets Space 67:201. doi:10.1186/
s40623‑015‑0359‑z
Kobayashi H, Koketsu K, Miyake H, Takai N, Shigefuji M, Bhattarai M, Sapkota SN(2016) Joint inversion of teleseismic, geodetic, and near‑field waveform
datasets for rupture process of the 2015 Gorkha, Nepal, earthquake. Earth
Planets Space 68:66. doi:10.1186/s40623‑016‑0441‑1
Kubo H, Dhakal YP, Suzuki W, Kunugi T, Aoi S, Fujiwara H (2016) Estimation of
the source process of the 2015 Gorkha, Nepal, earthquake and simula‑tion of long‑period ground motions in the Kathmandu basin using
a one‑dimensional basin structure model. Earth Planets Space 68:16.
doi:10.1186/s40623‑016‑0393‑5
Kumahara Y, Chamlagain D, Upreti BN (2016) Geomorphic features of active
faults around the Kathmandu Valley, Nepal, and no evidence of surface
rupture associated with the 2015 Gorkha earthquake along the faults.
Earth Planets Space 68:53. doi:10.1186/s40623‑016‑0429‑x
Lacroix P (2016) Landslides triggered by the Gorkha earthquake in the Lang‑tang valley, volumes and initiation processes. Earth Planets Space 68:46.
doi:10.1186/s40623‑016‑0423‑3
Natsuaki R, Nagai H, Motohka T, Ohki M, Watanabe M, Thapa RB, Tadono T,
Shimada M, Suzuki S (2016) SAR interferometry using ALOS‑2 PALSAR‑2
data for the Mw 7.8 Gorkha, Nepal earthquake. Earth Planets Space 68:15.
doi:10.1186/s40623‑016‑0394‑4
Ogata Y, Tsuruoka H (2016) Statistical monitoring of aftershock sequences: acase study of the 2015 Mw7.8 Gorkha, Nepal, earthquake. Earth Planets
Space 68:44. doi:10.1186/s40623‑016‑0410‑8
Sakai H, Fujii R, Sugimoto M, Setoguchi R, Paudel MR (2016) Two times lower‑
ing of lake water at around 48 and 38 ka, caused by possible earthquakes,
recorded in the Paleo‑Kathmandu lake, central Nepal Himalaya. Earth
Planets Space 68:122. doi:10.1186/s40623‑016‑0413‑5
Sapkota SN, Bollinger L, Perrier F (2016) Fatality rates of the Mw ~ 8.2, 1934,
Bihar–Nepal earthquake and comparison with the April 2015 Gorkha
earthquake. Earth Planets Space 68:40. doi:10.1186/s40623‑016‑0416 ‑2Sato HP, Une H (2016) Detection of the 2015 Gorkha earthquake‑induced
landslide surface deformation in Kathmandu using InSAR images fromPALSAR‑2 data. Earth Planets Space 68:47. doi:10.1186/s40623‑016‑0425‑1
Takai N, Shigefuji M, Rajaure S, Bijukchhen S, Ichiyanagi M, Dhital MR, Sasatani
T (2016) Strong ground motion in the Kathmandu Valley during the2015 Gorkha, Nepal, earthquake. Earth Planets Space 68:10. doi:10.1186/
s40623‑016‑0383‑7
Yamada M, Hayashida T, Mori J, Mooney WD (2016) Building damage survey
and microtremor measurements for the source region of the 2015
Gorkha, Nepal, earthquake. Earth Planets Space 68:117. doi:10.1186/
s40623‑016‑0483‑4

Authors’ contributions
All authors read and approved the final manuscript.
Author details
1
The University of Tokyo, Tokyo, Japan. 2 Department of Mines and Geology,
Kathmandu, Nepal. 3 Nepal Academy of Science and Technology, Khumaltar,
Kathmandu, Nepal. 4 Department of Geology, School of Mines, Universityof Zambia, Lusaka, Zambia. 5 CEA, Arpajon, France. 6 Geospatial Information
Authority of Japan, Tsukuba, Ibaraki, Japan. 7 Okayama University, Okayama,
Japan.
Received: 27 December 2016 Accepted: 27 December 2016

References
Bhattarai M, Adhikari LB, Gautam UP, Bollinger L, Hernandez B, Yokoi T,
Hayashida T (2016) Establishing a reference rock site for the site effectstudy in and around the Kathmandu valley, Nepal. Earth Planets Space
68:81. doi:10.1186/s40623‑016‑0454‑9
Bollinger L, Tapponnier P, Sapkota SN, Klinger Y (2016) Slip deficit in central
Nepal: Omen for a repeat of the 1344 AD earthquake? Earth Planets
Space 68:12. doi:10.1186/s40623‑016‑0389‑1
Chum J, Liu J‑Y, Laštovička J, Fišer J, Mošna Z, Baše J, Sun Y‑Y (2016) Ionosphericsignatures of the April 25, 2015 Nepal earthquake and the relative role ofcompression and advection for Doppler sounding of infrasound in theionosphere. Earth Planets Space 68:24. doi:10.1186/s40623‑016‑0401‑92

Earth, Planets and SpaceFRONTIER LETTER Open Access

Detailed crustal deformation and fault rupture of the 2015 Gorkha
earthquake, Nepal, revealed from ScanSAR-based
interferograms of ALOS-2
Tomokazu Kobayashi*, Yu Morishita and Hiroshi Yarai
Earth, Planets and Space 2015, 67:201 DOI: 10.1186/s40623-015-0359-z
Received: 13 August 2015, Accepted: 6 November 2015, Published: 14 December 2015

Abstract
We have successfully detected widely distributed ground displacements for the 2015 Gorkha earthquake by applying a ScanSAR-based
interferometry analysis of Advanced Land Observing Satellite 2 (ALOS-2) L-band data. A major displacement area extends with a length ofabout 160 km in the east-west direction, and the most concentrated crustal deformation with ground displacement exceeding 1 m is located
20–30 km east from Kathmandu. A quasi-vertical displacement estimated by combining theascending and the descending data indicates upheaval of about 1.4 m at maximum. We
inverted the synthetic aperture radar interferometry (InSAR) data including both of the main
shock (moment magnitude (Mw) 7.8) and the largest aftershock (Mw 7.3) to construct a slip
distribution model. Our model shows a nearly pure reverse fault motion with a slip amount ofapproximately 6 m at maximum, and the spatial extent is zonally distributed within a distanceof 50 to 100 km from the surface along downdip direction. The downdip end of the slip isquite consistent with that of the interseismic coupling area geodetically inferred in previous
studies. On the other hand, there is no significant slip at shallow depth in spite of the fact thatthe plate interface is thought to be fully locked there, may be suggesting that there still
remains a potential of fault slip. The slip distribution unnaturally bifurcates in the east, and we
can identify a clear-cut slip deficit area with a radius of ~10 km just west side of the Mw 7.3
event, where the slip amount reaches only 20 cm at most. This area is presumably subjected toa strong shear stress which should promote a reverse fault slip. There is a possibility to
produce a fault slip equivalent to Mw ~7.0 in the future although we do not know if the slip
heterogeneity would be smoothed out by a seismic event or an aseismic event.

Keywords: ALOS-2, InSAR, ScanSAR, Crustal deformation, Gorkha earthquake, Nepal, Slip
distribution, Slip deficit

Figure 1*Corresponding author: Tomokazu Kobayashi, kobayashi-t96dv@mlit.go.jp

FRONTIER LETTER Open Access

Two times lowering of lake water at around 48 and 38 ka, caused bypossible earthquakes, recorded in the Paleo-Kathmandu
lake, central Nepal Himalaya
Harutaka Sakai*, Rie Fujii, Misa Sugimoto, Ryoko Setoguchi and Mukunda Raj Paudel
Earth, Planets and Space 2016, 68:31 DOI: 10.1186/s40623-016-0413-5
Received: 30 October 2015, Accepted: 12 February 2016, Published: 27 February 2016

Abstract
Sedimentary facies and micro-fossil analyses, and AMS14C dating were performed in order to reveal the water-level fall eventsand draining process of the lake (Paleo-Kathmandu Lake) that existed in the past in the Central Nepal Himalaya. The
sedimentary facies change from the lacustrine Kalimati Formation to the deltaic Sunakothi Formation in the southern andcentral Kathmandu basin, and the abrupt and prominent increase of phytoliths Bambusoideae and Pediastrum, andcontemporaneous decrease of sponge spicule and charcoal grains around 48 and 38 ka support the lowering of water level atthese times. According to the pollen analysis, both events occurred under rather warm and wet climate, thus supporting thatthey were triggered by tectonic cause and not by climate change. The
Geotectonic division of Nepal Himalaya
first event might be linked to a possible occurrence of a large
MCT
MCT: Main Central Thrustearthquake with an epicenter in the vicinity of the Paleo-Kathmandu
MBT: Main Boundary Thrust
Lake. The occurrence of a mega landslide in Langtang area close to thenorth of the Kathmandu Valley producing pseudotachylite dated at
MBT
MCT
51 ± 13 ka could be linked to this earthquake. Finally, the water was
MBT
completely drained out from the remnant lake at the central part of the
Kathmandu basin by ca.12 ka.
30°N

Thakkhola

Jumla

29°

Mt. Manaslu

April 25 2015, M 7.8

May 12 2015, M 7.3

Langtang

TansenGranitic rocks

Mt.Everest

Tibetan Tethys sediments

Higher and Lesser Himalayan Crystallines

SiwalikGroup

Kali Gandaki Supergroup (Nawakot Complex)
Tansen Group including Dumri Formation

Keywords: Central Nepal, Paleo-Kathmandu lake, Lacustrine

Intermontane and foreland basin sediments

sediments, Deltaic sediments, Draining of lake water,
AMS14C age*Corresponding author: Harutaka Sakai, hsakai@kueps.kyoto-u.ac.jp
3

Quaternary sediments (Terai Plain)
80°

81°

82°

83°

28°

Taplejung0

Kathmandu
basin

Ilam 27°

100 km84°

Figure 1

Dhankuta
85°

86°

87°

88°E

The 2015 Gorkha, Nepal, Earthquake and Himalayan Studies: First Results

FULL PAPER

Open AccessSlip deficit in central Nepal: omen for a repeat of the 1344 AD
earthquake?
L. Bollinger*, P. Tapponnier, S. N. Sapkota and Y. Klinger
Earth, Planets and Space 2016, 68:12 DOI: 10.1186/s40623-016-0389-1
Received: 26 October 2015, Accepted: 16 January 2016, Published: 28 January 2016

Abstract
In 1255, 1344, and 1408 AD, then again in 1833, 1934, and 2015, large earthquakes, devastated Kathmandu. The 1255 and1934 surface ruptures have been identified east of the city, along comparable segments of the Main Frontal Thrust (MFT).
Whether the other two pairs of events were similar is unclear. Taking into account charcoal’s age inheritance, we revisit thetiming of terrace offsets at key sites to compare them with theAseismic record since 1200 AD. The location, extent, and momentof the 1833 and 2015 events imply that they released only asmall part of the regional slip deficit on a deep thrust segment
B
that stopped north of the Siwaliks. By contrast, the 1344 or 1408
C
AD earthquake may have ruptured the MFT up to the surface incentral Nepal between Kathmandu and Pokhara, east of thesurface trace of the great 1505 AD earthquake which affected
western Nepal. If so, the whole megathrust system in Nepal
broke in a sequence of earthquakes that lasted less than threecenturies, with ruptures that propagated up to the surface fromeast to west. Today’s situation in the Himalayan seismic sequence
might be close to that of the fourteenth century.

Keywords: Himalayan earthquakes, Seismic cycle,
Paleoseismology, Inbuilt age

Figure 2*Corresponding author: L. Bollinger, laurent.bollinger@cea.fr

FULL PAPER

Open Access

SAR interferometry using ALOS-2 PALSAR-2 data for the Mw 7.8
Gorkha, Nepal earthquake
Ryo Natsuaki*, Hiroto Nagai, Takeshi Motohka, Masato Ohki, Manabu Watanabe, Rajesh B. Thapa,
Takeo Tadono, Masanobu Shimada and Shinichi Suzuki
Earth, Planets and Space 2016, 68:15 DOI: 10.1186/s40623-016-0394-4
Received: 25 October 2015, Accepted: 21 January 2016, Published: 1 February 2016

Abstract
The Advanced Land Observing Satellite-2 (ALOS-2, “DAICHI-2”) has been observing Nepal with the Phased Array type L-band
Synthetic Aperture Radar-2 (PALSAR-2) in response to an emergency request from Sentinel Asia related to the Mw 7.8 Gorkha
earthquake on April 25, 2015. PALSAR-2 successfully detected not only avalanches and local crustal displacements but also
continental-scale deformation. Especially, by the use of the ScanSAR mode, we are able to make interferograms that cover the entire
displacement area of the earthquake. However, we did encounter some fundamental problems with the ScanSAR and incorrect
settings of PALSAR-2 operation that have now been fixed. They
include (1) burst overlap misalignment between two ScanSAR
observations, which limits the number of pairs available and thequality of the interferogram, (2) non-crustal fringes which are derived
from co-registration error and/or ionospheric effect and, (3) incorrect
setting of the center frequency in the Stripmap beam F2-6. In thispaper, we describe their problems and solutions. The number ofinterferometric pairs are limited by (1) and (3). The accuracy of theinterferograms are limited by (2) and (3). The experimental results
showed that current solutions for (2) and (3) work appropriately.

Keywords: Gorkha earthquake, ALOS-2, PALSAR-2, InSAR, Synthetic
Aperture Radar (SAR), ScanSAR interferometry,
Stripmap-ScanSAR interferometry

Figure 1*Corresponding author: Ryo Natsuaki, natsuaki.ryo@jaxa.jp
4

Earth, Planets and Space

FULL PAPER

Open Access

Ionospheric signatures of the April 25, 2015 Nepal earthquake andthe relative role of compression and advection for Doppler
sounding of infrasound in the ionosphere
Jaroslav Chum*, Jann-Yenq Liu, Jan Laštovička, Jiří Fišer, Zbyšek Mošna, Jiří Baše and Yang-Yi Sun
Earth, Planets and Space 2016, 68:24 DOI: 10.1186/s40623-016-0401-9
Received: 10 October 2015, Accepted: 5 February 2016, Published: 17 February 2016

Abstract
Ionospheric signatures possibly induced by the Nepal earthquake are investigated far outside the epicentral region in Taiwan(~3700 km distance from the epicenter) and in the Czech Republic (~6300 km distance from the epicenter). It is shown thatthe ionospheric disturbances were caused by long period, ~20 s, infrasound waves that were excited locally by verticalcomponent of the ground surface motion and propagated nearly vertically to the ionosphere. The infrasound waves areheavily damped at the heights of F layer at around 200 km, so their amplitude strongly depends on the altitude ofobservation. In addition, in the case of continuous Doppler sounding, the value of the Doppler shift depends not only on theadvection (up and down motion) of the reflecting layer but also on the compression/rarefaction of the electron gas and henceon the electron density gradient. Consequently, under significant differences ofreflection height of sounding radio waves and partly also under large differencesin plasma density gradients, the observed ionospheric response at larger distancesfrom the epicenter can be comparable with the ionospheric response observed atshorter distances, although the amplitudes of causative seismic motions differ bymore than one order of magnitude.

Keywords: Infrasound, Seismic waves, Ionosphere, Wave propagation, Remotesensing

Figure 1*Corresponding author: Jaroslav Chum, jachu@ufa.cas.cz

FULL PAPER

Open Access

Detection of the 2015 Gorkha earthquake-induced landslide surface
deformation in Kathmandu using InSAR images fromPALSAR-2 data
Hiroshi P. Sato* and Hiroshi Une
Earth, Planets and Space 2016, 68:47 DOI: 10.1186/s40623-016-0425-1
Received: 2 October 2015, Accepted: 4 March 2016, Published: 17 March 2016

Abstract
Previous studies reported that the 2015 Gorkha earthquake (Mw 7.8), which occurred in Nepal, triggered landslides in mountainous
areas. In Kathmandu, earthquake-induced land subsidence was identified by interpreting local phase changes in interferograms
produced from Advanced Land Observing Satellite-2/Phased Array type L-band Synthetic Aperture Radar-2 data. However, theassociated ground deformation was not discussed in detail. We studied line-of-sight (LoS) changes from InSAR images in the SE areaof Tribhuvan International Airport, Kathmandu. To obtain the change in LoS caused only by local, short-wavelength surface
deformation, we subtracted the change in LoS attributed to coseismic deformation from the original change in LoS. The resulting
change in LoS showed that the river terrace was driven to the bottom of the rivervalley. We also studied the changes in LoS in both ascending and descending InSAR
images of the area along the Bishnumati River and performed 2.5D analysis. Removing
the effect of coseismic deformation revealed east–west and up–down components oflocal surface deformation, indicating that the river terrace deformed eastward andsubsided on the western riverbank of the river. On the east riverbank, the river terrace
deformed westward and subsided. However, in the southern part of the river basin,
the river terrace deformed westward and was uplifted. The deformation data and fieldsurvey results indicate that local surface deformation in these two areas was notcaused by land subsidence but by a landslide (specifically, lateral spread).

Keywords: Landslide, Earthquake, Liquefaction, Lateral spread, Land subsidence,
Gorkha, Nepal, PALSAR-2, InSAR

Figure 2*Corresponding author: Hiroshi P. Sato, satou.hiroshi37@nihon-u.ac.jp
5The 2015 Gorkha, Nepal, Earthquake and Himalayan Studies: First Results

FULL PAPER

Open Access

Establishing a reference rock site for the site effect study in andaround the Kathmandu valley, Nepal
Mukunda Bhattarai*, Lok Bijaya Adhikari, Umesh Prasad Gautam, Laurent Bollinger,
Bruno Hernandez, Toshiaki Yokoi and Takumi Hayashida
Earth, Planets and Space 2016, 68:81 DOI: 10.1186/s40623-016-0454-9
Received: 13 October 2015, Accepted: 26 April 2016, Published: 17 May 2016

Abstract
We propose a reference site for the site effect study in and around the Kathmandu valley, Nepal. The used data were theaccelerograms recorded at two stations, DMG and KKA, and velocity seismograms co-recorded at the PKIN station during nine
shallow local and regional earthquakes of local magnitude equal to or greater than 5.0. The DMG station is located on the thicksediments of the Kathmandu valley, whereas the others are rock sites. The KKA station is located on the granite and gneisses of the
Shivapuri Lekh about 10 km northwest of the capital, and the PKIN station is in
the tunnel of an old iron mine on the southern slope of the Phulchauki Hill about
15 km southeast. The spectral ratios of the ground motion records of the DMG
station compared to those of the PKIN station, for all considered earthquakes,
confirm that the DMG station has amplification ranging from 1 to 10 in thefrequency range of 0.5–10 Hz, and spectral ratios of the KKA station referenced by
the PKIN station show that the KKA station has significant amplification in thefrequency range of 4–10 Hz and the peak value of the spectral ratio is at mostover 25. Therefore, the site amplification in and around Kathmandu valley would
be significantly underestimated in the frequency range from 4 to 10 Hz if therecords of the KKA station were used as a proxy for input seismic motions to thesediment. Based on the above analysis, we propose that the PKIN station should
be considered as a reliable reference site for the assessment of seismic hazards inand around the Kathmandu valley.

Keywords: Reference site, Site effect, Kathmandu valley, Spectral ratio

Figure 1*Corresponding author: Mukunda Bhattarai, mb2058@yahoo.com

LETTER

Open Access

Strong ground motion in the Kathmandu Valley during the 2015
Gorkha, Nepal, earthquake
Nobuo Takai*, Michiko Shigefuji, Sudhir Rajaure, Subeg Bijukchhen, Masayoshi Ichiyanagi,
Megh Raj Dhital and Tsutomu Sasatani
Earth, Planets and Space 2016, 68:10 DOI: 10.1186/s40623-016-0383-7
Received: 26 October 2015, Accepted: 6 January 2016, Published: 26 January 2016

Abstract
On 25 April 2015, a large earthquake of Mw 7.8 occurred along the Main Himalayan Thrust fault in central Nepal. It was caused by a collision of
the Indian Plate beneath the Eurasian Plate. The epicenter was near the Gorkha region, 80 km northwest of Kathmandu, and the rupture
propagated toward east from the epicentral region passing through the sediment-filled Kathmandu Valley. This event resulted in over 8000
fatalities, mostly in Kathmandu and the adjacent districts. We succeeded in observing strong
ground motions at our four observation sites (one rock site and three sedimentary sites) in theaKathmandu Valley during this devastating earthquake. While the observed peak groundacceleration values were smaller than the predicted ones that were derived from the use of aground motion prediction equation, the observed peak ground velocity values were slightly
larger than the predicted ones. The ground velocities observed at the rock site (KTP) showed a
simple velocity pulse, resulting in monotonic-step displacements associated with thepermanent tectonic offset. The vertical ground velocities observed at the sedimentary sites
had the same pulse motions that were observed at the rock site. In contrast, the horizontal
ground velocities as well as accelerations observed at three sedimentary sites showed long
duration with conspicuous long-period oscillations, due to the valley response. The horizontal
valley response was characterized by large amplification (about 10) and prolonged oscillations.
However, the predominant period and envelope shape of their oscillations differed from site tosite, indicating a complicated basin structure. Finally, on the basis of the velocity response
spectra, we show that the horizontal long-period oscillations on the sedimentary sites hadenough destructive power to damage high-rise buildings with natural periods of 3 to 5 s.

Keywords: 2015 Gorkha Nepal earthquake, Kathmandu Valley, Strong ground motion,
Velocity pulse motion, Valley response

Figure 1*Corresponding author: Nobuo Takai, tki@eng.hokudai.ac.jp
6Earth, Planets and SpaceLETTER

Open Access

Estimation of the source process of the 2015 Gorkha, Nepal, earthquakeand simulation of long-period ground motions in the Kathmandu
basin using a one-dimensional basin structure model
Hisahiko Kubo*, Yadab P. Dhakal, Wataru Suzuki, Takashi Kunugi, Shin Aoi and Hiroyuki Fujiwara
Earth, Planets and Space 2016, 68:16 DOI: 10.1186/s40623-016-0393-5
Received: 30 October 2015, Accepted: 21 January 2016, Published: 5 February 2016

Abstract
The source rupture process of the 2015 Gorkha, Nepal, earthquake was estimated by the joint kinematic source inversion withnear-field waveforms, teleseismic waveforms, and geodetic data. The estimated seismic moment and maximum slip are
7.5 × 1020 Nm (Mw 7.9) and 7.3 m, respectively. The total source
duration is approximately 50 s. The derived source model has a
84˚
85˚
86˚
unilateral rupture toward the east and a large-slip area north of
GCMT
Kathmandu with the maximum slip. Using the estimated source
GHER
CHLM
model together with a one-dimensional (1-D) velocity basin structure
BESI
model, long-period (> 4 s) ground motions were simulated at a site
28˚
DMAU
located in the Kathmandu basin, where strong ground motions with
SYBC
KKN4
predominant components in a 4–5s period were observed during the
KIRT KATNP
NAST2015 Gorkha earthquake. This simulation demonstrated that the
DAMA
SNDL
BELT
major features of the observed waveforms can be reproduced by oursource model and the 1-D basin structure model.
km

Keywords: The 2015 Gorkha earthquake, Source rupture process,

27˚

0

RMTE

100

Long-period ground motions in the Kathmandu basin,
Joint source inversion, Waveform simulation

m
0.0

7.3

Figure 2*Corresponding author: Hisahiko Kubo, hkubo@bosai.go.jp

LETTER

Open Access

Aftershock activity of the 2015 Gorkha, Nepal, earthquake
determined using the Kathmandu strong motion
seismographic array
Masayoshi Ichiyanagi*, Nobuo Takai, Michiko Shigefuji, Subeg Bijukchhen, Tsutomu Sasatani,
Sudhir Rajaure, Megh Raj Dhital and Hiroaki Takahashi
Earth, Planets and Space 2016, 68:25 DOI: 10.1186/s40623-016-0402-8
Received: 27 October 2015, Accepted: 5 February 2016, Published: 18 February 2016

Abstract
The characteristics of aftershock activity of the 2015 Gorkha, Nepal, earthquake (Mw 7.8) were evaluated. The mainshock andaftershocks were recorded continuously by the international Kathmandu strong motion seismographic array operated by
Hokkaido University and Tribhuvan University. Full waveform data without saturation for all events enabled us to clarify
aftershock locations and decay characteristics. The aftershock distribution was determined using the estimated local velocity
structure. The hypocenter distribution in the Kathmandu metropolitan region was well determined and indicated earthquakes
located shallower than 12 km depth, suggesting that aftershocks occurred at depths shallower than the Himalayan main
thrust fault. Although numerical investigation suggested lessresolution for the depth component, the regional aftershock
epicentral distribution of the entire focal region clearly indicatedearthquakes concentrated in the eastern margin of the major slip
region of the mainshock. The calculated modified Omori law’s p valueof 1.35 suggests rapid aftershock decay and a possible hightemperature structure in the aftershock region.

Keywords: 2015 Gorkha Nepal earthquake, Aftershock activity, Local
seismographic array

Figure 1*Corresponding author: Masayoshi Ichiyanagi, ichimasa@mail.sci.hokudai.ac.jp
7

The 2015 Gorkha, Nepal, Earthquake and Himalayan Studies: First Results

LETTER

Open AccessFatality rates of the Mw ~8.2, 1934, Bihar–Nepal earthquake
and comparison with the April 2015 Gorkha earthquake
Soma Nath Sapkota*, Laurent Bollinger and Frédéric Perrier
Earth, Planets and Space 2016, 68:40 DOI: 10.1186/s40623-016-0416-2
Received: 10 September 2015, Accepted: 11 February 2016, Published: 11 March 2016

Abstract
Large Himalayan earthquakes expose rapidly growing populations of millions of people to high levels of seismic hazards, in particular
in northeast India and Nepal. Calibrating vulnerability models specific to this region of the world is therefore crucial to thedevelopment of reliable mitigation measures. Here, we reevaluate the >15,700 casualties (8500 in Nepal and 7200 in India) from theMw ~8.2, 1934, Bihar–Nepal earthquake and calculate the fatality rates for this earthquake using an estimation of the population
derived from two census held in 1921 and 1942. Values reach 0.7–1 % in the epicentral region, located in eastern Nepal, and 2–5 % in
the urban areas of the Kathmandu valley. Assuming a constant vulnerability, we obtain, if the same earthquake would have repeatedin 2011, fatalities of 33,000 in Nepal and 50,000 in India. Fast-growing population in India indeed must unavoidably lead to increased
levels of casualty compared with Nepal, where the population growth is smaller. Aside from that probably robust fact, extrapolations
have to be taken with great caution. Among other effects, building and life
Chandigarh
vulnerability could depend on population concentration and evolution of
Dehra Dunconstruction methods. Indeed, fatalities of the April 25, 2015, Mw 7.8 Gorkha
Inhabitants per (30s)
Xigazeearthquake indicated on average a reduction in building vulnerability inurban areas, while rural areas remained highly vulnerable. While effective
Dehli
PokharaGorkhascaling laws, function of the building stock, seem to describe these
Kathmandu
TimphuDarjeelingdifferences adequately, vulnerability in the case of an Mw >8.2 earthquake
Lucknow
Faizabadremains largely unknown. Further research should be carried out urgently so
Kanpur
Muzzafarpur
that better prevention strategies can be implemented and building codes
Patna
Monghyr
Varanasireevaluated on, adequately combining detailed ancient and modern data.
Ap

pr

ox

.p

os

iti

on

of

th

e d

own

0

dip

en

do

ft

he

100 200 300 400 500 600 700 800 900 1000
2

0

km

100

200

oc

l

k

ed

fa u

lt z

on

e

Keywords: Earthquake, Nepal, Mortality, Fatalities, Power law, Building
vulnerability, Mitigation measures

Figure 1*Corresponding author: Soma Nath Sapkota, sapkota.research@gmail.com

LETTER

Open Access

Statistical monitoring of aftershock sequences: a casestudy of the 2015 Mw7.8 Gorkha, Nepal, earthquake
Yosihiko Ogata* and Hiroshi Tsuruoka
Earth, Planets and Space 2016, 68:44 DOI: 10.1186/s40623-016-0410-8
Received: 2 December 2015, Accepted: 11 February 2016, Published: 17 March 2016

Abstract
Early forecasting of aftershocks has become realistic and practical because ofreal-time detection of hypocenters. This study illustrates a statistical procedure
for monitoring aftershock sequences to detect anomalies to increase theprobability gain of a significantly large aftershock or even an earthquake larger
than the main shock. In particular, a significant lowering (relative quiescence) inaftershock activity below the level predicted by the Omori–Utsu formula or the
epidemic-type aftershock sequence model is sometimes followed by a large
earthquake in a neighboring region. As an example, we detected significant
lowering relative to the modeled rate after approximately 1.7 days after the main
shock in the aftershock sequence of the Mw7.8 Gorkha, Nepal, earthquake ofApril 25, 2015. The relative quiescence lasted until the May 12, 2015, M7.3 Kodari
earthquake that occurred at the eastern end of the primary aftershock zone.
Space–time plots including the transformed time can indicate the local places
where aftershock activity lowers (the seismicity shadow). Thus, the relativequiescence can be hypothesized to be related to stress shadowing caused byprobable slow slips. In addition, the aftershock productivity of the M7.3 Kodari
earthquake is approximately twice as large as that of the M7.8 main shock.

Keywords: Epidemic-type aftershock sequence (ETAS) model, Omori–Utsu
formula, Change-point, Probability gain, GUI software package
XETAS, Relative quiescence, Seismicity shadow*Corresponding author: Yosihiko Ogata, ogata@ism.ac.jp
8

Figure 1

Earth, Planets and SpaceLETTER

Open Access

Landslides triggered by the Gorkha earthquake in theLangtang valley, volumes and initiation processes
Pascal Lacroix
Earth, Planets and Space 2016, 68:46 DOI: 10.1186/s40623-016-0423-3
Received: 21 October 2015, Accepted: 3 March 2016, Published: 17 March 2016

Abstract
The Gorkha earthquake (Nepal, 2015, Mw 7.9) triggered many landslides. The most catastrophic mass movement was a debris
avalanche that buried several villages in the Langtang valley. In this study, questions are raised about its volume and initiation.
I investigate the possibility of high-resolution digital surface models computed from tri-stereo SPOT6/7 images to resolve thisissue. This high-resolution dataset enables me to derive an inventory of 160
85°25’E
85°30’E
landslides triggered by this earthquake. I analyze the source of errors andestimate the uncertainties in the landslide volumes. The vegetation prevents
to correctly estimate the volumes of landslides that occured in vegetatedareas. However, I evaluate the volume and thickness of 73 landslides
developing in vegetated-free areas, showing a power law between theirsurface areas and volumes with exponent of 1.20. Accumulations anddepletion volumes are also well constrained for larger landslides, and I findthat the main debris avalanches accumulated 6.95 × 106 m3 of deposits in thevalley with thicknesses reaching 60 m, and 9.66 × 106 m3 in the glaciated part
above 5000 m asl. The large amount of sediments is explained by an initiationof the debris avalanche due to serac falls and snow avalanches from five
Gorkha epicenter
Landslide inventory, this study
separate places between 6800 and 7200 m asl over 3 km length.
86˚

CHINA

28°15’N

28°15’N

85˚

NEPAL

Langtang

28˚

Kathmandu

86˚

Keywords: Landslides, Seismic triggering, Nepal, DEM, SPOT, Volumes,
Optical satellite photogrammetry, Debris avalanche

28°10’N

28°10’N85˚

BGS landslide inventory
2015-2014 DEM
+50

-40

85°25’E

85°30’E

Figure 1

Corresponding author: Pascal Lacroix, pascal.lacroix@ujf-grenoble.fr

LETTER

Open AccessGeomorphic features of active faults around the Kathmandu Valley,
Nepal, and no evidence of surface rupture associated withthe 2015 Gorkha earthquake along the faults
Yasuhiro Kumahara*, Deepak Chamlagain and Bishal Nath Upreti
Earth, Planets and Space 2016, 68:53 DOI: 10.1186/s40623-016-0429-x
Received: 30 October 2015, Accepted: 18 March 2016, Published: 2 April 2016

Abstract
The M7.8 April 25, 2015, Gorkha earthquake in Nepal was produced by a slip on the low-angle Main Himalayan Thrust, a décollement below
the Himalaya that emerges at the surface in the south as the Himalayan Frontal Thrust (HFT). The analysis of the SAR interferograms led to theinterpretations that the event was a blind thrust and did not produce surface ruptures associated with the seismogenic fault. We conducted aquick field survey along four active faults near the epicentral area around the Kathmandu Valley (the Jhiku Khola fault, Chitlang fault,
Kulekhani fault, Malagiri fault and Kolphu Khola fault) from July 18–22, 2015. Those faults are located in the Lesser Himalaya on the hanging
side of the HFT. Based on our field survey carried out in the area where most typical tectonic
landforms are developed, we confirmed with local inhabitants the lack of any new surface ruptures
along these faults. Our observations along the Jhiku Khola fault showed that the fault had somedefinite activities during the Holocene times. Though in the past it was recognized as a low-activity
thrust fault, our present survey has revealed that it has been active with a predominantly right-lateral
strike-slip with thrust component. A stream dissecting a talus surface shows approximately 7-mright-lateral offset, and a charcoal sample collected from the upper part of the talus deposit yieldedan age of 870 ± 30 y.B.P, implying that the talus surface formed close to 870 y.B.P. Accordingly, a single
or multiple events of the fault must have occurred during the last 900 years, and the slip rate weestimate roughly is around 8 mm/year. The fault may play a role to recent right-lateral strike-slip
tectonic zone across the Himalayan range. Since none of the above faults showed any relationshipcorresponding to the April 25 Gorkha earthquake, it is possibility that a potential risk of occurrence oflarge earthquakes does exist close to the Kathmandu Valley due to movements of these active faults,
and more future work such as paleoseismological survey is needed to assess the risk.

Keywords: 2015 Gorkha earthquake, Active fault, Surface rupture, Tectonic landform, Nepal, Jhiku
Khola fault

Figure 2*Corresponding author: Yasuhiro Kumahara, kumakuma@hiroshima-u.ac.jp
9The 2015 Gorkha, Nepal, Earthquake and Himalayan Studies: First Results

LETTER

Open AccessAnalysis of strong ground motions and site effects at Kantipath,
Kathmandu, from 2015 Mw 7.8 Gorkha, Nepal, earthquake
and its aftershocks
Yadab P. Dhakal*, Hisahiko Kubo, Wataru Suzuki, Takashi Kunugi, Shin Aoi and Hiroyuki Fujiwara
Earth, Planets and Space 2016, 68:58 DOI: 10.1186/s40623-016-0432-2
Received: 2 November 2015, Accepted: 29 March 2016, Published: 12 April 2016

Abstract
Strong ground motions from the 2015 Mw 7.8 Gorkha, Nepal, earthquake and its eight aftershocks recorded by a strong-motion seismographat Kantipath (KATNP), Kathmandu, were analyzed to assess the ground-motion characteristics and site effects at this location. Remarkably
large elastic pseudo-velocity responses exceeding 300 cm/s at 5 % critical damping were calculated
for the horizontal components of the mainshock recordings at peak periods of 4–5 s. Conversely, theashort-period ground motions of the mainshock were relatively weak despite the proximity of the site
to the source fault. The horizontal components of all large-magnitude (Mw ≥ 6.3) aftershock
recordings showed peak pseudo-velocity responses at periods of 3–4 s. Ground-motion prediction
equations (GMPEs) describing the Nepal Himalaya region have not yet been developed. A
comparison of the observational data with GMPEs for Japan showed that with the exception of thepeak ground acceleration (PGA) of the mainshock, the observed PGAs and peak ground velocities at
the KATNP site are generally well described by the GMPEs for crustal and plate interface events. A
comparison of the horizontal-to-vertical (H/V) spectral ratios for the S-waves of the mainshock andaftershock recordings suggested that the KATNP site experienced a considerable nonlinear site
response, which resulted in the reduced amplitudes of short-period ground motions. The GMPEs
were found to underestimate the response values at the peak periods (approximately 4–5 s) of thelarge-magnitude events. The deep subsurface velocity model of the Kathmandu basin has not been
well investigated. Therefore, a one-dimensional velocity model was constructed for the deep
sediments beneath the recording station based on an analysis of the H/V spectral ratios for S-wave
coda from aftershock recordings, and it was revealed that the basin sediments strongly amplified thelong-period components of the ground motions of the mainshock and large-magnitude aftershocks.

Keywords: Gorkha earthquake, Kathmandu basin, Site effects, Long-period ground motion

Figure 2*Corresponding author: Yadab P. Dhakal, ydhakal@bosai.go.jp

LETTER

Open Access

Joint inversion of teleseismic, geodetic, and near-field waveform
datasets for rupture process of the 2015 Gorkha, Nepal, earthquake
Hiroaki Kobayashi*, Kazuki Koketsu, Hiroe Miyake, Nobuo Takai, Michiko Shigefuji,
Mukunda Bhattarai and Soma Nath Sapkota
Earth, Planets and Space 2016, 68:66 DOI: 10.1186/s40623-016-0441-1
Received: 31 October 2015, Accepted: 11 April 2016, Published: 26 April 2016

Abstract
The 2015 Gorkha earthquake and its aftershocks caused severe damage mostly in Nepal, while countries around theHimalayan region were warned for decades about large Himalayan earthquakes and the seismic vulnerability of thesecountries. However, the magnitude of the Gorkha earthquake was smaller than those of historical earthquakes in Nepal, andthe most severe damage occurred in the north and northeast of Kathmandu. We explore
reasons for these unexpected features by performing a joint source inversion ofteleseismic, geodetic, and near-field waveform datasets to investigate the rupture
process. Results indicate that the source fault was limited to the northern part of central
Nepal and did not reach the Main Frontal Thrust. The zone of large slip was located in thenorth of Kathmandu, and the fault rupture propagated eastward with an almost constantvelocity. Changes in the Coulomb failure function (ΔCFF) due to the Gorkha earthquake
were computed, indicating that southern and western regions neighboring the source
fault are potential source regions for future earthquakes related to the Gorkha
earthquake. These two regions may correspond to the historical earthquakes of 1866 and1344. Possible future earthquakes in the regions are predicted, and the warning for
Himalayan seismic hazards remains high even after the Gorkha earthquake.

Keywords: Rupture process, Gorkha earthquake, Coulomb failure function*Corresponding author: Hiroaki Kobayashi, khiro@eri.u-tokyo.ac.jp
10

Figure 2

Earth, Planets and SpaceLETTER

Open Access

Building damage survey and microtremor measurements forthe source region of the 2015 Gorkha, Nepal, earthquake
Masumi Yamada*, Takumi Hayashida, Jim Mori and Walter D. Mooney
Earth, Planets and Space 2016, 68:117 DOI: 10.1186/s40623-016-0483-4
Received: 17 January 2016, Accepted: 7 June 2016, Published: 13 July 2016

Abstract
We performed a damage survey of buildings and carried out microtremor observations in the source region of the 2015
Gorkha earthquake. Our survey area spans the Kathmandu valley and areas to the east and north of the valley. Damage ofbuildings in the Kathmandu valley was localized, and the percentage of the totally collapsed buildings was less than 5 %. Eastof the Kathmandu valley, especially in Sindhupalchok district, damage of buildings was more severe. In the center of Chautara
and Bahrabise, towns in Sindhupalchok district, the percentage of the totally collapsed houses exceeded 40 %. North of the
Kathmandu valley, the damage was moderate, and 20–30 % of the buildings were totally collapsed in Dhunche. Based on thepast studies and our microtremor observations near the strong motion station, the H/V spectrum in Kathmandu has a peak ataround 0.3 Hz, which reflects the velocity contrast of the
deep sedimentary basin. The H/V spectra in Bahrabise,
Chautara, and Dhunche do not show clear peaks, whichsuggests that the sites have stiff soil conditions. Therefore,
the more severe damage outside the Kathmandu valley
compared with the relatively light damage levels in thevalley is probably due to the source characteristics of theearthquake and/or the seismic performance of buildings,
rather than the local site conditions.

Keywords: 2015 Gorkha earthquake, Masonry structure,
Earthquake damage, Strong motion,
Microtremor survey

Figure 1*Corresponding author: Masumi Yamada, masumi@eqh.dpri.kyoto-u.ac.jp

11Information for Contributors
General1.

Manuscripts should be submitted through the journal’s Editorial Manager system(https://www.editorialmanager.com/epsp/default.aspx).

2.

Only papers not previously published will be accepted, and the emphasis is on theoriginality of concept or observation.

3.

Four varieties of article types are available.
3.1“Full papers” without word limit.

3.2“Express Letters” have a limit of 5000 words including the title page, abstract,
keywords, main text, declarations, references, figure legends and table legends.
The sum of the number of figures and tables should be less than or equal to 5.

3.3“Frontier Letters” can be submitted upon invitation by the Editor-in-Chief. “Frontier
Letters” have a limit of 11,000 words including legends for figures and tables. One
figure or table not exceeding one A4 page is counted as 500 words.

3.4
4.

“Technical reports” describe the technical development of instrument or software.

Authors retain the copyright, and distribution of articles is free under cc-by license.

Technical
1.

Manuscripts should be written in English with double spacing.

2.

Each manuscript should be organized in the following order: title, authors’ names,
affiliations, abstract, key words, main text, acknowledgement, appendix, references, andsupplementary materials.

3.

The corresponding author should be clearly indicated.

4.

The abstract is limited to 300 words and should be informative and include principal
findings and conclusions. Please avoid abbreviations.

5.

The main text can have multiple free headings.

6.

High-resolution figures should be provided in the following format; PDF (preferred
format for diagrams), PNG (preferred format for photos or images), EPS ,TIFF, JPEG, BMP.

7.

References must follow the Springer Basic style.

Correspondence
If you have any questions, please contact editorial@earth-planets-space.com.

© EPS Steering Committee 2017 All rights reserved.
A Grant-in-Aid for Publication of Scientific Research Results (251001) from Japan
Society for the Promotion of Science is used for printing.

Contents
Special issue “The 2015 Gorkha, Nepal, earthquake and Himalayan studies: First results”. . . . . . . . . . . . . . . Hiroe Miyake, Soma Nath Sapkota, Bishal Nath Upreti, Laurent Bollinger, Tomokazu Kobayashi and Hiroshi Takenaka
Detailed crustal deformation and fault rupture of the 2015 Gorkha earthquake, Nepal, revealed from ScanSAR-based
interferograms of ALOS-2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Tomokazu Kobayashi, Yu Morishita and Hiroshi Yarai
Two times lowering of lake water at around 48 and 38 ka, caused by possible earthquakes, recorded in the PaleoKathmandu lake, central Nepal Himalaya. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Harutaka Sakai, Rie Fujii, Misa Sugimoto, Ryoko Setoguchi and Mukunda Raj Paudel
Slip deficit in central Nepal: omen for a repeat of the 1344 AD earthquake?
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . L. Bollinger, P. Tapponnier, S. N. Sapkota and Y. Klinger
SAR interferometry using ALOS-2 PALSAR-2 data for the Mw 7.8 Gorkha, Nepal earthquake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Ryo Natsuaki, Hiroto Nagai, Takeshi Motohka, Masato Ohki, Manabu Watanabe,
Rajesh B. Thapa, Takeo Tadono, Masanobu Shimada and Shinichi Suzuki

Ionospheric signatures of the April 25, 2015 Nepal earthquake and the relative role of compression and advection for
Doppler sounding of infrasound in the ionosphere. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Jaroslav Chum, Jann-Yenq Liu, Jan Laštovička, Jiří Fišer, Zbyšek Mošna, Jiří Baše and Yang-Yi Sun
Detection of the 2015 Gorkha earthquake-induced landslide surface deformation in Kathmandu using InSAR images
from PALSAR-2 data. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hiroshi P. Sato and Hiroshi Une
Establishing a reference rock site for the site effect study in and around the Kathmandu valley, Nepal. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Mukunda Bhattarai, Lok Bijaya Adhikari, Umesh Prasad Gautam, Laurent Bollinger,
Bruno Hernandez, Toshiaki Yokoi and Takumi Hayashida

Strong ground motion in the Kathmandu Valley during the 2015 Gorkha, Nepal, earthquake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Nobuo Takai, Michiko Shigefuji, Sudhir Rajaure, Subeg Bijukchhen, Masayoshi Ichiyanagi,

1
3

3
4

4

5
5

6

Megh Raj Dhital and Tsutomu Sasatani

6

Estimation of the source process of the 2015 Gorkha, Nepal, earthquake and simulation of long-period ground motions in the
Kathmandu basin using a one-dimensional basin structure model. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hisahiko Kubo, Yadab P. Dhakal, Wataru Suzuki, Takashi Kunugi, Shin Aoi and Hiroyuki Fujiwara
Aftershock activity of the 2015 Gorkha, Nepal, earthquake determined using the Kathmandu strong motion
seismographic array. . . . . . . . . . . . . . . . . Masayoshi Ichiyanagi, Nobuo Takai, Michiko Shigefuji, Subeg Bijukchhen, Tsutomu Sasatani,

7

Sudhir Rajaure, Megh Raj Dhital and Hiroaki Takahashi

7

Fatality rates of the Mw ~8.2, 1934, Bihar–Nepal earthquake and comparison with the April 2015 Gorkha earthquake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Soma Nath Sapkota, Laurent Bollinger and Frédéric Perrier 8
Statistical monitoring of aftershock sequences: a case study of the 2015 Mw7.8 Gorkha, Nepal, earthquake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yosihiko Ogata and Hiroshi Tsuruoka 8Landslides triggered by the Gorkha earthquake in the Langtang valley, volumes and initiation processes. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pascal Lacroix 9
Geomorphic features of active faults around the Kathmandu Valley, Nepal, and no evidence of surface rupture associatedwith the 2015 Gorkha earthquake along the faults. . . . . . . . . . . . Yasuhiro Kumahara, Deepak Chamlagain and Bishal Nath Upreti 9
Analysis of strong ground motions and site effects at Kantipath, Kathmandu, from 2015 Mw 7.8 Gorkha, Nepal,
earthquake and its aftershocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Yadab P. Dhakal, Hisahiko Kubo, Wataru Suzuki, Takashi Kunugi, Shin Aoi and Hiroyuki Fujiwara 10
Joint inversion of teleseismic, geodetic, and near-field waveform datasets for rupture process of the 2015 Gorkha,
Nepal, earthquake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Hiroaki Kobayashi, Kazuki Koketsu, Hiroe Miyake, Nobuo Takai, Michiko Shigefuji,
Mukunda Bhattarai and Soma Nath Sapkota

10

Building damage survey and microtremor measurements for the source region of the 2015 Gorkha, Nepal, earthquake. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Masumi Yamada, Takumi Hayashida, Jim Mori and Walter D. Mooney 11

Cover image: After Kobayashi, T. et al., Earth, Planets and Space 2015, 67:201 DOI: 10.1186/s40623-015-0359-z