ISSN 0917-057X

防災科学技術研究所研究資料 第三九七号

第397号

September 2015

Technical Note of the National Research Institutefor Earth Science and Disaster Prevention: No.397

2015 年 4 月ネパール地震 (Gorkha 地震 )における建物被害に関する情報収集調査速報
Flash Report on the Damage of Masonry Housing Caused by
Earthquake in the case of Gorkha Earthquake, 25 April 20154

年 月ネパール地震

2015)

地震 における建物被害に関する情報収集調査速報(GorkhaTennodai 3-1, Tsukuba, Ibaraki, 305-0006 Japan

防災科学技術研究所

National Research Institute for Earth Science and Disaster Prevention

国立研究開発法人
国立研
開発法人

防災科学技術研究所
National Research Institute for Earth Science and Disaster Prevention, Japan

防災科学技術研究所研究資料
第 327 号

防災科学技術研究所 45 年のあゆみ（付録 DVD）224pp．2009 年 3 月発行

第 328 号

地すべり地形分布図 第 41 集
「盛岡」
18 葉
（5 万分の 1）．2009 年 3 月発行

第 329 号

地すべり地形分布図 第 42 集
「野辺地・八戸」
24 葉（5 万分の 1）．2009 年 3 月発行

第 330 号

地域リスクとローカルガバナンスに関する調査報告

第 331 号

防災科学技術研究所研究資料
第 370 号

強震動評価のための千葉県・茨城県における浅部・深部地盤統合モデルの検討（付録 CD-ROM)
3 月発行

第 371 号

野島断層における深層掘削調査の概要と岩石物性試験結果（平林・岩屋・甲山）（付録 CD-ROM） 27pp．2012 年
12 月発行53pp．2009 年 3 月発行

E-Defense を用いた実大 RC 橋脚（C1-1 橋脚）震動破壊実験研究報告書 -1970 年代に建設された基部曲げ破壊タイ

第 372 号

長岡における積雪観測資料 (34) (2011/12 冬期 )31pp．2012 年 11 月発行

プの RC 橋脚震動台実験（付録DVD） 107pp．2009 年 1 月発行

第 373 号

阿蘇山一の宮および白水火山観測井コア試料の岩相記載（付録 CD-ROM） 48pp．2013 年 2 月発行
霧島山万膳および夷守台火山観測井コア試料の岩相記載（付録 CD-ROM） 50pp．2013 年 3 月発行

第 332 号

強震ネットワーク

強震データ

Vol. 25（平成 20 年 No. 1）（CD-ROM 版）．2009 年 3 月発行

第 374 号

第 333 号

強震ネットワーク

強震データ

Vol. 26（平成 20 年 No. 2）（CD-ROM 版）．2009 年 3 月発行

第 375 号

新庄における気象と降積雪の観測（2011/12 年冬期） 49pp．2013 年 2 月発行

平成 17 年度大都市大震災軽減化特別プロジェクトⅡ 地盤基礎実験 - 震動台活用による構造物の耐震性向上研究 -第 376 号

地すべり地形分布図 第 51 集「天塩・枝幸・稚内」20 葉（5 万分の 1）．2013 年 3 月発行（付録 CD-ROM） 62pp．2009 年 10 月発行

第 377 号

地すべり地形分布図 第 52 集「北見・紋別」25 葉（5 万分の 1）．2013 年 3 月発行

第 335 号

地すべり地形分布図 第 43 集
「函館」
14 葉
（5 万分の 1）．2009 年 12 月発行

第 378 号

地すべり地形分布図 第 53 集「帯広」16 葉（5 万分の 1）．2013 年 3 月発行

第 336 号

全国地震動予測地図作成手法の検討（7 分冊＋ CD-ROM 版）．2009 年 11 月発行

第 379 号

東日本大震災を踏まえた地震ハザード評価の改良に向けた検討

第 337 号

強震動評価のための全国深部地盤構造モデル作成手法の検討（付録 DVD）
．2009 年 12 月発行

第 380 号

日本の火山ハザードマップ集

第 338 号

地すべり地形分布図 第 44 集
「室蘭・久遠」21 葉（5 万分の 1）．2010 年 3 月発行

第 381 号

長岡における積雪観測資料 (35)（2012/13 冬期） 30pp．2013 年 11 月発行

第 339 号

地すべり地形分布図 第 45 集「岩内」14 葉（5 万分の 1）．2010 年 3 月発行

第 382 号

地すべり地形分布図 第 54 集「浦河・広尾」18 葉（5 万分の 1）．2014 年 2 月発行

第 340 号

新庄における気象と降積雪の観測 (2008/09 年冬期 ) 33pp．2010 年 3 月発行

第 383 号

地すべり地形分布図 第 55 集「斜里・知床岬」23 葉（5 万分の 1）．2014 年 2 月発行
地すべり地形分布図 第 56 集「釧路・根室」16 葉（5 万分の 1）．2014 年 2 月発行

第 334 号

410pp．2013 年

349pp．2012 年 12 月発行

第 2 版（付録 DVD） 186pp．2013 年 7 月発行

第 341 号

強震ネットワーク

強震データ

Vol. 27（平成 21 年 No. 1）（CD-ROM 版）．2010 年 3 月発行

第 384 号

第 342 号

強震ネットワーク

強震データ

Vol. 28（平成 21 年 No. 2）（CD-ROM 版）．2010 年 3 月発行

第 385 号東京都市圏における水害統計データの整備（付録 DVD） 6pp．2014 年 2 月発行

第 386 号

The AITCC User Guide –An Automatic Algorithm for the Identification and Tracking of Convective Cells–

第 343 号

阿寺断層系における深層ボーリング調査の概要と岩石物性試験結果（付録 CD-ROM）15pp．2010 年 3 月発行

第 344 号

地すべり地形分布図 第 46 集「札幌・苫小牧」
19 葉（5 万分の 1）．2010 年 7 月発行

33pp．

2014 年 3 月発行

第 345 号

地すべり地形分布図 第 47 集
「夕張岳」16 葉（5 万分の 1）．2010 年 8 月発行

第 387 号

第 346 号

（2006/07 , 2007/08 , 2008/09 冬期）47pp．2010 年 9 月発行
長岡における積雪観測資料（31）

第 388 号

地すべり地形分布図 第 57 集「沖縄県域諸島」25 葉（5 万分の 1）．2014 年 3 月発行

第 347 号

地すべり地形分布図 第 48 集
「羽幌・留萌」17 葉（5 万分の 1）．2010 年 11 月発行

第 389 号

長岡における積雪観測資料 (36)（2013/14 冬期） 22pp．2014 年 12 月発行

第 348 号

平成 18 年度 大都市大震災軽減化特別プロジェクト実大 3 層 RC 建物実験報告書（付録 DVD）68pp．2010 年 8 月発行

第 390 号

新庄における気象と降積雪の観測（2013/14 年冬期） 47pp．2015 年 2 月発行

防災科学技術研究所による深層掘削調査の概要と岩石物性試験結果（足尾・新宮・牛伏寺）（付録 CD-ROM）12pp．

第 391 号

大規模空間吊り天井の脱落被害メカニズム解明のためのＥ－ディフェンス加振実験 報告書 －大規模空間吊り天

第 349 号

2010 年 8 月発行

新庄における気象と降積雪の観測（2012/13 年冬期） 47pp．2014 年 2 月発行

井の脱落被害再現実験および耐震吊り天井の耐震余裕度検証実験－
第 392 号

第 350 号

アジア防災科学技術情報基盤（DRH-Asia) コンテンツ集

第 351 号

新庄における気象と降積雪の観測（2009/10 年冬期） 31pp．2010 年 12 月発行

第 393 号

地すべり地形分布図 第 59 集「伊豆諸島および小笠原諸島」10 葉（5 万分の 1）．2015 年 3 月発行
地すべり地形分布図 第 60 集「関東中央部」15 葉（5 万分の 1）．2015 年 3 月発行

第 352 号
第 353 号

266pp．2010 年 12 月発行

193pp．2015 年 2 月発行

地すべり地形分布図 第 58 集「鹿児島県域諸島」27 葉（5 万分の 1）．2015 年 3 月発行

平成 18 年度 大都市大震災軽減化特別プロジェクトⅡ 木造建物実験 - 震動台活用による構造物の耐震性向上研究 -第 394 号

（付録 CD-ROM）120pp．2011 年 1 月発行

第 395 号

水害統計全国版データベースの整備．2015 年発行予定

地形・地盤分類および常時微動の H/V スペクトル比を用いた地震動のスペクトル増幅率の推定

第 396 号2015 年 4 月ネパール地震（Gorkha 地震 ) における災害情報の利活用に関するヒアリング調査 58pp．2015 年 7 月発行

242pp．

2011 年 1 月発行
第 354 号

地震動予測地図作成ツールの開発（付録 DVD）155pp．2011 年 5 月発行

第 355 号

ARTS により計測した浅間山の火口内温度分布（2007 年 4 月から 2010 年 3 月） 28pp．2011 年 1 月発行

第 356 号

長岡における積雪観測資料（32）（2009/10 冬期） 29pp．2011 年 2 月発行

第 357 号

浅間山鬼押出火山観測井コア試料の岩相と層序（付録 DVD） 32pp．2011 年 2 月発行

第 358 号

強震ネットワーク

強震データ

Vol. 29（平成 22 年 No. 1）（CD-ROM 版）．2011 年 2 月発行

第 359 号

強震ネットワーク

強震データ

Vol. 30（平成 22 年 No. 2）（CD-ROM 版）．2011 年 2 月発行

第 360 号

K-NET・KiK-net 強震データ（1996 － 2010）（DVD 版 6 枚組）．2011 年 3 月発行

第 361 号

統合化地下構造データベースの構築 ＜地下構造データベース構築ワーキンググループ報告書＞ 平成 23 年 3 月
238pp．2011 年 3 月発行

第 362 号

地すべり地形分布図 第 49 集
「旭川」16 葉（5 万分の 1）．2011 年 11 月発行

第 363 号

長岡における積雪観測資料（33）（2010/11 冬期） 29pp．2012 年 2 月発行

第 364 号

新庄における気象と降積雪の観測（2010/11 年冬期） 45pp．2012 年 2 月発行

第 365 号

地すべり地形分布図 第 50 集
「名寄」16 葉（5 万分の 1）．2012 年 3 月発行

第 366 号

浅間山高峰火山観測井コア試料の岩相と層序（付録 CD-ROM） 30pp．2012 年 2 月発行

第 367 号

防災科学技術研究所による関東・東海地域における水圧破砕井の孔井検層データ

第 368 号

台風災害被害データの比較について（1951 年～ 2008 年，都道府県別資料）（付録 CD-ROM）
19pp．2012 年 5 月発行

29pp．2012 年 3 月発行

第 369 号

E-Defense を用いた実大 RC 橋脚（C1-5 橋脚）震動破壊実験研究報告書 - 実在の技術基準で設計した RC 橋脚の耐– 編集委員会 –
（委員長）

下川 信也

（委 員）
森川 信之
平島 寛行
三好 康夫

木村 尚紀
佐々木智大

防災科学技術研究所研究資料 第 397 号
平成 27 年 9 月 4 日 発行
編集兼 国立研究開発法人
発行者

防災科学技術研究所〒 305-0006

茨城県つくば市天王台3－1
電話 (029)863-7635

http://www.bosai.go.jp/

（事務局）
臼田裕一郎

横山 敏秋

（編集・校正）樋山 信子

印刷所 前 田 印 刷 株 式 会 社
茨 城 県 つ く ば 市 山 中 152-4© National Research Institute for Earth Science and Disaster Prevention 2015

震性に関する震動台実験及びその解析 （付録DVD） 64pp．2012 年 10 月発行※防災科学技術研究所の刊行物については，ホームページ（http://dil-opac.bosai.go.jp/publication/）をご覧下さい．
表紙写真 ・・・・ Casualties and Damage of Masonry Housing Caused by Gorkha Earthquake.

Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

Flash Report on the Damage of Masonry Housing Caused by Earthquake
in the case of Gorkha Earthquake, 25 April 2015
Tsuneo OHSUMI*, Hiroshi IMAI*, and Hiroshi INOUE*

Abstract
An earthquake with a magnitude of 7.8 (Mw) occurred at 11:56 NST, (local time) on 25 April 2015, in the central part of
Nepal (Gorkha). The National Research Institute for Earth Science and Disaster Prevention (NIED) organized a damage
survey team and dispatched it to the affected area during 26 May to 3 June for the investigation into the damage andcollection of information and data. This report outlines the findings of this investigation undertaken by the NIED teamon the various aspects of the earthquake disaster in the Kathmandu valley. The primary purpose of the first survey is tocollect the current statistical information of the damage brick / stone masonry hosing and to confirm availability of data
and their sources for the following surveys. The motivation of the survey is to obtain ground truth data to calibrate andimprove the wide-area damage estimation system using satellite data under development by NIED. We also carry out
actual building damage survey by ourselves at selected areas. We collect information of structural differences between
damaged and non-damaged buildings, their classifications and distribution, time-dependent demography, and other social
aspects specific to Nepal.
Key words: Gorkha Nepal Earthquake, Kathmandu, Masonry, Ground truth

Disaster Prevention (NIED) organized a damage survey teamand dispatched it to the affected area during 26 May to 3
June for the investigation into the damage and collection of
information and data. This report outlines the findings of thisinvestigation undertaken by the NIED team on the various
aspects of the earthquake disaster in the Kathmandu valley(Fig. 1).

1. Introduction
An earthquake with a magnitude of 7.8 (Mw) occurredat 11:56 NST, (local time) on 25 April 2015, in the central
part of Nepal (Gorkha). The epicenter was east-southeast of
Lamjung, 77 km south-west of Kathmandu, 28.15 at the northlatitude and 84.71 at the east longitude, and the depth was 15
km (USGS). According to the statistics by The Nepal Police
on 22 June the number of deaths 8,660 and injured 21,952
for the main shock and deaths 172 and injured 3,470 for theaftershock. It was also reported that more than 5,000,000
buildings and houses were damaged and about half of those
had which collapsed. This earthquake was officially named
as The 2015 Gorkha Nepal earthquake, since the hypocenter
was located in the Gorkha region.
A major aftershock with a moment magnitude of 7.3 (Mw)occurred at 12:51 NST on 12 May 2015. The epicenter was
75 km noth-east of Kathmandu and near the Chinese border,
27.82 at the north latitude and 86.08 at the east longitude, andthe depth was 19 km (USGS).
The National Research Institute for Earth Science andFig. 1 Survey Route.
(OpenStreetMap https://www.openstreetmap.org/)* 3-1 Tennodai, Tsukuba, Ibaraki, 305-0006, Japan－1－

Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

one plate could not be sub-ducted under the other1). Thus,
the Main Himalayan Thrust is dipping at a low angle 6° 14° towards north (Mukhopadhyay, 2014) 2). Tectonics of theHimalaya region are expected to continue to rise more than 1
cm/yr1).
2.2 2015 Gorkha Nepal Earthquake and Risk Assessment
Results of JICA 2002
During “The study on earthquake disaster mitigation in
the Kathmandu Valley (JICA, 2002)” 3), hazard analysis anddamage analysis were conducted. The ultimate purpose of thisearthquake disaster analysis is to recognize the phenomena
involved when an earthquake occurs near the Kathmandu
Valley in the future. Based on the disaster scenario, a disasterprevention plan can be established. The scenario earthquake
fault models are shown in Fig. 2.2.
Nepal lies on an active seismic zone ranging from Java– Myanmar – Himalayas – Iran and Turkey, where manylarge earthquakes have occurred in the past. The historicalearthquake catalogue shows the high seismicity along theHimalaya and also the occurrence of huge earthquakes.
Kathmandu has suffered damage due to earthquakes several
times, among them the 1934 Bihal-Nepal earthquake caused
the most serious damage. The damage of the earthquake
will be different depending on the type and location of theearthquake, such as a huge earthquake outside of the Valley
and a small to middle-scale one within the Valley. In the
study, four scenario earthquakes have been set, among them
two hypothetical earthquakes were chosen in JICA 2002
report.
1) 1934 earthquake (Mw 8.4)
2) Mid Nepal Earthquake (Mw 8.0)
3) North Bagmati earthquake (Mw 6.0)
4) Kathmandu Valley local earthquake (Mw 5.7)

At the beginning of the report the tectonics and theseismicity are briefly introduced, and the characteristics ofthe recorded earthquake ground motions are discussed fromthe view point of the fault rupture mechanism. The India
plate sub-ducts along the Main Himalayan Thrust beneaththe Eurasian plate. The Main Himalayan Thrust is dipping at
a low angle towards north. Tectonics of the Himalaya region
are expected to most continue to rise more than 1 cm/yr.
There were three kings in the Kathmandu valley. Theirpalaces were in Kathmandu, Bhaktapur, and Lalitpur / Patan.
The difference between the renovation works done at thesepalaces was significant (Not for the historic structures of theold royal palace). Damage to the Old Sanku was serious, thebrick and cement mortar houses were seriously damaged.
These structures did not have reinforced concreate (RC)columns.
A numerous number of huge slope failures which occurredin mountainous areas and buried villages and valleys, which
resulted in the loss of many lives. Many houses that werecaught in landslides, had limited damage. However, the whole
scope of the slope failures is not clear at this present time,
because any detailed and total survey in the mountainous area
as not been carried out. Thus, the number of causalities will
be increase as they are found.
2. Tectonics of Nepal and Earthquake Ground Motion
2.1 Tectonic Interpretation of the 2015 Gorkha Nepal
Earthquake on April 25, 2015
The India plate sub-ducts along the Main Himalayan
Thrust beneath the Eurasian plate. Among the most dramaticand visible creations of plate-tectonic forces are the lofty
Himalayas, the two large landmasses of India and Eurasia,
driven by plate movement to collide. Because both thesecontinental landmasses have about the same rock density,

Fig. 2.1 Cross-section of the Main Himalayan Thrust (USGS: The April-May 2015 Nepal Earthquake Sequence)
Generalized cross section showing the approximate locations of slip during the 25 April and 12 May 2015
ruptures on the Main Himalayan Thrust, and approximate aftershock locations of both events.
MFT = Main Frontal Thrust, MBT = Main Boundary Thrust, MCT = Main Central Thrust.
Cross section generalized after Lave and Avouac, 2001 and Kumar et al., 2006.

－2－

Flash Report on the Damage of Masonry Housing Caused by Earthquake in the case of Gorkha Earthquake, 25 April 2015 − T. OHSUMI et al.

The First case is the 1934 earthquake (Mw 8.4) model,
in which the 1934 Bihal-Nepal Earthquake fault model isin the blue area. The second case is namely the Mid Nepal
Earthquake (M w 8.0), which was the most devastating
one which is in the green area. This model was is basedon seismic gaps in Nepal. The third model is the frequent
occurrence area of the small earthquakes in the near northernpart of the Kathmandu Valley which is in the red area. Thiscase correspond with the high-frequency component areaof Yagi’s model. Also, a major aftershock with a moment
magnitude of 7.3 (M w) on 12 May 2015 occurred to theclose hypocenter in this model. The fourth model is basedon the clear lineament in the Kathmandu Valley, as small as
magnitude 5.7 (Mw).

Fig. 2.2 The scenario earthquake fault models (JICA2002).

3. Historical Palace and Building in Urban Area
During the Malla dynasties up to 1768, there were threekings in the Kathmandu valley. Their palaces were in
Kathmandu, in Bhaktapur, and in Lalitpur/ Patan. The center
areas of these palaces are called “Durbar Square”.
3.1 Bhaktapur“Bhakta means” Devotee in Sanskrit, and “pur” means
city. Thus, Bhaktapur is the city of devotees. Bhaktapur’s
Durbar Square is a conglomeration of pagodas and Sikhara
style temples grouped around a 55 Window Palace of brick
and wood (Fig. 3.1).
Many of Sikhara in Bhaktapur’s Durbar Square wereseverely damaged. The steel frame reinforced Chayslin duga
temple (left) (Fig. 3.2). This temple was no damaged. During
the 1934 earthquake Chyasilin Mandap was completely
destroyed. Architects Götz Hagmüller and Niels Gutschow set
about rebuilding this temple due to the metal reinforcements
by GTZ fund. The Vatsala temple (center), which is Newarstyle temple, ca.1690, was destroyed. Yaksheshvara temple(right) survived.

was destroyed (Fig. 3.5). The large, white Fasi Dega Temple
was dedicated to Shiva and it was one of the tallest temples
in the second part of Bhaktapur Durbar Square.
Taumadhi Square
Nyatapola Temple, which is a five-storied pagoda, wasbuilt by King Bhupatindra Malla in 1702 (Fig. 3.6). Thisis one of the tallest pagoda-style temples in Kathmandu
Valley and is famous for its massive structure and subtle
workmanship. This temple survived in an earthquake in1934. This temple remained with a minimum of damage, thereliability of the building technology is being evaluated. The
Bhairavnath temple was destroyed by an earthquake in 1934and subsequently rebuilt.
Dattatreya Square
Dattatreya square in Bhaktapur suffered only one small
casualty in terms of collapsed temples. The main Dattatreya
temple and others still stand. This temple was originally built
in 1427 and is dedicated to Dattatraya, an incarnation ofVishnu.
The God Bishnu festival is held in the Datrataya Temple(Fig. 3.7). Usually, this festival is organized every year from
July to August. In front of this temple, two statues watchmen/
guardians are standing, who provide against evil anddisasters. Two watchmen hold Grakata, which is the preferredweapon of Lancers.

Harisankara temple
This structure materials are polished decorative bricks ofhigh quality terracotta for lintels of doors and for decorative
layers are integrated into the facades (Fig. 3.3). Insidematerials are unburned bricks and timber frames. Thissikhara had to be demolished later.
Chasin Mandapa and Siddhilakshmi Shikhara
Chasin Mandapa (left) was broken in the lintel (Fig. 3.4).
Siddhilakshmi Shikhara (right) survived, except the top offinial. This temple’s construction used stone and Indian style.
This style developed in India during the late 6th century, it
only appeared in Nepal during the late Licchavi period, 9th
century. There was no damage to the statues of guarding lions
and the steps leading to the main entrance. The Fasi Dega

The Nepal calendar is currently 2072. Thus, Nepal 1990
B.S. (Bikram Sambat) correspond to 1934A.D. State, thistemple collapsed but has not been rebuilt (Fig. 3.8). If suchnon-reconstruction of historical buildings that have been lost
during earthquakes does not proceed, it will be a major blow
to the future Nepal’s tourism-oriented country.

－3－Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

Fig. 3.1 Bhaktapur before / after the earthquake (Photo. by T. Ohsumi), before / after the 1934 earthquake (Courtesy of MoHA).

Fig. 3.2 Rinforced Chayslin duga temple (left) by steel frame, Vatsala temple (center) was destroyed and Yaksheshvara
temple (right) survived (Photo. by T. Ohsumi).

Fig. 3.3 This sikhara was demolished (Photo. by T. Ohsumi).

Fig. 3.4 Chasin Mandapa (left) and Siddhilakshmi
Shikhara (right) (Photo. by T. Ohsumi).

－4－

Flash Report on the Damage of Masonry Housing Caused by Earthquake in the case of Gorkha Earthquake, 25 April 2015 − T. OHSUMI et al.

Before the earthquake

After the earthquake

Fig. 3.5 The Fasi Dega was destroyed (Photo. by T. Ohsumi).

Fig. 3.6 Nyatapola temple (left) and Bhairavnath temple (right) are no damage (Photo. by T. Ohsumi).

Fig. 3.7 Main Dattatreya temple at Dattatreya Square (left), twowatchmen / guardians hold Grakata (right) (Photo. by T.
Ohsumi).

－5－

Fig. 3.8 This temple collapsed in 1934 earthquake, but has notbeen rebuilt (Photo. by T. Ohsumi).

Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

3.2 Lalitpur/ PatanIn Lalitpur of the Royal Palace, Patan is “Lalitpur” inSanskrit, is called “Yela” in Newari, it means the city ofbeauty.
The Patan palace was renovated with assistance fromthe Kathmandu Valley preservation trust (KVPT) and theSumitomo Foundation in 2013.
Thus, in Patan, 2015, after the earthquake, this place had
only partial damage at Gajur and Baymvah (Fig. 3.9-10).
Krishna Sikhara survived. Jagannarayan Temple (left),
Vishnu Temple(ceter) and Narasimha Sikhara from 1598
（front）were survived (Fig. 3.11).
Fig. 3.10 Taleju three-tiered temple Lalitpur(Photo. by T. Ohsumi).

Fig. 3.9 Patan 2015, after the earthquake, this place had partial damage at Gajur and Baymvah (right)(Photo. by T. Ohsumi).

Krishna Sikhara
Fig. 3.11 Jagannarayan Temple (left), Vishnu Temple (ceter) and Narasimha Sikhara survived(Photo. by T. Ohsumi).

3.3 Kathmandu
The old palace structures in Kathmandu’s Durbar Square,
which had no renovation, had severe damage (Fig. 3.12). On
the left side of the white structure, which was Lana Dynasty
150 years ago. On the right side of a four-tiered brown
temple, which was Gorkha Dynasty 300 years ago.
The Kasthamandap temple was built by king Laxmi

Narsingha Malla in the early 16th century. The whole temple
was made from a single tree (Fig. 3.13). Kasthamandap is
said to be the etymology of Kthmandu. The earthquake on
April 25, 2015 caused severe damage to this temple and it
collapsed.
Westside of the Ring Road in Kathmandu, RC framebuildings were tilted. At Gongabu, northwest of Ring Road,－6－

Flash Report on the Damage of Masonry Housing Caused by Earthquake in the case of Gorkha Earthquake, 25 April 2015 − T. OHSUMI et al.

and at Sitapatla, southwest of Ring Road, the building
damage was caused by the soft ground area on the riverbranch (Fig. 3.14). At west side of the Ring Road in
Kathmandu, RC frame buildings were tilted (Fig. 3.15). At

the branch point of the Bagmati River and the TransformorRiver, collapsed buildings fell onto and destroyed the next
building (Fig. 3.16).

Fig. 3.12 Kathmandu Durbar Square after theearthquake (right), before earthquake(left) (Photo. by T. Ohsumi).

Fig. 3.13 Kasthamandap temple before theearthquake (a) / after the earthquake(b) (Photo. by T. Ohsumi).

bacFig. 3.14 At Gongabu, RC frame buildings were tilted (a,b). A shear crack in the first flower (c) (Photo. by T. Ohsumi).
－7－Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

Fig. 3.15 At west side of the Ring Road in Kathmandu, RC frame buildings were tilted (Photo. by T. Ohsumi).

(OpenStreetMap https://www.openstreetmap.org/)

Fig. 3.16 At the branch point of the Bagmati River and the Transformor River, collapsed building fell onto anddestroyed the next building (Photo. by T. Ohsumi).

－8－

Flash Report on the Damage of Masonry Housing Caused by Earthquake in the case of Gorkha Earthquake, 25 April 2015 − T. OHSUMI et al.

3.5 Sankhu
The houses damaged by the earthquake have been
demolished with the support of the Canadian Forces in
Sankhu. Heavy equipment was brought from Canada (Fig.
3.18). RC buildings were partially damaged the difference
appears remarkable (Fig. 3.19). Damage in Sankhu wasenormous, the brick and cement mortar houses without
RC columns had a lot of damage. Structures having no RC
columns on the corner, a vertical crack in a brick masonrywall was generated. Outer wall structures of buildings isbaked brick with cement mortar joints to withstand rain.
Inside wall of buildings is adobe bricks with mud mortar (Fig.
3.20).

3.4 Madhyapur Thimi
In JICA2002, building types were classified for the whole
Katmandu. The investigation was mainly based on visualobservations. In order to supplement, it was made frombuilding inventory survey result, topographic maps and aerial
photographs.
The building type classification map defined each rate ofstructure as 500 m×500 m mesh (Fig. 3.17: upper). In Sano
Thimi (Fig. 3.17: a), with newer buildings, the damage has
been reduced. Old Thimi located on a small hill (Fig. 3.17: b),
the houses were destroyed in 1934 rebuilt and again received
severe damages.

Fig. 3.17 The building type classification map in
Thimi, Sano Thimi (a) and Old Thimi (b)(Photo. by T. Ohsumi).

Fig. 3.18 In Sankhu, heavy equipment from Canada(Photo. by T. Ohsumi).

Fig. 3.19 RC buildings were partially damaged, thedifference appears remarkable in Sankhu(Photo. by T. Ohsumi).

－9－Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

Fig. 3.20 A vertical crack in a brick masonry wall was generated from the corner (a).
Structures having no RC columns on the corner (b) (Photo. by T. Ohsumi).

4. Landslides, Suburbs, Rural Areas
4.1 Landslides
A numerous number of huge slope failures which occurredin the mountainous area buried villages and valleys, andresulted in the loss of many lives. We visited a landslide zone
in Ramche, and it is located in the northwest of Kathmandu
city in a mountainous area. Many of fallen rocks were on
the roads, also we encountered a bus that hit by falling rocks(Fig. 4.1). Thick talus is deposited in the landslide area in
Ramche, in Rasuwa district (Fig. 4.2). The town is locatedat an altitude of 2,068 m. There are houses that had beencaught in a landslide, but the damage was limited. However,
the whole scope of the slope failures is not clear at thepresent time, because any detailed and total survey in themountainous area has not been carried out. Thus, causalities
will increase as they are found.
4.2 Suburbs and Rural areas
The number of casualties is concentrated in the north-eastof Kathmandu Sindhupal Chok district. We visited east
Bhimeshwar (formerly Charikot), Bhimeshwar Municipality,
is 50 km east of Dhulikhela. The town is located at an altitudeof 1,554 m. The name of the district Dolakha came from the
Dolakha Town situated north-east of the capital Charikot.
These areas had many casualties. According to the local
people, the aftershock felt stronger than the main shock. The
aftershock’s hypocenter occurred just below this area. Many
houses collapsed in the aftershock.

Urban and rural housing is significantly different. In thesuburban and rural areas there are many stone houses, a lotof damage occurred. The collapse of heavy stones used into
house construct, took away many.
In Dolakha district, adobe style houses collapsed. First,
this adobe houses collapsed at the gable and cracked at cornerby ground motion. Many adobe style houses broken at gable(Fig. 4.3). Stone style houses also collapsed by delamination.
Stone style houses also collapsed by delamination. Stone
style housing used a shaped schist as stone masonry material.
Typical case of stone construction the masonry used was a
mud mortar in the joints. The wall thickness was more than
50 cm. Many 2-3-story housing the floor is half-timbered.
CGI sheet (galvanized wave plate) is used for roofing in
half-timbered housing (Fig. 4.4).

－ 10 －

Fig. 4.1 Bus was hit in falling rocks in Dhikure,on BaglungRajmara High way (Photo. by T. Ohsumi).

Flash Report on the Damage of Masonry Housing Caused by Earthquake in the case of Gorkha Earthquake, 25 April 2015 − T. OHSUMI et al.

RamcheFig. 4.2 Thick talus is deposited in the landslide area in Ramche (Photo. by T. Ohsumi).

Fig. 4.3 Adobe style houses collapsed at the gable part in Charikot, Bhimeshwor Municipality (Photo. by T. Ohsumi).

Charikot

Fig. 4.4 Stone style house in Charikot, Bhimeshwor Municipality (Photo. by T. Ohsumi).

－ 11 －

Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

5. Discution
According to the statistics by The Nepal Police on 22 June
the number of deaths 8,660 and injured 21,952 for the main
shock and deaths 172 and injured 3,470 for the aftershock(Table 1). It was also reported that more than 5,000,000
buildings and houses were damaged and about half of those
had which collapsed, number is increasing now.
Why this area had concentrated casualties?
First, this rural area’s housing style is mainly stone
masonry. The collapse of heavy stone took away many
lives. The damaged typical housings in mountainous
region, damages were concentrated in the non-engineered
construction housings. In rural area, unreinforced masonry,
using the material available in the region, is the main
construction method. Regardless of the masonry material,
serious damage of the houses were caused masonry with mud
mortar. This housing construction method in urban areas,
which constructed more than 30 years ago. In the rural areas,
this type of housings are also currently in the people housing
construction. Thus, retrofitting of low-cost housing for such
non-engineers is a key issue.
A mud mortar, which is especially low adhesive strength,
adhesion between the material of housing is reduce during
earthquake duration time. A brittle material or structure
fractures or suddenly breaks while subjected to bending,swaying, and deforming. The mud mortar avoids the brittle
structure due to the little tendency to deform before it
fractures.
A typical low-story part of earthquake damaged housing
causes shear failure of masonry wall. Typical failure patternof non-engineered housings are out of plane by poor bonding
strength.
A stone masonry building with an RC lintel band thatsurvived this earthquake.
According to “Guidelines for Earthquake Resistant
Non-Engineered Construction” 4), horizontal bands or ring
beams show detail.
The most important horizontal reinforcing is throughreinforced concrete bands provided continuously through allload bearing longitudinal and transverse walls at plinth, lintel,
and roof eave levels, as well as at top of gables according torequirements as stated hereunder:
1) Plinth band: This should be provided where the soil is
soft or uneven in its properties as happens in hill areas.
It also serves as damp proof course. This band is not too
critical.
2) Lintel band: This is the most important band andis incorporated in all door and window lintels. Its
reinforcement should be extra to the lintel band steel.
3) Roof band: This band is required at eaves level ofpitched roofs and also below or level with suspended
floors which consist of joists and flooring elements, so
as to properly integrate them at ends and fix them into
the walls.
Second, there are major high-frequency (1 Hz) seismic
radiation exist in this earthquake waveform. Fig. 5.4 shows
earthquake rupture model for the 2015 main shock (Yagi andOkuwaki, 2015)5). This model inverted teleseismic P-wave
data applying a novel formulation that takes into accountthe uncertainty of Green’s function by using Yagi andFukahata (2011)6), which uses waveform inversion from the
IRIS (Incorporated Research Institutions for Seismology)7)
waveform (time-series) data. The fault length and widthof the rupture plane are east-west 150 km long, including
Kathmandu and the region from north to south 120 km and
4.1 m or more.
Yagi et al. (2012) 8) developed a new back-projection
method that uses teleseismic P-waveforms to integrate
the direct P-phase with reflected phases from structural
discontinuities near the source and used to estimate thespatiotemporal distribution of the seismic energy releaseof the 2015 Gorkha Nepal earthquake from the IRIS GSN(Global Seismographic Network) and FDSN (International
Federation of Digital Seismograph Networks) Information
data.
The area of major high-frequency (1 Hz) seismic radiation
extended east-south-east from the hypocenter. Main slip
distributes near the Kathmandu Valley. The main slip iscomparatively small near hypocenter. Slip distribution bysource inversion analysis is shown by contour map in Fig. 5.4.
The area is north of the Kathmandu Valley and near North
Bagmati scenario earthquake model.
The major high-frequency (1 Hz) seismic radiation area by
hybrid back-projection analysis is read from Yagi’s analysis
and shown by pink colored square region. The area is northof Kathmandu Valley and near the North Bagmati scenario
earthquake model. The major high-frequency (1 Hz) seismic
radiation caused the damage to buildings and housing in the
Kathmandu Valley.

Table 1 Human Damage Information by the Earthquake.by
Nepal Police.

－ 12 －

Human Damage
Area

Arrea

InjuredUnder
treatment

Identified
To be identified
dead bodies
dead bodies

KV

1,721

11,04446

1,707

Easten Region

55

323

1

55

0

Central Region

6,425

6,348

79

6,417

2

Western Region

457

1,100

720

457

0

Mid-West Region

2

22

1

2

0

Far-Western Region
Total

Death

12

-

2

-

-

0

8,660

18,839

847

8,638

14

Flash Report on the Damage of Masonry Housing Caused by Earthquake in the case of Gorkha Earthquake, 25 April 2015 − T. OHSUMI et al.

Fig. 5.1 Casualties and injured people by Nepal Police.

Fig. 5.2 Typical failure pattern of Non-engineered housings left: Nuwakot, right: Ksthmandu (Photo. by H. Imai).

－ 13 －

Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

Fig. 5.3 Seismic RC band for stone and brick masonry (NSET promoted in Dolakha, Nepal)(Photo. by H. Imai) (upper figure from Arya (2013) 4)).

Fig. 5.4 Source Model of 2015 Gorkha Nepal Earthquake.

－ 14 －

Flash Report on the Damage of Masonry Housing Caused by Earthquake in the case of Gorkha Earthquake, 25 April 2015 − T. OHSUMI et al.

6. Characteristic of this Earthquake Summary and Conclusions
1) Westside of the Ring Road in Kathmandu, RC framebuildings were tilted. The building damage was causedby the soft ground area on the river branch.
2) RC buildings were partially damaged the difference
appears remarkable. The brick and cement mortar houses
without RC columns had a lot of damage. Structures
having no RC columns on the corner, a vertical crack ina brick masonry wall was generated.
3) The number of casualties is concentrated in thenorth-east of Kathmandu Sindhupal Chok district. Many
houses collapsed in the aftershock. Urban and rural
housing is significantly different. In the suburban andrural areas there are many stone houses, a lot of damage
occurred. The collapse of heavy stones used into house
construct, took away many.
4) Three kings in the Kathmandu valley palaces werein Kathmandu, Bhaktapur, and Lalitpur / Patan. The
difference between the renovation works done at thesepalaces was significant (Not for the historic structures ofthe old royal palace).
5) In the rural areas, stone masonry type of housings arealso currently in the people housing construction. Thus,
retrofitting of low-cost housing for such non-engineers
is a key issue.
6) The major high-frequency (1 Hz) seismic radiation
caused the damage to buildings and housing in the northof Kathmandu Valley.
Nepal and Japan has a long history of cooperation inearthquake engineering and many joint research projects havebeen carried out in the academic field for earthquake disastermitigation.
2016 is the 60th anniversary of the established of Nepaleseand Japanese diplomatic relations. All of the membersof the NIED team wish to strengthen our partnership inearthquake engineering between Nepal and Japan through thecooperation for the investigation into this earthquake disasterand through future joint research projects.

Acknowledgments
This research of survey for The Gorkha Nepal Earthquake
was supported by Dr. Ganesh K Jimee, Dr. Gopi K basyal andDr.Ramesh Guragain with NSET. We also thank Dr. Sujan
Raj Adhikari with NSET provided which valuable earthquake
engineering information.
Reference
1) The imalayas: Two continents collide [This Dynamic
Earth, USGS].
http://pubs.usgs.gov/gip/dynamic/himalaya.html
2) Mukhopadhyay, B., Clusters of Moderate Size
Earthquakes along Main Central Thrust (MCT) in
Himalaya. International Journal of Geosciences, 2011,
2, 318-325 doi:10.4236/ijg.2011.23034 Published Online
August 2011.
http://www.SciRP.org/journal/ijg
3) Risk Assessment Results of 2002 “The Study on
Earthquake Disaster Mitigation in the Kathmandu
Valley”.
4) Arya, A. S., Boen, T., Ishiyama, Y., Guidelines for
Earthquake Resistant Non-Engineered Construction,
UNESCO, 2013.
http://unesdoc.unesco.org/images/0022/002290/229059E.
pdf#search=’non+engineered+constrcution+guideline’5) Yagi, Y. and Okuwaki, R., Slip distribution by source
inversion analysis is shown by contour map and the
major high-frequency (1 Hz) seismic radiation area by
hybrid back-projection analysis for the 2015 Gorkha
Nepal Earthquake (Interim) ver.2.
http://www.geol.tsukuba.ac.jp/~yagi-y/EQ/20150425/
index.html
6) Yagi, Y. and Fukahata, Y., 2011, Rupture processof the 2011 Tohoku-oki earthquake and absoluteelastic strain release, Geophys. Res. Lett, 38, L19307,
doi:10.1029/2011GL048701.
7) IRIS, Incorporated Research Institutions for Seismology:
https://www.iris.edu/hq/programs/gsn/
8) Yagi, Y., Nakao, A., and Kasahara, A., Smooth and rapid
slip near the Japan Trench during the 2011 Tohoku-oki
earthquake revealed by a hybrid back-projection method,
Earth Planet. Sci. Lett., doi: 10.1016/j.epsl.2012.
(Accepted: July 27, 2015)－ 15 －

Technical Note of the National Research Institute for Earth Science and Disaster Prevention: No. 397; September, 2015

2015 年 4 月ネパール地震 (Gorkha 地震 ) における建物被害に関する情報収集調査速報
大角恒雄＊・今井

弘＊・井上

公＊

＊

防災科学技術研究所，災害リスクユニット

要旨2015 年 4 月 25 日 11 時 56 分（現地時間），ネパール中北部を震源域とするマグニチュード（Mw）7.8 の地震が発生し，首都カトマンズを中心とする広い領域で，主としてレンガ組積造建物が倒壊による多くの被害が発生した．この報告書は，5 月 26 日から 6 月 3 日にかけてカトマンズ盆地を中心にデータ収集として，調査団を派遣し，その調査速報である．この 1 次調査の目的は，かねてより進めている
地震ハザード・リスク評価，地震被害推定手法の研究として，現地の煉瓦組積造及び石造りの建物調査を実施した．また，防災科研が進めている衛星データからの被害想定のためのクランド・ツルースの利活用に関する研究の成果を活用し，今後の詳細建物調査につなげるものである．地震によって倒壊した建物，被害を受けなかった建物調査を行い，ネパール国の今回の地震からの復旧・復興ならびに将来の地震災害軽減に資するため現地調査および情報収集を行った．
キーワード：コルカ・ネパール地震，カトマンズ，煉瓦組積造，石造り，グランド・ツルース－ 16 －