14th Asian Regional Conference on Soil Mechanics and Geotechnical Engineering - After two months JGS(Japan Geotechnical Society) Motoki Kazama, Tohoku University 1 Introduction Earthquake Tsunami Nuclear power plant Damage to infrastructural facilities Features of disaster Problems with Geotechnical Engineering Conclusions and remarks 2 1
Outline of damage (Victims and building damage) Scale, geography and affected places Difficulty of returning home in metropolitan areas 3 Extensive damage In a large area Very large Tsunami Unexpected accident in the nuclear plants Everyone was a victim Many victims Progressive Distribution Delay of supplies Rescue of survivors Search for bodies Chain damage Delay of recovery efforts, Prolongment 4 2
Scale Tohoku Region Source Region 500 X 200km Japan Sea Pacific Ocean 1000km 6 Name of prefectures Iwate pref. Miyagi pref. Fukushima pref. 200km 7 3
Most Affected Areas Iwate pref. Sanriku Rias coast Miyagi pref. Fukushima pref. Sendai Basin ( 仙台湾 ) Nuclear power plant ( 原子力発電所 ) 8 9000 8000 7000 6000 5000 4000 3000 2000 1000 0 Death toll:15,037, Missing: 9,487 Iwate Miyagi Death toll Missing Fukushima 70000 60000 50000 40000 30000 20000 10000 0 Totally Partially Iwate Miyagi Fukushima Totally damaged houses: 90,042 buildings Partially damaged houses:36,072 buildings Total damage cost (From world bank)$236 billion (Kobe earthquake was $124 billion) 9 4
Most Affected Areas(2) in Miyagi pref. Kesen-numa City Osaki plain Sanriku Rias Coast Onagawa Town Sendai City Sendai plain Ishinomaki City 10 11 5
Eurasian Plate 0.9 cm/y Pacific Plate 8.5cm/y [ 全国地質調査業協会連合会 : 豊かで安全な国土のマネジメントのために,1998 年,p.20] 12 Date 2011/3/11/14:26 Southeast distance off Oshika Peninsula 130 km Depth 24 km Magnitude Mw=9.0 Fault length about 450 km width about 200 km Duration of principal slip 3 min There were three main asperity ruptures 14 6
Epicenter From JMA 15 Japanese strong motion observation agencies NIED(National Research Institute for Earth Science and Disaster Prevention) (K-NET, KiK-net)About 1,600 points JMA(Japan meteorological agency) about 600 points Earthquake information network of each prefecture : 3,800 points Port and airport research institute Public works research institute Building research institute Highway companies Japan Rail companies Universities Municipalities Gas companies Councils Etc. Measureed seismic intensity by K- NET and KiK-net 1 6 7
http://www.jma.go.jp/jp/quake/ 17 Intensity 6-strong People can only move by crawling and may bounce on the floor Not fixed furniture only moves and may fall Buildings with low earthquake resistance tilt or fall Huge cracks in the land appear and land slides occur. JMA(Japan Meteorological Agency) 気象庁 http://www.jma.go.jp/jma/kishou/know/shindo/shindokai.html 8
気象庁 : 報道発表資料 平成 23 年 (2011 年 ) 東北地方太平洋地震 について ( 第 28 報 ), 平成 23 年 3 月 25 日 http://www.kyoshin.bosai.go.jp/kyoshin/topics/tohokuta iheiyo_20110311/nied_kyoshin1j.pdf 20 Aftershocks http://www.jma.go.jp/jma/press/1105/06a/kaisetsu20110506170 0.pdf 2011 The Great East Japan Earthquake M>5 Cumulated number 400 300 1994 east-hokkaido Earthquake (M8.2) 200 100 5 aftershocks over M.7 60days from main earthquake 21 9
Comparison of the acceleration records (seismic intensity 7) of past earthquakes Acceleration records Response velocity spectra 1995 Kobe earthquake 2004 Nigataken Chuetsu earthquake 2011 off the Pacific coast of Tohoku Earthquake 1~2 seconds amplitude which determine the damage was small 25 Influence from the three main ruptures at the source region North of Miyagi Pref. Main rupture at Miyagi coast was predominant Fukushima Pref. Both Miyagi coast and Ibaraki coast ruptures had an influence South of Fukushima Pref. Ibaraki coast rupture was predominant Area with intensity over 6-strong was widespread. Earthquake motion features Duration was long Period content of 1~2 s was less than the 1995 Kobe earthquake The generation of many aftershocks exacerbated the damage 27 10
28 Continental plate Sea plate Earthquake between plates Subsidence uplift Plate subduction 29 11
Up-down In horizontal plane Oshika: 580cm Oshika: 120cm (The Geospatial Information Authority of Japan) 30 1 2 Before After Before (before) After (2011.3.12) (before) (2011.3.12) 3 1 (before) (2011.3.12) (2011.3.12) 2 4 Index Altitude (m) 3 The area under average sea level (T.P. ±0m) The area under flood tide level (T.P. +0.7m) The area under largest recorded (T.P. (before) +1.6m) (2008) (2011) Before After Growth rate 3km 2 16km 2 5.3 times 32km 2 56km 2 1.8 times (2008) 83km 2 111km 2 1.3 times (Minister of Land, Infrastructure, Transport and Tourism) (2011.3.12) 4 (2011) 31 12
32 Port & Harbour Res. Inst. http://www.pari.go.jp/info/tohokueq/20110328mlit.html 日立造船 HP より http://www.hitachizosen.co.jp/other/hitz-tech.html 33 13
6.7 m 55 cm 34 Run-up Height of Tsunami Run-up height Maximum height: 38.9m at Omoe Peninsula in Miyakocity. The highest record ever before in Japan was of 38.2 m at Ryori bay.. 東北地方太平洋沖地震津波合同調査グループ http://www.coastal.jp/ttjt/ 35 14
気象庁 HP より http://www.jma.go.jp/jma/kishou/know/faq/faq26.html Tsunami height Tide measurement station Tide level under normal condition Inundation depth Inundation height Run-up height 36 JAXA ALOS AVNIR-2 画像 (3/14 撮影 ) 災害制御研究センター, 千葉工大, 関西大, 防衛大, 大阪市立大ほか 11 機関の合同調査結果を表示 2011 年 5 月 2 日 復興構想会議資料 37 15
JAXA ALOS AVNIR-2 画像 (3/14 撮影 ) Tsunami flood depth displayed using space interpolation East Sendai Expressway 仙台河川国道事務所および災害制御研究センター 左図 の調査結果を表示 2011 年 5 月 2 日 復興構想会議資料 38 Number of houses in flooded areas (Estimated) Reported damaged houses Damage rate (Totally and partially) Iwate Pref. 46,900 16,077 34% Miyagi Pref.(North of Tagajoshi) 107,700 Miyagi Pref.(South of Sendai) 46,500 40,027 26% Fukushima Pref. 17,300 2,417 14% Total 218,400 58,521 27% Number of damaged houses(totally and partially) at Hanshin Awaji earthquake : 249,180 Relational expression of the house damage and flood for the great Indian ocean tsunami(relationship of tsunami damage) Koshimura et al. (2009) Depending on flood depth At 2 m about 20% of houses are washed out At 4 m about 80% of houses are washed out by Prof. Koshimura (Tohoku Univ.) 40 16
Sanriku Rias Shore Onagawa bay(after 1 month) Kesenuma http://www.youtube.com/watch?v=mflektrtoii&feat ure=related Center of the city Ishinomaki(1 month after) Sendai plain low-land area(youtube) http://www.youtube.com/watch?v=rm3hdodpiey Natori Yuriage area 41 Even RC buildings fell Onagawa town 17
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Damage caused by scouring behind the slope toe of the coast embankment Tide prevention forest damage by Prof. Tanaka (Tohoku Univ.) Scour hole Non damaged pine Yamamoto shore Washed out Embankment Scour Hole 47 Washout at discontinuous coast embankment Only back side washout gentle slope embankment Embankment totally damaged -Sandy shore erosion -Tide prevention forest destruction Rubble embankment Before disaster by Prof. Tanaka (Tohoku Univ.) Higashi Matsushima Suzaki coast Geographical Survey Institute March 12, 2011 Before disaster Before disaster (Google street view) After disaster 49 20
660m by Prof. Mano (Tohoku Univ.) 50 by Prof. Mano (Tohoku Univ.) Houses behind standing coast trees were flooded only 1 floor. This is 1/3~ 1/4 of flood depth at houses behind collapsed coast trees. The house at the red circle was moved from its original place. 51 21
Not the subject of this report. 52 55 22
Hydrogen explosion Hydrogen explosion Hydrogen explosion Melted fuel rod Obvious ruptures due to explosion water Injection of nitrogen to container explosion water Meltdown? Meltdown? Building remained intact water Obvious ruptures due to explosion Injection of freshwater to fuel storing pool No fuel in the core, because of regular check Obvious ruptures due to explosion 56 http://www.tohoku-epco.co.jp/information/1182212_821.html の情報を図化 Number 停電戸数 of blackout ( 戸 ) houses 5,000,000 4,500,000 4,000,000 3,500,000 3,000,000 2,500,000 2,000,000 1,500,000 1,000,000 500,000 0 3/11 14:46 off the pacific coast of Tohoku earthquake About 4.40 million houses were power failure 4/7 aftershock 0 10 20 30 40 50 60 Elapsed 地震発生からの経過時間 time from the main shock ( 日 (days) ) 23
59 60 24
Port & Harbour Res. Inst. http://www.pari.go.jp/info/tohoku -eq/20110328mlit.html North part (990m) South part (670m) http://www.yomiuri.co.jp/science/news/ 20110402-OYT1T00753.htm Depth -63m to +6m The deepest break water in the world 61 General design of Break Water stability Hydrostatic pressure In outside of port Hydrostatic pressure In inside of port Support pressure acting on the mound 25
Failure mechanism of breakwater 1Large difference of sea level between the front and behind of the breakwater. 2Huge horizontal force loaded to Caisson Tsunami Flow +10.8m Water level difference: 8.2m +2.6m 4Mound Scouring 3Strong flow in the joint part of the Caisson Sanriku rias coast(kamaishi port office) 64 26
destroyed revetment ( at least 6 berths were destroyed and 4 of those were next to each other.) 65 Natori City, Yuriage fisherman s port Wharf anchorage exposure(tie road is not broken) 67 27
Sendai airport was swallowed by the tsunami(march 11 4 p.m.) 毎日 jp HP より ( 手塚耕一郎氏撮影 ) 68 Sendai airport swallowed by the tsunami South treatment center Sendai airport Iwanuma city, swallowed by the tsunami(march 11 3:56P.M) 毎日 jp HP より ( 手塚耕一郎撮影 ) 28
Sendai Airport In-situ survey(3/29)of Runway Runway status immediately after damage 毎日 jp HP より ( 佐々木順一氏撮影 ) Cars were recollected by US army Countermeasures before the Earthquake Restoration after the Earthquake Repaired cracks 72 29
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By JR-east Kagami-ishi~Sukagawa Izumizaki~Yabuki Shinden~Ishigoe Umegasawa~Shinden 78 By JR-east 79 31
Around Shinchi station, Jo-ban Line station and train, stricken by the tsunami Damage to bridge (Railway, JR-east) Structural damage to the Shinkansen: Sendai, Miyagi Pref. Shiroishizao~Sendai south Nagamachi Nagamachi viaduct bridge Old design code New design code Left: Moment crack was confirmed in columns of old viaduct bridges. Right: Parallel viaduct bridges of local lines were designed based on new seismic design criteria and spiral reinforcement was arranged in column hinges. 土木学会東日本大震災特別委員会総合調査団調査速報会資料より 81 32
Damage status by earthquake motion (Tohoku Shinkansen line) Structural damage of Shinkansen (1) Structural form : Viaduct bridge with RC beam-slab frame - Nakasone viaduct Num.1 Photo by JR east Column failure after earthquake Jack-up and restoration using sectional repair Tokyo direction Morioka direction Repair points 土木学会東日本大震災特別委員会総合調査団調査速報会資料より 82 Damage by earthquake motion Structural damage of Shinkansen: Electrification pillars Sendai, Miyagi It was confirmed that at 540 sites electrification pillars were tilted, cracked or broken (At April 4, 2011) 土木学会東日本大震災特別委員会総合調査団調査速報会資料より 83 33
JR kesen-numa line Koizumi bridge L=182m 国土交通省東北地方整備局提供 Pier washed away 84 34
86 87 35
Damaged sites 北上川 旧北上川 鳴瀬川 (Miyagi) 平成 23 年 4 月 19 日現在 北上川 旧北上川 鳴瀬川 大崎市 27 6 7 5 19 18 17 11 10 29 4 Inland damaged sites 3 涌谷町 登米市 26 9 松島町 22 21 20 8 Damaged sites at river mouth 北上川 石巻市 25 1 2 24 Damaged sites 28 鳴瀬川 東松島市 Pacific ocean Pacific ocean (The number indicates the order in the restoration process) 88 東北地方整備局による River mouth sites Catastrophic destruction The tsunami overflowed the embankments washout failure and erosion Ishinomaki( 石巻市月浜地区 釜谷地区 ) Higashi-matsushima( 東松島市野蒜 ) Watari( 亘理町荒浜 ) Inland areas Crack due to earthquake and settlement liquefaction of base ground and embankment material was the major cause of damage Ohsaki( 大崎市 ), Kakuta( 角田市 ) Wakuya( 涌谷町 美里町 ) Marumori( 丸森町 ) Date( 伊達市 ) 89 36
2 東北地方整備局による River mouth of New-kitakami Damage status Restoration work 北上大橋 北上川 断面図 津波による堤防の流出 Failure portion L=1,100m 富士沼 北上大橋 北上川 宮城県石巻市釜谷地先 ( 北上川水系北上川下流右岸 3.8k~4.6k+16m 延長 1,100m) 90 23 Damage condition River mouth of Abukuma 東北地方整備局による Embankment cross-section before earthquake Tsunami overflowed the embankment and it is thought that water dig the soil. Bank erosion caused by the tsunami was greater than a person s height Restoration works 断面図 宮城県亘理郡亘理町荒浜地先 阿武隈川水系 阿武隈川下流 右岸 0.0k-170m~0.0k+100m 延長 270m) Removal of damaged revetment 92 37
11 Inland, Naruse river Damage status Restoration works 鳴瀬川 東北地方整備局による Embankment cross-section before earthquake 鳴瀬川 They continued the restoration by night The embankment was so badly destroyed it is difficult to guess the original shape For restoration works a road was made to employ double closing construction using steel sheet piles 断面図 Restoration works using sheets to prevent rain flooding 宮城県大崎市下中ノ目地先 ( 鳴瀬川水系鳴瀬川左岸 30.0k~30.5k+37 延長 320m) 93 14 Inland, Abukuma River Damage status Restoration works 東北地方整備局による Embankment destroyed in river direction 断面図 Since the embankment was destroyed it is difficult to guess the original shape Pounded steel sheet piles 宮城県角田市枝野地先 ( 阿武隈川水系阿武隈川下流右岸 30.6k+34m~31.4k+160 延長 800m) 94 38
96 Liquefaction damage is remarkable, especially around Tokyo Bay and the Tone river in the Kanto region. The total area of liquefaction is more than 42 km 2. This is more than the 34 km 2 generated at the time of the Christchurch (New Zealand) earthquake. In the Tohoku region there is no visible liquefaction damage. Liquefaction did occur, but the tsunami erased the evidence. 97 39
Evidence of Liquefaction can be seen before the tsunami struck Natori, Miyagi Prefecture From Kyodo News Helicopter (4/19 Same place) 98 98 国土交通省東北地方整備局 99 40
Inner embankment near Eai and Kyu-kitakami rivers intersection at Kitawabuchi, Kanancho, Ishinomaki 上図は 地図閲覧サービス ( ウォッちず ) および カシミール 3D を用いて国土地理院発行の電子国土基本図 ( 地図情報 ) による 2 万 5 千分の 1 地形図を引用し, それに加筆したものである. 100 Osaki City(Furukawa Station) In front of Furukawa Station Furukawa Nakazato 10 1 41
by Prof. Yasuda Tokyo Bay:Sand covers thickly an extensive area 103 by Prof. Towhata Liquefaction damage around Tokyo Bay 104 42
Scouring around building (Water treatment center at South of the pref.) 10 5 Road Num.45 Nami-ita Bridge(Iwate prefecture Ohtsuchicho) 国土交通省東北地方整備局提供 復建技術コンサルタント提供 The soil behind the abutment of the road bridge was washed away. Restoration was completed by March 17. The upper parts of the superstructure and pier of a pedestrian bridge at river mouth were washed upstream. 10 6 43
Land development sites 擁壁 Large scale fill Cut Valley fill Natural ground Boundary Different motion causes large strains Rigid Small motion Small strains Soft Large motion Large strains 108 Distribution of damage due to earthquake in land development sites Fill Boundary Cut Totally dest. Partially dest. One part dest. Ground failure Road crack Fence damage Settlement 109 44
E F A B Legend Large cracks Small cracks Sliding direction D C Damaged places and cracks in land development sites confirmed by in-situ survey. 11 0 Red color:fill Blue color:cut map received originally from Fukken gijutsu consultant Co. (Fill and cut survey were not included.) 11 1 45
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The treatment status of household waste in Sendai. (Tsunami waste is not included) Google Maps 11 4 11 5 47
11 6 Refine the design code of liquefaction damage assessment against long duration earthquakes. Ensure the ductility of the earth structure when the seismic load is greater than the design load. Develop risk assessment and earthquake-resistant design methods at land development sites. Provide earthworks anti-tsunami and anti-scouring measures. Apply methods for effective use of earthquake waste, especially how to improve the characteristics of deposited soil. Treatment of the soil contaminated by radiation. 11 7 48
It was confirmed that there was liquefaction phenomenon from Aomori to Kanagawa region for intensities over 5-strong. Do the coastal metropolitan area and Tohoku region have different liquefaction level due to their earthquake history? We have to recognize that there are large areas with high potential risk of liquefaction in newly developed area. Regarding deformation of earthworks and liquefaction, earthquakes of 2-3 minutes in duration are fatal. 118 The places damaged during the 1978 Miyagi earthquake were damaged again. Also, new places were damaged. We need to assess the countermeasures and define the difference between the damaged and non damaged places. Regarding land development sites: the damage was larger at fill sites, but there are also many fill sites not damaged. 11 9 49
Anti-scouring of earthworks. Washout prevention of embankments. Foundation structure of tsunami shelter buildings. Estimation of mound bearing capacity breakwaters against tsunami. 120 The soils (beach sand and clay from the seabed and riverbed) washed away by the tsunami were deposited inland When soils get dry and are scattered, they can be a cause of infection. Geotechnical engineering technologies for treating dredged mud ponds and lakes can be used. 12 1 50
First, the failure mode should be controlled To accomplish this, it is necessary to know the behavior after failure This method can improve the toughness of earthworks This is the same as for resistance to liquefaction 12 2 We are presently evacuating to other building. 12 3 51