ground motion during 2011 east japan earthquake
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Ground motions and Structural Responses caused by the Great Tohoku-Kanto Earthquake, March 11, 2011
Dionysius Siringoringodion@bridge.t.u-tokyo.ac.jp
Bridge & StructureUniv. of Tokyo
2011 Great Tohoku-Kanto EarthquakeMagnitude : Mw 9.0 (JMA)Date : March 11, 2011
Trigger time : 14:46 JST
Epicenter Depth : 24 km (JMA), 32km (USGS)
Location : 38.103°N, 142.860°E (JMA, as of 2011-03-13)
Region : on the pacific coast along from Sanriku to Ibaraki coast,Japan
Fourth largest in the world since 1900, and the largest in Japan since modern instrumentation recordings began 130 years ago.
World’s largest earthquake
Sumatra 2004 (Mw9.0)
Chile 1960 (Mw9.5)
Chile 2010 (Mw8.8)
Alaska 1964 (Mw9.2)
Andreanov 1957 (Mw9.1)
Kamchatka 1957 (Mw9.0)
Tohoku Kanto 2011 (Mw9.0)
Source : Earthquake research institute (ERI Univ of Tokyo)
Casualty : Confirmed Death 11,620, unaccounted for 16,464 (until April 1, 2011)
Source: Geospatial Information Authority of Japan, http://www.gsi.go.jp/cais/topic110315-index-e.html
Vertical Deformation and Slip Distribution from model (prelimiary results) (Geospatial Information Authority of Japan)
source : Japan Meteorology Agency (JMA)Note: in some areas intensity are updated later on to larger value.
Observed JMA Seismic Intensity distribution
Tsunami Warning Issued right after the earthquake by JMA
Maximum Height of Tsunami, Measured and Simulated by Model (Yushiro Fujii (IISEE, BRI) and Kenji Satake (ERI, Univ. of Tokyo))
Solid lines in red and blue indicate the observed tsunami waveform and syntetic ones, respectivelySource: http://iisee.kenken.go.jp/staff/fujii/OffTohokuPacific2011/tsunami.html
Station Location Code Provider
Distance (km) PGA (xG)Horizontal
GroundmotionTo epicenter To Fault
TSUKIDATE MYG004 KNET 125.9 75.1 2.755SHIOGAMA MYG012 KNET 118.1 67.4 2.009
HITACHI IBR003 KNET 245.2 58.7 1.631SENDAI MYG013 KNET 126.1 71.8 1.548HOKOTA IBR013 KNET 292.3 77.8 1.383MOTEGI TCG014 KNET 276.8 87.7 1.23
HAGA TCGH16 KIKNET 283 95.1 1.221NISHIGOU FKSH10 KIKNET 238 106.3 1.084
OSHIKA MYG011 KNET 75.7 49.7 0.94YAMAMOTO MYGH10 KIKNET 136 67.9 0.889
MIYAKOJI FKSH19 KIKNET 173 69.1 0.874BATOU TCGH13 KIKNET 262 90.2 0.857
IWASE IBRH11 KIKNET 293 91.8 0.844MITO IBR006 KNET 275.3 70.8 0.802
GOZENYAMA IBRH15 KIKNET 268 78.7 0.797
TOHWA MYG003 KNET 103 59.2 0.797RIKUZENTAKATA IWTH27 KIKNET 107 54.3 0.753
KAMAISHI IWT007 KNET 114.3 49 0.711
UTATSU MYG002 KNET 87.2 52.1 0.671
SOHMA* FKS001 KNET 140 63.8 0.632
* SOHMA is located about 43 km from Fukushima Daiichi Power plant
List of Ground Motions with largest Horizontal Peak Acceleration (Data provided by K-Net and Kik-Net Service)
MYG: Miyagi prefecture, IBR/IBRH: Ibaraki, TCG: Tochigi, FKS/FKSH: Fukushima, IWT: Iwate
Taneichi
Kamaishi
Tsukidate
Shiogama
Sendai
Soma
Hitachi
Characteristics of ground motions (E-W)
Fault plane
Taneichi
Kamaishi
Tsukidate
Shiogama
Sendai
Soma
Hitachi
Characteristics of ground motions (N-S)
Fault plane
• Ground motions near the source display two remarkable phases of mainshock suggesting the existence of a least two areas of large slip.
• In the northern part of the source area the first phase is predominant, while in the southern part and in Kanto region, this phase is not visible.
• These two phases of ground motion suggest large slip areas in the North and South regions respectively.
Characteristics of ground motions (NIED preliminary report)
50 100 150 200 250 300-1000
0
1000
Time(s)
Acc
(cm
/s2 )
MYG004-EW
50 100 150 200 250 300
-2000
0
2000
Time(s)
Acc
(cm
/s2 )
MYG004-NS
0 50 100 150 200 250 300-2000
0
2000
Time(s)
Acc
(cm
/s2 )
MYG004-UD
Max =1.25 G
Max =2.75 G
Max =1.8 G
Records with largest PGA : Tsukidate Station, Miyagi. Distance to epicenter : 125.9 Km, Distance to Fault 75Km (K-NET)
Tohoku-Kanto 2011 Magnitude 9
Tsukidate Station, PGA = 2.75G(Seismic intensity 6.67 )
Hyogo-ken Nanbu earthquake (Kobe 1995) Magnitude 7.2 Kobe-JMA station , PGA=0.82GSeismic intensity 7
Two main shock events last for 2 minutes
One main shock event lasts for about 30 seconds
One main shock event lasts for about 20 seconds
Niigata-Chuetsu Earthquake (Oct 23, 2004) Magnitude 6.8 Ojiya station, PGA=1.33G Seismic intensity 7
Comparisons with the Kobe 1995 and Niigata Chuetsu 2004 Earthquakes
Acceleration amplitude and duration of shaking, this earthquake is much larger than Kobe 1995.
Records from Soma City about 43km from Fukushima Power Plant. Distance to epicenter 140km, distance to the fault 63 km (K-NET)
Reactor was designed to sustain maximum PGA 440 gals. TEPCO has planned to reinforce the reactors so they could withstand horizontal shaking of 600 gals, after the government reviewed their quake-resistance standards 5 years ago. But the work was not finished.Source: NHK-TEPCO (http://www3.nhk.or.jp/daily/english/01_39.html)
Acceleration Response Spectra for several large ground motions and comparison with the current Japanese code
Ground motion Type I is for plate boundary type large-scale earthquake
Ground motion Type II is for inland direct strike type earthquake, such as the Hyogo-ken Nanbu Earthquake (Kobe 1995) ,
Class (e.g.I and III) is divided according to ground condition, and the ones depicted on figure are the maximum for each type.
Accel amplitude for short period structure. are larger than the current code.
Ground motion Type I is for plate boundary type large-scale earthquake
Ground motion Type II is for inland direct strike type earthquake, such as the Hyogo-ken Nanbu Earthquake (Kobe 1995) ,
Class (e.g.I and III) is divided according to ground condition, and the ones depicted on figure are the maximum for each type.
Acceleration Response Spectra for several large ground motions and comparison with the current Japanese code
Accel amplitude for long period structures (highrise building, long-span bridge) are smaller than the current code.
Comparison of Tohoku-Kanto 2011 Response Spectrum to other recent large earthquake in Japan
Envelope of Kobe 1995 Spectra
Envelope of Tohoku-Kanto 2011 Spectra
Compared to Kobe 1995 earthquake, the Tohoku-Kanto 2011 spectra :
1.contains larger amplitude for short period oscillation (less than 0.5 sec or higher than 2Hz), but smaller amplitude for structure with longer period (larger than 0.5sec).2.Has the maximum PGA of almost 3 times the maximum PGA of Kobe 19953.has narrower range for large spectra amplitude (0.2 – 0.4 sec), while the Kobe spectra has a very wide range of large amplitude (0.2 – 2 sec).
Comparison with world’s well-known earthquakes
Station Location Code ProviderDistance (km) PGA (xG)
To epicenter To Fault Horizontal
Groundmotion Matsudo (Chiba) CHB002 KNET 356.7 136.1 0.290
Mizue (Tokyo) TKY027 KNET 365.7 143.4 0.216Shiohama (Tokyo) TKY020 KNET 372.6 150.4 0.147Sunamachi (Tokyo) TKY013 KNET 371.8 149.3 0.144Shinonome (Tokyo) TKY016 KNET 374.7 152.3 0.164
Urayasu (Chiba) CHB008 KNET 368.7 145.6 0.160Chiba City (Chiba) CHB009 KNET 362 138 0.183
Yokohama (Kanagawa) KNG002 KNET 402.4 178.1 0.168Kawaguchi (Saitama) SIT011 KNET 364.9 146.8 0.184
Ground motions recorded near Tokyo metropolitan area
Acceleration Response Spectra for several ground motions in Tokyo metropolitan area
Acceleration Response Spectra for several ground motions around Tokyo metropolitan area
Acceleration Response Spectra for several ground motions in and around Tokyo Metropolitan area and comparison with Building Code
Long Period Ground Motion Characteristics recorded in Tokyo metropolitan area
Long period shaking for about 1.5 minuteis a particular concern to high-rise buildings and long-span bridges
Long Period Ground Motion Characteristics recorded in Tokyo metropolitan area
Sunamachi (K-NET Data)
Dominated by Less than 1Hz vibration
Long Period Ground Motion Characteristics recorded in Tokyo metropolitan area
Shiohama (K-NET Data)
Long Period Ground Motion Characteristics recorded in Tokyo metropolitan area
Urayasu city (K-Net Data)
Displacement Response Estimation of High-rise Building in Tokyo area
Surveyed from 256 Buildings in Japan. (Miyakoshi & Horike 2008)
The responses of top floor due Tohoku-Kanto Earthquake is calculated using the following assumptions:
1.One story height is 3m. 2.Predominant Natural period of building follows the relationship: T= 0.023 H (height m)3.The building response can be modeled by SDOF response with predominant natural period as defined in (2)4.Structural system remains linear throughout the excitation5.Damping ratio 5%
Input Ground motion TKY013-EW
Response Estimation of High-rise Buildings in Tokyo area : Sunamachi
Intense shaking for about 2 minutes
Input Ground motion CHB008-EW
Response Estimation of High-rise Building in Tokyo area : Urayasu
Intense shaking for about 1.5-2 minutes
Input Ground motion TKY020-EW (KNEt Data)
Response Estimation of High-rise Building in Tokyo area : Shiohama
Intense shaking for about 1.5-2 minutes
Response Estimation of High-rise Building in Tokyo area : Hongo, Bunkyo-ku
Input Ground motion Univ. of Tokyo UTK (BRI Data)
Intense shaking for about 1.5 minutes
Drop in vibration frequency indicating the structural softening when the base isolation/sliding system starts to engage
Structural first frequency in small (linear) excitation
Measured response of a base-isolation 14-story building in Tokyo area
Measured girder response of a long-span cable-stayed bridge in Kanto area(midspan length : 460m)
Max vertical disp 19.5cm
Max transverse disp 61.8cm
Max long disp 24.5cm
DisclaimerUnless mentioned otherwise, charts, figures, and computations are
produced by author.Others are compiled from the following data source :
Seismographs network in Japan : K-Net Japan, KikNet, Building Research Institute Japan (BRI)Japan Meteorology Agency, Geospatial Information Agency of Japan, Earthquake Research Institute (ERI Univ of Tokyo), NHK, TEPCO
Tokyo 2011-04-0114:46
:.
2011-03-1114:46
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