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March 11, 2011 M9.0 Tohoku, Japan Earthquake

Erol Kalkan, U.S. Geological Survey, Menlo Park, ekalkan@usgs.gov

Volkan Sevilgen, Seismicity.net , San Carlos, CA vsevilgen@usgs.gov

日本語要約

2011年3月11日に、東北地方太平洋沖地震(M9.0)が沈み込む太平洋プレートと北 米プレートとの境界部で発生した。破壊は、長さ500km, 幅200kmの断層に沿って 5分間続き、日本列島周辺での有史における最大級の地震の1つとなった。解析に は、防災科学技術研究所の273点のK-NET観測点および112点のKiK-net観測点 (2011年3月25日時点)における強震記録を使用した。KiK-net観測点には、100m 以上の深さのボアホールの底と地表に強震計が設置されている。K-NET観測点に は地表のみに設置されている。水平方向の最大の加速度は、断層面から約75.1km に位置する宮城県の観測点で記録され、重力の2.7倍であった。断層面から151km 離れた東京においても、水平方向に重力の5分の1の大きさの加速度が記録された。

Plain English Summary

March 11, 2011 Tohoku earthquake M=9.0 occurred on the subduction plate boundary between the Pacific and North American plates. The rupture lasted for 5 minutes along the 500 km long and 200 km wide fault which created one of the largest known earthquakes in and around Japan. The plots below use the Japanese strong motion recordings from 273 K-NET and 112 KiK-net stations (as of March 25, 2011) of NIED. KiK-net stations are located at the surface which subject to more soft soil amplification than the downhole stations (at 100 m depth) at the same location. Knet stations are located only at the surface. The strongest horizontal shaking recorded was 2.7 times larger than gravity at Miyagi prefecture located at about 75.1 km of the fault. In Tokyo, which is 151 km away from the fault, horizontal ground shaking recorded was one fifth of gravity.

Resumen Español

El 11 de marzo 2011 en la frontera de subducción entre la placas pacifica y norteamericana se produjo el terremoto Tohoku de magnitud 9,0. La ruptura se prolongó durante 5 minutos a lo largo de un área de 500x200 kilómetros cuadrados generando uno de los mayores terremotos conocidos dentro y alrededor de Japón. Las figuras mostradas a continuación utilizan registros japoneses de movimiento fuerte obtenidos de 273 estaciones K-net y 112 estaciones KiK-net (al 25 de marzo de 2011) de la red NIED. Las estaciones KiK-net superficiales fueron sometidas a mayores amplificaciones de suelo blando que las estaciones a 100 m de profundidad (downhole stations) en el mismo lugar. Las estaciones K-net están ubicadas solamente en la superficie. Las más fuertes aceleraciones horizontales registradas fueron 2,7 veces mayores que la aceleración de la gravedad en la prefectura de Miyagi, ubicada a unos 75,1 kilómetros de la falla. En Tokio, que esta a 151 km de la falla, las aceleraciones horizontales registradas fueron de un quinto de la aceleración de la gravedad.

Turkce Ozet

Büyüklüğü 9 olan 11 Mart 2011 Tohoku depremi Kuzey Amerika ile Pasifik plakaları arasındaki yitim plaka sınırında meydana gelmiştir. Uzunluğu 500 genişliği 200 kilometre olan fayın 5 dakika süreyle kırılmasıyla oluşan bu deprem Japonya'nın bilinen en büyük yer sarsıntılarından birisidir. Aşağıdaki şekillerde kullanılan kuvvetli yer hareketi kayıtları, Japonya'nın 273 K-NET ve 112 KIK-net istasyonlarından elde edilmiştir. KiK-net istasyonları hem yüzeyde hem de kuyu içinde 100 m derinlikte kayıtçılara sahiptir. Yüzeyde ölçülen KiK-net değerlerinin daha yüksek olması zemin büyütmesinden kaynaklanmaktadır. Bu depremde kaydedilmiş en yüksek yatay yer hareketi, faya yaklaşık 75,1 km uzaklıktaki Miyagi vilayetinde yerçekiminin 2.7 katı olarak gerçekleşmiştir. Faydan 151 km uzaklıkta bulunan Tokyo ise yerçekiminin beşte biri kadar kuvvetle sallanmıştır.

Top 5 Ground Motion Records (Acceleration, Velocity, Displacement and Response Spectra Plots) (3.9 Mb) (March 25, 2011)

最大加速度上位5観測点における地震動(加速度、速度、変位、応答スペクトル)

Los 5 mejores registros sísmicos (graficas de aceleración, velocidad, desplazamiento y espectros de Respuesta

En yuksek ivmeli 5 kayit icin(ivme, hiz ve deplasman egrileri ve tepki spektrumlari)


Tohoku Earthquake Peak Ground Acceleration (PGA) Maps for Japan and Tokyo Metropolitan Area (6 Mb) (March 17, 2011)

東北地方太平洋沖地震で観測された最大加速度(PGA)

Mapas de aceleración máxima del terreno (PGA) para Japón y el área metropolitana de Tokio registradas durante el terremoto de Tohoku

Japonya ve Tokyo icin Tohoku depreminin olusturdugu en yuksek ivme degerleri haritalari

K-NET and KiK-net Data on Google-Earth (click to see processed wave-forms, PGA, PGV, PGD and Spectra Accelerations from 0.2 to 10 s)

 

 

STRONG MOTION RECORDINGS OF THE M9.0 TOHOKU EARTHQUAKE

The largest peak ground acceleration (PGA) of 2.7 g was recorded in the North-South direction at Miyagi prefecture - MYG04 station located at 75.1 km of the fault ( vectorized PDF of this figure is available here, 102 Kb)

Location of near-source strong motion stations; shown also is the source process (Figure is taken from NIED event summary page)


Downloadable Material

K-NET Data (273 Stations)

KiK-net Data (112 Stations)

Peak Table of Unprocessed Records (Excel File)

Peak Table of Unprocessed Records (Excel File)

Acknowledgment

Original strong motion data is obtained from K-NET and KiK-net of NIED, JAPAN. Special thanks are extended to NIED for making the strong motion data available immediately after the earthquake. We also wish to thank Dr. Makoto Matsubara for Japanese and Dr. Juan Carlos Reyes for Spanish translations

 

 

 

 

 

 

 

 

For technical support please contact Volkan Sevilgen, USGS

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