We estimated wave speeds of the tsunami triggered by the 2011 Great East Japan Earthquake, using a large number of video files. Speeds of car and people during evacuation were also estimated from the videos at 26 sites in 13 areas in the Tohoku region. The estimated wave speeds at ocean near coast is 21m/s, while speed on land is 11m/s. On the other hand, the estimated speeds of car and human are 14m/s and 3m/s, respectively. Then, we referred to the results of interviews to people evacuated from the tsunami damage. Furthermore we evaluated the tsunami’s arrival time and compared its relation with evacuation time. Based on the results, the evacuation being started at about 30 minutes after the occurrence of the earthquake, and in fact, it had to be necessary to begin evacuation action within a few minutes of the Earthquake’s occurrence. It is necessary to evacuate immediately after an major thrust earthquake that may occur in the Pacific coast. For this purpose, education and training regarding basic tsunami information transmission is required.

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Optical satellite images are widely used to detect building damage due natural disasters in the world. However, since optical satellites images are mostly acquired from the vertical direction, they can observe only the roofs of buildings. Building damage such as to side-walls or mid-story collapse is often overlooked because the upper surfaces of buildings do not change too much in the vertical view. This paper proposes the method to detect this kind of building damage from the change in layover effects and radar shadow in SAR intensity images.Multi-temporal TerraSAR-X images covering Sendai-Shiogama Port and Fukushima No. 1 Nuclear Power Plant were employed to detect building damages due to tsunamis and hydrogen explosions after the 2011 Tohoku, Japan earthquake. The difference in backscattering coefficients before and after the event in layover and radar-shadow areas could show the damages to side-walls of buildings located in these sites.

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The seismic behavior of railway vehicle was investigated to consider the mechanism of derailment by an earthquake. A scale of 1 to 10 railway vehicle model was vibrated by five types of seismic wave, which are Off Tokachi Earthquake, Niigata Prefecture Chuetsu Earthquake, Noto Peninsula Earthquake, Niigata Prefecture Off Chuetsu Earthquake and Iwate Miyagi Inland Earthquake. The speed of the vibrated model were 0km/h, 3km/h, 6km/h and 9km/h. For each condition, the model was vibrated ten times and derailment probabilities were found. By this study, it was shown that derailment probabilities tend to be higher when railway vehicle is running. Also, it was found that limits of effective value of input and response acceleration are different for stopping vehicle and running vehicle.

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In order to build an earthquake observation system that everyone can use, we construct a sensor network system by utilizing a cloud system. The sensor network system can archive seismic response information on tens of thousands of residential buildings. In this system, once a sensor is settled and communication is established, sensor information and earthquake records will be uploaded automatically on cloud. Then, public can see sensor information and observed waveforms, as well as download waveforms through the Internet. On the other hand, the house owner does not have to construct and maintain a data server. We installed dozens system for ordinary homes in Fujisawa and Nagaoka cities, and conducted a proof experiment. In this paper, we compare records observed by professional seismographs and the MEMS accelerometers built in the small mobile hand-held device.

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We carried out damage investigation around the seismic stations where high JMA seismic intensity scales were recorded in the 2011 off the Pacific Coast of Tohoku Earthquake and reported damage situation in Miyagi. We found some heavily damaged buildings around some stations, such as JMA Osaki-Shi-Furukawamikka-Machi, and some minor damage such as small damage to the wall or damaged roof tiles, but we found few heavy damage to buildings around most the seismic stations in spite of large JMA seismic scales. We investigated properties of strong ground motions and found very short period below 0.5 second was dominated in most strong ground motions and the 1-1.5 second response which has close relationship with heavy damage to buildings was low.

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We carried out damage investigation around the seismic stations where high JMA seismic intensity scales were recorded in the 2011 off the Pacific Coast of Tohoku Earthquake and reported damage situation in Ibaraki, Tochigi, and Fukushima. We found some minor damage such as small damage to the wall or damaged roof tiles, but we found few heavy damage to buildings around most the seismic stations in spite of large JMA seismic scales.

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