SEGJ Technical Conference

Ultra-high density questionnaire seismic intensity survey and ground vibration characteristics by microtremor observations in Ichinoseki City of Iwate Prefecture, for the 2011 off the Pacific coast of Tohoku Earthquake and the aftershock occurred at April 7 in 2011

Abstract To clarify the vibration characteristics in ichinoseki City of Iwate Prefecture, the survey of seismic intensity was done using questionnaires for both the 2011 off the Pacific coast of Tohoku Earthquake and the aftershock occurred at April 7, 2011. However, in the area many houses were damaged by a main shoch and aftershock on April 7. In the Akaogi area located in western Ichinoseki, it turned out1111, that it is large. And, microtremor observations were done at 89 points where seismic intensity were estimated, using a three-component seismometer. Averaged amplitudes, predominant periods and H/V spectra of observed microtremors were examined.In the Akaogi area, it turned out that a H/V peak and excellence frequency serve as a large value, and it becomes a value small in Yamamemachi and the Yamanome area. It is thought that a ground shaking amplification factor becomes large with a high-frequency belt, and, as for a Akaogi area, an amplification factor becomes large with a low frequency belt in Yamanome and a Yamamemachi area.