SEGJ Technical Conference

Vibration characteristics of the campus, Building 9, Tokyo Metropolitan University Minami-Osawa, before and after The 2011 off the Pacific coast of Tohoku Earthquake by microtremor observation

Abstract To evaluate quantitatively about the extent to which the damaged structure after the occurrence of large earthquakes, it is very important in considering the risk assessment and after repair. In this study, microtremor data was observed before and after off the Pacific coast of Tohoku Earthquake Building 9 Campus Minami-Osawa, Tokyo Metropolitan University in (Bldg. 9 below), attempted to extract the vibration characteristics by seismic interferometry, the analysis results before and after the earthquake there by comparison, made it clear what has changed how the vibration characteristics of Building 9 at the before and after the earthquake that occurred on March 11, 2011. As a result, it was found that the natural frequency of the Building 9 is reduced about 16%, shear wave velocity is approximately 24% decline, decay Q value is declined about 7%.