Poster

[DM-P-03] Comparison of house damage and microtremor results in past earthquakes

*Tsutomu Ochiai¹, Takahisa Enomoto¹, Yoshiya Oda², Michio Miyano³, Eisuke Ikuta³, Manuel Navarro⁴ (1. Kanagawa University (Japan), 2. Tokyo Metropolitan University (Japan), 3. Osaka City University (Japan), 4. Almeria University (Spain))

Generally, The seismic ground motion consists of seismic source, path, and site amplification characteristics. In this paper, we will focus on the site amplification characteristics. We will compare the H/V spectrum ratio (hereinafter referred to as MHVR) obtained from the microtremor observation results and the simple ground hazard value obtained from MHVR with the house damage caused by past earthquakes. Next, from there, the validity of a simple ground hazard value evaluation method using microtremors will be examined. In this paper, we targeted the 1974 Izu-Hanto-Oki Earthquake and the 1995 Hyogoken Nanbu Earthquake. In the Izu area, the difference in house damage caused by the earthquake is considered to be the effect of ground characteristics. In Iruma, the characteristics of house damage were consistent with the MHVR and simple ground hazard value obtained from microtremors. On the other hand, in Irozaki, where the difference in house damage is considered to be the effect of fault activity rather than the ground characteristics, the difference in, microtremor results within the area is small. In the Kobe area, the predominant periods and the simple ground hazard value tended to increase in the damaged area (B area). It is not enough to analyze the large and small damage based on the results of constant microtremor observations, and it is necessary to consider local effects such as irregularities in the underground structure and the existence of faults. In the future, we would like to proceed with similar studies in different earthquakes and regions.