Application Of Surface-Wave Method To The Evaluation Of Local Site Effect Of 2007 Noto Earthquake

Autor: Koichi Hayashi, Tsutomu Hirade, Yu Shizhou, Kosh Nath Adhikari, Masahito Tamura
Rok vydání: 2008
Předmět:
Zdroj: 21st EEGS Symposium on the Application of Geophysics to Engineering and Environmental Problems.
DOI: 10.3997/2214-4609-pdb.177.61
Popis: A surface-wave method and micro-tremor array measurements have been carried out at Central Anamizu, Ishikawa Prefecture, Japan in order to investigate local site effect of earthquake in terms of near surface S-wave velocity model. Many houses were collapsed or severely damaged by the 2007 Noto Earthquake at the Central Anamizu. Collapsed or damaged houses were concentrated around the K-NET Anamizu strong ground motion observation station. It seems that the near surface heterogeneity may strongly affect surface ground motion during the earthquake. The investigation result shows that S-wave velocity down to the depth of 20m has strong heterogeneity at the site. Low velocity layer, in which S-wave velocity is 60m/s, beneath the K-NET Anamizu disappears at the other side of the park only 50m away from the K-NET. Swedish ram soundings were also carried out round the K-NET and the results agreed with one of surface-wave method very well. Two-dimensional site amplification was calculated by finite-difference method using the S-wave velocity model obtained through the investigation. The calculation shows that near-surface heterogeneity strongly affects amplification of the site.
Databáze: OpenAIRE