高密度常時微動計測・臨時地震観測に基づく南海トラフ巨大地震における和歌山県広川町での津波避難不可能時間算出のための強震動評価  [in Japanese] PREDICTION OF STRONG MOTION AND DIFFICULT TIME FOR TSUNAMI EVACUATION WITH HIGH DENSITY IN HIROKAWA TOWN, WAKAYAMA PREFECTURE, JAPAN, DURING A SCENARIO EARTHQUAKE WITH <i>M</i><sub>W</sub>9.0 ALONG THE NANKAI TROUGH BASED ON THE SMGA MODELS CONSIDERING LOCAL SITE EFFECTS  [in Japanese]

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Abstract

本稿では,南海トラフ巨大地震において巨大津波の来襲が懸念されている和歌山県広川町の街地・平地を対象地域として,強震動の作用が津波避難に及ぼす影響について基礎的な検討を行った.その際,当該地域において臨時地震観測ならびに常時微動計測を高密度に行い,得られた観測・計測結果に基づきサイト増幅特性を評価することで,南海トラフ巨大地震によって当該地域に作用する強震動を高密度に予測した.その結果,サイト増幅特性の差異に主に起因して,当該地域内での予測地震動の特性に有意な差異が見受けられること,強震動の作用が津波避難に及ぼす影響が比較的大きいことなどが明らかとなった.

 During a scenario earthquake with <i>M</i><sub>W</sub>9.0 along the Nankai Trough, not only strong motion but also huge tsunami is predicted in Hirokawa Town, Wakayama Prefecture, Japan. In this study, first, based on the empirical relationship between microtremor H/V spectrum and site amplification factor, the site amplification factors from seismic bedrock to ground surface at the 476 sites in the tsunami attack area were evaluated. Seismic waveforms in the area were then predicted with very high density based on the SMGA models considering the empirical site amplification factors. Using the detailed distribution of JMA seismic intensity and difficult time for tsunami evacuation due to the predicted seismic waveforms, finally, we discussed the influence which the action of the strong motion has on evacuation.

Journal

  • Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE))

    Journal of Japan Society of Civil Engineers, Ser. A1 (Structural Engineering & Earthquake Engineering (SE/EE)) 72(4), I_68-I_81, 2016

    Japan Society of Civil Engineers

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