日本地球惑星科学連合2019年大会

講演情報

[E] ポスター発表

セッション記号 H (地球人間圏科学) » H-DS 防災地球科学

[H-DS09] 地すべりおよび関連現象

2019年5月28日(火) 17:15 〜 18:30 ポスター会場 (幕張メッセ国際展示場 8ホール)

コンビーナ:千木良 雅弘(京都大学防災研究所)、王 功輝(京都大学防災研究所)、今泉 文寿(静岡大学農学部)

[HDS09-P02] A comparison between the acoustic signals and seismic signals generated during a dam-break test

★Invited Papers

*Zheng-yi Feng1Hao-yang Huang1Chia-Ming Chuang1 (1.Department of Soil and Water Conservation, National Chung Hsing University, Taichung, Taiwan)

キーワード:dam break, landslide, slope, acoustic signal, seismic signal, flood

Natural events, such as landslide, sediment transport, flooding, etc., usually release energy to produce acoustic waves and seismic waves. Acoustic wave is transmitted through air and seismic wave is transmitted through geologic structure. Therefore, the characteristics of acoustic waves and the seismic waves induced by these events should be different. This study focus on the differences in the acoustic signals and seismic signals during a dam-break test performed by the authors. We built a model dam and slope in a creek for the test. We filled the dam with water and caused it to overflow. The overflow water caused the downward erosion of the dam. The flood due to the dam-break eroded the toe of the model slope causing the slope to collapse locally. We set up microphones to collect acoustic signals and installed accelerometers to collect vertical seismic signals generated by the flood and collapse events during the test. During the test we also used unmanned aerial vehicle (UAV) to continuously take photos for the collapsed areas for making the digital surface model (DSM) of the slope to analyze the volumes of the collapsed materials. We used Hilbert-Huang Transform (HHT) to obtain the time-frequency spectra for the acoustic signals and seismic signals. From the spectra, we compared the energy and frequency content of the two kinds of signals and their differences. The results show that the acoustic signal showing earlier indication of overtopping than that of the seismic signal. In addition, the acoustic and seismic signals generated during the flood can correspond to each other. The collapse events of the slope during the flood can be investigated also by examining the time-frequency spectrum of the seismic signal. Usually the signals of the collapse events can be distinguished from the flooding signals.