Seismology-based early identification of dam-formation landquake events.
Seismology-based early identification of dam-formation landquake events.
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DOI：
10.1038/srep19259
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发表时间：
2016-01-12
影响因子：
4.6
通讯作者：
Huang HH
中科院分区：
文献类型：
--
作者：
Chao WA;Zhao L;Chen SC;Wu YM;Chen CH;Huang HH
岩崩、山体滑坡和泥石流等陆地地震事件造成的水坝溃决而引发洪水，可能导致严重的河岸侵蚀和河流附近人口稠密地区的淹没。地震波可以由陆地地震事件产生，陆地地震事件可以被描述为作用在地球上的与时间相关的力（卸载/重新加载周期）。在本研究中，我们对十个事件的陆地地震力历史（LFH）进行了长周期（LP，周期≥20秒）波形的反演，这提供了边坡破坏的起始、传播和终止阶段的定量特征。当将LP波形获得的结果与高频（HF，1–3 Hz）地震信号一起分析时，我们发现在最近台站的HF波形中清楚地记录了相对较强的晚至地震相位（称为筑坝相位或D相位），这可能标志着崩塌体滑入河流甚至可能撞击对岸地形屏障的时间。因此，我们在本研究中开发的分析LP和HF波形的方法具有很高的潜力，可以利用宽带地震记录近乎实时地识别五次筑坝陆地地震事件（DFLE），从而可以及时向下游居民提供即将发生的洪水的警告。
Flooding resulting from the bursting of dams formed by landquake events such as rock avalanches, landslides and debris flows can lead to serious bank erosion and inundation of populated areas near rivers. Seismic waves can be generated by landquake events which can be described as time-dependent forces (unloading/reloading cycles) acting on the Earth. In this study, we conduct inversions of long-period (LP, period ≥20 s) waveforms for the landquake force histories (LFHs) of ten events, which provide quantitative characterization of the initiation, propagation and termination stages of the slope failures. When the results obtained from LP waveforms are analyzed together with high-frequency (HF, 1–3 Hz) seismic signals, we find a relatively strong late-arriving seismic phase (dubbed Dam-forming phase or D-phase) recorded clearly in the HF waveforms at the closest stations, which potentially marks the time when the collapsed masses sliding into river and perhaps even impacting the topographic barrier on the opposite bank. Consequently, our approach to analyzing the LP and HF waveforms developed in this study has a high potential for identifying five dam-forming landquake events (DFLEs) in near real-time using broadband seismic records, which can provide timely warnings of the impending floods to downstream residents.