title: Seismology-based early identification of dam-formation landquake events.
abstract: 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.
authors.affiliation: Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan.
authors.forename: Wei-An
authors.initials: WA
authors.lastname: Chao
authors.affiliation: Institute of Earth Sciences, Academia Sinica, Nankang, Taipei 11529, Taiwan.
authors.forename: Li
authors.initials: L
authors.lastname: Zhao
authors.affiliation: Department of Soil and Water Conservation, National Chung Hsing University, Taichung 40227, Taiwan.
authors.forename: Su-Chin
authors.initials: SC
authors.lastname: Chen
authors.affiliation: Department of Geosciences, National Taiwan University, Taipei 10617, Taiwan.|National Center for Research on Earthquake Engineering, National Applied Research Laboratories, Taipei 10668, Taiwan.
authors.forename: Yih-Min
authors.initials: YM
authors.lastname: Wu
authors.affiliation: Central Geological Survey, MOEA, Taipei 23568, Taiwan.
authors.forename: Chi-Hsuan
authors.initials: CH
authors.lastname: Chen
authors.affiliation: Department of Geology and Geophysics, University of Utah, Salt Lake City, USA.|Seismological Laboratory, California Institute of Technology, Pasadena, CA 91125, USA.
authors.forename: Hsin-Hua
authors.initials: HH
authors.lastname: Huang