Article,
Evaluating critical rainfall conditions for large-scale landslides by detecting event times from seismic records
Natural Hazards and Earth System Sciences Discussions, (2018)
DOI: https://doi.org/10.5194/nhess-2018-126
Abstract
<p><strong>Abstract.</strong> One of the purposes of slope disaster research is to establish an early warning method for rainfall-induced landslides. The insufficient observational records of the past, however, have inhibited the analysis of critical rainfall conditions. This dilemma may be resolved by extracting the times of landslide occurrences from the seismic signals recorded by adjacent seismic stations. In this study, the seismic records of the Broadband Array in Taiwan for Seismology (BATS) were examined to identify the ground motion triggered by large-scale landslides occurring from 2005 to 2014. After the signals from local and teleseismic earthquakes were eliminated, 62 landslide-induced seismic signals were identified. The seismic signals provided the occurrence times of the landslides for assessment of the rainfall conditions, including rainfall intensity (<i>I</i>, mm/h), duration (<i>D</i>, h), and cumulated rainfall (<i>R</i>, mm). Comparison of three common rainfall threshold models (<i>I</i>–<i>D</i>, <i>I</i>–<i>R</i>, and <i>R</i>–<i>D</i>) revealed duration and cumulated rainfall to be the crucial factors in developing a forecast warning model. In addition, a critical volume of water model, (<i>I</i><span class="thinspace"></span>−<span class="thinspace"></span>1.04)<span class="thinspace"></span>·<span class="thinspace"></span><i>D</i><span class="thinspace"></span>=<span class="thinspace"></span>452<span class="thinspace"></span>mm, combining statistical and deterministic approaches was established through analysis of rainfall information from the 62 large-scale landslides that occurred.</p>
