豪雨觸發之大規模山崩的降雨條件分析

Rainfall Triggering Threshold for Large Scale Landslides

林冠瑋(Guan-Wei Lin) ； 顏心儀(Hsin-Yi Yen) ； 郭賢立(Hsien-Li Kuo)

《工程環境會刊》 35期 (2015/07) Pp. 1-16

https://doi.org/10.6562/JEE.2015.35.1

摘要

本研究是針對2005年至2009年間，481處因降雨而發生大規模山崩（面積大於0.1平方公里），所進行之台灣寬頻地震網地動訊號的分析工作。收集的資料在排除區域地震與遠震的時間後,判釋出45個因崩塌作用產生之地動訊號。藉由地動訊號對應之崩塌發生的時間資訊，並配合各項降雨資料，來進行大規模崩塌發生之降雨條件的分析。統計分析的結果顯示，大規模山崩的發生與累積降雨量的多寡有一定的相關性，其降雨門檻值也明顯高於淺層崩塌。在24小時的降雨條件下，70%大規模山崩之發生機率，所需之有效累積降雨量大約為1345 mm。

關鍵字

大規模崩塌 ； 地動訊號 ； 降雨門檻

並列摘要

The study collected the seismic records of the Boradband Array in Taiwan for Seismology (BATS) to identify the ground motion probably triggered by totally 481 large landslides having areas larger than 0.1 km^2 from 2005-2009. After eliminating the signals from local and teleseismic earthquakes, 45 landslide-triggered seismic signals were interpretated. The landslide-triggered seismic signals provided accuracte timing of landslide initation to assess the rainfall conditions for large landslide. The preliminary results about critical rainfall for large landslides includes (1) the amount of cumulative rainfall is the major factor to trigger large landslide, (2) the I-D rainfall threshold for large landslide is significantly higher than that for shallow landslides, and (3) the amount of effective cumulative rainfall for 70% occurrence probability for large landslides should be 1345 mm.

並列關鍵字

Large Scale Landslide ； Seismic Signal ； Rainfall Threshold