A Comparison of Spatial Distribution of Storm-Triggered and Earthquake-Triggered Landslides--The Case of the Chenyulan Drainage Basin
Resource
地理學報, 35, 001-016
Journal
地理學報
Journal Issue
35
Pages
001-016
Date Issued
2004-03
Date
2004-03
Author(s)
Chang, T.Y.
Hsu, M.L.
Abstract
Heavy rainfalls and earthquakes are the most important triggers for landslides in Taiwan. This study aims to compare the spatial distribution and characteristics of landslides triggered by Typhoon Herb and the Chi-Chi Earthquake. Applying GIS techniques. Geomorphological and geological information Contained in aerial photos, maps and digital elevation model (DEM) are analyzed. Through aerial photo interpretation, we have identified 217 slope failures induced by Typhoon Herb on July 31, 1996 and 229 landslides triggered by the Chi-Chi Earthquake on September 21, 1999. The spatial distribution and morphological characteristics of the landslides triggered by the two events are analyzed. The results show:(1)Landslides triggered by the Chi-Chi Earthquake are mostly located in sedimentary formations while slope failures induced by Typhoon Herb are randomly distributed regardless of geology; (2) Landslides triggered by the earthquake are mostly located on slopes with 39 to 45 degree inclination, while those triggered by Typhoon Herb are mostly on 30 to 41 degree slopes; (3) Landslides induced by the earthquake are on slopes with a contributing area of less than 1 hectare, while those induced by the typhoon are on slopes with a contributing area of larger than 1 hectare; and (4) Due to topographic magnification of seismic waves, earthquake-induced landslides in the region of sedimentary formations tend to occur on the hill tops. While in the region of metamorphic formations most of them are found at the foot of slopes.
Subjects
地震
崩塌
降雨
陳有蘭溪
集流面積
Landslides
Rainfall
Earthquake
Chenyulan
Contributing area
Type
journal article
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