Dynamic Analysis on Rainfall-Induced Landslide Activity in High Seismic Intensity Areas of the Wenchuan Earthquake Using Remote Sensing Image
TANG Chuan
QI Xin
DING Jun
YANG Tai-ping
LUO Zhen-fu
Abstract：A catastrophic earthquake always intensively disturbs ground strata and affects the slope stability for a long period of time. The Wenchuan earthquake not only triggered serious coseismic landslides, but also extensively accelerated the landslide activity during the subsequent heavy rains. Based on the interpretation of high resolution of aerial photographs, 1214 landslides are identified, most of which are shallow landslides, rock falls, and rock slides triggered in the high seismic intensity region of the Wenchuan earthquake near the Beichuan City and along the valleys of the Jianjiang River. A heavy rainfall on 24 September, 2008 triggered more landslides and debris flows in the central part of the area affected by the Wenchuan earthquake. The accumulated precipitation triggering landslides and debris flows is 272. 7 mm in two days, while the rainfall amount and intensity recorded in this area have a return period of about 20 years. 878 new landslides in the study area of 340 kmz are identified by interpretation of SPOT images. To understand the impact of the Wenchuan earthquake on the landslide occurrence due to subsequent heavy rainfall, this study mainly focuses on the variations in the the density of coseismic landslides and following rainfall-induced landslides through aerial photographs and SPOT images. Comparison of aerial photographs taken on 18 May, 2008(after the "5·12" Wenchuan earthquake) and SPOT images taken on 14 October, 2008 (after "9·24" rainstorm event) indicates that the landslide number in the study area increases by 42%, while landslide area increases by 46. 6%, which shows the great impact of the heavy rainfall after the earthquake on the development and activity of landslides in the study area. The above study results also show that the Wenehuan earthquake affected area is particularly susceptible to landslides and debris flow occurrence after extreme rainfall events.
Keywords：Wenchuan earthquakelandslide activityremote sensing imageheavy rainfallintepretation.
Publication Date：2010-01-01
Online Publishing Date：2025-08-15(First online date of this platform, not the publication date of the document)
Pages：7( 317-323 )