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| Rainfall and landslides caused by Typhoon Morakot in Southern Taiwan |
| LI Meng-Xi, JIANG Quan-Feng, LIN Huan-Han |
| (Department of Soil & Water Conservation, National Pingtung University of Science & Technology, 91201,Pingtung, Taiwan, China) |
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Abstract The purpose of this study is to discuss the relationship between the heavy rainfall and the massive landslides caused by Typhoon Morakot,which killed more than 500 people in southern Taiwan.The landslide areas induced by the heavy rainfalls were identified by the satellite image analyses and the rainfall conditions, including the rainfall intensity, the cumulative rainfall, the rainfall duration and the return period of the rainfall were also analyzed in Gaoping river watershed during Typhoon Morakot. The results show:1)The rainfall characteristics of Typhoon Morakot are long duration rainfall (mean value= 3.3 d), huge rain accumulation (mean value=1 677 mm) and high intensity rainfall (mean value=80.5 mm/ h);2) The 48-hour rainfall record (2 319 mm) at Welliaoshan station approaches the record in Taiwan (2 361 mm); 3)The estimated return periods of maximum rainfall intensity from 10-hour to 72-hour at Sinan, Welliaoshan, and Yuyoushan stations during Typhoon Morakot well exceeded 200 years of Welliaoshan station; 4) After Typhoon Morakot, the increased landslide areas and landslide rate were 141.24 km2 and 4.92%. The landslide rate increased with the cumulative rainfall and the rainfall intensity.
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Received: 11 November 2011
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