Characteristics of hazards induced by extremely heavy rainfall in Central Taiwan - Typhoon Herb

In 1996, Typhoon Herb devastated Taiwan, moving across the northwestern part of the island. Historically, typhoons traveling such a route have frequently caused worse damage than typhoons on other routes. Herb brought record-breaking precipitation to Taiwan, especially the central part of the island. The heavy rainfall led to more than 1315 landslides and 20 debris flows. Seventy-three lives were lost, 463 people were wounded, and property losses of about 1 billion USD were sustained. This study presents the distinct characteristics of Typhoon Herb as well as the induced hazards, including their extraordinary size and recurrent nature. The focus is on central Taiwan, where the severest hazards were encountered. Furthermore, the geological, geomorphologic and engineering factors, which may have magnified the consequences of the hazards, are also discussed. A comparison of hazards in other countries is also made and the results indicate that the extremely heavy rainfall encountered as well as the existence of a boundary fault in the study area are the most susceptible factors inducing the extraordinary hazards. (C) 2000 Elsevier Science B.V. All rights reserved.