Advances of Geo-Disaster Mitigation Technologies in Taiwan

Abstract

Taiwan is located in the typhoon district of the Pacific Ocean and is hit by typhoons averaged 3.6 times annually. Many large scale hillside development projects were undertaken in the past decades. These areas have become very vulnerable to natural hazard and usually are subject to heavy damage under slope-land disasters. The loss of people’s lives and properties are severe. The average death toll was 8.26 casualties per event from 1981 to 1999. Starting from 1992, huge resources had been spent in the research of debris flows and landslides. After the assessment and warning system started on 2000, the number of casualties decreased to an averaged 2.23 per event between 2000 and 2008 and the average decreased as time progress. There were 22 large landslides or debris flows in 2008, but the average casualty was only 0.55 per event. This paper describes the technology advances from 2000 to 2010 in Taiwan. The most important advances are in the assessment technology, warning technology and mitigation concepts. The assessment method started with pure empirical formula, then improved to delimiting hazard zone numerically. The most recent change is to include social vulnerability in assessment. The warning system started with very local monitoring to nationwide warning with fine resolution quantitative precipitation estimation with multiple sensor radar system. The warning time has improved to more than 24 h before the disaster. The concept for mitigation changes from traditional structure countermeasures to ecological means. However the most fundamental change is the shifting emphasis from structure mitigation to non-structure mitigation with planning, education and drills.