Development and Implementation of Disaster Reduction Technology in Taiwan

In order to improve the efficiency of disaster reduction, the government of Taiwan has taken a number of initiatives in the development of disaster reduction technology since 1982, including the 1st, 2nd and 3rd 5-year plans for hazards prevention research, and the National Science and Technology Program for Hazards Mitigation (NAPHM). In this article, the contents and achievements of the 5-year plans and the NAPHM are briefly reviewed. On the one hand, the 5-year plans have produced meaningful research results; on the other hand, the NAPHM has provided a mechanism for integrating and translating the research results into technologies that can be implemented. The NAPHM was transformed in 2003 into the National Science and Technology Center for Disaster Reduction (NCDR) to further enhance the development and implementation of disaster technology. The mission and major future works of the NCDR are discussed.     

Numerical simulation on a tremendous debris flow caused by Typhoon Morakot in the Jiaopu Stream,Taiwan

In August 2009,Typhoon Morakot brought a large amount of rainfall with both high intensity and long duration to a vast area of Taiwan.Unfortunately,this resulted in a catastrophic landslide in Hsiaolin Village,Taiwan.Meanwhile,large amounts of landslides were formed in the Jiaopu Stream watershed near the southeast part of the Hsiaolin Village.The Hsiaolin Village access road（Provincial Highway No.21 and Bridge No.8） was completely destroyed by the landslide and consequent debris flow.The major scope of this study is to apply a debris flow model to simulate the disaster caused by the debris flow that occurred in the Jiaopu Stream during Typhoon Morakot.According to the interviews with local residents,this study applied the destruction time of Bridge No.8 and Chen＇s house to verify the numerical debris flow model.By the spatial rainfall distributions information,the numerical simulations of the debris flow are conducted in two stages.In the first stage（before the landslide-dam failure）,the elevation of the debris flow and the corresponding potential damages toward residential properties were investigated.In the second stage（after the landslidedam failure）,comparisons of simulation results between the longitudinal and cross profiles of the Jiaopu Stream were performed using topographic maps and satellite imagery.In summary,applications of the adopted numerical debris flow model have shown positive impact on supporting better understanding of the occurrence and movement of debris flow processes.     

岩溶洞穴分类新思考

根据一固定流域范围内相对于岩溶合水层的水流运动方式,将洞穴划分为流入、流出和穿越含水层三种类型;并指出:只要外部环境相对稳定,洞穴在流域中所处位置,所执行功能和拥有水动力条件就会随之保持稳定,形成一定成因类型的洞穴,其发育就会表现出很好的延续性和系统性,并展示出相应的形态特征。      

Seismo-ionospheric precursor of the 2008 Mw7.9 Wenchuan earthquake observed by FORMOSAT-3/COSMIC

The seismo-ionospheric precursor prior to the Mw7.9 earthquake near Wenchuan, China, on 12 May 2008 was observed by the FORMOSAT-3/COSMIC satellite constellation. By binning radio occultation observations, the three-dimensional ionospheric structure can be obtained to monitor the ionospheric electron density variation prior to the earthquake. It has been determined that near the epicenter the F2-peak height, hmF2, descends about 25 km and the F2-peak electron density, NmF2, decreases about 2 × 10⁵ el/cm³ around noon within 5 days prior to the earthquake. The integrated electron content decreases more than 2 TECU between 250 and 300 km altitude.