A Oiscussion on the Characteristics, Impacts and Emergency Response of Chi-Chi Earthquake
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A Oiscussion on the Characteristics, Impacts and Emergency Response of Chi-Chi Earthquake I IANG-CHUN CHEN :".. ;oclate Professor, Institute of Building and Planning, National Taiwan University I", 'Iect Co-Director & Group Leader, Mitigation Management System AHSlRACf Chi-Chi earthquake is the strongest earthquake hit Taiwan in the last hundred years period and caused ,ignificant impacts, and it also tested the four-level system with a real and severe situation. Under this C( Indition, there are three major purposes of the paper: the first, 10 illustrate the conditions and characteristics "f the disaster; the second, to illustrate the response of the central and local governments and the civil organizations in the first 10 days after the disaster. Lastly, we'll discuss the social and economic impacts of the Chi-Chi earthquake on the hazarded area, and provide some possibilities for the future. KEYWORDS: Chi-Chi earthquake, emergency response, hazard mitigation. I. Introduction 1.1 Background Chi- Chi earthquake, recorded ML 7.3 on the Richter scale by the Central Weather Bureau while 7.6 by National Earthquake Information Center ofthe United States Geological Survey, hit central Taiwan area at 17:47 GMT, Sep. 20, 1999(Sep. 21 at 1:47 AM local time in Taiwan). It is the strongest earthquake hit Taiwan in the last hundred years period, and also the first massive earthquake after the modernization of Taiwan. Although the natural disaster from typhoons, thunderstorms and earthquakes are not rare here, Chi-ehi earthquake still caused significant impacts. During the past decades, it is getting complicated of the disasters caused by natural hazJlrds, widely spread fire and manufacturing factory accidents, 10 deal with the situations, a three-level system for hazard prevention and mitigation is proposed. The Chi- Chi earthquake tested the system with a real and severe situation. It is important for the ones who concern hazard prevention and mitigation 10 scrutinize how the system works. 1.2 Objectives and Methods By means ofexamining the actions ofthe central and local governments after the earthquake, the major purpose ofthe paper is 10 provide possibilities for the follow-up research concerning the deal ofhuge natural disasters. Specifically, the paper collects and analyzes the investigation materials and interviews the related persons. Firstly, it is illustrated in the paper about the conditions and characteristics ofthe disaster. Secondly, the response ofthe central and local governments and the civil organizations after the disaster have been Copyright © International Association for Fire Safety Science 79 lllllllllietl II III"l: lhe lillie tllIlIclIslon from September 21 to 30. Lastly, wc'll dl8Cllll~ lhl" SlIlI"I The earthquake caused substantial damage and heavy casualties on this island, nlltl ccollomlr impllcts of the Chi-Chi earthquake on the hazarded area, lind mllke suggl'sllllllS especially in central Taiwan. In summary, li)r Ililurc improvement ofTaiwan's hazards prevention and mitigation systems. Death toll: 2,415 persons (Nantou County 891, Taichung 1,175 ) In addition, since the hazard area is very broad, PuJi is selected as the empirical case to have a closer look of the emergence response of local government. We interviewed people Missing: 29 persons who worked in the hazard area to compile the main tasks during the 10 days after the earthquake hit. Subtotal : 2,444 persons Wounded: 11,305 persons (severe wounded l around 700) Affected: around 310,000 persons, about 1.4 % ofthe total population ofTaiwan 2 2. Description ofthe Condition of Chi-Chi Earthquake Building damage: collapsed 51,711, damaged 53,768 , subtotal 105,479 (28,217 collapsed and 28,974 damaged in Nanyou; 18,608 collapsed and 18,452 damaged in Taichung) 2. I General Description 3 Property damage : 341.2 billions NT dollars, around US$ 10.7 billion The preliminary epicenter for Chi-Chi earthquake locates at latitude 23.81 degrees north and longitude 120.9 degrees east, 12.5km from Sun Moon Lake, a famous scenic spot in Nantou County, or about 150 kilometers south-southwest of Taipei. The depth of Chi-Chi 2.2 The Characteristics of the Earthquake Disaster earthquake is about 7 to 10 kilometers and the magnitude is ML7.3 ( CWB) . It was caused by the Chelungpu Fault shown in figure 1, which is about 105 km in length and extends across Hsinchu, Taichung and Nantou Counties). From the facts that the maximal vertical movement reaches II meters and the maximal level movement reaches 10 meters, we can imagine how As described above, Chi-Chi earthquake caused significant loss in Taiwan. Moreover, strong the destructive power was. the characteristics ofthe disaster area are categorized as following: 119 120 121 122 123 26 I) Characteristics ofthe disaster area 1 ' The hazard area is broad The length of Chelungpu Fault locates from Juoshuei River to the 24 north rim of Da-an stream, passing through Tsaotun, Chushan, Mingjian, ChungHsing HsinTsun, Tsautuen, Wu-Fung, Taiping, Da-Kung, 23 Fengyuen, Shihkung, Tunghsing, Dongshi, and Drou-Lang, which lasts over 105 kilometers; and Che1ungpu 22 Figure 3: The townships ofthe main disaster area. I Wounded who have to be hospitalized over 30 days. 2 according to current regulations. 21 3 including property and business loss but not including casualty, business invoice loss and historical and INDEX: * EPICENTER ecological damages. Figure 1: the Chelungpu Fault and the main Figure 2: The location ofthe epicenter disaster area ofChi-Chi earthquake. ofChi-Chi earthquake. 80 81 I~ Ihru~1 "uull n luull Ihul pushes from cast IowaI'd west. Thc:re:lIlrc, the: RIC-U Oil ,he' rural and mountain area, where the populations and the communities were loeated euslc:rn side of' the ('helungpu Fault encountered strong shake. The: main dlslISlt'r area scattcring, the traffic conditions were poor, and the communication systems had not indude Nantou County, Taichung County, Beituen district of Taiehung City, DOIl-l.i" been well established. Therefore, the emergency and rescue activities were not ('ity and Kukung township of Yunlin County, Yuanlin township of Changhua ( '(llility. performed smoothly at the very beginning. Juolan and Taian township of Miaoli County, totally 90.5 square kilometers. ( Figure 3) Ill' This earthquake caused multiple disasters that included the urban type damages and the rural and mountain type damages, such as: ii, The hazard area attributed small villages and agricultural areas In the broad hazard area described above, most parts are not urbanized areas. Only Puli (population 88,64 I) and Tunghsing (population 59,013 ) 4 are major towns, a. Different type damages to private buildings: The damage types by the different kind while others are small towns. Among these areas, only few of them have the functions of buildings included the clay brick buildings and brick houses in rural area, the of local commercial activities, while most of them are daily living and commercial connected low-rise multiple dwelling houses in suburban area, and the middle- and center and agricultural and forest areas. high-rise apartment buildings in urban area. b. Sever damages to public buildings: More than 125 elementary and junior high schools were destroyed, as well as several local administration buildings were iii, Most ofthe hazard areas are remote and sensitive mountain areas collapsed. As a result, the entire education and local govemment's functions were down after the earthquake. Between the Chelungpu Fault and the Central Mountain area, most are hills and steep cliffs besides the tableland area aside the fault. They are the areas of remote c. Sever damages to lifelines and infrastructures: Most of high-voltage power systems villages, where the geology is fragile and sensitive. which included the generating plants, major transformer stations (including Chun-liao high-voltage transformer station), the power cables, and the power line towers were damaged. Therefore, more than two third of the entire Taiwan areas iv' Most ofthe hazard areas are multi-culture and scenic industry areas were out ofpower from days to weeks. In the meantime, due to the offset of faults, landslide and falling rocks, lots of the highways and roads were damaged or In addition to the attributes above, the disaster area is also the place of obstructed. multi-culture area including aboriginal, Hakka and Ho-lo. The famous sight-seeing spot, the Sun Moon Lake, locates in the area. The area is full of scenic resources that d. Sever geo-technical hazards: due to the fault rupture, the strong surface shaking, and make the scenic industry ofthe area prosperous. the S(·ft soil layer on the top of faults this earthquake cause a lot of geo-technical hazards, such as: The vertical or lateral offset between both sides of fault that result the sever 2) Characteristics ofearthquake damages building or structure damages and the limitation of rebuild the buildings or structures. The huge landslides at Tsaoling and Jiu-fen-er mountains areas block the i ' Considering the magnitude of this terrible earthquake measured 7.3 on Richter scale, several streams and rivers that formed several temporary reservoirs. When the death toll was only 2,444 (includes missing). The main reasons cause this result, the reservoirs now are fully filled with the collected water, they may cause the as discussed above, can be summarized as following: (A) the most affected areas dam to collapse and flood over the down stream areas. near to the Sun Moon Lake, where is a low population, mostly rural and mountain area, (B) the occurrence time is 1: 47 a.m. when most ofpeople had fallen asleep and The conditions of large volume of loose rocks and the soft soil created on this most of commerce activities were ceased. Therefore, the number of death was not earthquake are getting worse, especially during heavy raining days or very severe.