Preliminary Magnetic Study of the Quaternary Red-Soil Bed on Linkou Terrace,Northern Taiwan

臺灣北部林口臺地第四紀紅土塵的磁學研究

李德貴(Teh-Quei Lee) ； 林淑芬(Sue-Fen Lin) ； 周漢強(Han-Chiang Chou)

《Terrestrial, Atmospheric and Oceanic Sciences》 10卷4期 (1999/12) Pp. 763-776

並列摘要

The 21 September 1999 Chi-Chi earthquake(M(subscript L)=7.3)was the largestinland quake occurred in Taiwan in the past 100 years.According to directfield observations,a significant thrust rupture was occurred along the activeShuangtung fault and Chelungpu fault.From the integrated displacementderived from free-field strong motions around the source area,horizontaldisplacements over 9m and vertical offsets reaching 3.4m are obtainedat the station TCU068 located nearby the northern section ofChelungpu fault.Based on the field observations of slip distribution overthe entire 77-km surface break and the integrated displacement waveforms,we have arrived at the following findings:An obvious small offset at about3 sec prior to the principal offset is observed at two sites close to the southernpart of Shuangtung fault.This small offset is not shown on the otherstations.We propose that a relatively small event,probably with a magnitudeof about 6.0,occurred about 3 sec before the major rupture,that islocated at the Shuangtung fault about 8km east of the Chelungpu fault.The induced northward propagating rupture along the Chelungpu faulthas reached a maximum permanent offset over 9m at the northern sectionof fault.This northern section of the Chelungpu fault was identified as oneof the heaviest damaged areas.

並列關鍵字

Quaternary ； Red-Soil ； Linkou ； Magnetic Susceptibility