HR: 0830h
AN: G31B-0716    [PDF]
TI: Plate Boundary Observatory in Taiwan
AU: * Yu, S
EM: yusb@earth.sinica.edu.tw
AF: Institute of Earth Sciences, Academia Sinica, 128 Academia Rd. Sec.2, Nankang, Taipei, TW 115 Taiwan
AU: Tsai, C
EM: tsai@ss2.cwb.gov.tw
AF: Central Weather Bureau, MOTC, 64 Gonyen Rd., Taipei, TW 100 Taiwan
AB: The island of Taiwan is situated in the plate boundary zone between the Eurasian and the Philippine Sea plates. The Philippine Sea plate is subducting northwestward underneath the Eurasian plate along the Ryukyu Trench in the north, while the Eurasian plate underthrusts the Philippine Sea plate along the Manila Trench in the south. Taking advantage of the extremely high strain rate in the Taiwan area, an integrated National Science Council project, Plate Boundary Observatory in Taiwan (PBOT), was initiated following the idea of US PBO. The scientific goal of PBOT is to observe the crustal deformation on various temporal and spatial scales in the Taiwan plate boundary zone employing available state of the art techniques for measuring crustal strain. The techniques include seismology, Global Positioning System (GPS), Interferometric Synthetic Aperture Radar (InSAR), borehole strainmeter, and earthquake geology. They are complementary to each other and form a complete spectrum of measuring various periods of crustal strain. The process of crustal deformation is generally quite slow. To obtain a reliable result, we usually need to persist in the observations for several years or even decades. Thus the PBOT should be a long-term project. In the first phase of 3 years period from 2003 to 2006, we will focus on the two areas, i.e. the plate suture zone in the Longitudinal Valley area and the western Taiwan where the higher seismic hazard is expected. A five-year national program, entitled ­Program for Earthquake and Active-fault Research (PEAR)­" was initiated after the disastrous 1999 Chi-Chi earthquake (Mw 7.6). As part of the PEAR, a dense continuous GPS array consisting of 150 new and about 50 pre-existing stations will be completed in the Taiwan area by the end of 2005 through a joint effort by the Central Weather Bureau and the Institute of Earth Sciences, Academia Sinica. The 50 new stations are going to be evenly distributed around the Taiwan Island. The other 100 stations will be densely deployed near the major active faults and potential earthquake source areas. The enormous continuous GPS data collected by the array will give us the unprecedented opportunity to study the crustal deformation in Taiwan. The near real time spatial and temporal variations of crustal strain can be realized and their correlation with seismic activity will be studied. Using GPS data from the dense array, the slow slip events related to fault-creep and subduction may be detected. In the event of a major earthquake, the continuous GPS array provides the precise measurements of preseismic, coseismic, and postseismic deformations. It may shed light on the process of strain accumulation and energy release through an earthquake cycle. The present-day fault-slip rates of major active faults in Taiwan will be estimated. These results provide the important information for seismic risk analysis and lead to the effective reduction of earthquake disaster
DE: 1206 Crustal movements--interplate (8155)
DE: 1208 Crustal movements--intraplate (8110)
DE: 1243 Space geodetic surveys
DE: 8107 Continental neotectonics
DE: 8110 Continental tectonics--general (0905)
SC: Geodesy [G]
MN: 2003 Fall Meeting