HR: 0800h
AN: T51A-0317    [Abstracts]
TI: Crustal Q Tomography in Taiwan
AU: * Sonley, E
EM: esonley@binghamton.edu
AF: Department of Geological Sciences, Binghamton University,Vestal Parkway East, Binghamton, NY 13902, United States
AU: Wu, F T
EM: francis@binghamton.edu
AF: Department of Geological Sciences, Binghamton University,Vestal Parkway East, Binghamton, NY 13902, United States
AB: While 3-D crustal velocity structures in an active orogen can be derived from travel time tomography, other rock properties are needed for a more complete characterization of the orogen. The anelastic quality factor (Q) provides constraints on the thermal condition or perhaps fluid activity within the rocks. With the recent deployment of a PASSCAL broadband array in Taiwan, enhancing the existing BATS and Central Weather Bureau networks, the station density has increased significantly and a rich archive of broadband local earthquake data has become available. The advantages of using broadband data, rather than the previously available short period data, include the increase of spectral width, better instrumental calibration and stronger S wave signals. As a first step we derive an approximate structure using dt* calculated from the ratio of P and S wave spectra, after Roth et al. (1999), for paths between earthquakes and stations. By using their "best" Qp/Qs value of =1.75 we perform a tomographic inversion to derive a regional measurements of Qs in three dimensions. These preliminary Qs results from broadband data indicate higher values of Qs in Eastern Taiwan when compared to the western plain, both at the surface and at a depth of 30 km. These results are similar in distribution to the Qs tomography results of Chen (1998). We will use the methodology of Roth et al. (1999) to develop more robust 3-D Qs as well as Qp distributions for Taiwan using the broadband data now available.
DE: 7203 Body waves
DE: 8104 Continental margins: convergent
DE: 8150 Plate boundary: general (3040)
DE: 8175 Tectonics and landscape evolution
DE: 8180 Tomography (6982, 7270)
SC: Tectonophysics [T]
MN: 2007 Fall Meeting