HR: 1340h
AN: S53B-0195    [Abstracts]
TI: Surface-Wave Focal Mechanism, Velocity and Q Models of the 29 May 2004 South Korea Earthquake
AU: * Nguyen, B V
EM: bao@aftac.gov
AF: Bao V. Nguyen, HQ AFTAC/TTR 1030 S. Highway A1A, Patrick AFB, FL 32925-3002 United States
AB: The South Korea earthquake event of 29 May 2004 was reported by the USGS as follows: mb = 5.3, Origin Time = 10:14:28.44, Latitude = 36.63N, Longitude = 129.93E. In this study, I will present the focal mechanism of this event, as well as the average velocity and Q models from inversions. Corrected Love-wave and Rayleigh-wave amplitude data from 15 GSN stations (MDJ, YSS, MAJO, TATO, QIZ, SSE, KMI, ENH, XAN, LSA, INCN, BJT, WMQ, ULN, and HIA) were used in the search for focal mechanism employing the technique of Nguyen and Herrmann (1992, SRL). Eigenfunctions were computed from the average crustal model that was obtained by inversion from surface-wave group velocities of these stations. Surface-wave attenuation coefficients were obtained using the technique of Tsai and Aki (1969). The focal mechanism of this event has a nodal plane with dip = 55 deg, slip = 65 deg, and strike = 160 deg. P-wave first motions were used to constrain the nodal planes. The seismic moment obtained is 3.79E+23 dyne-cm. The source depth is 11 km. The average velocity and Qb models obtained by inversions are tabulated as follows: Layer Number, Layer Thickness (km), P (km/sec), S (km/sec), Density (g/cm3), Poisson's Ratio, Qa/Qb: L1, 3.0, 4.4826, 2.5880, 2.3876, 0.25, 354/157, L2, 9.0, 6.1420, 3.5461, 2.7426, 0.25, 364/162, L3, 8.0, 6.2784, 3.6249, 2.7835, 0.25, 377/168, L4, 25.0, 7.2880, 4.2078, 3.0722, 0.25, 434/193, L5, 0.0, 8.1984, 4.6019, 3.3814, 0.27, 508/226.
UR: http://home.cfl.rr.com/bao/AGU
DE: 7230 Seismicity and seismotectonics
DE: 7255 Surface waves and free oscillations
DE: 7205 Continental crust (1242)
DE: 7215 Earthquake parameters
SC: Seismology [S]
MN: 2004 AGU Fall Meeting