HR: 0830h
AN: S31E-0820    [PDF]
TI: Joint Analysis of Regional Broadband Waveforms and Travel Times for Crustal Structure Using the Genetic Algorithm
AU: * Chang, S
EM: joshua@snu.ac.kr
AF: School of Earth and Environmental Sciences, Seoul National University, Shillim 9-dong Gwanak-gu, Seoul, 151747 Korea, Republic of
AU: Baag, C
EM: baagce@snu.ac.kr
AF: School of Earth and Environmental Sciences, Seoul National University, Shillim 9-dong Gwanak-gu, Seoul, 151747 Korea, Republic of
AB: A method is proposed to estimate crustal velocity structures using regional broadband waveforms and travel times. This method makes up for the weak point of waveform inversion that could produce distorted crustal stuructures in the case of low signal-to-noise ratio (SNR) of seismic data. Travel time data can complement waveform data in inverse problems for crustal structure, because P wave arrivals (e.g., Pg, PmP, and Pn) are generally clear in spite of low SNR. In addition, short-period seismograms that have nothing to do with broadband waveform modeling can be used to get travel time data. The genetic algorithm, a global optimization method, is adopted as a forward-modeling approach to avoid trapping in local minima in nonlinear problems. After updating the epicenter, focal depth, and focal mechanism based on the resulting crustal model, we update the model performing the forward computation again. We iterate this procedure until the synthetics from the estimated crustal model has no more improvement.
DE: 7203 Body wave propagation
DE: 7205 Continental crust (1242)
DE: 7218 Lithosphere and upper mantle
DE: 7260 Theory and modeling
SC: Seismology [S]
MN: 2003 Fall Meeting