Simultaneous Determination of Earthquake Source Parameters Using Far-Field P waves: Focal Mechanism, Seismic Moment, Rupture Length and Rupture Velocity

Lin, Tzu Wei; Hwang, Ruey Der; Fong, Kuo; Tsai, Yu‐Hui

doi:10.3319/tao.2006.17.3.463(t)

Cited by 8 publications

(25 citation statements)

References 10 publications

(29 reference statements)

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“…(A1) in the following form (Lin et al 2006 (Kennett and Engdahl 1991) is used to calculate the travel time of seismicwaves as well as several parameters. The attenuation filter Q(t) is calculated by Azimi's law using t* = 1.0 (travel time over quality factor) for the P-waves (cf.…”

Section: Discussionmentioning

confidence: 99%

“…Lin et al 2006;Hwang et al 2010Hwang et al , 2012; also see Appendix A). Before the multiple-event analysis using the forward modeling of Pwaves, we used an empirical Green's function (EGF) deconvolution technique to investigate roughly the multiple sources of the 2008 Wenchuan earthquake.…”

Section: Multiple Event Analysis and Radiated Seismic Energymentioning

confidence: 99%

“…Thus, by searching for a succession of source duration and focal depths, the appropriate source duration, focal depth and pseudo radiation patterns are obtained for each station by minimizing misfits between the observed and synthetic seismograms (cf. Lin et al 2006Hwang et al 2010Hwang et al , 2012.…”

Section: Appendix a (1) Calculation Of The Far-field P-wavesmentioning

confidence: 99%

“…, and M 0 R sP , which are called the pseudo radiation patterns by Lin et al (2006). Equation (A3) can be resolved by the standard least-squares technique.…”

Section: Appendix a (1) Calculation Of The Far-field P-wavesmentioning

confidence: 99%

“…The 2008 Wenchuan earthquake was a shallow source such that the synthetic P-waves must include two depth phases (pP-and sP-waves), excluding the direct P-wave (cf. Lin et al 2006;Hwang et al 2010Hwang et al , 2012. The P-waves were created synthetically following the iasp91 velocity model (Kennett and Engdahl 1991) (also see Appendix A).…”

Section: Focal Depths For Sub-eventsmentioning

confidence: 99%

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Multiple Event Analysis of the 2008 Mw 7.9 Wenchuan Earthquake: Implications for Variations in Radiated Seismic Energy During Faulting

Hwang¹

2013

Terr. Atmos. Ocean. Sci.

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A forward modeling of P-waves for the 2008 Wenchuan earthquake revealed at least seven sub-events that occurred during faulting with the largest event (i.e., the third sub-event) located at a position ~50 km northeast of the epicenter. Simulations of P-waves showed that it would be more appropriate to model the P-waves using thrust faulting for the first three sub-events and using strike-slip faulting for the last four. In other words, the faulting for the 2008 Wenchuan earthquake was composed substantially of two mechanisms; the former was a thrust faulting and the latter was a strike-slip rupture. The mechanical transition was near the town of Beichuan, ~100 km northeast of the epicenter. Variations in radiated seismic energy (E S ) showed the largest E S released from the fourth sub-event. Results also indicated remarkable distinctions between E S and E S0 (called the available energy). On the whole, the total E S , which was higher than E S0 estimated from static stress drop, suggested that the earthquake should be interrupted by a stress model of abrupt-locking. Further, the former thrust faulting released a relatively lower amount of E S than the latter strike-slip event. Orowan's stress model, i.e., E S ≈ E S0 , can specify former thrust ruptures implying a high rupture velocity. Because E S > E S0 for latter strike-slip ruptures, a stress model of abrupt-locking, implying higher dynamic stress drop and lower friction during an earthquake, can account for the feature of the latter ruptures. This might suggest that the 2008 Wenchuan earthquake should have a high rupture velocity, perhaps approaching the crustal Swave velocity or even higher.

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Section: Discussionmentioning

confidence: 99%

Section: Multiple Event Analysis and Radiated Seismic Energymentioning

confidence: 99%

Section: Appendix a (1) Calculation Of The Far-field P-wavesmentioning

confidence: 99%

“…, and M 0 R sP , which are called the pseudo radiation patterns by Lin et al (2006). Equation (A3) can be resolved by the standard least-squares technique.…”

Section: Appendix a (1) Calculation Of The Far-field P-wavesmentioning

confidence: 99%