Stochastic Finite-Fault Modeling of Ground Motion from the 2010 Rigan Earthquake, Southeastern Iran

Please join us for a grad student seminar this Friday March 8 at 3:30 pm in rm 155 Geology presented by Maryam Safarshahi, PhD Candidate:

Stochastic Finite-Fault Modeling of Ground Motion from the 2010 Rigan Earthquake, Southeastern Iran

This study is based on the 20 December 2010 Rigan earthquake that occurred in southeastern Iran, using the ground-motion simulation based on the stochastic finite-fault model. This earthquake was recorded by 23 stations. First, from the analysis of spectral amplitudes of horizontal components of the records, I estimated an empirical function describing the amplitude decay of shear waves with distance in the Rigan region. The values of S-wave quality factor QS within the frequency range of 1–24 Hz were found to be Qs = (99± 19) f(0.58±0.12)

Next, I obtained the spectral decay parameter ‘Kappa’ from the slopes of smoothed amplitudes of the

Fourier spectra of acceleration at higher frequencies. The estimated zero-distance Kappa value was 0.06. Finally, I used these estimated parameters and the stochastic finite-fault model for simulating the strong ground motion and rupture characteristics. The main event was characterized in terms of peak ground acceleration (PGA), peak ground velocity, peak ground displacement, Arias intensity, Fourier spectra, and the response spectra of ground shaking. My near-field estimates for the main event is in good agreement with the near-field estimates reported by other studies.

At present, I am also working on a new, large earthquake dataset provided by the Iranian Seismological Center (IRSC).The dataset contains over 66,000 miniSEED files from 83 seismic stations in Zagros region of Iran. I am preparing the data for studies of coda, regional-phase amplitudes, relocation, reflections, and tomography.