Scaling of finite-source parameters at Parkfield, California

Kathryn E. Wooddell, Doug S. Dreger, Taka'aki Taira, Robert M. Nadeau, & Luca Matagnini

Submitted August 15, 2016, SCEC Contribution #7000, 2016 SCEC Annual Meeting Poster #064

We determine finite-source slip models for Parkfield earthquakes ranging in magnitude from M1.8 to M4.1 by inverting relative moment rate functions (RMRF) obtained from empirical Green’s function (eGF) deconvolution. The method is based on Mori and Hartzell (1990). We then use the derived slip models to estimate the stress change following the method of Ripperger and Mai (2004), and compare with published results for the 2004 Parkfield mainshock. These results provide an update to the study presented at SSA in April 2016, and they show that many microearthquakes display a level of complexity comparable to slip models of larger earthquakes. We will present the results in terms of the scaling of peak slip, average slip, and rupture area, as well as the peak and average stress drops inferred from the finite-source based stress change calculations. The updated results indicate that on average the events behave self-similarly, and the stress drops are consistent with corner frequency based estimates of Imanishi and Ellsworth (2006), Allmann and Shearer (2007), and Abercrombie (2014). On the other hand, the peak slip and stress drops seem to follow the relationship proposed by Nadeau and Johnson (1998) in which the peak stress drop increases for decreasing scalar moment.

Key Words
scaling, stress drop, Parkfield, inversion, relative moment rate, empirical Green's function

Citation
Wooddell, K. E., Dreger, D. S., Taira, T., Nadeau, R. M., & Matagnini, L. (2016, 08). Scaling of finite-source parameters at Parkfield, California. Poster Presentation at 2016 SCEC Annual Meeting.


Related Projects & Working Groups
Fault and Rupture Mechanics (FARM)