Comprehensive Detection and Relocation of the 2010 Mw7.2 El Mayor-Cucapah Foreshock Sequence

Dongdong Yao, Zhigang Peng, Xiaofeng Meng, Xiaowei Chen, Raul R. Castro, & Sizuang Deng

Submitted August 15, 2016, SCEC Contribution #6757, 2016 SCEC Annual Meeting Poster #216

Large earthquakes are sometimes preceded by foreshocks, and the exact relationship between foreshocks and mainshock nucleation is still unclear. Here we present a comprehensive foreshock detection of the 2010 Mw7.2 El Mayor-Cucapah, Mexico, earthquake, using continuous waveforms recorded by the South California Seismic Network (SCSN). Specifically, continuous waveforms from SCSN stations within 150 km epicentral distances were first downloaded. We use ~70 foreshocks listed in SCSN catalog [Hauksson et al., 2010] as templates, and scan through continuous recordings starting from 20 days before up to the mainshock. Currently, ~400 events are detected and we find nearly continuous episodes of foreshock sequence, with the most intensive activity within 42 hours prior to the mainshock. We also identify foreshocks from the triggered-mode recordings by the Red Sísmica del Noroeste de México (RESNOM) network. Even though there were no continuous waveforms for detection, they can be used to verify the existence of newly detected events and provide additional phase arrivals at nearby stations. By combining phase information from RESNOM and SCSN stations, we further perform HypoDD relocations for all ~400 foreshocks. By closely examining spatio-temporal evolutions of newly detected foreshock sequence, we hope to better understand the nucleation process of the 2010 Mw7.2 El Mayor-Cucapah mainshock.

Yao, D., Peng, Z., Meng, X., Chen, X., Castro, R. R., & Deng, S. (2016, 08). Comprehensive Detection and Relocation of the 2010 Mw7.2 El Mayor-Cucapah Foreshock Sequence. Poster Presentation at 2016 SCEC Annual Meeting.

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