Interseismic Velocity Field and Seismic Moment Release in Northern Baja...

Sandwell, D. (2018), Interseismic Velocity Field and Seismic Moment Release in Northern Baja California, Mexico by J. Alejandro González-Ortega, J. Javier González-García, and David, Seismological Research Letters, 89, 526-533, doi:10.1785/0220170133.

We have analyzed all available continuous Global Positioning System (cGPS) and campaign-mode GPS data from northern Baja California, Mexico, covering the 1993.1–2010.1 period to obtain a consistent interseismic velocity field to derive a continuous strain-rate field. The analysis shows concentrations of high strain rate along the Imperial/Cerro Prieto fault system extending from the Salton Sea to the Gulf of California, with strike-slip faulting consistent with principal strain axes direction within the area of largest historical and instrumental seismic release. We translated the strain rate into geodetic moment accumulation rate to evaluate the potential of seismic activity of the region and compare with the actual seismic release of historical and instrumental earthquake catalog. Comparison of regional moment accumulation rate based on geodesy (M _ g0 ! 6:3 " 1:3 × 1018 N · m=yr) to the corresponding moment release rate by earthquakes (M _ s0 ! 2:7 " 0:8 × 1018 N · m=yr) highlights a moment rate deficit equivalent to an M w 7.5–7.8 earthquake. As part of this accumulated moment was released by the recent 2010 M w 7.2 El Mayor–Cucapah earthquake, these results can provide input constraints on earthquake forecasts for the northern Baja California fault system. Electronic Supplement: Tables of Global Positioning System (GPS) velocities, earthquake catalog, and figures comparing interpolation methods and earthquake catalogs.

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Earth Surface & Interior Program (ESI)