Deformation in the Yuha Desert from the 2010 M7.2 El Mayor – Cucapah Earthquake

Andrea Donnellan, Jay W. Parker, Michael B. Heflin, John B. Rundle, Lisa Grant Ludwig, & Gregory A. Lyzenga

Published August 15, 2018, SCEC Contribution #8774, 2018 SCEC Annual Meeting Poster #167

UAVSAR and GPS measurements were collected north of the US Mexico border spanning the 2010 M7.2 El Mayor – Cucapah earthquake from 6 months before to 7 years following the event. The area includes the Yuha Desert, Ocotillo area, and Salton Trough. The area northwest of the north end of the rupture in the Yuha Desert and Ocotillo area shows extensive surface fracturing of the crust in a network on conjugate faults with little broad scale deformation. The Salton Trough northeast of the rupture shows little surface fracturing but a large gradient of deformation. The asymmetric deformation can be explained by a contrast in lithology between the compliant Salton Trough and rigid Peninsular Ranges. Postseismic motions in the Yuha Desert can be fit with a rate strengthening logarithmic decay from afterslip on the El Mayor – Cucapah rupture. Deformation from the M5.7 Ocotillo aftershock was observed with UAVSAR and the deformation matches the focal mechanism for the depth, geometry, and slip of the event. Afterslip continued for several years on the Ocotillo aftershock section and the Yuha fault and can be explained by stress decay from afterslip on the mainshock rupture. While deformation in this area can be explained by rate and state friction laws, migration of fluid in the Salton Trough is likely to have occurred there.

Key Words
Geodetic, GPS, UAVSAR, Ocotillo, El Mayor - Cucapah, afterslip

Citation
Donnellan, A., Parker, J. W., Heflin, M. B., Rundle, J. B., Grant Ludwig, L., & Lyzenga, G. A. (2018, 08). Deformation in the Yuha Desert from the 2010 M7.2 El Mayor – Cucapah Earthquake . Poster Presentation at 2018 SCEC Annual Meeting.

Related Projects & Working Groups
Stress and Deformation Over Time (SDOT)