Dynamic Rupture Modeling of the M7.2 2010 El Mayor‐Cucapah Earthquake: Comparison With a Geodetic Model

Abstract

The 2010 Mw 7.2 El Mayor‐Cucapah earthquake is the largest event recorded in the broader Southern California‐Baja California region in the last 18 years. Here we try to analyze primary features of this type of event by using dynamic rupture simulations based on a multifault interface and later compare our results with space geodetic models. Our results show that starting from homogeneous prestress conditions, slip heterogeneity can be achieved as a result of variable dip angle along strike and the modulation imposed by step over segments. We also considered effects from a topographic free surface and find that although this does not produce significant first‐order effects for this earthquake, even a low topographic dome such as the Cucapah range can affect the rupture front pattern and fault slip rate. Finally, we inverted available interferometric synthetic aperture radar data, using the same geometry as the dynamic rupture model, and retrieved the space geodetic slip distribution that serves to constrain the dynamic rupture models. The one to one comparison of the final fault slip pattern generated with dynamic rupture models and the space geodetic inversion show good agreement. Our results lead us to the following conclusion: in a possible multifault rupture scenario, and if we have first‐order geometry constraints, dynamic rupture models can be very efficient in predicting large‐scale slip heterogeneities that are important for the correct assessment of seismic hazard and the magnitude of future events. Our work contributes to understanding the complex nature of multifault systems.

New Fault Slip Distribution for the 2010 Mw 7.2 El Mayor Cucapah Earthquake Based on Realistic 3D Finite Element Inversions of Coseismic Displacements Using Space Geodetic Data

“…Similar to Fialko et al (2010), Wei, Fielding, et al (2011), Wei, Sandwell, et al (2011), Kyriakopoulos et al (2017), and Huang et al (2017), most of the slip is found near the epicenter (Pescadores Fault) and at the end of the Indiviso fault. However, in the preferred model of Kyriakopoulos et al (2017), the slip from the Pescadores Fault to the Borrego Fault does not show any interruption while we are able, instead, to find a good correspondence with areas having low or no slip like the PIAZ and PAZ accommodation zones (Figures 1 and 12). Our joint inversions also show a greater and deeper slip at the southernmost plane, with respect to the starting solution of Huang17.…”

“…However, in the preferred model of Kyriakopoulos et al. (2017), the slip from the Pescadores Fault to the Borrego Fault does not show any interruption while we are able, instead, to find a good correspondence with areas having low or no slip like the PIAZ and PAZ accommodation zones (Figures 1 and 12). Our joint inversions also show a greater and deeper slip at the southernmost plane, with respect to the starting solution of Huang17.…”

“…(2011), Kyriakopoulos et al. (2017), and Huang et al. (2017), most of the slip is found near the epicenter (Pescadores Fault) and at the end of the Indiviso fault.…”

Fracture Advancing Step Tectonics Observed in the Yuha Desert and Ocotillo, CA, Following the 2010 Mw7.2 El Mayor‐Cucapah Earthquake

“…The fault ruptured northward to southernmost California just across the California/Mexico border (Figure ). Two main fault segments connected by a smaller extensional fault ruptured away from the epicenter with dominantly right‐lateral strike‐slip motion (J. M. Fletcher et al, ; Huang et al, ; Kyriakopoulos et al, ; Wei et al, ) and with an additional smaller segment striking slightly more northerly terminating the north end of the rupture. The segments dip northwest south of the epicenter and northeast north of the epicenter.…”

Extent of Low‐Angle Normal Slip in the 2010 El Mayor‐Cucapah (Mexico) Earthquake From Differential Lidar

“…An initial elastic dislocation model by Fialko et al () indicates 59° and 89°SW dips along the southern and northern Indiviso fault, a 79°NE dip on the Laguna Salada fault, and 71°NE dips on three segments that approximate the Pescadores, Borrego, and Paso Superior faults (Figure d). This model has since been used as the basis for dynamic rupture simulations (Kyriakopoulos et al, ) and modeling of postseismic deformation (González‐Ortega et al, ). An alternative model by Wei et al () shows a 60°SW dip on the Indiviso fault, a 60°NE dip for a fault segment approximating the Laguna Salada, Pescadores, and Borrego faults, and a 50°NE dip for the Paso Superior fault (Figure e).…”