Rupture process of 2011 Mw7.1 Van, Eastern Turkey earthquake from joint inversion of strong-motion, high-rate GPS, teleseismic, and GPS data

Abstract

We analyzed the rupture process of the 2011 Mw7.1 Van, Eastern Turkey earthquake using teleseismic, strong-motion, 1-Hz GPS waveforms and static GPS displacement measurements. We performed data sensitivity analyses using four different rupture scenarios. Overall, when geodetic and seismic datasets are modeled jointly, slip distribution is well-constrained and rupture velocity can be obtained. The 2011 Van earthquake is a case where none of the available datasets are sufficient to constrain the slip distribution and the rupture kinematics on their own. This study confirms that rather than fitting one dataset perfectly, using multiple datasets jointly leads to a better-constrained slip distribution. The kinematic model obtained from the joint inversion of all the available data shows a 45-km-long bilateral rupture with two sub-events; one larger slip patch propagating up-dip and toward west of the hypocenter and a smaller second slip patch toward the east. The highest slip is to the west of the hypocenter with a peak value of 4.5 m. The slip is confined to the depths of 7.5 to 20 km and the shallower part of the fault remains unbroken. The average rupture velocity is around 3 km/s, close the Rayleigh wave velocity. The rupture is faster with shorter rise times for the larger sub-event toward the west, while the rise times are longer for the smaller sub-event to the east. This difference in seismic behavior might be related to the segmentation of the fault.