Toward Viscoelastic Block Models of the North Anatolian Fault: Integrating Geodetic and Delayed Stress Triggering Constraints in Three-Dimensions

Abstract:

The North Anatolian fault (NAF) has produced a series of 10 Mw>6.7 westward propagating earthquakes over the last 75 years. The surface deformation associated with both the viscoelastic response to these earthquakes as well as steady tectonic motion has been geodetically observed for the past two decades. We seek to develop a three-dimensional viscoelastic block model of the greater NAF region which simultaneously explains: 1) nominally interseismic GPS velocities prior to the 1999 Mw=7.5 Izmit earthquake, 2) decadal scale postseismic deformation transients, 3) the delayed viscoelastic triggering of NAF earthquakes over the last 8 decades, and 4) geological estimates of Holocene fault slip rates. Here we present preliminary results demonstrating the assembly of a kinematically consistent three-dimensional viscoelastic block model and describe a cost function formulation that may be used to solve for a best-fitting set of viscosities.