Block Modeling in the Vertical Dimension Constrained by Three-Component GPS Measurements Abstract

abstract

  • We are developing an analytical procedure for solving for crustal block motions in complex fault zones using all three components of GPS velocity constraints. Traditional block modeling assumes that the Earth's lithosphere is divided into elastic spherical caps that come into contact and are locked (not slipping) at the surface, but slip continually below seismogenic depths during the interseismic time. In areas of tectonic extension or contraction, however, where the blocks have a component of motion normal to the faults, these models predict variations in the vertical interseismic velocity. Thus vertical component GPS velocities could conceivably be used as an additional constraint on the model, if the tectonic signals are large enough. Using the vertical component data could possibly be helpful for constraining the dips on faults, the long-term rate of uplift of mountain ranges, and subsidence of valley bottoms. We will explore the use of vertical component GPS measurements to constrain such a model. In particular we will present 1) the analytical formulation of block models that use the vertical component, 2) the predictions made by a new block model of the northern Walker Lane, western Great Basin, United States that was constrained by horizontal GPS measurements, 3) compare the predictions to vertical GPS rates measured from the EarthScope Plate Boundary Observatory and MAGNET GPS networks in the northern Walker Lane. These models may also be useful for identifying where additional sites could be deployed to best measure interseismic vertical motions

publication date

  • 2010

presented at event