Development of a three-dimensional upper crustal velocity model of the Goldstream Valley, central Alaska

The uppermost crustal velocity structure of the Goldstream Valley, central Alaska is investigated using a series of five explosions that were detonated in schist bedrock and recorded at >120 local stations to develop 1-D and 3-D models of the upper crust. Simple refraction analyses reveal that both P- and S-wave arrival times are azimuth dependent, with the fastest velocities in the southeast and northeast directions. The S-wave velocity structure of the upper crust is also determined through multiple filter analysis and a damped, least squares inversion of 0.2-2 sec period Rg waves. The shear wave velocity model from the surface-wave analysis is combined with the refraction analysis results to develop 1-D P- and S-wave models to a depth of 2 km. In order to better constrain P- and S-wave velocity variations both laterally and with depth throughout the Goldstream Valley, 3-D velocity models are produced using a numerical simulation model.