Copyright (c) 2013 Utah State University All rights reserved. http://digitalcommons.usu.edu/govdocs_geology Recent documents in Geology en-us Sun, 27 Jan 2013 04:26:29 PST 3600 http://digitalcommons.usu.edu/govdocs_geology/2 http://digitalcommons.usu.edu/govdocs_geology/2 Mon, 12 Sep 2011 10:18:12 PDT The basic purpose of the research carried out under this grant was to obtain a better understanding of deformation processes in the western United States. The research considered both deterministic models and random or statistical models. One important aspect of deformation is the rheology of the lithosphere. We have been one of the leading proponents of an intracrustal asthenosphere. This is a soft zone at mid-crustal depths that has an important effect on a variety of tectonic phenomena.

]]> United States, National Aeronautics and Space Administration http://digitalcommons.usu.edu/govdocs_geology/1 http://digitalcommons.usu.edu/govdocs_geology/1 Thu, 30 Jun 2011 10:30:00 PDT Several earthquake recordings at Golden, Colorado in the magnitude range 4-6, were digitized and were used to investigate the feasibility of adding them together to simulate a larger earthquake (magnitude 7.0-7.5). The test path of the Wasatch Front, Utah to the WWSSN station at Golden was selected (distance=400-500 km). The hypothetical causative fault was given dimensions on the order of 45 km long by 20 km wide and was divided into "cells," representative in size to the "seed" events rupture dimensions and with other variations. The results were evaluated by total energy and amplitude criteria. The final waveforms were judged to be adequate predictions at the lower frequency end of the spectra. The high frequency content was controlled by the spectra of the seed earthquakes whose magnitudes were too large to adequately reproduce the Green's function response at these frequencies. It is recommended that this technique be used at smaller distance ranges or at stations whose sensitivity is set high enough so as to record the smaller magnitude earthquakes, more representative of impulse responses at all frequencies.

]]> United States Department of Defense, Air Force Geophysics Laboratory