Accession Number : ADA175203

Title :   Simulating a Large Wasatch Front, Utah, Earthquake Using Small Earthquake Recordings as Green's Functions.

Descriptive Note : Environmental research papers Sep 83-Oct 85,

Corporate Author : AIR FORCE GEOPHYSICS LAB HANSCOM AFB MA

Personal Author(s) : Johnston,Janet C.

Report Date : 28 MAY 1986

Pagination or Media Count : 58

Abstract : Several earthquake recordings at Golden, Colorado in the magnitude ranges 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. Keywords: Seismic waves; Seismic data; Synthetic waveforms; Green's function addition; Wasatch front earthquake; Seismic hazard; Earthquake prediction.

Descriptors :   *EARTHQUAKES, *SIMULATION, *EARTHQUAKE WARNING SYSTEMS, ADDITION, AMPLITUDE, COLORADO, FREQUENCY, GREENS FUNCTION, HAZARDS, LOW FREQUENCY, PATHS, PREDICTIONS, PULSES, RECORDING SYSTEMS, RESPONSE, SEISMIC DATA, SEISMIC WAVES, SYNTHESIS, UTAH, WAVEFORMS

Subject Categories : Seismology

Distribution Statement : APPROVED FOR PUBLIC RELEASE