Infrasound signal characteristics of small earthquakes

Update Item Information
Title Infrasound signal characteristics of small earthquakes
Publication Type thesis
School or College College of Mines & Earth Sciences
Department Geology & Geophysics
Author Hale, John Mark
Date 2013-08
Description The University of Utah Seismograph Stations recorded 293 earthquakes (3.0 < M < 5.9) between April 17, 2007 and June 30, 2012. During this time, four-element infrasound data were collected from three permanent (NOQ, BGU, and EPU; installed 2006 - 2007) and six temporary (BRP, WMU, HWU, FSU, LCM, and PSU; installed summer of 2010) seismo-acoustic arrays. Unique epicentral infrasound observations from nine earthquakes with M 3.6 - 5.9 are identified and characterized. The detections were recorded from normal, oblique normal, and strike-slip faulting earthquakes at distances of 156 - 695 km and depths of 5 - 12 km. We use ray-tracing through ground-to- space atmospheric models from the epicenters to each array to determine the atmospheric turning altitude and associated wind velocities. Distance and wind corrected amplitudes match previously determined scaling relations. However, the duration observations from smaller magnitude earthquakes suggest the possibility of an additional scaling relation for events M < 4.6. This possible change in duration scaling relation is inconsistent with the hypothesis that infrasound duration scales with the areal extent of the epicentral region subjected to a threshold peak ground acceleration. The predicted ground motions show that the area subject to the threshold increases more rapidly with increased magnitudes. Overall, the small percentage of infrasound detections from the total possible suggests that infrasound is not a robust method of detecting and characterizing small earthquake sources.
Type Text
Publisher University of Utah
Subject Earthquakes; Infrasound; Nuclear discriminant; Ray tracing; Western United States
Dissertation Institution University of Utah
Dissertation Name Master of Science
Language eng
Rights Management Copyright © John Mark Hale 2013
Format application/pdf
Format Medium application/pdf
Format Extent 1,113,847 bytes
Identifier etd3/id/2545
ARK ark:/87278/s6tf35hc
Setname ir_etd
ID 196121
Reference URL https://collections.lib.utah.edu/ark:/87278/s6tf35hc
Back to Search Results