Analysis and selection of magnitude relations for the Working Group on Utah Earthquake Probabilities

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Abstract

Prior to calculating time-independent and -dependent earthquake probabilities for faults in the Wasatch Front region, the Working Group on Utah Earthquake Probabilities (WGUEP) updated a seismic-source model for the region (Wong and others, 2014) and evaluated 19 historical regressions on earthquake magnitude (M). These regressions relate M to fault parameters for historical surface-faulting earthquakes, including linear fault length (e.g., surface-rupture length [SRL] or segment length), average displacement, maximum displacement, rupture area, seismic moment (Mo ), and slip rate. These regressions show that significant epistemic uncertainties complicate the determination of characteristic magnitude for fault sources in the Basin and Range Province (BRP). For example, we found that M estimates (as a function of SRL) span about 0.3–0.4 units (figure 1) owing to differences in the fault parameter used; age, quality, and size of historical earthquake databases; and fault type and region considered.

Additional publication details

Publication type Conference Paper
Publication Subtype Conference Paper
Title Analysis and selection of magnitude relations for the Working Group on Utah Earthquake Probabilities
Year Published 2015
Language English
Publisher Utah Geological Survey
Contributing office(s) Geologic Hazards Science Center
Description 30 p.
Larger Work Type Report
Larger Work Subtype State/Local Government Series
Larger Work Title Basin and Range Province Seismic Hazards Summit III, Utah Geological Survey Miscellaneous Publication 15-5
Conference Title Basin and Range Province Seismic Hazards Summit III