Calculating California seismicity rates
Open-File Report
2007-1437-I
Prepared in cooperation with the California Geological Survey and the Southern California Earthquake Center
By: Karen R. Felzer
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Abstract
Empirically the rate of earthquakes = magnitude M is well fit by the Gutenberg-Richter relationship, logN=a-bM (1) where N is the number of earthquakes = M over a given time period, a is the number of M = 0 earthquakes over the same period, and b is a parameter that determines the ratio of larger to smaller earthquakes (Ishimoto and Iida 1939; Gutenberg and Richter 1944). Thus to characterize the seismicity rate, N, and risk in a given region we need to solve for the values of a and b. Here we are concerned with solving for the long term average values of these parameters for the state of California. My primary data source is a catalog of 1850-2006 M = 4.0 seismicity compiled with Tianqing Cao (Appendix H). Because earthquakes outside of the state can influence California I consider both earthquakes within the state and within 100 km of the state border (Figure 1).
| Publication type | Report |
|---|---|
| Publication Subtype | USGS Numbered Series |
| Title | Calculating California seismicity rates |
| Series title | Open-File Report |
| Series number | 2007-1437 |
| Chapter | I |
| DOI | 10.3133/ofr20071437I |
| Edition | Version 1.0 |
| Year Published | 2008 |
| Language | English |
| Publisher | U.S. Geological Survey |
| Publisher location | Reston, VA |
| Contributing office(s) | Earthquake Hazards Program, Earthquake Science Center |
| Description | iii, 41 p. |
| Larger Work Type | Report |
| Larger Work Subtype | USGS Numbered Series |
| Larger Work Title | Appendix I in The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2) |
| Google Analytic Metrics | Metrics page |