OFR 97–464: Page [1]
Introduction
Reliable earthquake catalogs are essential for probablistic seismic hazard analysis. Part of the hazard in the new national seismic hazard maps (Frankel et al, 1996) comes from smoothed historical seismicity, so it was important for us to find or make a suitable catalog for the contiguous 48 states. Initially, we had access to the following catalogs.
Preliminary Determination of Epicenters (PDE)
We downloaded a PDE catalog for the map area from the National Earthquake Information Center (NEIC) computer in Golden, Colorado, using NEIC's catalog-search software: 23o <= latitude <= 52o , -127o <= longitude <= -65o , magnitude >= 3.0, time >= 1960. It includes offshore earthquakes and earthquakes in southern Canada and northern Mexico. In our version of the PDE catalog each record contains zero to four magnitude entries: mb and/or Ms determined by NEIC and/or up to two magnitude values (of any type) contributed by other agencies. For contributed magnitudes the magnitude type and contributing agency are listed. This catalog contains approximately 18,000 records from 1960 to June 1995.
Decade of North American Geology (DNAG)
We downloaded a DNAG catalog (Engdahl and Rinehart, 1991) for the map area from the NEIC computer in Golden using NEIC's catalog-search software: 23o <= latitude <= 52o , -127o <= longitude <= -65o , magnitude >= 3.0. It includes offshore earthquakes and earthquakes in southern Canada and northern Mexico. In our version of the DNAG catalog each record contains one magnitude entry (apparently the largest of all reported magnitude values) of any type. The magnitude type and contributing agency are listed. This catalog contains approximately 24,300 records from 1534 to December 1985.
California Division of Mines and Geology (CDMG)
The CDMG catalog (M. Petersen, personal communication, 1995) covers California (including offshore) and adjacent parts of Nevada, Arizona, and Mexico. In our version each record contains a single ML-like magnitude (or moment magnitude for some large earthquakes where ML might have saturated) with magnitude >= 4.0. This catalog contains approximately 5,200 records from 1800 to August 1994.
New Mexico Earthquakes 1962-1994 (NEWMEX)
Sanford et al (1995) studied seismicity in New Mexico since 1962, and published a catalog that...>>NEXT
Last Update: Thursday, February 16, 2006 9:58
