Circular 210: Earthquake catalogs for New Mexico and bordering areas: 1869–1998

by: A. R. Sanford, K. Lin, I. Tsai, and L. H. Jaksha, 2002, 104 pages.

Summary

Records of earthquakes for a specific area over a given period of time are significant sources of data for researchers of earthquake activity. Such records allow researchers to evaluate seismic hazards and make more accurate predictions concerning the likely location-and magnitude-of future earthquakes. The catalogs presented here represent more than 40 years of research, provide an accurate historical record of earthquakes in New Mexico, and document a number of trends. A disproportionate number of earthquakes are centered in the Rio Grande valley near Socorro, New Mexico, in a tight cluster of earthquakes known as the Socorro Seismic Anomaly. The enhanced seismic activity of this region is believed to be the result of the stretching of the earth's crust over a large body of magma that exists at a depth of 12 miles below the region. This anomaly occupies less than 1% of the study area but accounts for 23% of the earthquakes of magnitude 2.0 or greater. Two parallel east-northeast trends are also apparent: an alignment the authors call the Socorro fracture zone and, to the north, the Jemez lineament, a large-scale fracture zone that extends from southwest of Grants, New Mexico, to Los Alamos, Española, and beyond to the northeast corner of the state. Surprisingly, with the exception of the Socorro Seismic Anomaly, no discernable trend is apparent for the Rio Grande rift, a major flaw in the earth's crust that bisects the state north to south and along which the Rio Grande flows.

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Data files

The data presented in Circular 210 are also available for download from our data repository < https://geoinfo.nmt.edu/repository/index.cfm?rid=20020001 > (the repository was created subsequent to publication of this Circular).

Since the publication of Circular 210, additional data have been published in New Mexico Geology:

• Data for 1999–2004 was published in New Mexico Geology v. 28 n. 4 and in a separate repository for that article: < https://geoinfo.nmt.edu/repository/index.cfm?rid=20060001 >.
• Data for 2005–2009 was published in New Mexico Geology v. 35 n. 1 and in a separate repository for that article: < https://geoinfo.nmt.edu/repository/index.cfm?rid=20130001 >.

Note that these data should be used in conjuction with the circular text, which can be purchased from our publications department or downloaded above (PDF version). The data is available as spreadsheets in MS Excel (xls) and as comma delimited text (csv) formats.