The Los Alamos Seismic Network: History, Status and Updated Monitoring of North-Central New Mexico Seismicity

Session: Recent Advances in Very Broadband Seismology [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

The seismicity of north-central New Mexico is not well studied. This is due partly to the complexity of the local tectonics of north-central New Mexico, partly to the limited regional-scale seismic station coverage and partly to the low rate of seismicity. The Los Alamos Seismic Network (LASN) has been operated by Los Alamos National Laboratory (LANL) since 1973 and provides the primary earthquake monitoring for the region. LASN’s spatial extent has grown to roughly 600 sq km over the last 10 years by the addition of 11 stations to the original 7, but it is still best suited for local seismicity monitoring. LASN has detected more than 2500 small earthquakes from 1973 to present. Roughly 900 of these earthquakes were located within 150 km of LANL. On average, about 20-25 local earthquakes per year are recorded, most with magnitudes less than 1.5. These are not listed in other network catalogs. In general, the seismicity occurs at a steady rate and is spatially diffuse and scattered. Some earthquakes are associated with diverse, tectonic features such as the Pajarito fault system, the Rio Grande rift, Valles Caldera and the Nacimiento Uplift, but most are not related to known or well-mapped faults. There have also been numerous earthquake swarms superimposed on this background seismicity. These are poorly understood and none appear to be associated with Valles Caldera, which is remarkably quiet seismically. Recent LASN station expansion and upgrades have allowed the detection of very small caldera-related events and small felt events near Los Alamos. We will present the history of LASN from 1973 to present, including a description of the current LASN station configurations, station coverage and instrument improvements. We will also show updated LASN earthquake locations for north-central New Mexico and review the historic, pre-LASN seismicity of the region. LASN data can be supplied by request.

Presenting Author: Peter M. Roberts

Authors