The Prairie Spring earthquake swarm: a seismic event in the Chupadera Mesa region, central New Mexico
Allan R. Sanford
A strong earthquake swarm located a short distance west of Chupadera Mesa produced 348 shocks with magnitudes of 0.2 or greater from 14 February 1990 through 31 August 1990. The cumulative seismic moment for the swarm in combination with assumptions on the ratios of rupture width to length and rupture displacement to length yielded an estimate of 2.9 km2 for the rupture area. This estimate is in agreement with the rupture areas estimated from the geographic distribution of epicenters and focal depths, and the fault dip from a composite fault mechanism based on P-wave first motions. An eye fit to the distribution of 68 epicenters indicates the fault rupture had a strike on the order of N66W. The strike of the composite fault-plane solution is on the order of N48W. Uncertainties in both estimates indicate an average strike of ~N57W, an unusual orientation compared to the northerly strikes for most faults in the Socorro area. This suggests that the Prairie Spring swarm location and mechanism may be related to the WNW trending Capitan lineament. Activation of the fault producing the swarm earthquakes may have been caused by stresses created by steady–state inflation of the Socorro mid–crustal magma body
- Sanford, Allan R., 2009, The Prairie Spring earthquake swarm: a seismic event in the Chupadera Mesa region, central New Mexico, in: Geology of the Chupadera Mesa, Lueth, Virgil W.; Lucas, Spencer G.; Chamberlin, Richard M., New Mexico Geological Society, Guidebook, 60th Field Conference, pp. 139-144.