
Courtesy Jana Pursley, NMT
Seismicity in central New Mexico, southwestern United States, is dominated by earthquakes occurring above the mid-crustal Socorro Magma Body (SMB). The SMB is a sill-like feature ≥ 3400 km2 in area, with a top surface at 19-km depth spanning the inner Rio Grande rift half-graben system. Inflation of the magma body at rates of several mm/year, perhaps coupled with shallow transport of aqueous fluids, is the prevailing model for the region’s long-standing and anomalous seismicity. Clustered swarms of small magnitude earthquakes have been noted since the 1860s throughout this region, and have been recorded instrumentally since the early 1960’s (Figure 1, blue squares, Sanford et al., 20021).