Lake Roberts Dam is located in Grant County in southwestern New Mexico. Tectonically the damsite is within the Southern Basin and Range Province and the Rio Grande rift as defined by Machette (1998). Although the historical seismicity in the region has been low, the site has undoubtedly been shaken by past large prehistoric earthquakes caused by active regional faults and in historical times, as recently as 1887 (Figures 2 to 4).
