Geologic map of Sierra El Mayor quake area

Ramon Arrowsmith at ASU passed along this geologic map by Fletcher Spelz of the source area for the magnitude 7.2 Easter Sunday, Sierra El Mayor earthquake in northern Baja California, Mexico (black star).

update 4-8-10 19:23 - Received this anonymous comment: The embedded colored geological map is from the paper by J. Fletcher and R. Spelz, Geosphere, v. 5, no. 4, August 2009, doi: 10.1130/GES00206. "Patterns of Quaternary deformation and rupture propagation associated with an active low-angle normal fault, Laguna Salada, Mexico: Evidence of a rolling hinge?"