Earthquakes in California and Nevada
Each year seismic networks record more than 30,000 earthquakes with magnitudes (M) as small as 1.0 in California and Nevada. Historic accounts indicate more than 360 earthquakes of M ≥5.5 have occurred in this region between 1836 and 1994. This map depicts the recent and historic seismicity in three ways. The small red dots represent epicenters of earthquakes between 1 January 1980 and 31 January 1994. The black circles depict all known epicenters of M≥5.5 earthquakes since 1836. A number adjacent to an epicenter location refers to an entry in the table "Known M≥6.5 Earthquakes since 1836." The hachured regions indicate the surface projection of fault rupture for significant earthquakes as inferred from geologic observations of surface deformation and estimates of subsurface faulting from geophysical methods. Tightly spaced hachures represent vertical, strike-slip faults, and wider spaced hachures designate slipping faults.