Geology topics
Robert P. Masse
Publications and source records attributed to Robert P. Masse.
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.
United States National seismograph network
The USGS National Earthquake Information Center (NEIC) has planned and is developing a broadband digital seismograph network for the United States. The network will consist of approximately 150 seismograph stations distributed across the contiguous 48 states and across Alaska, Hawaii, Puerto Rico and the Virgin Islands. Data transmission will be via two-way satellite telemetry from the network sites to a central recording facility at the NEIC in Golden, Colorado. The design goal for the network is the on-scale recording by at least five well-distributed stations of any seismic event of magnitude 2.5 or greater in all areas of the United States except possibly part of Alaska. All event data from the network will be distributed to the scientific community on compact disc with read-only memory (CD-ROM).