Recent Earthquakes in California and Nevada


Data sources


California highways were extracted and compiled by volunteer Kirstin Mortensen and Carl Mortensen. Nevada placenames were supplied by Ken Smith and David Vonseggern at UNR, Nevada roads by Robert Miller at USGS.

Faults for the index map were provided by Art Frankel and Jim Lienkaemper. Faults on the zoomed-in maps came from C.W. Jennings, 1992, California Division of Mines and Geology Open-File Report 92-03. (This map has been superseded by Jennings, C.W., 1994, Fault activity map of California and adjacent areas, with locations and ages of recent volcanic eruptions: California Division of Mines and Geology, Geologic Data Map No. 6, map scale 1:750,000.)

Andy Michael wrote the programs to prepare the earthquake data. Doug Neuhauser and Steve Malone assisted with advice and examples in the construction of the catalog merging software. Bob Simpson - with lots of help and suggestions from Bill Ellsworth, Dave Oppenheimer, and Andy Michael - designed the base maps, links, and programs that update the web pages. Jim Luetgert designed and programmed the waveforms pages for northern California. In addition Carl Mortensen, Steve Malone, Lind Gee, Lucy Jones, Stan Silverman, Paul Reasenberg, sharp-eyed Lynn Dietz and many others offered valuable ideas and suggestions.

The appearance of these pages was greatly improved with help and suggestions from Sara Boore. (She bears no responsibility for the remaining defects!) Paul Reasenberg helped select colors that would be distinguishable by color-blind viewers. Barbara Simpson offered advice on colors, and suggested ways to make the earthquake lists more readable.


Maps are updated using the GD library originally written by Thomas Boutell, and the GD interpreter tgd written by Bradley K. Sherman. Program XV by John Bradley and xpaint by David Koblas were used extensively in the preparation of the basemaps. Many thanks to these gentlemen for their nifty programs!

The earthquake location data, seismologist comments, and additional information (e.g., seismogram images and mechanisms) are distributed using a program called ProductClient (PDL). An indexer written in Python by Shang-Lin Chen works with the PDL system to generate the catalog of earthquake locations used to generate these earthquake maps.