Earthquake Information

Parkfield Earthquake

A magnitude 6.0 earthquake occurred near the central California town of Parkfield Tuesday morning September 28. The Office of Emergency Services (OES) is reporting that there is no significant damage and no casualties as a result of this earthquake. A series of aftershocks were felt, the largest recorded was a preliminary M5.0 that occurred four minutes after the main shock.

Parkfield, which is located along the San Andreas fault zone, is well-known in the scientific community. Geologists and seismologists from government agencies and universities have been monitoring this rural area for earthquakes since the late 1970's. In 1985 the Parkfield Earthquake Experiment was launched by the U.S. Geological Survey and the State of California to better understand what happens on a fault before, during and after an earthquake. The project has involved more than 100 researchers from government agencies and universities.

Scientists from the California Geological Survey are en route to investigate geologic features in the affected area and assist local agencies if requested. CGS geologists will document any occurrences of ground failure such as fault rupture, liquefaction, and/or landslides. This information will be incorporated to our earthquake hazard mapping programs. Please return to our website over the next couple days and weeks and we will try to provide pictures and commentary from field work related to this earthquake.

Summary of Surface Fault Rupture Mapping 

DOC News Release of October 13, 2004 - Early Data Assessment

Shake Map of the  Parkfield Earthquake

USGS Poster of the Parkfield Earthquake

Strong-Motion Data from the M6.0 Parkfield Earthquake

Other Agencies' Information about the Parkfield Earthquake


More historical Parkfield information can be found in:  Toppozada, T. R., D. M. Branum, M. S. Reichle, and C. L. Hallstrom (2002) San Andreas Fault Zone, California: M>=5.5 Earthquake History, Bulletin of the Seismological Society of America, Vol. 92, No. 7, pp 2555-2601.