![]() ![]() Geological Survey Geophysical Investigations Map GP - 932. Visit the agency’s site to opt into its Earthquake Notification Service. , 1981, Maps showing aeromagnetic anomalies, faults, earthquake. These faults are considered “active” and are likely to cause another earthquake.Īll data in this project comes from the U.S. Southern California Seismic Network Earthquake Research Affiliates Historical Earthquakes in Southern California Clickable Fault Map of Southern California. Our optional fault layer shows fault lines from the USGS that cross the Bay Area that have seen evidence of seismic activity in the last 150 years. At intensity VIII and beyond, structural engineers help determine how to categorize the quake based on observable damage, which can include rails bent, bridges destroyed and buildings shifted off their foundations. An intensity VII quake is widely felt and can destroy poorly built structures. These are preliminary ground shaking maps, normally posted within several minutes of the earthquake origin time. The measure is designated using Roman numerals.Ī quake at intensity III can be felt near the epicenter, but with no damage to structures. ShakeMaps are generated automatically following moderate and large earthquakes. Photo credits: (1) Arnold Genthe, Steinbrugge Collection of the UC Berkeley Earthquake Engineering Research Center (2) Bulletin of the Seismological Society of America (3) Portland Cement Association (4) Bolt. Rather than a gauge of pure shaking, intensity takes into account the effects on people and damage to infrastructure. Click on image for selected historic California earthquake photos. Intensity contours show how strongly a quake was felt and are displayed on the Quake Tracker when available. Quakes below magnitude 3.0 are often not felt and do not appear on this map. The Quake Tracker displays quakes from the past 30 days with magnitudes above 3.0 in Northern California, 4.0 in Southern California, 5.0 in the United States, and 7.0 in North America. ![]()
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