Overlay represents area within CalVO's jurisdiction.
California Volcano Observatory's mission
As a part of the U.S. Geological Survey's Volcano Hazards Program, the
California Volcano Observatory aims to advance scientific understanding
of volcanic processes and lessen the harmful impacts of volcanic activity
in the volcanically active areas of California and Nevada.
Saturday, December 07, 2013 11:36 AM PST
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
Volcano Hazard Mitigation Included in California Multi-hazard Mitigation Plan
October 29, 2013
On October 6, 2013 the California Office of Emergency Services (CalOES) published its 2013 State of California Multi-Hazard Mitigation Plan
complete with a chapter from the USGS on volcano hazard mitigation. This document is the official statement of the State's hazard identification, vulnerability analysis, and hazard mitigation strategy. Volcanic eruptions occur in California about as frequently as the largest San Andreas Fault Zone earthquakes. Our State Geologist, John Parrish states, "California is the most geologically diverse state in the Nation. We are known for our earthquakes, landslides, and flood hazards. But our nearly forgotten hazard is our volcanoes." With as many as ten eruptions in the last 1,000 years, recognizing the potential for renewed volcanism in California is an essential first step in mitigating hazardous impacts.
You can see the full Mitigation Plan
on the CalOES website.
Magnitude 3.8 earthquake in Long Valley region is tectonic, and not volcanic, in origin
October 21, 2013
A magnitude 3.8 earthquake occurred on October 21, 2013 at 10:04 PDT 18 km (11 miles) SE of the town of Mammoth Lakes in eastern California. It was weakly felt by some in Mammoth Lakes, Bishop, and nearby areas. This event occurred in area of persistently high seismicity beneath the Sierra Nevada mountains, and follows magnitude 3.3 and 3.4 events that occurred nearby on October 11. These earthquakes are occurring at a depth of about 8 km (5 miles) beneath the surface, and appear to related to regional tectonic stresses (combination of strike-slip and extensional faulting) rather than volcanic unrest in Long Valley caldera. For more information about the earthquake, visit the event webpage
. Click image to right for mapped location and description.
Instrumentation Installed for Continuous Monitoring of Carbon Dioxide Emissions at Horseshoe Lake, Mammoth Mountain
July 02, 2013
Since 1990, high levels of carbon dioxide (CO2) in the soil have killed trees within about a 75-acre area adjacent to Horseshoe Lake on the south side of Mammoth Mountain. This CO2 migrates upwards to the surface from depth beneath the mountain. In June 2013, a new measurement array was installed by the USGS adjacent to Horseshoe Lake to continuously monitor changes in CO2 emissions over space and time. At the heart of this instrumentation is a set of atmospheric sensors mounted on a tripod tower above the ground surface. These sensors make high-frequency measurements of atmospheric CO2 concentrations and wind speeds and directions. Using the "eddy covariance" method, these measurements are then used to calculate rates of CO2 emission from land areas around the instrument tower (which change with atmospheric conditions such as wind speed and direction) on a half-hourly basis. Continuous monitoring of CO2 emissions should allow for better understanding of the relationships between changes in these emissions and variations in local weather conditions and activity (for example, seismicity) beneath Mammoth Mountain.