Long Valley
Long Valley Caldera is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. This area of eastern California has produced numerous volcanic eruptions over the last 3 million years including the massive, caldera-forming eruption 760,000 years ago. The most recent eruptions occurred just 500 to 600 years ago from vents along the Mono Crater-Inyo crater volcanic chain, which extends south from Mono Lake into the western part of Long Valley caldera.
A strong earthquake swarm in May of 1980, which included four magnitude 6 earthquakes near the southern margin of the caldera and increased uplift and extension of the Long Valley Caldera, marked the onset of the latest a period of activity in the caldera. This activity continues today and includes recurring earthquake swarms and continued dome-shaped uplift of the central section of the caldera accompanied by changes in thermal springs and gas emissions.
In addition to crustal deformation measurements, the USGS Long Valley Observatory monitors earthquakes, hydrologic conditions, gas discharge, and other geophysical conditions in the Long Valley Caldera region.
Map of Instrument Sites
Data Plots
Most instruments take measurements every 10-minutes. Seven day plots are updated every 30-minutes. Thirty day plots are updated daily.
| Instrument | Plots | |
|---|---|---|
| Dilatometers | past 7-days | past 30-days |
| Magnetometers | past 7-days | past 30-days |
| Tiltmeters | past 7-days | past 30-days |
The plots and data on this site are generated automatically and are not reviewed. They should not be used for engineering, legal, or any other critical applications.
