Long Valley Observatory Recent Status Report, Updates, and Information Releases

LONG VALLEY OBSERVATORY WEEKLY UPDATE
Friday, May 21, 2010 3:03 PM PDT (Friday, May 21, 2010 22:03 UTC)


LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 7231 ft (2204 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

Seventeen earthquakes between magnitude M=1.0 and M=3.0 occurred in the Long Valley region since the last update on May 14, 2010. All but three of the events were located in the Sierra Nevada south of the caldera. The others (including the M=3.0) were located ~ 20 km (12 miles) north of the Town of Mammoth Lakes. This level of activity is considered normal for the area.



Long Term Trends

Seismic Trend: Earthquake activity within and adjacent to the caldera has remained low since mid-1999 averaging just five to ten earthquake per day with magnitudes less than M=2 and an occasional event as large as M=3. see details.

Deformation trend: Renewed uplift of the resurgent dome that began in early 2002 ended in early 2003 largely offsetting the 2 cm of subsidence that accumulated from early 1999 through the end of 2001. The resurent dome has since shown minor fluctuations in uplift and subsidence but remains roughly 80 cm higher than in the late 1970's. see details.

CO2 trend: The diffuse carbon dioxide gas flux in the Horseshoe Lake tree-kill area has shown little change from the relatively high levels of 50 to 150 tons per day sustained for the past several years; see details.

Update Archive and Quarterly and Annual Summaries | Reference map for place names

See USGS Volcanic Activity Alert-Notification System for more information about the alert system.