LONG VALLEY OBSERVATORY WEEKLY UPDATEThursday, January 12, 2012 5:46 PM PST (Friday, January 13, 2012 01:46 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

Fifteen earthquakes with magnitudes between M=1.0 and M=1.8 occurred in the Mammoth Lakes-Long Valley region in the last seven days. The events were located in the Sierra Nevada, with the exception of three earthquakes in the caldera east of the town of Mammoth Lakes and one event in Round Valley.

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.