Is there a place on the WEB where I can get up to date information on events pertaining to the Long Valley Volcano? I understand there has been a new series of tremors in this area. What significance does this have?

Rick

Hi Rick,

There is a long Valley home page on the web, but I don't know its address. Try doing a web search, or better yet, go to the Cascades Volcano Observatory home page (linked from VolcanoWorld), and they have a link to Long Valley. Below is the report that just came about the seismicity at Long valley.

Sincerely,

Scott Rowland

An earthquake swarm in the south moat of Long Valley began with a magnitude M=3.9 earthquake at 10:14 AM (PST) on Friday March 29th and continued through the weekend. As of 7:00 AM Monday morning (April 1), the swarm has produced some 18 earthquakes with magnitudes M=3 or greater including three with M=3.9 and two with M=4.0. The rate of earthquake activity was greatest from Saturday evening through early Sunday morning when our computers were detecting and locating more than 40 events per hour for several hours. The total number of detected and located earthquakes (M>0.5) exceeds 1,000 through 7:00 AM today. A gradual decline in the rate of earthquake activity that began early Sunday morning was interrupted by M=3.5 and 3.7 earthquakes at 11:18 AM (PST) and 11:27 AM on Sunday and then again by M=3.3 and 3.9 events at 6:07 and 6:13 PM on Sunday afternoon. The earthquakes in this swarm are clustered 10 to 11 km ESE of Mammoth Lakes (just south of the airport) and at depths of 7 to 11 km beneath the surface.

We have seen no evidence for significant ground deformation associated with this swarm activity.

Five or more M>3 earthquakes in a 24 hour period places the caldera in a C-STATUS. The current C-STATUS will expire at 6:30 PM (PST) on Wednesday April 3rd barring if the current decline in activity continues.

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