Recent Status Report, Updates, and Information Releases

LONG VALLEY OBSERVATORY DAILY UPDATESaturday, November 21, 2009 10:04 AM PST (Saturday, November 21, 2009 18:04 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located just one small earthquake in the vicinity of Long Valley caldera since the last update at 9:26 AM (PST) on November 20. This was a magnitude M=1.6 earthquake at 3:51 PM on the 20th centered at the depth of 5 miles beneath the eastern outskirts of Mammoth Lakes (1/4 mile north of the corrals).

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATEFriday, November 20, 2009 9:26 AM PST (Friday, November 20, 2009 17:26 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located three small earthquakes in the vicinity of Long Valley caldera since the last update at 9:16 AM (PST) on November 19. Magnitude M=0.3 and M=0.1 earthquakes at 9:16 and 11:45 PM on the 19th were located beneath the Mammoth Mountain. A M=0.5 earthquake at 3:59 AM on the 20th was located in the Sierra Nevada south of the caldera (7 miles west of Tom's Place).

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATEThursday, November 19, 2009 9:31 AM PST (Thursday, November 19, 2009 17:31 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located three small earthquakes in the vicinity of Long Valley caldera since the last update at 8:01 AM (PST) on November 18. A M=0.4 earthquake at 8:50 AM on the 18th was located beneath the southwest flank of Mammoth Mountain (1 mile west of Mammoth Pass). Three earthquakes were located beneath the Sierra Nevada south of the caldera. The largest was a M=1.6 event at 10:05 AM on the 18th located 4 miles NW of Round Valley.

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATEWednesday, November 18, 2009 8:01 AM PST (Wednesday, November 18, 2009 16:01 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located three small earthquakes in the vicinity of Long Valley caldera since the last update at 9:56 AM (PST) on November 17. All three occurred in a cluster near Grinnell Lake in the Sierra Nevada south of the caldera (11 miles SW of Tom's Place). The largest was a M=2.2 earthquake at 11:04 AM on the 17th. It was followed by M=2.0 and M=1.0 earthquakes at 1:41 PM and 4:06 PM, respectively.

Post-processing identified a sequence of four small earthquakes beneath Mammoth Mountain that were not included in yesterday's update. They occurred between 12:16 and 12:27 AM on the 17th. The largest were M=0.4 events at 12:16 and 12:27 AM.

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATETuesday, November 17, 2009 9:56 AM PST (Tuesday, November 17, 2009 17:56 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located two small earthquakes in the vicinity of Long Valley caldera since the last update at 7:28 AM (PST) on November 16. A magnitude M = 0.1 earthquake at 5:44 PM on the 16th was followed 15 seconds later by a M=0.3, both located beneath the north flank of Mammoth Mountain.

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATEMonday, November 16, 2009 7:28 AM PST (Monday, November 16, 2009 15:28 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located five small earthquakes in the vicinity of Long Valley caldera since the last update at 9:05 AM (PST) on November 15. A magnitude M=1.2 earthquake at 12:27 PM on the 15th was located beneath Mammoth Mountain. A cluster of four earthquakes centered 0.5 mile SE of Grinnell Lake in the Sierra Nevada south of the caldera (11 miles SW of Tom's Place) included a M=2.6 earthquake at 5:34 PM on the 15th followed four minutes later by a M=1.3 aftershock. Two additional M=1.3 earthquakes in this cluster occurred at 3:45 and 4:02 AM on the 16th.

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATESunday, November 15, 2009 9:10 AM PST (Sunday, November 15, 2009 17:10 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located two small earthquakes in the vicinity of Long Valley caldera since the last update at 9:58 AM (PST) on November 14. Both were located in the Sierra Nevada south of the caldera. The largest was a magnitude M=1.4 earthquake at 2:39 PM on the 14th located 9 miles SW of Tom's Place.

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATESaturday, November 14, 2009 9:58 AM PST (Saturday, November 14, 2009 17:58 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located five small earthquakes in the vicinity of Long Valley caldera since the last update at 9:23 AM (PST) on November 13. One was a M=0.2 earthquake at 11:29 AM on the 13th located beneath Mammoth Mountain (3 miles WSW of Mammoth Lakes). The other four were located in the Sierra Nevada south of the caldera. The largest was a M=1.3 earthquake at 1:46 AM on the 14th located 11 miles SW of Tom's Place.

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATEFriday, November 13, 2009 9:23 AM PST (Friday, November 13, 2009 17:23 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located just one small earthquake in the vicinity of Long Valley caldera since the last update at 9:01 AM (PST) on November 12. This was a M=0.3 earthquake at 2:54 AM on the 13th located beneath Mammoth Mountain (4 miles WSW of Mammoth Lakes).

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.
LONG VALLEY OBSERVATORY DAILY UPDATEThursday, November 12, 2009 9:01 AM PST (Thursday, November 12, 2009 17:01 UTC)

LONG VALLEY VOLCANIC CENTER VOLCANO (CAVW #1203-14-)
37°42' N 118°52'12" W, Summit Elevation 11122 ft (3390 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The real-time computer system located just one small earthquake in the vicinity of Long Valley caldera since the last update at 9:36 AM (PST) on November 11. This was a M=1.7 earthquake at 4:13 AM on the 12th located in the Sierra Nevada south of the caldera (11 miles SW of Tom's Place).

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The Long Valley Observatory (LVO) monitors and studies earthquakes, ground deformation, degassing, and other types of geologic unrest in and around the Long Valley Caldera. The 15 by 30 km Long Valley Caldera was formed during an eruption 760,000 years ago and is located 20 km south of Mono Lake along the east side of the Sierra Nevada in east-central California. There have been multiple smaller eruptions since the caldera-forming eruption with the most recent occurring 250 years ago in Mono Lake at the north end of Mono-Inyo Craters volcanic chain. LVO is one of the five USGS Volcano Observatories that monitor volcanoes within the United States for science and public safety.

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

For more information about the Volcano Alert Level and Aviation Color Code, please see the USGS Volcanic Activity Alert-Notification System web page.

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Page Last Modified: Thursday, 01-Oct-2009 10:11:07 (dyv)