Nothing major yet, but:
- HVO raised Mauna Loa’s status to Aviation Code Yellow on July 2nd.
For the past several months, earthquake and ground deformation rates at Mauna Loa Volcano have exceeded long term background levels. An eruption is not imminent and current rates are not cause for alarm. However, they do indicate changes in the shallow magma storage system at Mauna Loa.
Following a significant earthquake swarm in October 2018, HVO seismic stations have recorded an average of at least 50 shallow, small-magnitude earthquakes per week beneath Mauna Loa’s summit, upper Southwest Rift Zone, and upper west flank. This compares to a rate of fewer than 20 per week in the first half of 2018. Shallow earthquakes are occurring in locations similar to those that preceded Mauna Loa’s most recent eruptions in 1975 and 1984.
During this same time period, GPS instrumentation and satellite radar have measured ground deformation consistent with renewed recharge of the volcano’s shallow magma storage system. The current rate and pattern of ground deformation is similar to that measured during inflation of Mauna Loa in 2005 and again from 2014 – 2018.
Together, these observations indicate the volcano is no longer at a background level of activity. Accordingly, HVO is elevating the Mauna Loa alert level to ADVISORY and the aviation color code to YELLOW.
Alert levels and aviation color codes are explained here: https://volcanoes.usgs.gov/vhp/about_alerts.html
This increase in alert level does not mean that an eruption is imminent nor that progression to an eruption is certain. A similar increase in activity occurred between 2014 and 2018 and no eruption occurred.
Here’s their Mauna Loa page.
- One of the strong aftershocks from Friday’s magnitude 7.1 quake in southern California has triggered a swarm of small quakes in a nearby volcanic field, per the California Volcano Observatory (CalVO).
CALIFORNIA VOLCANO OBSERVATORY INFORMATION STATEMENT
U.S. Geological Survey
Saturday, July 6, 2019, 10:42 AM PDT (Saturday, July 6, 2019, 17:42 UTC)
COSO VOLCANIC FIELD VOLCANO (VNUM #323180)
36°1’48” N 117°49’12” W, Summit Elevation 7874 ft (2400 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN
An earthquake swarm started on the evening of July 5 at the southern margin of Coso Volcanic Field in Inyo County, California. The swarm activity was triggered by a magnitude M5.4 earthquake at 9:19 PM PDT located 20 km (~20 miles) ESE of Little Lake, which itself was likely an aftershock of the M7.1 earthquake that occurred about an hour earlier 17 km NNE of Ridgecrest, and south of the Coso area. An average of about 30 earthquakes per hour have been detected since, most within the range of magnitude M1 to M3. No ground deformation indicative of volcanic activity has been detected, and there is no imminent threat of an eruption. The California Volcano Observatory will continue to monitor the situation for any sign of volcanic activity and provide updates as warranted.
Where to go for additional information:
Background on Coso Volcanic Field
Latitude: 36.03° N
Longitude: 117.82° W
The Coso Volcanic Field is located on the eastern side of the Sierra Nevada mountains at the northern end of the Mojave Desert, about 64 km (~40 miles) north of Ridgecrest. The field covers about 150 square miles primarily within the Naval Air Weapons Station at China Lake, and is comprised of lava domes, lava flows, and cinder cones erupted over the past 250,000 years. The most recent eruption was about 40,000 years ago.
The U.S. Geological Survey will continue to monitor these volcanoes closely and will issue additional updates and changes in alert level as warranted. For a definition of alert levels see http://volcanoes.usgs.gov/activity/alertsystem/icons.php.
As part of the U.S. Geological Survey’s Volcano Hazards Program, the California Volcano Observatory aims to advance scientific understanding of volcanic processes and lessen the harmful impacts of volcanic activity in the volcanically active areas of California and Nevada. For additional USGS CalVO volcano information, background, images, and other graphics visit http://volcanoes.usgs.gov/observatories/calvo/. For general information on the USGS Volcano Hazard Program http://volcanoes.usgs.gov. Statewide seismic information for California and Nevada can be found at http://earthquake.usgs.gov/earthquakes/recenteqscanv/.
Featured image: CalVO Operations Room, stock photo, USGS via Wikimedia