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Alert Level: ADVISORY, Color Code: YELLOW
2020-11-26 19:48:30 UTC





HAWAIIAN VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Thursday, November 26, 2020, 9:48 AM HST (Thursday, November 26, 2020, 19:48 UTC)


MAUNA LOA VOLCANO (VNUM #332020)
19°28'30" N 155°36'29" W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Activity Summary: Mauna Loa Volcano is not erupting. Rates of deformation and seismicity have not changed significantly over the past week and remain above long-term background levels.

Observations:

During the past week, HVO seismometers recorded 136 small-magnitude earthquakes across the whole volcano, 91 of which were under the volcano's summit and upper-elevation flanks, including a cluster in the volcano's west flank. Most of these earthquakes occurred at shallow depths of less than 8 kilometers (~5 miles) below ground level.

Global Positioning System (GPS) measurements show overall continued slow summit inflation, consistent with magma supply to the volcano's shallow storage system.

Gas concentrations and fumarole temperatures at both the summit and Sulphur Cone on the Southwest Rift Zone remain stable.

Webcam views have revealed no changes to the landscape over the past week.

For more information on current monitoring of Mauna Loa Volcano, see: https://www.usgs.gov/volcanoes/mauna-loa/monitoring






Background: Mauna Loa is the largest active volcano on our planet, rising gradually to 4,170 m (13,681 ft) above sea level. Its long submarine flanks descend an additional 5 km (3 mi) below sea level to the ocean floor. The ocean floor directly beneath Mauna Loa is, in turn, depressed by the volcano's great mass another 8 km (5 mi). This places Mauna Loa's summit about 17 km (56,000 ft) above its base. The enormous volcano covers half of the Island of Hawaiʻi.

Eruptions typically start at the summit and, within minutes to months of eruption onset, about half of the eruptions migrate into either the Northeast or Southwest Rift Zones. Since 1843, the volcano has erupted 33 times with intervals between eruptions ranging from months to decades. Mauna Loa last erupted 35 years ago, in 1984.

Mauna Loa eruptions tend to produce voluminous, fast-moving lava flows that can impact communities on the east and west sides of the Island of Hawaiʻi. Since the mid-19th century, the city of Hilo in east Hawaiʻi has been threatened by seven Mauna Loa lava flows. Mauna Loa lava flows have reached the south and west coasts of the island eight times: 1859, 1868, 1887, 1926, 1919, and three times in 1950.

MORE INFORMATION:

Activity summary for Mauna Loa is also available by phone: (808) 967-8866

Subscribe to these messages: https://volcanoes.usgs.gov/vns2/

Webcam images: https://www.usgs.gov/volcanoes/mauna-loa/webcams

Photos/video: https://www.usgs.gov/volcanoes/mauna-loa/photo-video-chronology

FAQs of Mauna Loa: https://www.usgs.gov/volcanoes/mauna-loa/faqs

Summary of volcanic hazards from eruptions: https://www.usgs.gov/observatories/hawaiian-volcano-observatory/hazards

Recent earthquakes in Hawaiʻi (map and list): https://www.usgs.gov/volcanoes/mauna-loa/monitoring

Explanation of Volcano Alert Levels and Aviation Color Codes: https://www.usgs.gov/natural-hazards/volcano-hazards/about-alert-levels

CONTACT INFORMATION:

askHVO@usgs.gov

The Hawaiian Volcano Observatory is one of five volcano observatories within the U.S. Geological Survey and is responsible for monitoring volcanoes and earthquakes in Hawaiʻi.