Mauna Loa Volcano Eruption Update

HAWAIIAN VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Thursday, October 14, 2021, 9:31 AM HST (Thursday, October 14, 2021, 19:31 UTC)

 
An aerial view of the prominent 1940 cinder-and-spatter cone on the floor of Mauna Loa's summit caldera.
An aerial view of the prominent 1940 cinder-and-spatter cone on the floor of Mauna Loa's summit caldera. The cone, about 100 m (330 ft) high, was built during a 134-day-long eruption that began on April 7, 1940. Most of the caldera floor around the cone is covered by last lava flows erupted in 1984.

Photo courtesy of USGS

MAUNA LOA

Current Volcano Alert Level: ADVISORY
Current Aviation Color Code: YELLOW

Activity Summary: Mauna Loa Volcano is not erupting. Rates of seismicity at the summit remain slightly above long-term background levels, but have not changed significantly over the past week. Other monitoring data streams—ground deformation, gas discharge, and visual observations—show no significant changes.

Observations:
During the past week, HVO seismometers recorded 84 small-magnitude earthquakes—all below M3.0—beneath the summit and upper-elevation flanks of Mauna Loa. The majority of these earthquakes occurred at shallow depths less than 8 kilometers (5 miles) below sea level.

Measurements of ground deformation, using Global Positioning System (GPS) instruments, confirm that the surface of the volcano has not moved significantly over the past week.

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

Webcam views have shown no changes to the landscape at the Mauna Loa summit or on the lower flanks of the volcano over the past week.

Last updated: October 18, 2021

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