Mauna Loa - Volcano Updates

Alert Level: ADVISORY, Color Code: YELLOW 2019-09-12 18:07:18

U.S. Geological Survey
Thursday, September 12, 2019, 8:07 AM HST (Thursday, September 12, 2019, 18:07 UTC)

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 in the past week and persist above long-term background levels.

Observations: During the past week, approximately 49 small-magnitude earthquakes (all smaller than M2.5) were detected beneath the upper elevations of Mauna Loa. Most of the earthquakes occurred at shallow to intermediate depths of less than 10 km (~6 miles) below ground level.

Global Positioning System (GPS) and Interferometric Synthetic Aperture Radar (InSAR) measurements show continued summit inflation, consistent with magma supply to the volcano’s shallow storage system.

No significant changes in volcanic gas release were measured at Sulphur Cone on the Southwest Rift Zone. Fumarole temperatures remain stable at Sulphur Cone and within the summit caldera.

Updates on the status of Mauna Loa Volcano will be issued each week on Thursdays until further notice.

For more information on current monitoring of Mauna Loa Volcano, see:

Background: Mauna Loa is the largest 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.


Kilauea Activity summary also available by phone: (808) 967-8862

Other Hawaiian volcanoes summary also available by phone: (808) 967-8877

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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.