Link to USGS home page.
Contact USGS

  • Assess
  • Prepare
  • Forecast
  • |
  • Activity
  • Products
  • Observatories
  • About

Alert Level: NORMAL, Color Code: GREEN
2018-12-08 03:16:31 UTC

U.S. Geological Survey
Friday, December 7, 2018, 5:16 PM HST (Saturday, December 8, 2018, 03:16 UTC)

19°28'30" N 155°36'29" W, Summit Elevation 13681 ft (4170 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

No significant changes in earthquake activity were detected in November. Most of the Mauna Loa activity were located at the typical areas: beneath the northwest flank and summit caldera. Mauna Loa had a short-lived period of elevated seismic activity that lasted about four hours on 2018-11-18 UTC (mid-afternoon to evening, 2018-11-17 HST). Most of the swarm earthquakes were located at 5-6 km (model) depth, beneath the northwest flank of the volcano. The largest earthquake for Mauna Loa in November was a M2.9, which occurred during the swarm.

There was no significant change in deformation trends across the volcano in November.

HVO continues to monitor the volcano closely.

Background: Mauna Loa is the largest active volcano on Earth. 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 34 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 Hawai`i. Since the mid-19th century, the city of Hilo in east Hawai'i 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.

From 2014 through much of 2017, HVO seismic stations recorded variable, but overall elevated rates of shallow, small-magnitude earthquakes beneath Mauna Loa's summit, upper Southwest Rift Zone, and west flank. During that same time period, HVO measured ground deformation consistent with input of magma into the volcano's shallow magma storage system.

This notice contains additional volcanoes not displayed: Hualalai (NORMAL/GREEN), Mauna Kea (NORMAL/GREEN), Haleakala (NORMAL/GREEN), Lo`ihi (UNASSIGNED/UNASSIGNED).


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

Subscribe to these messages:

Webcam images:


Lava flow maps:

Definitions of terms used in update:

Overview of Kīlauea summit (Halemaʻumaʻu) and East Rift Zone (Puʻu ʻŌʻō ) eruptions:

Summary of volcanic hazards from Kīlauea eruptions:

Recent earthquakes in Hawaiʻi (map and list):

Explanation of Volcano Alert Levels and Aviation Color Codes:


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.