USGS HVO Information Statement — Magnitude-4.0 earthquake under Lō‘ihi seamount, south of the Island of Hawai‘i

The earthquake was centered about 42 km (26 miles) southeast of Nāʻālehu, under Lō‘ihi seamount at a depth of 11 km (7 miles). A map showing its location is posted on the HVO website at https://www.usgs.gov/observatories/hawaiian-volcano-observatory/earthquakes. More details are available at the National Earthquake Information Center website at https://earthquake.usgs.gov/earthquakes/eventpage/hv72502537/.

Moderate shaking, with maximum Intensity of V on the Modified Mercalli Intensity Scale, has been reported across the Island of Hawai‘i. At that intensity, significant damage to buildings or structures is not expected. The USGS "Did you feel it?" service (http://earthquake.usgs.gov/dyfi/) received 3 felt reports within the first hour of the earthquake.

According to HVO Scientist-in-Charge Ken Hon, the earthquake had no apparent effect on Kīlauea or Mauna Loa volcanoes. “We see no detectable changes in activity at the summits or along the rift zones of Lōʻihi, Kīlauea, or Mauna Loa as a result of this earthquake. Aftershocks are possible and could be felt.” HVO continues to monitor Kīlauea, Mauna Loa, and other Hawaiian volcanoes for any changes.

Lōʻihi seamount is an active volcano on the seafloor south of Kīlauea Volcano, about 30 km (19 miles) from the shoreline of the Island of Hawaiʻi. The top of the seamount is about 975 m (3,199 feet ) below sea level. The volcano consists of a broad summit area marked by three pit craters and two prominent rift zones extending from the summit about 22 km (13.6 mi) south-southeast and about 15 km (9.3 mi) north-northeast. The volcano likely has a shallow magma chamber between 1 to 2.5 km (0.6 to 1.6 mi) deep below the summit.

For information on recent earthquakes in Hawaii and eruption updates, visit the USGS Hawaiian Volcano Observatory website at https://www.usgs.gov/hvo.

Background: Intermittent earthquake activity has been recorded in the vicinity of Lō‘ihi since as early as 1952. The most energetic earthquake sequence occurred in July-August 1996, which included more than 4,000 earthquakes, with nearly 300 events larger than M3.0 and 95 events in the M4.0 to 4.9 range. More recently, a swarm of 100 earthquakes occurred on May 11, 2020, with 18 events in the M3.0 to 3.9 range. There are no working monitoring instruments on Lō‘ihi Volcano, whose peak is about 1,000 m (3,280 ft) below sea level. All real-time information about the volcano is derived from land-based seismometers on the Island of Hawai‘i.

More Information:
Lō‘ihi Seamount website: https://www.usgs.gov/volcanoes/loihi-seamount

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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/observatories/hawaiian-volcano-observatory/earthquakes

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

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.