USGS HVO Press Release — Earthquake Swarm Located Between Kīlauea and Mauna Loa Volcanoes

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Hawai‘i ISLAND, Hawai‘i — The U.S. Geological Survey's Hawaiian Volcano Observatory (HVO) recorded an earthquake swarm that began around 1:17 a.m., HST, on Wednesday, February 22, 2012. The earthquakes are located about 5 km (3 mi) north-northwest of Kīlauea volcano's summit, near Nāmakanipaio in Hawai‘i Volcanoes National Park, at depths of 2–5 km (1–3 mi).

The seismic swarm, which continues as of 3:00 p.m., has included more than 60 earthquakes, 14 of which were greater than magnitude-2. The largest was a magnitude-3.2 earthquake at 6:55 a.m.

These small earthquakes have not been widely felt on the Island of Hawai‘i. The USGS “Did you feel it?” Web site ( received less than 10 felt reports in the first12 hours following the onset of the swarm.

The earthquakes are located along the Ka‘ōiki Pali, a southeast-dipping normal fault near the boundary between Mauna Loa and Kīlauea volcanoes. This area has experienced episodic seismicity since the magnitude-6.6 Ka‘ōiki earthquake that occurred in November 1983.

Previous earthquake swarms have occurred along the Ka‘ōiki seismic zone in 1990, 1993, 1997, and, most recently, in February-March 2006. These swarms lasted from 1 day to several weeks, with earthquakes rarely exceeding magnitude-4.

Seismic swarms in the Ka‘ōiki area have sometimes heralded changes in Kīlauea's ongoing east rift zone eruption, but as of this writing, HVO monitoring networks have not detected any apparent changes in Kīlauea's summit or east rift zone eruptions or on Mauna Loa resulting from today’s swarm.

For more information on recent earthquakes in Hawai‘i and eruption updates, visit the Hawaiian Volcano Observatory website at


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Daily updates about ongoing eruptions, recent images and videos of summit and East Rift Zone volcanic activity, maps, and data about recent earthquakes in Hawaii are posted on the HVO website at

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