USGS HVO Press Release — Magnitude-4.0 Earthquake beneath the South Flank of Kīlauea Volcano

The earthquake was located about 18 km (11 miles) southeast of Kīlauea's summit and 45 km (28 miles) south of Hilo at a depth of 10 km (6.2 miles). In the first 12 hours after the earthquake the U.S. Geological Survey has received 87 felt reports mainly from the southeast portion of the Island of Hawai‘i. The preliminary magnitude was 4.2, but after analyst review, the final duration magnitude was determined to be 4.0.

This earthquake occurred nearly mid-way between the August 13, 2007, magnitude-5.4 earthquake and the August 15, 2007, magnitude-4.4 earthquake. This earthquake was in an area where we have seen 16 earthquakes of magnitude 4 or greater in the last 25 years. South flank earthquakes at this depth are at the base of the volcano and are in response to the south flank's movement toward the sea. Historically Kīlauea's south flank has shown increased earthquake activity when there are large amounts of extension and activity going on along the east rift, such as we have seen over the past 4–5 months.

These earthquakes have not caused any noticeable change to the current eruption of Kīlauea. Monitoring networks supported by HVO have detected no significant changes in activity.

The eruption is within the Kahauale‘a Natural Area Reserve. HVO will continue to monitor the situation closely and will post updates at http://volcano.wr.usgs.gov/hvostatus.php.

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 https://volcanoes.usgs.gov/observatories/hvo. 

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