Lō‘ihi Earthquake Swarm No Cause For Concern

Today, May 11, 2020, a flurry of 35 earthquakes (so far by 3pm) greater than magnitude 2.0 have been detected around Lō‘ihi seamount, ~30 miles offshore east of Ka Lae (South Point). The 3 largest thus far occurred between 12-1pm local time measuring M3.9, M3.7 & M3.8, with the map displaying 56 earthquakes in the area for the last 2 weeks. Most events fall into a depth range between 4-7.5 mi, with a couple of shallower events indicating more subtle adjustments. This can be seen by the time-depth plot graph included below, a useful tool to monitor whether the quakes become more shallow if they continue. Only if and when the number and intensity of shallow earthquakes increases, will we consider a possible submarine eruption. This type of activity occurs periodically and is of no concern to island residents -- who may feel ongoing earthquakes for a short time, especially in South Hawai‘i. As the summit of the submerged volcano sits about 3000 feet below sea level, the last eruption in 1996 had no significant effect (including no tsunami) on land, peaking with 13 earthquakes between M4.5-4.9 in the final ~2 weeks of the 3.5 week eruption which formed a new underwater pit crater. After the fact, scientists are still not sure if there was one or "possibly two" eruptions in the summer of 1996, to drive home the minimal impact to Hawai‘i islanders, yet there were over 1000 total earthquakes in that 6-week period. These events are separate, offshore from the deep Pāhala earthquake group, which remains persistently more active since first elevating in 2014-15 and then ramping up in 2018. The deeper, often longer-period quakes are currently attributed to the passage of magma through deep conduits near the hot spot source. We will continue to monitor and report on this activity and pass on any official statement which may be forthcoming from the USGS-HVO.