Lo`ihi Seamount is an active volcano built on the seafloor south of Kilauea about 30 km from shore. The seamount rises to 969 m below sea level and generates frequent earthquake swarms, the most intense of which occurred in 1996. An eruption at Lo`ihi has yet to be observed, but scientists from the University of Hawai`i have recently made many submersible dives to the volcano and deployed instruments on its summit to study Lo`ihi in much greater detail.

The summit of Lo`ihi is marked by a caldera-like depression 2.8 km wide and 3.7 km long. Three collapse pits or craters occupy the southern part of the caldera; the most recent pit formed during an intense earthquake swarm in July-August 1996. Named Pele's Pit, the new crater is about 600 m in diameter and its bottom is 300 m below the previous surface! Like the volcanoes on the Island of Hawaii, Lo`ihi has grown from eruptions along its 31-km-long rift zone that extends northwest and southeast of the caldera.

Lo`ihi Seamount Information

Summary of 1996 Activity
Description of the intense earthquake swarm in July-August 1996 and the changes observed in Lo`ihi's summit caldera; prepared by scientists of the Hawai`i Center for Volcanology, School of Ocean and Earth Science and Technology, University of Hawai`i Manoa. More than 4,000 earthquakes were recorded by HVO's seismic network during this swarm.

Summary of Lo`ihi activity reported in the monthly Bulletin of the Global Volcanism Network, Smithsonian Institution. All information contained in these reports is preliminary and subject to change.

Hawaiian Meaning
The name Lo`ihi means "long" in Hawaiian and was introduced in 1955 to describe the elongate shape of the seamount.

Height Above Sea Floor
Lo`ihi is built on the seafloor that slopes about 5 degrees beneath the seamount. Lo`ihi's northern base is 1,900 m below sea level, whereas its southern base is 4,755 m below sea level. Thus, the summit is about 931 m above the seafloor as measured from the base of its north flank and 3,786 m above the seafloor as measured from the base of its south flank.

Most Recent Activity
Earthquake Swarm (>4,000 events), July 16-August 9, 1996

Hawaiian Volcano Stage
In transition between pre-shield and shield stage

References:

The 1996 Lo`ihi Science Team, 1997, Researchers rapidly respond to submarine activity at Lo`ihi volcano, Hawaii: EOS, Transactions, American Geophysical Union, v. 78, no. 22, June 3, 1997, p. 229-233.