Contact:  Dane Konop                  IMMEDIATE RELEASE
                                      10/4/96

SCIENTISTS OBSERVE COLLAPSED DOME OF UNDERSEA VOLCANO LOIHI

The recent collapse of the lava dome of the underwater volcano Loihi off Hawaii has created a murky crater a half mile across and a thousand feet deep, and given scientists in a research mini-sub a close-up look at the ongoing birth of the next Hawaiian island, according to researchers just back from the site.

The research expedition aboard the RV Ka'imikai-o-Kanaloa (Hawaiian for "investigator god of the sea"), which began Sept. 25 and is continuing off the big island of Hawaii through Oct. 12, is sponsored by the Commerce Department's National Oceanic and Atmospheric Administration and led by Alexander Malahoff, director of the Hawaii Undersea Research Laboratory at the University of Hawaii.

"This was a Mount St. Helen-sized' volcanic event. Pele's Dome, an area on the southern rim of the volcano that previously had been considered very stable, has simply vanished into a giant pit, which we have named the Pele's Pit Crater.' What we learn from this event will have profound implications for virtually everything we now know about undersea volcanism--including the effects of volcanic carbon dioxide emissions on climate, the possible generation of tsunamis that could strike coastal areas, and the impacts on the microscopic organisms that live in and near sea floor vents," Malahoff said.

In a series of six dives into the volcano aboard the research submersible Pisces V, the NOAA-funded university scientists witnessed dramatic evidence of the impact of swarms of sea floor earthquakes that have struck Loihi since mid-July, including the collapse of giant lava rock formations, continuing subsea tremors and landslides, and the creation of new vents spewing a mix of superheated water, dissolved minerals and massive mats of chemosynthetic bacteria that limited the scientists' visibility to a meter or less.

Researchers operating from "K-o-K" also produced a new sonar map of the volcano and used Pisces V to photograph the new topography and hydrothermal venting there, sample seawater in and near the vents to measure concentrations of bacteria and minerals, install sea floor pressure monitoring devices that would signal further collapses of the sea floor, and identify locations to safely position other measuring devices for long-term monitoring.

The whole summit of the volcano, about 3,000 feet below sea surface, has collapsed, shaken by swarms of sea floor earthquakes and the withdrawal of magma within the volcano, said Malahoff, who made the first three of six dives into Loihi in Pisces V September 25-27. "A four to five square-mile area of the sea floor is completely devastated, strewn with bus-sized volcanic boulders, some so precariously perched that we had to be careful not to bump them with the sub. Compared to what I've observed here in past dives, perhaps 325 million cubic yards of volcanic rock slid into the volcano," he said.

"The currents are very tricky there. Water is flowing down into this newly formed pit on the northern end, where it percolates through the volcano, mixes with minerals and bacterial matter, then rushes out over a lip on the western edge of the volcano. We had to be careful in the sub not to get sucked down by the inflow on the north side of the volcano and buoyed up by the outflow on the western rim.

"The southern face of the volcano is the most active area now, but the whole volcano is very unstable. We think the landscape is still changing since vents that we had found in an earlier dive are no longer there. The northern end appears intact--for now," Malahoff said.

The water in the volcano is very turbid, with visibility down to about a meter in most places, clouded by a combination of dissolved minerals in the water and huge floating mats of chemosynthetic bacteria. The bacteria, which feed on dissolved nutrients, have immediately begun colonizing the new hydrothermal vents, according to University of Hawaii biologist James Cowen, who also dove into Loihi, as did his assistant Charles Holoway, on Sept. 28 and Sept. 30, respectively. Both collected samples of the chemosynthetic bacteria, which can be indicators of the type of inorganic material ejected from the vents, for follow-up studies in their laboratory.

University of Hawaii seismologist Fred Duennebier dove into the less active northern end of Loihi Sept. 29. The topography there appeared unaffected, with huge lava columns still standing. Duennebier will return to Loihi this winter to establish a permanent undersea geological observatory on the volcano to monitor future volcanic activity.

Submersible pilots Terry Kirby and Allen Wright of the Hawaii Undersea Research Laboratory operated the three-person Pisces V on all dives.

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NOTE TO EDITORS: NOAA will host a press briefing on findings of the ongoing expedition, featuring a video summary of the dives moderated by Alex Malahoff, at 10:30 a.m. Oct. 4 in the National Press Club, Washington, D.C. Copies of the video will be available.

All NOAA press releases and links to other NOAA material can be found on the NOAA Public Affairs World Wide Web home page http://www.noaa.gov/public-affairs. Additional Web link: http://www.soest.hawaii.edu/HURL/huri.html