Contact: Philip McGillivary
Date: March 6, 2000

Coast Guard helps Scientists Monitor Volcano

Alameda, California  –  The Coast Guard Cutter Polar Star is assisting scientists studying a large undersea volcano. The volcano, temporarily referred to as "Rockne" was mapped during a March, 1999 cruise on the research vessel Melville. First discovered in 1975 by Rockne Johnson, this volcano is located 45km east of Ta’u Island, the most easterly of the Samoan chain.

This volcano was the site of an eruption event detected by an undersea acoustic monitoring system, in 1973, and a swarm of magnitude 4.3-4.9 earthquakes in January, 1995. This suggests that the volcano is recently active, as does the very fresh, glassy appearance of rock samples dredged up from the site.  Because there is eruptive activity all along the Samoan chain, from Savai’i to Ta’u, a simple hot spot model has never been widely accepted for the Samoan chain. The new volcano is believed to be the current location of the Samoan hot spot, and with its discovery, the volcanoes of American Samoa can be considered consistent with a simple hot spot model with continuing activity along the island chain.

To further assess the volcano’s state of activity, a small group of scientists from the Scripps Institution of Oceanography and the Woods Hole Oceanographic Institution will board the Polar Star in late March for a short cruise to “Rockne” Volcano. This team, headed by Hubert Staudigel and Stan Hart, will deploy five ocean-bottom hydrophones onto the volcano, with the capability to “listen” for earthquakes and volcanic eruptions over the next eight to 10 months. The team will also look for temperature, salinity, and particulate anomalies in the waters above the volcano, which would indicate ongoing volcanic activity. The Polar Star is en route to its’ home port of Seattle, returning from the USCG icebreakers’ annual re-supply mission for the U.S. McMurdo Base in the Ross Sea, Antarctica. The ship will pick up the scientific party and hydrophones in Fiji, and put them off by helicopter on Ta’u, Samoa, after four days work at the site of the volcano.

-USCG-

For additional information:

Dr. Stan Hart, Woods Hole Oceanographic Institution

Dr. Hubert Staudigel, Scripps Institution of Oceanography

Dr. Phil McGillivary, USCG Icebreaker Science Liaison
PH 510-437-5355 / FAX 510-437-3055