Scripps Institution of Oceanography, UCSD
Volcano Expedition to the Marianas

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Saipan
Anatahan
Sarigan
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Maug
Uracas
April 2004
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Daily Journal


Day 4 | April 12, 2004

The Reconnaissance Fly-over

Dave Hilton's Log | Erik Hauri's Log
(See "the islands" under Expedition Calendar for movies of fly-over)

team and fixed wing aircraft

The team in front of the fixed wing aircraft

In preparation for our sampling expedition, we did a 6-hour fly-over by fixed wing aircraft along the 370-mile long volcanic chain. Initially, we maintained a 7000 ft altitude to get a broad overview of the islands. We are particularly interested in sighting helicopter landing spots as well as potential sampling locations for rocks and gases.

After 3 hours, we reached the northernmost islands, Asuncion, Maug and Uracas. We descended to about 3000 ft to get a better view of the volcanoes. Uracas, the northern-most volcano of the chain, is also the Marianas' most active volcano. This small island is completely covered by recent lava flows and ash.

Uracas

Uracas

The next volcano to the south is Maug, a partially submerged caldera. Maug consists of 3 islands. On our trip we will set up a base camp on Maug from where we will access Uracas to the north and Asuncion to the south. Asuncion is a symmetrical cone with very steep slopes, covered in vegetation.

Maug

Maug

Towards the end of our fly-over, we reached Anatahan which erupted in May, 2003. The flanks of Anatahan are still completely covered with ash from last year's eruption. We had a good view of the active crater. At the bottom of the crater are numerous fumaroles (gas vents) and what we believe is a solidified lava lake. As we flew by, a small explosion occurred. Gas and ash erupted from a small vent that opened in the lava lake. A close look showed glowing red lava below. Clearly, Anatahan is still active.

Anatahan

Anatahan

Erik Hauri
Today we had a very nice 6-hour overview flight of all the islands with Mike Cunningham. We started at 7000 feet and flew straight to Uracas, circled several times down low, then came back at 2000 feet swooping down over all the other islands close-up. The volcanoes seem fairly quiet, very few steam emissions that we could see. The exception was Anatahan, which had lots of steam coming out of the East crater, mainly from around the edge of a crusted-over lava lake. As we were flying past the crater, there was a small steam explosion in the center of the lava lake, which opened up for just a second to reveal the glowing red lava beneath. It was all caught on film by Lille Jaffe and you can see the movie here on the web site.

Also today, we had a visit with Juan Camacho and company over at the Emergency Management Office (EMO) to work on permits, which are required for us to land at several of the islands that are bird sanctuaries (Guguan, Agrigan and Uracas). While we were there, we got to see the seismic activity records for the two seismographs at Anatahan; it was busy! There has been lots of seismic activity there over the past 2 weeks, so much so that it appears that it might be dangerous to approach the East Crater. We have a lot of work to do on the west side of the island, which is sheltered from the current activity of the East crater, but we had hoped to sample rocks from the western wall of the caldera, and gases from the East Crater as well.