Daily Journal

The Reconnaissance Fly-over

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. [photo 1].

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 [photo 2]. The next volcano to the south is Maug, a partially submerged caldera [photo 3]. 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.

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 [photo 4]. A close look showed glowing red lava below. Clearly, Anatahan is still active.