On May 10, 2003 researchers and students from Washington University, Scripps Institute of Oceanography, and the Saipan Emergency Management Office (EMO) were aboard a ship Super Emerald, deploying seismographs in the Northern Mariana Islands. The seismographs are being deployed as part of a joint US-Japan Mariana Subduction Imaging Experiment, which is funded by the National Science Foundation. The goal of this experiment was to study the source regions of magma that erupts from the Mariana island arc by imaging the earth's mantle. This experiment involved the deployment of 20 land seismographs and 58 seismographs on the sea bottom. During the night of May 10-11 while the ship was approaching Anatahan Island, the scientists observed a tremendous lightning display ahead. As morning broke, they were astounded to see a pillar of steam and ash billowing to an altitude of 30,000 ft above Anatahan volcano. The group had actually visited Anatahan on May 6 to install a seismograph, and had not noticed any signs of the impending eruption. The seismograph was deployed in a small village, which fortunately was uninhabited. The ship reported the eruption to the Saipan Emergency Management Office, and had to detour around the island to avoid the ash fall. Anatahan volcano had not erupted previously during historic times.
Photos by Patrick Shore.