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Report on Pagan (United States) — October 1983

Scientific Event Alert Network Bulletin, vol. 8, no. 10 (October 1983)
Managing Editor: Lindsay McClelland.

Pagan (United States) Explosive eruption on 26 September

Please cite this report as:

Global Volcanism Program, 1983. Report on Pagan (United States) (McClelland, L., ed.). Scientific Event Alert Network Bulletin, 8:10. Smithsonian Institution. https://doi.org/10.5479/si.GVP.SEAN198310-284170.

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United States

18.13°N, 145.8°E; summit elev. 570 m

All times are local (unless otherwise noted)

Several former residents of Pagan, including Mayor Dan Castro, spent September on the island. The only activity they observed was an explosive eruption accompanied by glow that began at 0640 on the 26th. That evening, glow remained visible. Ash that fell on the village was collected from concrete slabs. The ash has been identified as magmatic, of medium-sand size, and depleted in fines.

Since Pagan's major eruption in May 1981, six or seven explosions have ejected enough tephra to cause ashfall in the village. The 26 September ash was the first to fall on the concrete slabs since they were swept clean in July.

Geologic Background. Pagan Island, the largest and one of the most active of the Mariana Islands volcanoes, consists of two stratovolcanoes connected by a narrow isthmus. Both North and South Pagan stratovolcanoes were constructed within calderas, 7 and 4 km in diameter, respectively. The 570-m-high Mount Pagan at the NE end of the island rises above the flat floor of the northern caldera, which may have formed less than 1000 years ago. South Pagan is a 548-m-high stratovolcano with an elongated summit containing four distinct craters. Almost all of the historical eruptions of Pagan, which date back to the 17th century, have originated from North Pagan volcano. The largest eruption of Pagan during historical time took place in 1981 and prompted the evacuation of the sparsely populated island.

Information Contacts: N. Banks, HVO.