Report on Pagan (United States) — 9 May-15 May 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 9 May-15 May 2012
Managing Editor: Sally Kuhn Sennert
Please cite this report as:
Global Volcanism Program, 2012. Report on Pagan (United States). In: Sennert, S K (ed.), Weekly Volcanic Activity Report, 9 May-15 May 2012. Smithsonian Institution and US Geological Survey.
18.13°N, 145.8°E; summit elev. 570 m
All times are local (unless otherwise noted)
According to NASA's Earth Observatory, a satellite image of Pagan acquired on 7 May showed a gas-and-steam plume drifting W. The plume's blue tint suggested the presence of sulfur dioxide; elevated levels of sulfur dioxide to the W of the volcano were detected in satellite images later that day. The USGS reported that minor steam-and-gas plumes were observed in partly cloudy satellite images during 4-11 May. The Volcano Alert Level remained at Advisory and the Aviation Color Code remained at Yellow.
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.