Report on Pagan (United States) — 4 April-10 April 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 4 April-10 April 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, 4 April-10 April 2012. Smithsonian Institution and US Geological Survey.
18.13°N, 145.8°E; summit elev. 570 m
All times are local (unless otherwise noted)
Clear-to-partly-cloudy satellite images of Pagan showed a gas-and-steam plume extending downwind from the summit vent during 30 March-6 April. The Aviation Color Code remained at Yellow and the Volcano Alert Level remained at Advisory. According to the Washington VAAC a pilot observed a plume containing a small amount of ash that rose to an altitude below 1.5 km (5,000 ft) a.s.l. on 7 April. Satellite imagery showed a gas-and-steam plume, with possible ash content, drifting 204 km SSW.
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.