Report on Pagan (United States) — 11 July-17 July 2012
Smithsonian / US Geological Survey Weekly Volcanic Activity Report, 11 July-17 July 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, 11 July-17 July 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 the USGS, a minor, low-altitude ash cloud from Pagan was reported by the Washington VAAC on 10 July and confirmed by the Alaska Volcano Observatory (AVO). The VAAC noted that the plume drifted almost 50 km NW at an altitude of 1.5 km (5,000 ft) a.s.l. Local observers indicated localized ashfall on or near the island. 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.