(2) Issued:(20110222/2317Z)
(3) Volcano:Pagan (CAVW# 0804-17=)
(4) Current Color Code:UNASSIGNED
(5) Previous Color Code:yellow
(6) Source:Northern Mariana Islands
(7) Notice Number:2011/N1
(8) Volcano Location:N 18 deg 7 min E 145 deg 48 min
(9) Area:Mariana Islands
(10) Summit Elevation:1870 ft (570 m)
(11) Volcanic Activity Summary:With the exception of a faint steam and gas plume observed on 24 January 2011, satellite data have detected no unusual activity at Pagan volcano in the past six weeks. The most recent known ash emission, which rose to 1.5 km above sea level and produced minor local ash fall, occurred on 11 August 2010. Based on these observations, we are lowering the color code at Pagan to unassigned.

Pagan is not monitored with ground-based geophysical instrumentation and the only source of information is satellite observation and occasional reports from observers who visit the island. We will continue to evaluate satellite imagery and on-island reports when they become available, but because the volcano is not monitored with ground-based instruments, we cannot provide advanced warning of activity.

Access to the island may be restricted by the CNMI government. Contact the EMO for the latest information.
(12) Volcanic cloud height:Unknown
(13) Other volcanic cloud information:Unknown
(14) Remarks:Pagan Island consists of two volcanoes: Mount Pagan on the north and South Pagan Volcano on the south. Mount Pagan is a stratovolcano that is growing within a 6-km-diameter caldera formed less than 9,400 years ago. South Pagan volcano is a large young stratovolcano with a summit caldera 2.8 km across. There are no known historical eruptions of South Pagan volcano. Mount Pagan is one of the most historically active volcanoes in the Northern Marianas. Its most recent large (VEI 4) eruption was in 1981. The volcano was intermittently active through 1996, producing mainly light ashfall from a column that would occasionally reach 10,000 feet above sea level. Following the 1981 eruption, destructive rain-triggered (secondary) debris flows buried large tracts of land, including the site of a village that contained a school, dispensary, church, power generating buildings, cisterns and associated infrastructure.

Mount Pagan is possibly the most dangerous volcano in the Northern Marianas. It is frequently active, and a full spectrum of acutely hazardous phenomena such as pyroclastic flows and surges, directed blasts, and secondary lahars (volcanic debris flows) have affected the relatively flat land close to the volcano; areas that are attractive for settlement. All known historical eruptions have originated at the central stratovolcano, but eruptions from flank or satellitic vents are possible. For instance, a large maar, with extensive surge deposits, formed on the west flank of Mount Pagan about 200 years ago.

(15) Contacts:USGS Northern Marianas Duty Scientist (808) 967-8815

CNMI Emergency Management Office (670) 322-8001