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.
GVN

December 12th, 2011
During 4-5 December, residents 3 km SW of Pagan reported ashfall that accumulated in their camp at a rate
of about 6.4 mm per day. They also described a plume from the summit that rose to an altitude of 640 m
(2,100 ft) a.s.l. and a sulfur smell that occasionally wafted through their camp. Based on satellite imagery, the
Washington VAAC reported a gas-and-ash plume that drifted mainly W on 5, 6, and 8 December.
Satellite imagery showed no further activity through 11 December.
GVN

April 1981
Large tephra cloud; lava flows; 53 evacuated
A strong explosive eruption from North Pagan began on 15 May. While reporting strong felt seismicity on the island,
radio operator Pedro Castro suddenly announced at 0915 that the volcano was erupting. Communication was then
cut off. An infrared image from the GMS at 1000 showed a very bright circular cloud about 80 km in diameter
over the volcano. The cloud spread SE at about 70 km/hour, and by 1600 its maximum height was estimated at
13.5 km from satellite imagery.
GVN


A fissure that formed during an eruption of Pagan volcano in the Mariana Islands in 1981 cuts across
the summit of the volcano. Three principal vents were active along the fissure. A cinder cone (foreground)
was constructed on the north flank, and vents on the north and south rims of the summit crater fed lava
flows that traveled down the flanks of North Pagan volcano. This June 16, 1981 photo shows South Pagan
volcano at the upper right.
Photo by U.S. Navy, 1981.