Darwin VAAC reports an ash plume up to 2.4 km (8 000 feet) was observed above the Manam volcano, Papua New Guinea at 00:30 UTC on April 27, 2015. It extended about 111 km to the west.
A pronounced SO2 plume can be seen on satellite data as well, Volcano Discovery reports.
Image credit: NOAA
According to GVP, Rabaul Volcano Observatory (RVO) reported that activity at both Manam's Southern Crater and Main Crater was low during March 1 - 18, 2015 although inclement weather made crater observations difficult; no noises were reported.
Seismicity had slowly and erratically increased since February 2, peaked on March 13 and remained at that level through March 15, and then increased again through March 18.
The seismicity was characterized by small-to-moderate, sub-continuous, and continuous volcanic tremor. Discrete low-frequency earthquakes were also recorded.
The 10-km-wide island of Manam, lying 13 km off the northern coast of mainland Papua New Guinea, is one of the country's most active volcanoes. Four large radial valleys extend from the unvegetated summit of the conical 1807-m-high basaltic-andesitic stratovolcano to its lower flanks. These "avalanche valleys" channel lava flows and pyroclastic avalanches that have sometimes reached the coast.
Five small satellitic centers are located near the island's shoreline on the northern, southern, and western sides. Two summit craters are present; both are active, although most historical eruptions have originated from the southern crater, concentrating eruptive products during much of the past century into the SE valley. Frequent historical eruptions, typically of mild-to-moderate scale, have been recorded since 1616. Occasional larger eruptions have produced pyroclastic flows and lava flows that reached flat-lying coastal areas and entered the sea, sometimes impacting populated areas. (GVP)
Featured image: Manam volcano on April 27, 2015. Image credit: NASA Terra/MODIS. Annotation: The Watchers