Bulusan, one of the most active volcanoes in the Philippines, is Luzon's southernmost volcano. It lies at the SE end of the Bicol volcanic arc occupying the peninsula of the same name that forms the elongated SE tip of Luzon island.
Explosive. In historic time, frequent small to moderate phreatic and phreatomagmatic ash eruptions. Mudflows from loose deposits on flank are often generated when heavy rains fall (e.g. during taifuns).
Bulusan is a young andesitic volcano built upon the NE rim of an older dacitic-to-rhyolitic caldera, the 11-km wide Irosin caldera, which was formed about 35,000-40,000 years ago.
Bulusan is flanked by several other large intracaldera lava domes and cones, including the prominent Mount Jormajan lava dome on the SW flank and Sharp Peak to the NE. The summit of 1565-m-high Bulusan volcano is unvegetated and contains a 300-m-wide, 50-m-deep crater. Three small craters are located on the SE flank.
Many moderate explosive eruptions have been recorded at Bulusan since the mid-19th century.
