A system in the North Pacific, maintained by the United States Navy and originally intended for the detection of submarines, has detected an event on average every 2 to 3 years.The most common underwater flow is pillow lava, a rounded lava flow named for its unusual shape. Less common are glassy, marginal sheet flows, indicative of larger-scale flows. Volcaniclastic sedimentary rocks are common in shallow-water environments. As plate movement starts to carry the volcanoes away from their eruptive source, eruption rates start to die down, and water erosion grinds the volcano down. The final stages of eruption cap the seamount in alkalic flows. There are about 100,000 deepwater volcanoes in the world, although most are beyond the active stage of their life. Some exemplary seamounts are Kamaʻehuakanaloa (formerly Loihi), Bowie Seamount, Davidson Seamount, and Axial Seamount. Subglacial
Subglacial eruptions are a type of volcanic eruption characterized by interactions between lava and ice, often under a glacier. The nature of glaciovolcanism dictates that it occurs at areas of high latitude and high altitude. It has been suggested that subglacial volcanoes that are not actively erupting often dump heat into the ice covering them, producing meltwater. This meltwater mix means that subglacial eruptions often generate dangerous jökulhlaups (floods) and lahars.The study of glaciovolcanism is still a relatively new field. Early accounts described the unusual flat-topped steep-sided volcanoes (called tuyas) in Iceland that were suggested to have formed from eruptions below ice.
The 1902 eruption of Mount Pelée completely devastated the island, destroying St. Pierre and leaving only 3 survivors. The eruption was directly preceded by lava dome growth. Mayon Volcano, the Philippines most active volcano. It has been the site of many different types of eruptions, Peléan included. Approximately 40 ravines radiate from the summit and provide pathways for frequent pyroclastic flows and mudflows to the lowlands below. Mayons most violent eruption occurred in 1814 and was responsible for over 1200 deaths. The 1951 eruption of Mount Lamington. Prior to this eruption the peak had not even been recognized as a volcano. Over 3,000 people were killed, and it has become a benchmark for studying large Peléan eruptions. Mount Sinabung, Indonesia. History of its eruptions since 2013 are showing the volcano emits pyroclastic flows with frequent collapses of its lava domes. Plinian
Plinian eruptions (or Vesuvian eruptions) are a type of volcanic eruption named for the historical eruption of Mount Vesuvius in 79 AD that buried the Roman towns of Pompeii and Herculaneum and, specifically, for its chronicler Pliny the Younger. The process powering Plinian eruptions starts in the magma chamber, where dissolved volatile gases are stored in the magma. The gases vesiculate and accumulate as they rise through the magma conduit. These bubbles agglutinate and once they reach a certain size (about 75% of the total volume of the magma conduit) they explode. The narrow confines of the conduit force the gases and associated magma up, forming an eruptive column.