• Visible observations were impossible because of winds and rain brought by the typhoon, but seismograph , barograph , and satellite observations recorded the second largest eruption of the 20th century-exceeded only by the giant 1912 eruption of Novarupta near Mount Katmai in Alaska. (britannica.com)
  • The Independent, Aug 16, 2015 (emphasis added): Japan's weather agency issued a warning… that the likelihood of the eruption of [Sakurajima] was extremely high… after it detected aspike in seismic activity… They have warned an evacuation of the city of just over 600,000people may be necessary. (abovetopsecret.com)
  • Underwater hydrophones showed a sudden increase in seismic energy about 2.6 hours before the eruption started about 400 kilometers off the Oregon coast, according to the scientific team. (voanews.com)
  • For four years before the 2011 eruption, marine geologist Bob Dziak and other team members noted that, while there was a gradual build up in the number of small earthquakes, there was only a small increase in the overall seismic energy produced from those earthquakes. (voanews.com)
  • Using seismic analysis , the team was able see just how the magma rose within the volcano about two hours before the eruption. (voanews.com)
  • Ongoing research has led to a better understanding of pyroclastic flows - rapid exhalations of gas, ash and rock dished out by explosive volcanoes like Soufrière Hills and its neighbour, Mount Pelée on Martinique, whose 1902 eruption killed 30,000 people. (bristol.ac.uk)
  • An undersea volcano has erupted off the coast of Oregon, spewing forth a layer of lava more than 12 feet (4 meters) thick in some places, and opening up deep vents that belch forth a cloudy stew of hot water and microbes from deep inside the Earth. (livescience.com)
  • The development signals that it might eventually be possible to forecast eruptions of undersea volcanoes. (voanews.com)
  • Minor, intermittent eruptions of ash began at the summit area, and a tiltmeter high on the volcano's east side began to lean outward. (britannica.com)
  • An eruption from the Kilauea volcano's summit shot ash and smoke into the air early Thursday on Hawaii's Big Island, and the resulting plume is expected to cover the surrounding area, according to the Hawaiian Volcano Observatory. (clickondetroit.com)
  • (CNN) - After an eruption from the Kilauea volcano's summit shot ash and smoke 30,000 feet into the air on Thursday, officials handed out almost 18,000 masks to help residents deal with the fallout. (clickondetroit.com)
  • Volcanic eruptions arise through three main mechanisms: Gas release under decompression causing magmatic eruptions Thermal contraction from chilling on contact with water causing phreatomagmatic eruptions Ejection of entrained particles during steam eruptions causing phreatic eruptions There are two types of eruptions in terms of activity, explosive eruptions and effusive eruptions. (wikipedia.org)
  • Earthquakes and steam explosions announced the reawakening of Mount Pinatubo in 1991, surprising many geologists because Pinatubo was not even listed in catalogs of world volcanoes. (britannica.com)
  • On April 2, steam explosions opened up three large steam and sulfur-gas vents, or fumaroles , along a fissure 3 km (1.9 mile) in length located high on the north flank of the volcano. (britannica.com)
  • On June 7 an eruption of steam and ash reached a height of 7 to 8 km (4.3 to 5 miles), and the next morning an observer in a helicopter confirmed that magma had indeed reached the surface. (britannica.com)
  • The remarkable hydrothermal features in Lassen Volcanic National Park include roaring fumaroles (steam and volcanic-gas vents), thumping mudpots, boiling pools, and steaming ground. (usgs.gov)
  • The hottest and most vigorous hydrothermal features in Lassen Volcanic National Park are at Bumpass Hell, which marks the principal area of upfl ow and steam discharge from the Lassen hydrothermal system. (usgs.gov)
  • Although most of the steam condenses near the surface, some reaches the surface through conduits to form fumaroles (steam and volcanic-gas vents), such as those at Bumpass Hell. (usgs.gov)
  • Recent explosions have been steam-driven, occurring when water beneath the ground or on the surface is heated by magma, lava, hot rocks or new volcanic deposits, the USGS says. (clickondetroit.com)
  • The eruption is not caused by magma, but by steam, and this is much harder to track in our current monitoring systems. (upi.com)
  • Characteristics of Magma Types of Magma Types of magma are determined by chemical composition of the magma. (coursehero.com)
  • Viscosity depends on primarily on the composition of the magma, and temperature. (coursehero.com)
  • The composition of the magma that formed this tablet was basically unchanged by its journey from the mantle to the surface, where it erupted to form a smooth, sinuous lava flow. (amnh.org)
  • Volcanoes form on land near coastal areas when a continental (land) plate and an oceanic plate converge or move toward each other. (encyclopedia.com)
  • Seamounts (underwater volcanoes) form when oceanic plates both converge (move toward each other) and diverge (move away from each other). (encyclopedia.com)
  • When oceanic plates diverge, magma seeps upward at the ridge between the plates to create new seafloor (a process called seafloor spreading ). (encyclopedia.com)
  • In a 25,000 mile horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. (enn.com)
  • It has been recognized for almost 50 years that the volcanic arcs form where one oceanic plate sinks beneath another,’ said Professor Philip England of Oxford University’s Department of Earth Sciences, an author of the report, ‘but while many models of this process have been put forward, none has been able to explain the location, and narrowness, of the volcanic arcs. (enn.com)
  • This magma is generated as the oceanic Juan de Fuca Plate, one of the tectonic plates making up the Earth s outer shell, plunges (is subducted ) beneath the continental North American Plate. (usgs.gov)
  • The chain is all that is visible of an ocean-bottom hydrophone, an instrument that detects earthquakes, buried in about six feet of new lava produced by a recent eruption at the Axial Seamount. (livescience.com)
  • The chain is all that is visible of an ocean-bottom hydrophone buried in about six feet of new lava from an April 2011 eruption of Axial Seamount. (voanews.com)
  • Mt. Agung Update: Why is it so hard to predict a volcanic eruption? (agu.org)
  • It could be it's easier to predict ocean eruptions, Chadwick said. (livescience.com)
  • The subterranean volcanic plume, 300 miles wide at its top end, may explain why ground along the Teton fault moves in directions just the opposite of those expected, a perplexing discovery that complicates efforts to predict when the fault might generate disastrous 7.5 earthquakes near the ski resorts of Jackson Hole. (innovations-report.com)
  • Mountains and volcanoes have been formed here by pressure being forced on plate boundaries to a point where they break and scrunch together to be mountains and sub-duct to make vents for lava to come up through and start layering up to make a volcano. (smore.com)
  • Due to nearby volcanic activity, these vents release hot mineral-laden water into the surrounding ocean. (encyclopedia.com)
  • Some volcanoes are cone-shaped mountains, some are flat-topped like mountain plateaus, some have fissure vents, which are cracks where the lava escapes, and others bulge like domes. (reference.com)
  • Indonesia's Mt. Agung may be on the cusp of its first eruption since 1963, an eruption that killed more than 1000 people. (agu.org)
  • But Columbia University volcanologists found that the eruption of Costa Rica's Irazú Volcano in 1963 was likely triggered by magma that took a nonstop route from the mantle over just a few months. (wikipedia.org)
  • Thanks to a monitoring system they developed to measure the mountain's minute movements, the team forecast the volcano was due for another eruption sometime before 2014. (livescience.com)
  • Professor Stephen Sparks of the University of Bristol, a geologist whose work has improved understanding of how volcanoes work and our ability to forecast deadly volcanic eruptions, will receive the 2015 Vetlesen Prize, an award considered to be the Nobel Prize of the earth sciences. (bristol.ac.uk)
  • Hydrothermal (hot water) features at Lassen Volcanic National Park fascinate visitors to this region of northeastern California. (usgs.gov)
  • Nowhere else in the Cascade Range of volcanoes can such an array of hydrothermal features be seen. (usgs.gov)
  • Water from rain and snow (meteoric water) that falls on the highlands of Lassen Volcanic National Park feeds the Lassen hydrothermal system. (usgs.gov)
  • We know there have been more than 60 hydrothermal eruptions in the last 100 years in New Zealand. (upi.com)
  • Monitoring and warning for hydrothermal eruptions is a huge challenge. (upi.com)
  • We have seen several other fatal hydrothermal catastrophies unfold in other parts of the world, such as the 2014 eruption of Mount Ontake in Japan . (upi.com)
  • In addition to producing hardened lakes of blobby lava, in places more than a mile (1.6 km) across, the eruption changed the architecture of the region's seafloor hot springs . (livescience.com)
  • The Axial Volcano rises 3,000 feet (900 m) above the seafloor, the most active of a string of volcanoes along the Juan de Fuca Ridge, a plate boundary where the seafloor is slowly pulling apart. (livescience.com)
  • The instruments kept track of the movement of the seafloor, which very gradually inflates and deflates like a giant, magma-filled balloon, Chadwick said, collapsing suddenly after an eruption, and rising, in this case, by about 6 inches (15 cm) per year in the lead up to an eruption. (livescience.com)
  • At shallower depths, lower pressure allows rising hot water to boil. (usgs.gov)
  • Eruptions were first detected in the 1990s, and, although technology has improved, getting to the underwater peaks to study them is difficult. (livescience.com)
  • The Lassen region is at the south end of the Cascade chain of volcanoes and at the west edge of the Basin and Range Province. (usgs.gov)
  • A 2010 study published in the journal Current Anthropology suggests that an eruption that occurred 39,000 years ago was so gigantic it changed the course of history. (tsunaminaturaldisaster.com)
  • The most well-observed are magmatic eruptions, which involve the decompression of gas within magma that propels it forward. (wikipedia.org)
  • In 1978, Sparks moved to the University of Cambridge, where he published a series of influential papers with mathematician Herbert Huppert on the physics of magma chambers beneath volcanoes. (bristol.ac.uk)