Volcanology and seismology

Tuya Volcanic Field

Tuya Volcanic Field, also called Tuya Butte or Tuya Lake Volcanic Field, is a Canadian volcanic field of Pleistocene subglacial tuyas in northern British Columbia's Northern Cordilleran Volcanic Province, the type area for the landform "tuya."

Udina

Udina (Bolshaya and Malaya Udina) is a pair of Holocene stratovolcanoes at the south end of Kamchatka's Kliuchevskaya group, Russia, with no known Holocene eruptions but seismic unrest in 2017-2019 suggesting possible magmatic reawakening.

Udokan Plateau

Udokan Plateau (Udokan volcanic plateau): a 3,000 km2 Miocene-to-Holocene volcanic field on the NE Baikal Rift in Siberia, Russia, with cinder cones, domes, and maars; last eruption at Chepe, 220 BCE.

Unexplained volcanic eruption

An unexplained volcanic eruption, often called a mystery eruption, is a large eruption identified from polar ice cores rather than written history, such as the still-unlocated 1809 event.

Ushkovsky

Ushkovsky (formerly Plosky) is a 3,943 m compound volcano at the NW end of Kamchatka's Kliuchevskaya group, with an ice-filled 4.5 x 5.5 km caldera and last eruption in 1890 CE.

Vaiyots-Sar

Vaiyots-Sar (Վայոցսար), also Dalik Tapa or Dar-Alages, is a pyroclastic cinder cone volcano in Vayots Dzor, Armenia, 2,575 m high, with Holocene lava flows, a 2000 BCE GVP eruption date, and a disputed 735 AD eruption legend.

Volcán de Fuego

Volcán de Fuego (Chiq'aq', "Fireplace"), also known as Fuego volcano, is a persistently active basaltic stratovolcano in southern Guatemala and Central America's historically most active volcano.

Volcanic area

Volcanic area: a region containing volcanoes, volcanic landforms, or volcanic deposits. Also called volcanic region or volcanic field; about 1,350 potentially active volcanoes worldwide, 800 million people within 100 km, organized by tectonic setting.

Volcanic ash

Volcanic ash, also called volcanic dust, is hard, abrasive tephra finer than 2 mm thrown out by explosive eruptions, the most widespread volcanic hazard and a serious threat to aircraft.

Volcanic crater

A volcanic crater is an enclosed depression at or around a volcanic vent, formed by explosive eruption or ground collapse; a collapse more than 1 kilometer across is a caldera.

Volcanic Eruptions

Volcanic eruptions: explosive or effusive release of magma, gas, and ash at Earth's surface. Named types include Hawaiian, Strombolian, Vulcanian, Peléan, and Plinian; hazards include pyroclastic flows, lahars, and ashfall.

Volcanic explosivity index

The volcanic explosivity index (VEI) is a 0 to 8 scale proposed in 1982 by Chris Newhall and Stephen Self to compare explosive eruptions by tephra volume.

Volcanic field

A volcanic field is a cluster of volcanoes or an area covered by volcanic rocks, in which individual centers usually erupt only once; fields may span millions of years.

Volcanic gas

Volcanic gas is the mixture of gases released from magma and volcanic vents, mainly water vapor, carbon dioxide, and sulfur dioxide, even when a volcano is not erupting.

Volcanic tremor

Volcanic tremor is a continuous seismic signal generated at volcanoes by the movement of magma, gas, or groundwater, lasting from minutes to days and widely used in eruption monitoring.

Volcanism of Iceland

Volcanism of Iceland, where the Mid-Atlantic Ridge crosses the Iceland plume, makes Iceland one of Earth's most volcanically active areas, averaging an eruption every four to five years.

Volcano

A volcano is a vent, or a landform built around one, on Earth or another planet through which molten rock, rock fragments, and gases erupt; most active ones encircle the Pacific as the Ring of Fire.

Vysoky

Vysoky (Vysokii, Visoky), volcano 300221, a 2,129 m Holocene stratovolcano in Kamchatka's Eastern Volcanic Arc, 4 km NE of Komarov; last confirmed eruption about 550 BCE (VEI 0), not the Slovak mountain Vysoká.

Wadati–Benioff zone

A Wadati–Benioff zone, also called the Benioff zone, is an inclined zone of earthquake foci tracing a subducting oceanic plate, reaching depths of about 700 km.

Whakaari / White Island

Whakaari / White Island, also called White Island, is an active volcano in the Bay of Plenty, New Zealand, some 48 km offshore; a 2019 eruption killed 22 tourists.

Yellowstone Caldera

Yellowstone Caldera: the 85 x 45 km volcanic depression formed by the Lava Creek Tuff eruption 640,000 years ago, youngest of three Yellowstone hotspot calderas, powering over 10,000 hydrothermal features and monitored by the Yellowstone Volcano Observatory.

Youngest Toba eruption

The Youngest Toba eruption was a VEI 8 supervolcanic eruption of the Toba volcano in northern Sumatra, Indonesia, about 74,000 years ago; its ash covered roughly 40 million km² of Earth's surface.

Yucamane

Yucamane (Yucamani), a 5,495 m Holocene stratovolcano in Tacna Region, southern Peru, southern edifice of the Yucamane-Calientes complex near Candarave; last confirmed eruption about 1320 BCE (VEI 5), ranked among the Central Volcanic Zone's highest-risk volcanoes and monitored at green alert by Peru's IGP.