Full glossary

Volcanic Ash Advisory Centers (VAAC) are research centres who monitor volcanic ash clouds in real time. Each time, a volcano erupts a significant ash cloud, short reports are issued and transmitted directly to air control centres. The 9 VAAC are located in London, Toulouse, Tokyo, Darwin, Anchorage, Washington, Montreal and Buenos Aireas and collectively cover most of the globe.

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Vakak (or Wakak) volcano is a field of 18 small volcanoes 115 km WSW of Kabul. It is the northernmost of a group of small volcanic fields in the Ghanzi region and consists of lava domes, one of which occupies an old caldera.
The age of its last eruption is unknown, but could be relatively recent (less than 10,000 years ago).

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The Valle del Bove is a huge horseshoe-shaped depression 7 km long, 5 km wide, and up to 1 km deep,paved with historic an prehistoric lava eruptions.
There are different theories about its creation but the most reliable according to scientists is that it is the result from a catastrophic landslide, or series of landslides that involved the eastern flank of the Etna Edifice about 10000 years ago.
Its steep and crumbly walls offer the opportunity to study the most ancient eruptive centers to better understand the history of the volcano and its processes.

The 22-km-wide Valles caldera was formed by 2 very large explosive eruptions 1.7 and 1.2 million years ago. Post caldera eruptions formed Redondo Peak dome inside the caldera.
The last eruptions of the caldera happened 50,000-60,000 years ago, depositing rhyolite ignimbrite deposits.
The caldera is still considered potentially active and has an active geothermal system with hot springs and fumaroles.

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The fishing harbour Vathy on Methana

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The Vatnafjöll volcanic system, lying immediately SE of Hekla volcano, is a 40-km-long, 9-km-wide collection of alkali basaltic fissures and crater rows.

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Veniaminof is one of the highest, largest and most active volcanoes on the Alaska Peninsula.

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Vernadskii Ridge comprises 3 groups of volcanoes in northern Paramushir Island, Kuril Islands, immediately south of active Ebeko volcano.
The Vernadskii and Bogdanovich groups of volcanoes are the southernmost of this complex and have been active during the past 10,000 years.

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Vestmannaeyjar is a mostly submarine volcanic system just off Iceland's south coast, famous for the appearance of Surtsey Island in 1963-67 and the destructive eruption on Heimaey Island in 1973.

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Veteran is a submarine volcano 34 km SSE off the Grand Catwick Rock, located off the SE coast of Vietnam.
In 1880, a new reef was reported at this location. In 1882, it had disappeared, suggesting that a volcanic eruption had occurred.
Discolored water at the site, possibly from fumarolic activity, was reported in 1928.
The area lies along a regional N-S-trending lineament related to extension produced by collision of the Australian plate.
(Source: Smithsonian / GVP)

Mt Victory Volcano is a dominantly andesitic stratovolcano on the NE coast of mainland New Guinea, 30 km from Tufi on Cape Nelson.
Mt Victory's summit contains a small crater lake. There is only 1 confirmed historical eruption from Victory volcano, but that consisted in long-lasting activity during the late 19thand until the 20th century, and its red crater glow was a well-known beacon for passing ships at that time. Pyroclastic flows occurred during this period of activity around 1880 and destroyed several villages and caused fatalities. At present, there is weak thermal activity.

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Viedma is a volcano underneath the Patagonian Icefield NW of Viedma Lake in southern Argentinia. Its existence was confirmed during the eruption in 1988. ONly parts of the volcano rise above the glaciers.

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The ability of a liquid to flow. Basalt magma has a relatively low viscosity making it runny, whereas rhyolite magma has a high viscosity making the magma thick and sticky.

The Vitim Plateau volcano is a vast volcanic field northeast of the Baikal Lake. Cinder cones and associated lava flows are spread over an area of about 10,000 sq km.

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Volcán Azul (also known as Volcán Blue) a group of 3 cinder cones located on the Atlantic coastal plain of Nicaragua. The volcanic cones are in an area covered by dense rainforest and were discovered during an aerial survey in the 1960s.

Note: There is another Cerro Azul volcano in Chile.

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Pathways of rising magma inside vertical fissures.

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Volcanic tremor is a continuous seismic signal with regular or irregular sine wave appearance and low frequencies (0.5-5 Hz).

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A volcaniclastic rock or loose deposit made of (older) volcanic fragments.

The science of studying volcanoes.

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A vulcanian (note the different term from "volcanic") eruption is an intermediately violent type of explosive eruption, stronger than strombolian explosions but much weaker than Plinian eruptions.
During vulcanian eruptions, a relatively large solid plug is ejected when magmatic gas pressure that had build up beneath it overcomes the strength of the plug.
In the same way as Stromboli island for strombolian eruptions, the term vulcanian was coined after the neighboring island of Vulcano in the Eolian Islands, where such eruptions had been observed during the eruption in 1888.

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The Vulsini volcanic complex in central Italy covers about 2200 sq km at the northern end of the Roman magmatic province.

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