Earthquake
An earthquake (also known as a quake, tremor or temblor) is the result of a sudden release of energy in the Earth's crust that creates seismic waves.
Tsunami
A tsunami also called a tsunami wave train, and at one time incorrectly referred to as a tidal wave, is a series of water waves caused by the displacement of a large volume of a body of water, usually an ocean, though it can occur in large lakes.
Tornado
A tornado (often referred to as a twister or, erroneously, a cyclone) is a violent, dangerous, rotating column of air that is in contact with both the surface of the earth and a cumulonimbus cloud or, in rare cases, the base of a cumulus cloud.
Floods
A flood is an overflow of an expanse of water that submerges land. The EU Floods directive defines a flood as a temporary covering by water of land not normally covered by water
Volcanic Eruptions
Volcanoes can cause widespread destruction and consequent disaster through several ways. The effects include the volcanic eruption itself that may cause harm following the explosion of the volcano or the fall of rock.
Subglacial Eruption
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Subglacial eruption: 1 water vapor cloud, 2 lake, 3 ice, 4 layers of lava and ash, 5 strata, 6 pillow lava, 7 magma conduit, 8 magma chamber, 9 dike.
A subglacial eruption is a volcanic eruption that has occurred under ice, or under a glacier. Subglacial eruptions can cause dangerous floods, lahars and create hyaloclastite and pillow lava. Subglacial eruptions sometimes form a subglacial volcano called a tuya. Tuyas in Iceland are called table mountains because of their flat tops. Tuya Butte, in northern British Columbia is an example of a tuya. A tuya may be recognized by its stratigraphy, which typically consists of a basal layer of pillow basalts overlain by hyaloclastite breccia, tuff, and capped off by a lava flow. The pillow lavas formed first as a result of subaqueous eruptions in glacial meltwater. Once the vent reaches shallower water, eruptions become phreatomagmatic, depositing the hyaloclastite breccia. Once the volcano emerges through the ice, it erupts lava, forming the flat capping layer of a tuya.
The thermodynamics of subglacial eruptions are very poorly understood. Rare published studies indicate that plenty of heat is contained in the erupted lava, with 1 unit-volume of magma sufficient to melt about 10 units of ice. However, the rapidity by which ice is melted is unexplained, and in real eruptions the rate is at least an order of magnitude faster than existing predictions.
Antarctica eruption
On January, 2008, the British Antarctic Survey (Bas) scientists led by Hugh Corr and David Vaughan, reported (in the journal Nature Geoscience) that 2,200 years ago, a volcano erupted under the Antarctica ice sheet (based on airborne survey with radar images). The biggest eruption in the last 10,000 years, the volcanic ash was found deposited on the ice surface under the Hudson Mountains, close to Pine Island Glacier. The ash covered an area the size of New Hampshire and was probably deposited from a 12 km high ash plume. Researchers have detected a mountainous peak some 100 meters beneath the surface believed to be the top of the tuya associated with this eruption.
List of volcanoes with Holocene subglacial eruptions
Iceland
- Bárðarbunga
- Eyjafjallajökull
- Grímsvötn
- Hveravellir
- Katla
- Kverkfjöll
- Prestahnúkur
- Snæfellsjökull
- Torfajökull
- Öræfajökull
South America
- Lautaro
- Sollipulli
