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.
Surtseyan Eruption
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Surtseyan eruption: 1 water vapor cloud, 2 cupressoid ash, 3 crater, 4 water, 5 layers of lava and ash, 6 stratum, 7 magma conduit, 8 magma chamber, 9 dike.
A Surtseyan eruption is a type of volcanic eruption that takes place in shallow seas or lakes. It is named after the island of Surtsey off the southern coast of Iceland.
These eruptions are commonly phreatomagmatic eruptions, representing violent explosions caused by rising basaltic or andesitic magma coming into contact with abundant, shallow groundwater or surface water. Tuff rings, pyroclastic cones of primarily ash, are built by explosive disruption of rapidly cooled magma. Other examples of these volcanoes: Capelinhos, Faial Island, Azores; and Taal Volcano, Batangas, Philippines.
Characteristics of Surtseyan Eruption
Although similar in nature to phreatomagmatic eruptions, there are several specific characteristics:
- Physical nature of magma: viscous; basaltic.
- Character of explosive activity: violent ejection of solid, warm fragments of new magma; continuous or rhythmic explosions; base surges.
- Nature of effusive activity: short, locally pillowed, lava flows; lavas may be rare.
- Nature of dominant ejecta: lithic, blocks and ash; often accretionary lapilli; spatter, fusiform bombs and lapilli absent.
- Structures built around vent: tuff rings
