Geological hazards

thumb|upright=1.35|Earthquake epicenters occur mostly along tectonic plate boundaries, especially on the Pacific [[Ring of Fire.]]

thumb|upright=1.35|Augustine Volcano (Alaska) during its eruptive phase on January 24, 2006

thumb|right|Quicksand and a warning sign about it at a gravel quarry in England thumb|Quicksand on the River Thames|Thames Quicksand, also known as sinking sand, is a colloid consisting of fine granular material (such as sand, silt or clay) and water. It forms in saturated loose sand when the sand is suddenly agitated. When water in the sand cannot escape, it creates a liquefied soil that loses strength and cannot support weight. Quicksand can form in standing water or in upward flowing water (as from an artesian spring). In the case of upward-flowing water, forces oppose the force of gravity

[[File:Supervolcano World Map.png|thumb|upright=1.5|World map of known VEI 7 and VEI 8 volcanoes

volcanic caldera in Yellowstone National Park in the United states

very rare type of natural disaster in which dissolved carbon dioxide (CO2) suddenly erupts from deep lake waters, forming a gas cloud capable of suffocating wildlife, livestock, and humans

thumb|Garland-like solifluction formed in the Swiss National Park thumb|Possible solifluction lobes in Acidalia Planitia on Mars as seen by [[HiRISE]] thumb|Solifluction sheets near Eagle Summit (Alaska)|Eagle Summit, [[Alaska]] Solifluction is a collective name for gradual processes in which a mass moves down a slope ("mass wasting") related to freeze-thaw activity. This is the standard modern meaning of solifluction, which differs from the original meaning given to it by Johan Gunnar Andersson in 1906.

thumb|right|upright=1.3|Diagram of the 1958 Lituya Bay earthquake and megatsunami|1958 Lituya Bay megatsunami, which proved the existence of megatsunamis A megatsunami is an extremely large wave created by a substantial and sudden displacement of material into a body of water.

massive volcanic formation resulting from flood basalt eruptions

geomorphic process by which soil, sand, regolith, and rock move downslope

geological phenomena in which water-laden masses of soil and fragmented rock rush down mountainsides

thumb|x180px|alt=Refer to caption|Cross section of a cirque glacier showing the bergschrund thumb|upright=1.3|alt=Three mountaineers on a snow-covered icefield with mountain peaks in the distance|A bergschrund—the long crack at the foot of the mountain slope—in the Ötztal Alps thumb|alt=Rocky peaks protruding from undulating ice masses|Open bergschrunds at Mont Dolent A bergschrund (from the German for mountain cleft; sometimes abbreviated in English to "schrund") is a crevasse that forms where moving glacier ice separates from the stagnant ice or firn above. It is often a serious obstacle for

result of a very large volume eruption of basalt lava

A hypercane is a hypothetical class of extreme tropical cyclone that could form if sea surface temperatures reached approximately , which is warmer than the warmest ocean temperature ever recorded. Such an increase could be caused by a large asteroid or comet impact, a large supervolcanic eruption, a large submarine flood basalt, or "incredible" global warming. There is some speculation that a series of hypercanes resulting from the impact of a large asteroid or comet contributed to the demise of the non-avian dinosaurs. The hypothesis was developed by Kerry Emanuel of MIT, who also coined the

type of glaciomarine clay

A cryoseism, ice quake or frost quake, is a seismic event caused by a sudden cracking action in frozen soil or rock saturated with water or ice, or by stresses generated at frozen lakes.

adverse geologic conditions capable of causing damage or loss of property and life

hotspot

conjectural soil type probably not found in nature

thumb|Mazuku forming in a low morphological depression on the foothills of Mt. Amiata, Italy, where CO2-rich fog accumulates in a ditch Mazuku (Swahili for "evil winds") are pockets of dry, cold carbon dioxide-rich gases released from vents or fissures in volcanically and tectonically active areas, mixed with dispersed atmospheric air and accumulating in typically low-lying areas. Since carbon dioxide (CO2) is ~1.5 times heavier than air, it tends to flow downhill, hugging the ground like a low fog and gathering in enclosed spaces with poor ventilation—such as lava tubes, ditches, depressions,