Sand volcano

A sand volcano is a sand cone, which is produced at the Earth's surface as a result of liquefaction of water-saturated sands in the subsurface and their subsequent emissions along a central channel. There is a conical hill, whose slopes have a slope corresponding to the angle of internal friction forms. This cone resembles a small volcano with a crater at the top, it can have sizes of a few millimeters to several meters.

The emergence of a sand volcano is often associated with the liquefaction of water-saturated sands in an earthquake. Sand volcanoes could be for example the earthquakes of New Madrid in the years 1811 and 1812 observed, partly also to linienhaftem emissions of sand merging.

Sand volcanoes can be readily detected in geological outcrops due to her ascension channel and the resulting sand cone. In recent years, intensive research has been operated such liquefaction structures to reconstruct the history of previous earthquakes.

The similar-looking mud volcanoes are caused by other processes, they are associated with the rise of warm or hot water or gases.