Sand boil
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Sand or mud boils occur when water under pressure wells up through a bed of sand or dirt. The water looks like it is boiling up from the bed, hence the name. While many boils are temporary and form in
Sand boils that erupted during the 2011 Canterbury earthquake.
Attempts to plug a sand boil with sandbags during the 2011 Missouri River floods. Many of the attempts were unsuccessful.
Sand boils and a silt-covered street after the 2011 Canterbury earthquake.
Cross section of a sand volcano in County Clare, Ireland
New Madrid seismic zone
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The New Madrid seismic zone, sometimes called the New Madrid fault line, is a major seismic zone and a prolific source of intraplate earthquakes in the Southern and Midwestern United States, stretchin
Sand boil
…is often associated with soil liquefaction and the ejection of fluidized sand that can occur in water-saturated sediments during an earthquake. The New Madrid seismic zone exhibited many such features during the 1811–1812 New Madrid earthquakes. Adjacent sand blows aligned in a row along a linear fracture within fine-grained…
The Great Earthquake at New Madrid, a 19th-century woodcut from Devens' Our First Century (1877)