Cone formed by the ejection of sand on a surface from a central point
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.
Sand boils, sand volcanoes, or sand blows occur when water under pressure wells up through a bed of sand.[1] The water looks like it is boiling up from the bed of sand, hence the name.