A sand volcano or sand blow is cone of sand formed by the ejection of sand onto a surface from a central point. The sand builds up as a cone with slopes at the sand's angle of repose. A crater is commonly seen at the summit. The cone looks like a small volcanic cone and can range in size from millimetres to metres in diameter.

The process is often associated with fluidization and the ejection of fluidized sand that can occur in water saturated sediments during an earthquake.

These are to be contrasted with mud volcanoes which occur in areas of geyser or subsurface gas venting. [1] [2]