A type of pyroclastic surge that forms at the base of volcano eruption columns and travels outward during some hydroclastic eruptions. As base surges move laterally away from the eruptive vent, they lose heat, sediment load, and velocity, which directly affects the resulting deposits. The sedimentary structures observed within surge deposits are also directly related to the amount of liquid water involved (Brand (2004) Rocky Mt. & and Cordill. Meeting GSA Abstract 37–5). See also R. Fisher and H.-U. Schmincke (1984).
Subjects: Earth Sciences and Geography — Ecology and Conservation.