pyroclastic ground surge

The relatively thin mantle of rock found around a volcanic vent; the thickness is not uniform, the internal stratification is not parallel to the top and bottom of the layer, and the extent is a few kilometers from the source.

Related terms:

• Pyroclastic Rock
• Pyroclastic Flow
• surge
• ground layer
• hurricane surge
• Storm Surge
• surge line
• ground pressure
• Ground Moraine
• ravelly ground