Lahar is an Indonesian word for a rapidly flowing mixture of rock debris and
water that originates on the slopes of a volcano. Lahars are also referred to
as volcanic mudflows or debris flows. They form in a variety of ways, chiefly
from the rapid melting of snow and ice by pyroclastic flows, intense rainfall
on loose volcanic rock deposits, the breakout of a lake dammed by volcanic
deposits, and as a consequence of debris avalanches.
Left: A lahar from the Unzen Volcano eruption in Kyushu,
Japan tore through this street in Shimabara, destroying cars and homes in the