Answer:
Lahar is an Indonesian word describing mudflows and debris flows
that originate from the slopes of a volcano. Both types of flows
contain a high concentration of rock debris to give them the
internal strength necessary to transport huge boulders as well
as buildings and bridges and to exert extremely high impact
forces against objects in their paths. Debris flows are coarser
and less cohesive than mudflows. As lahars become dilute in
downstream direction they become hyperconcentrated streamflows.
Lacking internal strength, the mixture of rock debris and water
takes on different flow properties. The coarser debris in this
type of flow is no longer held in suspension by matrix strength
and therefore settles to the bottom of the flow.
