15.4 When do mass movements occur?
Fig 15.24
A lahar in the Philippines in the wake of the eruption of Mt. Pinatubo (c. 1991). A lahar is a mixture of debris and ash saturated with water either from rain or from rapidly melted snow and ice from atop the volcano. Lahars such as this
buried whole cities, and in total they deposited a volume in the Philippines that would cover Washington D.C. to a depth of three stories.