GEOLOGY

Detailed explanation-1: -Lahars generally occur on or near stratovolcanoes, such as those of the Aleutian volcanic arc in Alaska and the Cascade Range in the Western U.S. A moving lahar looks like a roiling slurry of wet concrete, and as it rushes downstream, the size, speed, and amount of material carried can constantly change.

Detailed explanation-2: -Lahars transform the landscapes around Cascade Volcanoes. Small debris flows are common in the Cascades, where they form during periods of heavy rainfall, rapid snow melt, and by shallow landsliding. These relatively small debris flows seldom move more than a few miles down valleys.

Detailed explanation-3: -Lahars occur during volcanic eruptions-or, less predictably, through other processes on steep volcanic terrain-when large masses of water mixed with sediment sweep down and off volcano slopes and commonly incorporate additional sediment and water.

Detailed explanation-4: -Volcanic Hazards☆ A lahar (an Indonesian term for volcanic mudflow) is a slurry of rock debris and water that originates on the slopes of volcanoes. Such flows are called primary if they occur during eruptive activity, and secondary if they are posteruption.