Search results
Results from the WOW.Com Content Network
A lahar travels down a river valley in Guatemala near the Santa Maria volcano, 1989. A lahar (/ ˈ l ɑː h ɑːr /, from Javanese: ꦮ꧀ꦭꦲꦂ) is a violent type of mudflow or debris flow composed of a slurry of pyroclastic material, rocky debris and water.
A lahar is a debris flow related in some way to volcanic activity, either directly as a result of an eruption, or indirectly by the collapse of loose material on the flanks of a volcano. A variety of phenomena may trigger a lahar, including melting of glacial ice, sector collapse , intense rainfall on loose pyroclastic material, or the outburst ...
These are called lahars; [11] when the lahar contains large material such as blocks of rock and trees, it is a volcanic debris flow. [12] Lahars can form directly from a pyroclastic material flow flowing into a river, or could possibly form after the main eruption.
Lahar flows from the 1985 eruption of Nevado del Ruiz, which totally destroyed Armero in Colombia The most dangerous eruptive feature are the pyroclastic flows generated by material collapse, which move down the side of the mountain at extreme speeds [ 40 ] of up to 700 km (435 mi) per hour and with the ability to extend the reach of the ...
Other types of mudflows include lahars (involving fine-grained pyroclastic deposits on the flanks of volcanoes) and jökulhlaups (outbursts from under glaciers or icecaps). [6] A statutory definition of "flood-related mudslide" appears in the United States' National Flood Insurance Act of 1968, as amended, codified at 42 USC Sections 4001 and ...
A lahar is a volcanic mudflow or landslide. The 1953 Tangiwai disaster was caused by a lahar, as was the 1985 Armero tragedy in which the town of Armero was buried and an estimated 23,000 people were killed. [citation needed] Volcanoes rated at 8 (the highest level) on the volcanic explosivity index are known as supervolcanoes.
Get AOL Mail for FREE! Manage your email like never before with travel, photo & document views. Personalize your inbox with themes & tabs. You've Got Mail!
Lahars can result from heavy rainfall during or before the eruption or interaction with ice and snow. Meltwater mixes with volcanic debris causing a fast moving mudflow. Lahars are typically about 60% sediment and 40% water. [40] Depending on the abundance of volcanic debris the lahar can be fluid or thick like concrete. [41]