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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.
An example of the lava arcs formed during Strombolian activity. This image is of Stromboli itself. Strombolian eruptions eject volcanic bombs and lapilli fragments that travel in parabolic paths before landing around their source vent. [16] The steady accumulation of small fragments builds cinder cones composed completely of basaltic pyroclasts.
The word lahar is of Indonesian origin, but is now routinely used by geologists worldwide to describe volcanogenic debris flows. Nearly all of Earth's largest, most destructive debris flows are lahars that originate on volcanoes. An example is the lahar that inundated the city of Armero, Colombia.
At 11:30 p.m., the first lahar hit, followed shortly by the others. [30] One of the lahars virtually erased Armero; three-quarters of the town's 28,700 inhabitants were killed. [27] Proceeding in three major waves, this lahar was 30 m (100 ft) deep, moved at 12 m/s (39 ft/s; 27 mph), and lasted ten to twenty minutes.
Kelut Lahars 5110 Lahars caused 5,110 deaths, and destroyed or damaged 104 villages. Length 185 km (115 mi). [69] 16 Dec 1920 Haiyuan County, Ningxia, China 1920 Haiyuan earthquake >100,000 Loess flows and landslides over an area of 50,000 km 2 (19,000 sq mi). Failures in loess caused extreme fissuring, landslide dams, and buried villages. [69 ...
In 1991, damage to crops and property was estimated at $374 million (or $711 million today), to which continuing lahar floods added a further $69 million (or $127 million today) in 1992. In total, 42 percent of the cropland around the volcano was affected by more lahar floods, dealing a severe blow to the agricultural economy in the region. [21]
The 1963 eruption of Irazú Volcano in the Cordillera Volcánica Central was one of the most powerful eruptions in Costa Rica, especially for his destructive lahar.Signs of reactivation began to occur in 1961 in the form of microseisms; previously, several specialists warned that the Irazú Volcano could explode at any time.
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 ...