The Barrancas rock-avalanche, of northern Neuquén Province (Argentina): Its relation to the outburst flood of December 29, 1914
At some unknown time in the past, instability of the slope of C° Pelán resulted in a rock-avalanche that blocked the Barrancas valley as a landslide dam and formed the Carrilauquen lagoon. It is suggested that the trigger was a seismic shock, that resulted in complex movement of a proximal planar sl...
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| Formato: | JOUR |
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| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00044822_v56_n4_p466_GonzalezDiaz |
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| Sumario: | At some unknown time in the past, instability of the slope of C° Pelán resulted in a rock-avalanche that blocked the Barrancas valley as a landslide dam and formed the Carrilauquen lagoon. It is suggested that the trigger was a seismic shock, that resulted in complex movement of a proximal planar slide and a distal flow, with a velocity estimated at about 270 km/h. After obstructing the valley the avalanche climbed up the opposite side for over 180 meters. The Carrilauquen lagoon was over 22 km long and 100 m deep. The exceptionally snowy winter of 1914, followed by a very warm spring-summer season, resulted in a great inflow of water into the lagoon that raised its level until it overtopped the natural dam and caused it to collapse when weakened by increased hydrostatic pressure. A huge outburst flood (jokulklaup; aluvión) flowed through the breach, and caused great devastation in the Barrancas and Colorado valleys for over 1,250 km as far as the Atlantic coast. Some rock-avalanche morphometric parameters are estimated and associated geomorphological features are described. Oral accounts by local residents and contemporaneous newspaper reports were the principal sources for describing the damage downstream of the Barrancas landslide dam. |
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