page_title: Prediction of volcanic activity
hierarchical_section_title: Prediction of volcanic activity
caption_attribution_description: English: On May 18, 1980, at 8:32 a.m. Pacific Daylight Time, a magnitude 5.1 earthquake shook Mount St. Helens. The bulge and surrounding area slid away in a gigantic rockslide and debris avalanche, releasing pressure, and triggering a major pumice and ash eruption of the volcano. Thirteen-hundred feet (400 meters) of the peak collapsed or blew outwards. As a result, 24 square miles (62 square kilometers) of valley was filled by a debris avalanche, 250 square miles (650 square kilometers) of recreation, timber, and private lands were damaged by a lateral blast, and an estimated 200 million cubic yards (150 million cubic meters) of material was deposited directly by lahars (volcanic mudflows) into the river channels. Sixty-one people were killed or are still missing. USGS Photograph taken on May 18, 1980, by Austin Post. Català: El 18 de maig, a les 8:32 a. m. Temps del Pacífic, un terratrèmol de una magnitud de 5,1 va fer trontollar la muntanya St. Helens. La protuberància l'àrea circumdant relliscà en una gegantina esllavissada de roques i un allau de rocam, alliberant la pressió, desencadenà una erupció de pedra tosca i cendra del volcà. 400 metres del puig van col·lapsar o van sortir volant. Com a resultat 62 quilometres quadrats de la vall van ser emplenats per la runa, 650 quilometres quadrats de llocs d'esbarjo, bosc, i finques privades van ser damnificades per una ràfega lateral, i una quantitat estimada en 150 milions de metres cúbics de material van ser dipositats per corrents de fang volcànic en els canals del riu. Cinquanta set persones van morir o han desaparegut (18 de Maig de 1980, Austin Post, USGS) Español: Erupción del Monte Santa Helena Français&#160;: Le 18 mai 1980, à 8h32 minutes (heure du Pacifique), un tremblement de terre de 5,1 sur l'échelle de Richter secoue le Mont Saint Helens, marquant le début de l'éruption du mont Saint Helens en 1980.
context_page_description: Prediction of volcanic eruption, or volcanic eruption forecasting, is an interdisciplinary monitoring and research effort to predict the time and severity of a volcano's eruption. Of particular importance is the prediction of hazardous eruptions that could lead to catastrophic loss of life, property, and disruption of human activities.
context_section_description: Prediction of volcanic eruption, or volcanic eruption forecasting, is an interdisciplinary monitoring and research effort to predict the time and severity of a volcano's eruption. Of particular importance is the prediction of hazardous eruptions that could lead to catastrophic loss of life, property, and disruption of human activities.
caption: Mount St. Helens erupted explosively on May 18, 1980 at 8:32 a.m. PDT
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