Skipper ✪ Posted May 7, 2019 Posted May 7, 2019 (edited) Scientists have produced a new model to illustrate the December collapse of Indonesia's Anak Krakatau volcano and its subsequent tsunami. The results indicate that 0.2-0.4 per km of material on the southwestern flank of the volcano must have slipped into the sea to produce the destructive waves. The simulation matches the high-water readings recorded at tide gauges on Sumatran and Javan coasts. More than 400 people have lost their lives in the disaster; 33,000 were displaced. The event took almost everyone by surprise. The dangers of a landslide-generated tsunami stemming from a volcanic eruption were under-appreciated. Local after [CENSORED] tions certainly had no warning. Scientists also had to catch up, said Professor David Tappin, who presented the new model here at the European Geosciences Union General Assembly. Thinking had been strongly focused on tsunamis from big earthquakes, British Geological Survey and University College London told reporters. "Why is Anak Krakatau interesting? Because it's the first such event we've been able to investigate using all the modern technologies and understandings that have come about over the last 20 years," he explained. "These include numerical tsunami modeling, especially from non-seismic sources, satellite radar, high-resolution satellite photography before and after the event, and high-resolution seabed mapping." Anak Krakatau's collapse occurred on the evening of 22 December, during a period of renewed eruptive activity. A number of factors are thought to have precipitated what happened, including the height (340m), the steepness and inherent weakness of the volcanic structure; and the fact that it had grown close to - and had even migrated towards - the edge of a deep (220m) submarine trough. When the flank went into the sea, it would have pushed out a big wave in front of it and sucked down the water surface immediately behind. The model shows how the disturbance spread out across the Sunda Strait. Prof. Stephan Grilli, who led the modeling work at the University of Rhode Island, commented: "The numerical modeling of the eruption-generated tsunamis is far less developed than for other tsunami mechanisms - such as earthquakes and landslides." The Anak Krakatau event is timely in that it should stimulate the development of new models that will underpin improved mitigation strategies. " Edited May 8, 2019 by - Dark Closed
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