Luckily, one was just discovered last year -- an unnamed underwater volcano 22 miles west of Tongatapu, the main island in the country of Tonga. A survey of the sides of the volcano reveals a three-mile-long section of its flank may have collapsed, sending a wave up to 130 feet high crashing into the island. "Our guess is that it was comparable to Krakatau's wave," Hornbach said, referring to the famous eruption in 1883 that inundated the islands of Java and Sumatra with a tsunami 100 to 130 feet high. But the boulders strewn along Tongatapu are bigger than deposits made by Krakatau's tsunami. The team estimates that the largest, easily the size of a house, weighs some 1,600 metric tons. By comparison, the largest Krakatau boulder weighed 600 metric tons. "Look, we can't discount that something else may be going on here. A hypercane or some extremely powerful storm could have done it," he said. "But to my knowledge no storm has ever deposited anything bigger than car-sized boulders." "The giant-ness of the wave proposed here hasn't been seen in human time," Jose Borrerros of ASR Research, a marine consulting firm in Raglan, New Zealand, said. "I wouldn't dispute that it's possible, though you can never say for sure what caused it. It's really hard to nail this stuff down." Related Links: |
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