Posted on: Friday, September 3, 2004

Gigantic tsunami once hit Big Island

Associated Press

Scientists have determined a huge tsunami hit the Big Island 120,000 years ago, surging almost 4 miles inland and depositing fossil-laden sand up to an elevation of at least 1,600 feet.

The tsunami was generated by the Alika 2 Landslide, which came down the western slope of Mauna Loa, the University of Hawai'i's School of Ocean and Earth Science and Technology said Wednesday.

The resulting wave surged across a coral terrace, now at a depth of 1,400 feet, before moving inland, scientists said.

The wave left a deposit of smashed-up marine shells, chunks of lava rock, lumps of soil and fragments of coral, all cemented together by what was once coralline sand, the school said.

The findings are from an international group of scientists, led by University of Hawai'i researchers, who studied Kohala Volcano.

"These giant landslides seem to occur during periods of higher than normal sea level — like we have now," lead researcher Gary McMurtry said. "They pose a hazard not just in Hawai'i, but at all big oceanic volcanoes worldwide."