Hawaii, a benign place considered by many as “paradise,” unveils a dark past. A buried debris pile uncovered by researchers revealed that the destructive earthquake, which brought a tsunami on the Hawaii’s Kauai Island about 500 years ago, hinting a similar event might hit Hawaii’s shores in the near future.
“The earthquake with the magnitude of 9.0 happened in Alaska and brought 30-foot tall waves to Hawaii between 1425 and 1665. In contrast, the resulting tsunami was at least 3 times the size of a tsunami that caused damage in Hawaii in 1946,” LiveScience reported.
David Burney, a paleoecologist at the National Tropical Botanical Garden in Kalaheo, discovered the site back in the late 1990s, but his theory that a massive tsunami left the ocean debris found in the sinkhole was not verified until now.
In a recent study, Honolulu officials have modified their tsunami evacuation maps in case a destructive tsunami hits the region of around a million residents. As per the American Geophysical Union press release, the evacuation areas will be more than double in some locations on the new maps. A tsunami, to the size of the one in the study is projected to happen once every 1000 years, making the odds that it will happen in any given year quite small at 1%.
The sinkhole left by the tsunami that struck 500 years ago holds a layer of sediment with distinct traces of the ocean: coral fragments, mollusk shells and beach sand. The sediment remained a mystery until the 2011 Tohoku earthquake hit Japan and pulled tall, damaging waves inland to flood the island nation.
“The Japan’s earthquake was bigger than almost any seismologist ever thought. The live coverage showed the devastation it caused, I wonder, did we get it right in Hawaii? Are our evacuation zones the correct size?” he added.
Gerald Fryer, a geophysicist at the Pacific Tsunami Warning Center but not participated in the study said, “I have seen the deposit and I’m absolutely convinced it’s a tsunami, and it had to be a monster tsunami.”