Akibat anjakan dasar laut sebanyak 5 meter (16 kaki) punca tsunami yang melanda Jepun baru-baru ini. Tsunami Sumatera pada 2004 pula akibat anjakan dasar laut setinggi tidak kurang 12 meter ( 40 kaki). Jumlah mangsa setakat ini dianggarkan sebanyak 28,000 di Jepun. 2004? lebih 250,000 - juga hampir 10 kali ganda.
Seabed surge caused tsunamis
Japanese researchers say they have discovered that the seabed rose as much as 5 meters near the focus of the massive earthquake that struck off northeastern Japan on March 11th.
The research team was led by Ryota Hino, an Associate Professor at Tohoku University's Research Center for the Prediction of Earthquakes and Volcanic Eruptions.
The team analyzed data collected from a water-pressure gauge installed on the seabed 5,800 meters down and at a point 200 kilometers off the coast of Miyagi Prefecture, near the focus of the quake. The focus zone stretches about 450 kilometers north to south.
The data showed that the seabed rose by about 5 meters in the quake.
The researchers said the massive tsunamis were caused by the sudden rise in the seabed over wide areas.
They also believe the tsunami waves grew larger as they approached the coasts and encountered shallower water. They say this caused tsunami higher than 10 meters over wide areas.
Hino said the data on previous major quakes showed that the related seabed elevations were at the most 2 meters.
Friday, April 01, 2011 12:23 +0900 (JST)
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