From: "Matthew L. Brown" <[EMAIL PROTECTED]> Date: 10 February 2005 2:47:21 PM PST To: [EMAIL PROTECTED] Subject: Tsunami seabed pictured with sonar
http://www.newscientist.com/article.ns?id=dn6994
Dramatic 3D images of the ocean bed where a monstrous earthquake caused the Asian tsunami have been captured by a UK Royal Navy ship.
The images reveal a landscape transformed by the quake which occurred as the Indian tectonic plate pushed against the Burma plate - its leading edge being driven further beneath it.
The earthquake - now thought to have measured a colossal 9.3 on the Richter scale - displaced massive amounts of water and produced killer waves that sped to coastlines around the Indian Ocean on 26 December 2004.
The map of the ocean floor was captured using high-resolution multi-beam sonar from a UK Royal Navy survey ship, the HMS Scott. Marine geologists aboard the ship have identified several features that bear testament to the earthquake that wrenched the ocean bed.
Slabs of rock weighing millions of tonnes were dragged up to 10 kilometres along the seabed by the force of the displaced water. And while mountainous ridges 1,500 metres tall were forged from debris during the huge movement of earth, an oceanic trench several kilometres wide was ripped open.
Researchers from the Southampton Oceanography Centre, UK, and the British Geological Survey are analysing the pictures aboard the ship. The images should help scientists understand the geological process that produced the tsunami and ultimately assist with the construction of an early warning system for the Indian Ocean.
"From this we hope to better understand the geological processes which produced the earthquake and ultimately help to determine future earthquake and tsunami hazards so that everyone can be aware and prepared," said Lisa McNeill, of the Southampton Oceanography Centre.
