In February 2005, the Royal Navy vessel surveyed the seabed around the earthquake zone, which varies in depth between . The survey, conducted using a high-resolution, multi-beam sonar system, revealed that the earthquake had made a considerable impact on the topography of the seabed. thrust ridges created by previous geologic activity along the fault had collapsed, generating landslides several kilometres wide. One such landslide consisted of a single block of rock some high and long. The momentum of the water displaced by tectonic uplift had also dragged massive slabs of rock, each weighing millions of tonnes, as far as across the seabed. An oceanic trench several kilometres wide was exposed in the earthquake zone.