Sunda Trench is considered to be part of the Pacific Ring of Fire as well as one of a ring of oceanic trenches around the northern edges of the Australian Plate. In 2005, scientists found evidence that the 2004 earthquake activity in the area of the Java Trench could lead to further catastrophic shifting within a relatively short period of time, perhaps less than a decade. This threat has resulted in international agreements to establish a tsunami warning system in place along the Indian Ocean coast. For about half its length, off of Sumatra, it is divided into two parallel troughs by
Capture of Regina Trench army division), which had been brought from the Belgian coast. On 8 October, attacks by the 1st Canadian Division and the 3rd Canadian Division on Regina Trench, also failed. On 21 October, the 4th Canadian Division attacked the western portion of Regina Trench, as the 18th Division, 25th Division and the 39th Division of II Corps, attacked the part further west (known as Stuff Trench to the British). The Canadians met little opposition and gained the objective, as the II Corps divisions captured Stuff Trench in thirty minutes, giving the British control of the Thiepval Ridge. Three counter-attacks were repulsed