The west coast of Sumatra is dominated by the Sunda megathrust; a 5,500 km[7] long convergent boundary where the Australian Plate subducts beneath the Burma Plate and Sunda Plate at a rate of 60 millimetres (2.4 in) per year.[8] Convergence along this plate boundary is highly oblique, severely deforming the overriding Sunda Plate, where it is accommodated by the strike-slip motion along the Great Sumatran fault. The Great Sumatran fault is a 1,900-kilometre (1,200 mi)-long strike-slip fault system located onshore on the island of Sumatra, which is divided into about 20 segments.[9] The subduction zone offshore Sumatra has been responsible for several large earthquakes in 2004 and 2005.