Anatomy of the Sumatran Megathrust
The Sumatran Megathrust is a 5,000-kilometer long subduction zone west of Sumatra where the Indo-Australian plate subducts beneath the Eurasian plate at an average rate of 4-5 centimeters per year. This fault is one of the world's most dangerous earthquake zones and was responsible for the devastating 2004 Aceh earthquake.
The fault is divided into several segments, each with its own unique seismic characteristics. The Aceh segment, which produced the 2004 earthquake, is currently in a recovery phase, but other segments such as the Nias and Mentawai segments show high stress accumulation. Seismologists warn that a major earthquake with magnitude 8.0-9.0 can occur anywhere along this fault in the coming decades.
The implications for Sumatra and surrounding regions are serious. A major earthquake could trigger a tsunami affecting the entire Indian Ocean. Estimates suggest that the next megathrust earthquake could result in over 100,000 deaths and extensive infrastructure damage in an already vulnerable region.