The Nankai Trough is an active subduction zone where one of the plates in the earth's crust is slipping beneath another. It is one of the places where earthquakes of large magnitudes tend to occur. The Tonakai earthquake that created havoc in Japan in the year 1944 was caused because of Japan’s proximity to this place.
The Tonakai earthquake occurred at a magnitude of 8.1 on the moment magnitude scale. It triggered a large tsunami and caused 3,358 casualties including 1,223 deaths. The event destroyed 47,000 houses.
Nankai trough can be found off the coast of Japan on its southwest side. It is situated deep within the Pacific ocean and is known to be highly unstable. Violent, large-scale earthquakes have repeatedly occurred in places which are located in its vicinity.
The Nankai Trough Seismogenic Trough Zone Experiment (also called as, nanTroSEIZE) is a very difficult and dangerous project that is being handled by scientists from all over the world. Challenges include fragile geological formations, powerful currents, typhoons, and multiple cold fronts during the winter months.
Planning for the project had started 20 years back, and they have been drilling for more than 11 years, starting in September 2007. As per the mission’s website, the plan is to collect data to help understand the causes of earthquakes and tsunami. The data may also explain how water and rock interact to influence earthquakes.
This expedition will include deep drilling into the defect. Rocks will be collected and analyzed thoroughly to find the cause of such aggressive earthquakes. Slippery or solid rocks obtained from the crust of the earth will help the scientists in figuring out what conditions are responsible for making the earth’s crust act in such an intense way.