In the western Pacific Ocean, there is a trench known as the Tonga Trench. It is the second-deepest trench on Earth after the Mariana Trench and the deepest in the Southern Hemisphere.
The Tonga Trench was created millions of years ago by a process known as subduction, in which two tectonic plates collide and push one under the other.
The Tonga Trench is 850 miles long and typically reaches depths of 20,000 feet.
From the southwest corner of the Kermadec Plate to the northwest point of the Tonga Plate, there is a convergent plate boundary known as the Kermadec-Tonga subduction zone.
The Tonga Trench's Horizon Deep, located at 23.25833°S 174.726667°W, is its deepest point.
There are numerous volcanoes in the Tonga Trench, both active and dormant, and it is prone to earthquakes and tsunamis.