The Sulu Trench is an

oceanic trench Oceanic trenches are prominent long, narrow topographic depressions of the ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers in length. There are about of oceanic tren ...

in the

Pacific Ocean The Pacific Ocean is the largest and deepest of Earth's five oceanic divisions. It extends from the Arctic Ocean in the north to the Southern Ocean (or, depending on definition, to Antarctica) in the south, and is bounded by the contin ...

, located west of the islands of

Mindanao Mindanao ( ) ( Jawi: مينداناو) is the second-largest island in the Philippines, after Luzon, and seventh-most populous island in the world. Located in the southern region of the archipelago, the island is part of an island group of ...

and Sulu in the

Philippines The Philippines (; fil, Pilipinas, links=no), officially the Republic of the Philippines ( fil, Republika ng Pilipinas, links=no), * bik, Republika kan Filipinas * ceb, Republika sa Pilipinas * cbk, República de Filipinas * hil, Republ ...

. The trench reaches a depth of about 5,600 metres (18,400 ft), in contrast with the average depth of the South China Sea of about 1,500 metres (4,900 ft). The trench formed when the Sunda Plate (part of the

Eurasian Plate The Eurasian Plate is a tectonic plate that includes most of the continent of Eurasia (a landmass consisting of the traditional continents of Europe and Asia), with the notable exceptions of the Indian subcontinent, the Arabian subcontinent and ...

) subducts below the

Philippine Mobile Belt In the geology of the Philippines, the Philippine Mobile Belt is a complex portion of the tectonic boundary between the Eurasian Plate and the Philippine Sea Plate, comprising most of the country of the Philippines. It includes two subduction z ...

. The

convergent boundary A convergent boundary (also known as a destructive boundary) is an area on Earth where two or more lithospheric plates collide. One plate eventually slides beneath the other, a process known as subduction. The subduction zone can be defined by a ...

terminates at the

Negros Trench The Negros Trench is an oceanic trench located northeast of the Sulu Trench and west of Negros Island Region in Visayas, the trench is located in the Sunda Plate in the southwestern region of the Pacific Ocean. The depth of the Negros Trench ...

in the east. The Sulu Trench is not associated with frequent

earthquake An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

s, but hosts volcanoes south of the trench such as

Mount Malindang Mount Malindang is a complex volcano located in the province of Misamis Occidental in the southern island of Mindanao, Philippines. It is the highest point in the province. The least studied mountain range was formed through several volcanic act ...

Background

The Sulu Trench was formed from subduction of the

underneath the

Philippine sea plate The Philippine Sea Plate or the Philippine Plate is a tectonic plate comprising oceanic lithosphere that lies beneath the Philippine Sea, to the east of the Philippines. Most segments of the Philippines, including northern Luzon, are part o ...

which initiated during the

Early Miocene The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene epoch (geology), Epoch made up of two faunal stage, stages: the Aquitanian age, Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 annum, Ma to ...

(23.03-20.44 Million years ago), The trench was previously the site of a collision zone with the Palawan plate, which formed the

Philippine Trench The Philippine Trench (also Philippine Deep, Mindanao Trench, and Mindanao Deep) is a submarine trench to the east of the Philippines. The trench is located in the Philippine sea of the western North Pacific Ocean and continues NNW-SSE. It has a ...

8–9 million years ago, This trench is located southeast of the

Visayan Islands The Visayas ( ), or the Visayan Islands (Visayan: ''Kabisay-an'', ; tl, Kabisayaan ), are one of the three principal geographical divisions of the Philippines, along with Luzon and Mindanao. Located in the central part of the archipelago, it ...

, The rate of subduction in the Sulu Trench is approximately 8 cm/year. Although there are vast areas of subduction zones, some authors have considered this region to have low

seismic activity An earthquake (also known as a quake, tremor or temblor) is the shaking of the surface of the Earth resulting from a sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can range in intensity, fr ...

, There has been a decent amount of earthquakes with a magnitude ≥6.4 in the region, with the most recent during 1974 it hit the trench with a hypocenter depth of 24.0 km, Areas adjacent to the subduction zones have experienced large seismic activity. In 1942 Zamboanga Peninsula expirienced a M7.2.

Seismicity

This is a list of significant earthquakes related to the Sulu Trench which have a magnitude of 6.4 or bigger.

References

Oceanic trenches of the Philippine Sea Philippine tectonics Subduction zones {{marine-geo-stub