The Philippine Trench (also called the Philippine Deep, Mindanao Trench, and the Mindanao Deep) is a

submarine 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 t ...

to the east of the

Philippines The Philippines, officially the Republic of the Philippines, is an Archipelagic state, archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of List of islands of the Philippines, 7,641 islands, with a tot ...

. The trench is located in the Philippine sea of the western North Pacific Ocean and continues NNW-SSE. It has a length of approximately and a width of about from the center of the Philippine island of

Luzon Luzon ( , ) is the largest and most populous List of islands in the Philippines, island in the Philippines. Located in the northern portion of the List of islands of the Philippines, Philippine archipelago, it is the economic and political ce ...

trending southeast to the northern Maluku island of

Halmahera Halmahera, formerly known as Jilolo, Gilolo, or Jailolo, is the largest island in the Maluku Islands. It is part of the North Maluku Provinces of Indonesia, province of Indonesia, and Sofifi, the capital of the province, is located on the west coa ...

Indonesia Indonesia, officially the Republic of Indonesia, is a country in Southeast Asia and Oceania, between the Indian Ocean, Indian and Pacific Ocean, Pacific oceans. Comprising over List of islands of Indonesia, 17,000 islands, including Sumatra, ...

. At its deepest point, the trench reaches 10,540 meters (34,580 ft or 5,760 fathoms). PhilippineMobileBelt007

Immediately to the north of the Philippine Trench is the East Luzon Trench. They are separated, with their continuity interrupted and displaced, by Benham Plateau on 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 of ...

Geology

The Philippine trench is hypothesized to be younger than 8–9 million years old. The central part of the Philippine fault formed during the

Plio-Pleistocene The Plio-Pleistocene is an informally described geological pseudo-period, which begins about 5 million years ago (Mya) and, drawing forward, combines the time ranges of the formally defined Pliocene and Pleistocene epochs—marking from about 5&n ...

times is considered to be an active depression of the Earth's crust. The trench formed from a collision between the

Palawan Palawan (, ), officially the Province of Palawan (; ), is an archipelagic province of the Philippines that is located in the region of Mimaropa. It is the largest province in the country in terms of total area of . The capital and largest c ...

and Zamboanga plates. This caused a change in geological processes creating a

subduction zone Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

, that is dropping the ocean floor deeper. The rate of

subduction Subduction is a geological process in which the oceanic lithosphere and some continental lithosphere is recycled into the Earth's mantle at the convergent boundaries between tectonic plates. Where one tectonic plate converges with a second p ...

on these plates is estimated to be about 15 cm per year. A convergent zone borders an estimate of 45% of the Philippine Trench today. Although there are vast areas of subduction zones, some authors have considered this region to have low

seismic activity An earthquakealso called a quake, tremor, or tembloris the shaking of the Earth's surface resulting from a sudden release of energy in the lithosphere that creates seismic waves. Earthquakes can range in intensity, from those so weak they ...

, though the

USGS The United States Geological Survey (USGS), founded as the Geological Survey, is an government agency, agency of the United States Department of the Interior, U.S. Department of the Interior whose work spans the disciplines of biology, geograp ...

has recorded many earthquakes with magnitude ≥ 7.2 in the region as shown by the map to the side. Most recently, in 2012 the Philippine Trench experienced an earthquake of M_w 7.6 (the

2012 Samar earthquake An earthquake off the coast of Samar occurred on August 31, 2012, at 20:47 local time (12:47 UTC) in the Philippines. The populated islands of Visayas were struck by an earthquake of magnitude 7.6. The earthquake occurred at a depth of 45 k ...

). It hit the trench with a hypocenter depth of 34.9 km. Areas adjacent to the subduction zones have experienced large seismic activity. In 1897, northern Samar experienced a M_s 7.3 earthquake while in 1924 southern Mindanao experienced one with a M_s 8.2.

Depth

The trench reaches one of the greatest depths in the ocean. Its deepest point is known as

Emden Deep The Emden Deep, also known as the Galathea Deep or Galathea Depth, is the portion of the Philippine Trench exceeding depths in the south-western Pacific Ocean. Originally discovered by the German ship ''German cruiser Emden, Emden'' in 1927 ...

and reaches 10,540 meters (34,580 ft or 5,760 fathoms).

Sedimentation

Sedimentation of the Philippine trench contains slightly

metamorphosed Metamorphic rocks arise from the transformation of existing rock to new types of rock in a process called metamorphism. The original rock (protolith) is subjected to temperatures greater than and, often, elevated pressure of or more, causi ...

, calc-alkalic, basic,

ultrabasic rock Ultramafic rocks (also referred to as ultrabasic rocks, although the terms are not wholly equivalent) are igneous and meta-igneous rocks with a very low silica content (less than 45%), generally >18% MgO, high FeO, low potassium, and are usual ...

and sand grains. The southern area of the trench contains homogeneous blue

clay Clay is a type of fine-grained natural soil material containing clay minerals (hydrous aluminium phyllosilicates, e.g. kaolinite, ). Most pure clay minerals are white or light-coloured, but natural clays show a variety of colours from impuriti ...

silt Silt is granular material of a size between sand and clay and composed mostly of broken grains of quartz. Silt may occur as a soil (often mixed with sand or clay) or as sediment mixed in suspension (chemistry), suspension with water. Silt usually ...

and is poor in lime. Sand grains that were also found contained fresh

basaltic andesite Basaltic andesite is a volcanic rock that is intermediate in composition between basalt and andesite. It is composed predominantly of augite and plagioclase. Basaltic andesite can be found in volcanoes around the world, including in Central Ameri ...

. The sediments found in the trenches are hypothesized to have been deposited by

turbidity current A turbidity current is most typically an Ocean current, underwater current of usually rapidly moving, sediment-laden water moving down a slope; although current research (2018) indicates that water-saturated sediment may be the primary actor in ...

s. A turbidity current is an underwater current that moves rapidly and carries sediment.

Significant quakes

This is a list of significant quakes related to the Philippine Trench, which are 7.0+

Other trenches

Other known trenches in

the Philippines The Philippines, officially the Republic of the Philippines, is an archipelagic country in Southeast Asia. Located in the western Pacific Ocean, it consists of 7,641 islands, with a total area of roughly 300,000 square kilometers, which ar ...

are: *

Manila Trench The Manila Trench is an oceanic trench in the Pacific Ocean, located west of the islands of Luzon and Mindoro in the Philippines. The trench reaches a depth of about , in contrast with the average depth of the South China Sea of about . It i ...

East Luzon Trench The Philippine Trench (also called the Philippine Deep, Mindanao Trench, and the 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 ...

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 i ...

Sulu Trench The Sulu Trench is an oceanic trench in the Pacific Ocean, located west of the islands of Mindanao and Sulu in the Philippines. The trench reaches a depth of about 5,600 metres (18,400 ft), in contrast with the average depth of the South Ch ...

Cotabato Trench The Cotabato Trench is an oceanic trench in the Pacific Ocean, off the southwestern coast of Mindanao in the Philippines. Along this trench the oceanic crust of the Sunda Plate beneath the Celebes Sea is being subducted beneath the Philippi ...

References

{{coord missing, Pacific Ocean Philippine Sea Oceanic trenches of the South China Sea Philippine tectonics Subduction zones Geology of Indonesia