Manila Trench
Encyclopedia
The Manila Trench is an ocean
trench in the South China Sea
, west of the Philippines
. It reaches a depth of about 5,400 m, in contrast with the average depth of the South China Sea of about 1,500 m. It is created by subduction
, in which the Eurasian Plate
is subducting under the Philippine Mobile Belt
.
The Manila Trench is associated with frequent earthquake
s, and the plate movements
which give rise to it are also responsible for the arc
of volcano
es on the west side of the Philippine
island of Luzon
, including Mount Pinatubo
.
The Sunda Plate
(part of Eurasia) subducts under the Luzon Volcanic Arc
, producing this almost N-S trending trench. The trench is terminated in the north by the Taiwan
collision zone, and in the south by the Mindoro
terrane (Sulu-Palawan block colliding with SW Luzon). It is an area pervaded by negative gravity anomalies
.
Convergence between the Philippine Mobile Belt and the Manila Trench have been estimated using GPS measurements, and this value ranges from ~ 50+ mm/yr in Taiwan, to 100 mm/yr near N. Luzon, and ~ 50 mm/yr near Zambales
and ~20+mm/yr near Mindoro island... Plate locking between the Sundaland Plate and Luzon is about 1% coupled, almost unlocked as determined by elastic block models, suggesting that the trench absorbs the Philippine Mobile Belt
--Eurasian Plate
convergence.
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...
trench in the South China Sea
South China Sea
The South China Sea is a marginal sea that is part of the Pacific Ocean, encompassing an area from the Singapore and Malacca Straits to the Strait of Taiwan of around...
, west of the Philippines
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
. It reaches a depth of about 5,400 m, in contrast with the average depth of the South China Sea of about 1,500 m. It is created by subduction
Subduction
In geology, subduction is the process that takes place at convergent boundaries by which one tectonic plate moves under another tectonic plate, sinking into the Earth's mantle, as the plates converge. These 3D regions of mantle downwellings are known as "Subduction Zones"...
, in which the Eurasian Plate
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...
is subducting under the Philippine Mobile Belt
Philippine Mobile Belt
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 zones, the Manila Trench to the west and the Philippine Trench to the east, as well as the...
.
The Manila Trench is associated with frequent earthquake
Earthquake
An earthquake is the result of a sudden release of energy in the Earth's crust that creates seismic waves. The seismicity, seismism or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time...
s, and the plate movements
Plate tectonics
Plate tectonics is a scientific theory that describes the large scale motions of Earth's lithosphere...
which give rise to it are also responsible for the arc
Volcanic arc
A volcanic arc is a chain of volcanoes positioned in an arc shape as seen from above. Offshore volcanoes form islands, resulting in a volcanic island arc. Generally they result from the subduction of an oceanic tectonic plate under another tectonic plate, and often parallel an oceanic trench...
of volcano
Volcano
2. Bedrock3. Conduit 4. Base5. Sill6. Dike7. Layers of ash emitted by the volcano8. Flank| 9. Layers of lava emitted by the volcano10. Throat11. Parasitic cone12. Lava flow13. Vent14. Crater15...
es on the west side of the Philippine
Philippines
The Philippines , officially known as the Republic of the Philippines , is a country in Southeast Asia in the western Pacific Ocean. To its north across the Luzon Strait lies Taiwan. West across the South China Sea sits Vietnam...
island of Luzon
Luzon
Luzon is the largest island in the Philippines. It is located in the northernmost region of the archipelago, and is also the name for one of the three primary island groups in the country centered on the Island of Luzon...
, including Mount Pinatubo
Mount Pinatubo
Mount Pinatubo is an active stratovolcano located on the island of Luzon, near the tripoint of the Philippine provinces of Zambales, Tarlac, and Pampanga. It is located in the Tri-Cabusilan Mountain range separating the west coast of Luzon from the central plains, and is west of the dormant and...
.
The Sunda Plate
Sunda Plate
The Sunda Plate is the tectonic plate on which the majority of Southeast Asia is located. It was formerly considered a part of the Eurasian Plate, but GPS measurements have confirmed its independent movement at 10 mm/yr eastward relative to Eurasia...
(part of Eurasia) subducts under the Luzon Volcanic Arc
Luzon Volcanic Arc
The Luzon Volcanic Arc is a chain of volcanoes in a north south line across the Luzon Strait from Taiwan to Luzon. It is the northern extension of the Philippine Mobile Belt...
, producing this almost N-S trending trench. The trench is terminated in the north by the Taiwan
Taiwan
Taiwan , also known, especially in the past, as Formosa , is the largest island of the same-named island group of East Asia in the western Pacific Ocean and located off the southeastern coast of mainland China. The island forms over 99% of the current territory of the Republic of China following...
collision zone, and in the south by the Mindoro
Mindoro
Mindoro is the seventh-largest island in the Philippines. It is located off the coast of Luzon, and northeast of Palawan. The southern coast of Mindoro forms the northeastern extremum of the Sulu Sea.-History:...
terrane (Sulu-Palawan block colliding with SW Luzon). It is an area pervaded by negative gravity anomalies
Gravity anomaly
A gravity anomaly is the difference between the observed acceleration of Earth's gravity and a value predicted from a model.-Geodesy and geophysics:...
.
Convergence between the Philippine Mobile Belt and the Manila Trench have been estimated using GPS measurements, and this value ranges from ~ 50+ mm/yr in Taiwan, to 100 mm/yr near N. Luzon, and ~ 50 mm/yr near Zambales
Zambales
Zambales is a province of the Philippines located in the Central Luzon region. Its capital is Iba. Zambales borders Pangasinan to the north, Tarlac and Pampanga to the east, and Bataan to the south. The province lies between the South China Sea and the Zambales Mountains. With a land area of...
and ~20+mm/yr near Mindoro island... Plate locking between the Sundaland Plate and Luzon is about 1% coupled, almost unlocked as determined by elastic block models, suggesting that the trench absorbs the Philippine Mobile Belt
Philippine Mobile Belt
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 zones, the Manila Trench to the west and the Philippine Trench to the east, as well as the...
--Eurasian Plate
Eurasian Plate
The Eurasian Plate is a tectonic plate which includes most of the continent of Eurasia , with the notable exceptions of the Indian subcontinent, the Arabian subcontinent, and the area east of the Chersky Range in East Siberia...
convergence.