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The Sunda Trench, earlier known as and sometimes still indicated as the Java Trench, is an
oceanic trench Oceanic trenches are prominent, long, narrow topography, topographic depression (geology), depressions of the seabed, ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers ...
located in the
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
near
Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...
, formed where the Australian- Capricorn plates subduct under a part of the Eurasian plate. It is long with a maximum depth of 7,290 metres (23,920 feet). Its maximum depth is the deepest point in the
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
. The trench stretches from the
Lesser Sunda Islands The Lesser Sunda Islands (, , ), now known as Nusa Tenggara Islands (, or "Southeast Islands"), are an archipelago in the Indonesian archipelago. Most of the Lesser Sunda Islands are located within the Wallacea region, except for the Bali pro ...
past
Java Java is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea (a part of Pacific Ocean) to the north. With a population of 156.9 million people (including Madura) in mid 2024, proje ...
, around the southern coast of
Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...
to the
Andaman Islands The Andaman Islands () are an archipelago, made up of 200 islands, in the northeastern Indian Ocean about southwest off the coasts of Myanmar's Ayeyarwady Region. Together with the Nicobar Islands to their south, the Andamans serve as a mari ...
, and forms the boundary between the Indo-Australian plate and Eurasian plate (more specifically, Sunda plate). The trench is considered to be part of the Alpide belt as well as one of
oceanic trenches 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 ...
around the northern edges of the Australian plate. In 2005, scientists found
evidence Evidence for a proposition is what supports the proposition. It is usually understood as an indication that the proposition is truth, true. The exact definition and role of evidence vary across different fields. In epistemology, evidence is what J ...
that the 2004
earthquake 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 ...
activity in the area of the Java Trench could lead to further catastrophic shifting within a relatively short period, perhaps less than a decade. This threat has resulted in international agreements to establish a tsunami warning system in place along the
Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or approximately 20% of the water area of Earth#Surface, Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia (continent), ...
coast.


Characteristics

For about half its length, off of
Sumatra Sumatra () is one of the Sunda Islands of western Indonesia. It is the largest island that is fully within Indonesian territory, as well as the list of islands by area, sixth-largest island in the world at 482,286.55 km2 (182,812 mi. ...
, it is divided into two parallel troughs by an underwater ridge, and much of the trench is at least partially filled with sediments. Mappings after the
2004 Indian Ocean earthquake On 26 December 2004, at 07:58:53 local time (UTC+07:00, UTC+7), a major earthquake with a magnitude of 9.2–9.3 struck with an epicenter, epicentre off the west coast of Aceh in northern Sumatra, Indonesia. The Submarine earthquake, undersea ...
of the plate boundary showed a resemblance to
suspension bridge A suspension bridge is a type of bridge in which the deck (bridge), deck is hung below suspension wire rope, cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridg ...
cables, with peaks and sags, indicative of asperity and locked faults, instead of the traditional wedge shape expected.


Exploration

Some of the earliest explorations of the trench occurred in the late 1950s when Robert L. Fisher, a research geologist at the Scripps Institution of Oceanography, investigated the trench as part of a worldwide scientific field exploration of the world's ocean floor and sub-oceanic crustal structure. Bomb-sounding, echo-train analysis, and manometer were some of the techniques used to determine the depth of the trench. The research contributed to an understanding of the subduction characteristic of the Pacific margins. Various agencies have explored the trench in the aftermath of the 2004 earthquake, and these explorations have revealed extensive changes in the ocean floor.


Crewed descent

On 5 April 2019 Victor Vescovo made the first crewed descent to the deepest point of the trench in the Deep-Submergence Vehicle ''
Limiting Factor A limiting factor is a variable of a system that causes a noticeable change in output or another measure of a type of system. The limiting factor is in a pyramid shape of organisms going up from the producers to consumers and so on. A factor not l ...
'' (a Triton 36000/2 model submersible) and measured a depth of ± by direct CTD pressure measurements at 11°7'44" S, 114°56'30" E, about south of
Bali Bali (English:; Balinese language, Balinese: ) is a Provinces of Indonesia, province of Indonesia and the westernmost of the Lesser Sunda Islands. East of Java and west of Lombok, the province includes the island of Bali and a few smaller o ...
. The operating area was surveyed by the support ship, the Deep Submersible Support Vessel '' DSSV Pressure Drop'', with a Kongsberg SIMRAD EM124 multibeam echosounder system. The gathered data was donated to the GEBCO Seabed 2030 initiative. The dive was part of th
Five Deeps Expedition
The objective of this expedition is to thoroughly map and visit the deepest points of all five of the world's oceans by the end of September 2019. To resolve the debate regarding the deepest point of the Indian Ocean, the Diamantina fracture zone was surveyed by the Five Deeps Expedition in March 2019, recording a maximum water depth of ± at 33°37'52" S, 101°21'14" E for the Dordrecht Deep. This confirmed that the Sunda Trench was indeed deeper than the deepest location in the Diamantina Fracture Zone.


Associated seismicity

The
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 ...
of the Indo-Australian plate beneath a bloc of the Eurasian plate is associated with numerous earthquakes. Several of these earthquakes are notable for their size, associated tsunamis, and/or the number of fatalities they caused.


Sumatra segment

* 1797 Sumatra earthquake: magnitude 8.6–8.8 * 1833 Sumatra earthquake: magnitude 8.8–9.2 * 1861 Sumatra earthquake: magnitude ~8.5 * 1935 Sumatra earthquake: magnitude 7.7 * 2000 Enggano earthquake: magnitude 7.9 * 2002 Sumatra earthquake: A magnitude 7.3 earthquake that occurred at the boundary between the rupture areas of the 2004 and 2005 earthquakes listed below. *
2004 Indian Ocean earthquake and tsunami On 26 December 2004, at 07:58:53 local time ( UTC+7), a major earthquake with a magnitude of 9.2–9.3 struck with an epicentre off the west coast of Aceh in northern Sumatra, Indonesia. The undersea megathrust earthquake, known in the sci ...
: Mw 9.2–9.3 * 2005 Nias–Simeulue earthquake: magnitude 8.6 *
2007 Bengkulu earthquakes The 2007 Bengkulu earthquakes were a series of megathrust earthquakes that struck the Sunda Trench off the coast of Sumatra, Indonesia, with three of magnitude 7 or greater. A series of tsunami bulletins was issued for the area. The most powerf ...
: Series of earthquakes, the three largest were magnitude 8.5, 7.9, and 7.0. * 2008 Simeulue earthquake: magnitude 7.4 near the 2002 event. * 2009 Sumatra earthquakes: magnitude 7.6 *
2010 Mentawai earthquake and tsunami The 2010 Mentawai earthquake occurred with a Moment magnitude scale, moment magnitude of 7.8 on 25 October off the western coast of Sumatra at 21:42 local time (14:42 UTC). The earthquake occurred on the same fault that produced the 2004 Indian O ...
: magnitude 7.8


Java segment

* 1917 Bali earthquake: magnitude 6.6 * 1994 Java earthquake: magnitude 7.8 *
2006 Pangandaran earthquake and tsunami An earthquake occurred on July 17, 2006, at along a subduction zone off the coast of West Java, west and central Java, a large and densely populated island in the Indonesian archipelago. The shock had a Moment magnitude scale, moment magnitude ...
: magnitude 7.7 * 2009 West Java earthquake: magnitude 7.0 * 2019 Sunda Strait earthquake: magnitude 6.9


See also

* Banda Arc *
List of islands of Indonesia The islands of Indonesia, also known as the Indonesian Archipelago () or Nusantara, may refer either to the islands composing the country of Indonesia or to the geographical groups which include its islands. Indonesia is the world's largest a ...
*
Plate tectonics Plate tectonics (, ) is the scientific theory that the Earth's lithosphere comprises a number of large tectonic plates, which have been slowly moving since 3–4 billion years ago. The model builds on the concept of , an idea developed durin ...
* Sunda Arc *
Sunda Islands The Sunda Islands (; Tetun: ''Illa Sunda'') are a group of islands in the Indonesian Archipelago. They consist of the Greater Sunda Islands and the Lesser Sunda Islands. Etymology "Sunda" denotes the continental shelves or landmasses: the Sun ...
**
Greater Sunda Islands The Greater Sunda Islands (Indonesian language, Indonesian and Malay language, Malay: ''Kepulauan Sunda Besar'') are four tropical islands situated within the Indonesian Archipelago, in the Pacific Ocean. The islands, Borneo, Java, Sulawesi and S ...
**
Lesser Sunda Islands The Lesser Sunda Islands (, , ), now known as Nusa Tenggara Islands (, or "Southeast Islands"), are an archipelago in the Indonesian archipelago. Most of the Lesser Sunda Islands are located within the Wallacea region, except for the Bali pro ...
*
Sundaland Sundaland (also called Sundaica or the Sundaic region) is a biogeographical region of Southeast Asia corresponding to a larger landmass that was exposed throughout the last 2.6 million years during periods when sea levels were lower. It inc ...
*
Oceanic trench Oceanic trenches are prominent, long, narrow topography, topographic depression (geology), depressions of the seabed, ocean floor. They are typically wide and below the level of the surrounding oceanic floor, but can be thousands of kilometers ...


References


Further reading

* Špičák, A., V. Hanuš, and J. Vaněk (2007), ''Earthquake occurrence along the Java trench in front of the onset of the Wadati–Benioff zone: Beginning of a new subduction cycle?'', Tectonics, 26, TC1005 {{Authority control Extreme points of Asia Lowest points of the World Ocean Oceanic trenches of the Indian Ocean Geology of Indonesia Subduction zones