The Sunda Trench, earlier known as and sometimes still indicated as the Java 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 ...

located in the

Indian Ocean The Indian Ocean is the third-largest of the world's five oceanic divisions, covering or ~19.8% of the water on Earth's surface. It is bounded by Asia to the north, Africa to the west and Australia to the east. To the south it is bounded by ...

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 sixth-largest island in the world at 473,481 km2 (182,812 mi.2), not including adjacent i ...

, 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

. The trench stretches from the

Lesser Sunda Islands The Lesser Sunda Islands or nowadays known as Nusa Tenggara Islands ( id, Kepulauan Nusa Tenggara, formerly ) are an archipelago in Maritime Southeast Asia, north of Australia. Together with the Greater Sunda Islands to the west they make up ...

past

Java Java (; id, Jawa, ; jv, ꦗꦮ; su, ) is one of the Greater Sunda Islands in Indonesia. It is bordered by the Indian Ocean to the south and the Java Sea to the north. With a population of 151.6 million people, Java is the world's mo ...

, around the southern coast of

on to the

Andaman Islands The Andaman Islands () are an archipelago 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 maritime boundary between t ...

, and forms the boundary between

Indo-Australian Plate The Indo-Australian Plate is a major tectonic plate that includes the continent of Australia and the surrounding ocean and extends northwest to include the Indian subcontinent and the adjacent waters. It was formed by the fusion of the Indian an ...

and

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 an ...

(more specifically,

Sunda Plate The Sunda Plate is a minor tectonic plate straddling the Equator in the Eastern Hemisphere on which the majority of Southeast Asia is located. The Sunda Plate was formerly considered a part of the Eurasian Plate, but the GPS measurements hav ...

). The trench is considered to be part of the

Pacific Ring of Fire The Ring of Fire (also known as the Pacific Ring of Fire, the Rim of Fire, the Girdle of Fire or the Circum-Pacific belt) is a region around much of the rim of the Pacific Ocean where many volcanic eruptions and earthquakes occur. The Ring ...

as well as one of a ring of oceanic trenches around the northern edges of the

Australian Plate The Australian Plate is a major tectonic plate in the eastern and, largely, southern hemispheres. Originally a part of the ancient continent of Gondwana, Australia remained connected to India and Antarctica until approximately when India brok ...

. In 2005, scientists found

evidence Evidence for a proposition is what supports this proposition. It is usually understood as an indication that the supported proposition is true. What role evidence plays and how it is conceived varies from field to field. In epistemology, evidenc ...

that the 2004

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 ...

activity in the area of the Java Trench could lead to further catastrophic shifting within a relatively short period of time, perhaps less than a decade. This threat has resulted in international agreements to establish a tsunami warning system in place along the

coast.

Characteristics

For about half its length, off of

, 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 An earthquake and a tsunami, known as the Boxing Day Tsunami and, by the scientific community, the Sumatra–Andaman earthquake, occurred at 07:58:53 local time ( UTC+7) on 26 December 2004, with an epicentre off the west coast of northern ...

of the plate boundary showed resemblance to

suspension bridge A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridges, which lack vertical ...

cables, with peaks and sags, indicative of asperity and locked faults, instead of the traditional wedge shape expected.

Exploration

Some of the earliest exploration of the Trench occurred in the late 1950s when Robert Fisher, Research Geologist at the

Scripps Institution of Oceanography The Scripps Institution of Oceanography (sometimes referred to as SIO, Scripps Oceanography, or Scripps) in San Diego, California, US founded in 1903, is one of the oldest and largest centers for ocean and Earth science research, public servi ...

, 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

Limiting Factor to be prepared for a dive into the Atlantic Ocean

On 5 April 2019 Victor Vescovo made the first crewed descent to the deepest point of the trench in the Deep-Submergence Vehicle '' DSV Limiting Factor'' (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 () is a 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 neighbouring islands, notably Nusa Penida, Nusa Lembongan, and ...

. The operating area was surveyed by the support ship, the Deep Submersible Support Vessel ''

DSSV Pressure Drop USNS ''Indomitable'' (T-AGOS-7) was a United States Navy in service from 1985 to 2002. From 2003 until 18 June 2014, she was in commission in the National Oceanic and Atmospheric Administration (NOAA) as the oceanographic research ship NOAAS '' ...

'', with a Kongsberg SIMRAD EM124 multibeam echosounder system. The gathered data will be 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 The Diamantina Fracture Zone (DFZ) is an area of the south-eastern Indian Ocean seafloor, consisting of a range of ridges and trenches. It lies to the south of the mideastern Indian Ocean features of the Wharton Basin and Perth Basin, an ...

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 The Dordrecht Deep is located in the Diamantina Trench southwest of Perth, Western Australia. The Diamantina Trench is in the eastern part of the larger Diamantina Fracture Zone, which stretches from the Ninety East Ridge to the Naturaliste P ...

. This confirmed that the Sunda Trench was indeed deeper than the Diamantina Fracture Zone.

Associated seismicity

The

subduction Subduction is a geological process in which the oceanic lithosphere is recycled into the Earth's mantle at convergent boundaries. Where the oceanic lithosphere of a tectonic plate converges with the less dense lithosphere of a second plate, ...

of the

beneath a bloc 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 an ...

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 The 1797 Sumatra earthquake occurred at 22:00 local time on February 10. It was the first in a series of great earthquakes that ruptured part of the Sumatran segment of the Sunda megathrust. It caused a damaging tsunami that was particularly seve ...

: magnitude ~8.4 *

1833 Sumatra earthquake The 1833 Sumatra earthquake occurred on November 25 at about 22:00 local time, with an estimated magnitude in the range of 8.8–9.2 . It caused a large tsunami that flooded the southwestern coast of the island. There are no reliable records of t ...

: magnitude 8.8–9.2 *

1861 Sumatra earthquake Statistically, this year is considered the end of the whale oil industry and (in replacement) the beginning of the petroleum oil industry. Events January–March * January 1 ** Benito Juárez captures Mexico City. ** The first stea ...

: magnitude ~8.5 *

1935 Sumatra earthquake The 1935 Sumatra earthquake occurred at on 28 December. It had a magnitude of 7.7 and a maximum felt intensity of VIII (''Severe'') on the Mercalli intensity scale. It triggered a minor tsunami. Tectonic setting The island of Sumatra lies on th ...

: magnitude 7.7 *

2000 Enggano earthquake The 2000 Enggano earthquake struck at 23:28 local time on June 4 with a moment magnitude of 7.9 and a maximum Mercalli intensity of VI (''Strong''). The event occurred off the coast of southern Sumatra, Indonesia near Enggano Island. There were m ...

: magnitude 7.9 *

2002 Sumatra earthquake The 2002 Sumatra earthquake occurred at 01:26 UTC on 2 November. It had a magnitude of 7.4 on the moment magnitude scale with an epicenter just north of Simeulue island and caused three deaths. This earthquake is regarded as a foreshock of the 20 ...

: 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 An earthquake and a tsunami, known as the Boxing Day Tsunami and, by the scientific community, the Sumatra–Andaman earthquake, occurred at 07:58:53 local time ( UTC+7) on 26 December 2004, with an epicentre off the west coast of northern ...

: Mw 9.1–9.3 *

2005 Nias–Simeulue earthquake The 2005 Nias–Simeulue earthquake occurred on 28 March off the west coast of northern Sumatra, Indonesia. At least 915 people were killed, mostly on the island of Nias. The event caused panic in the region, which had already been devastated by ...

: magnitude 8.6 * September 2007 Sumatra earthquakes: 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 7.9 *

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 7.7

Java segment

* 1917 Bali earthquake: magnitude 6.6 *

1994 Java earthquake An earthquake occurred on June 3, 1994 at 01:17:37 local time (June 2, at 18:17:37 GMT) off the coast of Indonesia. The epicenter was off the eastern part of the southern Java coast, near the east end of the Java Trench. Earthquake This earthqua ...

: magnitude 7.8 * 2006 Pangandaran earthquake and tsunami: magnitude 7.7 * 2009 West Java earthquake: magnitude 7.0 *

2019 Sunda Strait earthquake The 2019 Sunda Strait earthquake occurred on the night of 2 August 2019, when a magnitude 6.9 earthquake rattled Sunda Strait at a moderate depth of 52.8 kilometres. The epicentre was located 214 km from Bandar Lampung, the capital of Lampung an ...

: magnitude 6.9

Characteristics

Exploration

Crewed descent

Associated seismicity

Sumatra segment

Java segment

See also

References

Further reading