The Sunda Trench, earlier known as, and sometimes still indicated as the Java Trench, is located
in the northeastern Indian Ocean, with a length of 2,600 kilometres.
The maximum depth of 7,725 metres, is the deepest point in the Indian Ocean.
The trench stretches from the Lesser Sunda Islands past Java, around the southern coast
of Sumatra on to the Andaman islands, and forms the boundary between Indo-Australian
Plate and Eurasian plate.
The trench is considered to be part of the Pacific Ring of Fire as well as one of a ring
of oceanic trenches around the northern edges of the Australian Plate.
There is scientific evidence that the recent earthquake 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 Indian Ocean coast.
Characteristics For about half its length, off of Sumatra,
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 of the plate boundary showed resemblance to
suspension bridge 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, investigated the trench as part of a world wide 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.
Associated seismicity The subduction 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 ~8.4
1833 Sumatra earthquake: Magnitude 8.8–9.2 1861 Sumatra earthquake: Magnitude ~8.5
1935 Sumatra earthquake: Magnitude 7.7 2000 Sumatra 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: Mw 9.1–9.3
2005 Sumatra earthquake: Magnitude 8.6 September 2007 Sumatra earthquakes: Series
of earthquakes, the three largest were magnitude 8.5, 7.9 and 7.0.
2009 Sumatra earthquakes: Magnitude 7.9 October 2010 Sumatra earthquake and tsunami:
Magnitude 7.7 Java segment
1917 Bali earthquake: Magnitude 8.6 1994 Java earthquake: Magnitude 7.8
May 2006 Java earthquake: Despite a Magnitude of only 6.3, this earthquake caused 5,782
deaths.
2006 Pangandaran earthquake and tsunami: Magnitude 7.7
2009 West Java earthquake: Magnitude 7.0 See also
Banda Arc Islands of Indonesia
Plate tectonic Sunda Arc
Sunda Islands Greater Sunda Islands
Lesser Sunda Islands
Sundaland Oceanic trench
References
Further reading Špičák, A., V. Hanuš, and J. Vaněk, 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