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77-763: The Andaman Sea (historically also known as the Burma Sea ) is a marginal sea of the northeastern Indian Ocean bounded by the coastlines of Myanmar and Thailand along the Gulf of Martaban and the west side of the Malay Peninsula , and separated from the Bay of Bengal to its west by the Andaman Islands and the Nicobar Islands . Its southern end is at Breueh Island just north of Sumatra , with

154-567: A back-arc basin center was created, which began to form the marginal basin which would become the Andaman Sea, the current stages of which commenced approximately 3–4 million years ago ( Ma ). The boundary between two major tectonic plates results in high seismic activity in the region (see List of earthquakes in Indonesia ). Numerous earthquakes have been recorded, and at least six, in 1797, 1833, 1861, 2004 , 2005, and 2007 , had

231-570: A magnitude of 8.4 or higher. On 26 December 2004, a large portion of the boundary between the Burma plate and the Indo-Australian plate slipped, causing the 2004 Indian Ocean earthquake . This megathrust earthquake had a magnitude of 9.3. Between 1,300 and 1,600 kilometres (810 and 990 mi) of the boundary underwent thrust faulting and shifted by about 20 metres (66 ft), with the sea floor being uplifted several meters. This rise in

308-794: A major generator of silt, which accumulated to form the fertile soils of north India and Bangladesh, and the loess of central Asia and north China. Loess has long been thought to be absent or rare in deserts lacking nearby mountains (Sahara, Australia). However, laboratory experiments show eolian and fluvial processes can be quite efficient at producing silt, as can weathering in tropical climates. Silt seems to be produced in great quantities in dust storms, and silt deposits found in Israel, Tunisia, Nigeria, and Saudi Arabia cannot be attributed to glaciation. Furthermore, desert source areas in Asia may be more important for loess formation than previously thought. Part of

385-440: A number of mechanisms. However, the main process is likely abrasion through transport, including fluvial comminution , aeolian attrition and glacial grinding. Because silt deposits (such as loess , a soil composed mostly of silt ) seem to be associated with glaciated or mountainous regions in Asia and North America, much emphasis has been placed on glacial grinding as a source of silt. High Asia has been identified as

462-482: A platy or bladed shape. This may be characteristic of how larger grains abrade, or reflect the shape of small quartz grains in foliated metamorphic rock , or arise from authigenic growth of quartz grains parallel to bedding in sedimentary rock . Theoretically, particles formed by random fracturing of an isotropic material, such as quartz, naturally tend to be blade-shaped. The size of silt grains produced by abrasion or shattering of larger grains may reflect defects in

539-687: A pollutant in water the phenomenon is known as siltation . Silt deposited by the Mississippi River throughout the 20th century has decreased due to a system of levees , contributing to the disappearance of protective wetlands and barrier islands in the delta region surrounding New Orleans . In southeast Bangladesh, in the Noakhali district , cross dams were built in the 1960s whereby silt gradually started forming new land called "chars". The district of Noakhali has gained more than 73 square kilometres (28 sq mi) of land in

616-639: A rough north–south line on the seabed of the Andaman Sea is the boundary between two tectonic plates , the Burma Plate and the Sunda Plate . These plates (or microplates) are believed to have formerly been part of the larger Eurasian Plate , but were formed when transform fault activity intensified as the Indian Plate began its substantive collision with the Eurasian continent . As a result,

693-709: A very significant position in the Indian Ocean, yet remained unexplored for a long period. To the south of Myanmar, west of Thailand, and north of Indonesia, this sea is separated from the Bay of Bengal by the Andaman and Nicobar Islands and an associated chain of sea mounts along the Indo-Burmese plate boundary. The Strait of Malacca (between the Malay Peninsula and Sumatra ) forms the southern exitway of

770-527: Is detritus (fragments of weathered and eroded rock) with properties intermediate between sand and clay . A more precise definition of silt used by geologists is that it is detrital particles with sizes between 1/256 and 1/16 mm (about 4 to 63 microns). This corresponds to particles between 8 and 4 phi units on the Krumbein phi scale . Other geologists define silt as detrital particles between 2 and 63 microns or 9 to 4 phi units. A third definition

847-418: 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 with water. Silt usually has a floury feel when dry, and lacks plasticity when wet. Silt can also be felt by the tongue as granular when placed on the front teeth (even when mixed with clay particles). Silt

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924-578: Is 31.5–32.5‰ (parts per thousand) in summer and 30.0–33.0‰ in winter in the southern part. In the northern part, it decreases to 20–25‰ due to the inflow of freshwater from the Irrawaddy River . Tides are semidiurnal with an amplitude of up to 7.2 metres (24 ft). The effect of wind stress on the ocean surface can be explained by wind stress curl . The net divergence of water in the ocean mixed layer results in Ekman pumping . The contrast between

1001-401: Is a common material, making up 45% of average modern mud . It is found in many river deltas and as wind-deposited accumulations, particularly in central Asia, north China, and North America. It is produced in both very hot climates (through such processes as collisions of quartz grains in dust storms ) and very cold climates (through such processes as glacial grinding of quartz grains.) Loess

1078-470: Is a drastic change in water depth over a short distance of 200 kilometres (120 mi), as one moves from the Bay of Bengal (around 3,500 metres (11,500 ft) deep) to the vicinity of islands (up to 1,000 metres (3,300 ft) depth) and further into the Andaman Sea. Water is exchanged between the Andaman Sea and the Bay of Bengal through the straits between the Andaman and Nicobar Islands. Out of these,

1155-626: Is a particular challenge for civil engineering . The failure of the Teton Dam has been attributed to the use of loess from the Snake River floodplain in the core of the dam. Loess lacks the necessary plasticity for use in a dam core, but its properties were poorly understood, even by the U.S. Bureau of Reclamation , with its wealth of experience building earthen dams . Silt is susceptible to liquefaction during strong earthquakes due to its lack of plasticity. This has raised concerns about

1232-531: Is as high as 3,000 millimetres (120 in)/year and mostly occurs in summer. Sea currents are south-easterly and easterly in winter and south-westerly and westerly in summer. The average surface water temperature is 26–28 °C (79–82 °F) in February and 29 °C (84 °F) in May. The water temperature is constant at 4.8 °C (40.6 °F) at the depths of 1,600 metres (5,200 ft) and below. Salinity

1309-710: Is carried through the vadose zone to be deposited in pore space. ASTM American Standard of Testing Materials: 200 sieve – 0.005 mm. USDA United States Department of Agriculture 0.05–0.002 mm. ISSS International Society of Soil Science 0.02–0.002 mm. Civil engineers in the United States define silt as material made of particles that pass a number 200 sieve (0.074 mm or less) but show little plasticity when wet and little cohesion when air-dried. The International Society of Soil Science (ISSS) defines silt as soil containing 80% or more of particles between 0.002 mm to 0.02 mm in size while

1386-421: Is caught in the Gulf of Thailand and 19% in the Andaman Sea. 40% is caught in waters outside Thailand's EEZ . Production numbers are significantly smaller for Malaysia and are comparable, or higher, for Myanmar. Competition for fish resulted in numerous conflicts between Myanmar and Thailand. In 1998 and 1999, they resulted in fatalities on both sides and nearly escalated into a military conflict. In both cases,

1463-601: Is common throughout the geologic record , but it seems to be particularly common in Quaternary formations. This may be because deposition of silt is favored by the glaciation and arctic conditions characteristic of the Quaternary. Silt is sometimes known as rock flour or glacier meal , especially when produced by glacial action. Silt suspended in water draining from glaciers is sometimes known as rock milk or moonmilk . A simple explanation for silt formation

1540-413: Is often found in mudrock as thin laminae , as clumps, or dispersed throughout the rock. Laminae suggest deposition in a weak current that winnows the silt of clay, while clumps suggest an origin as fecal pellets . Where silt is dispersed throughout the mudrock, it likely was deposited by rapid processes, such as flocculation . Sedimentary rock composed mainly of silt is known as siltstone . Silt

1617-528: Is soil rich in silt which makes up some of the most fertile agricultural land on Earth. However, silt is very vulnerable to erosion, and it has poor mechanical properties, making construction on silty soil problematic. The failure of the Teton Dam in 1976 has been attributed to the use of unsuitable loess in the dam core, and liquefication of silty soil is a significant earthquake hazard. Windblown and waterborne silt are significant forms of environmental pollution, often exacerbated by poor farming practices. Silt

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1694-519: Is sometimes also considered a marginal sea of the Atlantic. (coast-wise from north to south) (from east to west) While all other seas in the world are defined at least in part by land boundaries, there is only one sea which is defined only by ocean currents: Entities called "seas" which are not divisions of the World Ocean are not included in this list. Excluded are: Silt Silt

1771-634: Is that it is a straightforward continuation to a smaller scale of the disintegration of rock into gravel and sand. However, the presence of a Tanner gap between sand and silt (a scarcity of particles with sizes between 30 and 120 microns) suggests that different physical processes produce sand and silt. The mechanisms of silt formation have been studied extensively in the laboratory and compared with field observations. These show that silt formation requires high-energy processes acting over long periods of time, but such processes are present in diverse geologic settings. Quartz silt grains are usually found to have

1848-443: Is that silt is fine-grained detrital material composed of quartz rather than clay minerals . Since most clay mineral particles are smaller than 2 microns, while most detrital particles between 2 and 63 microns in size are composed of broken quartz grains, there is good agreement between these definitions in practice. The upper size limit of 1/16 mm or 63 microns corresponds to the smallest particles that can be discerned with

1925-445: Is the direct consequence of the presence of the wider shelf. The continental slope which follows the eastern shelf is quite steep between 9°N and 14°N. Here, the perspective view of the submarine topography sectioned along 95°E exposes the abrupt rise in depth of sea by about 3,000 metres (9,800 ft) within a short horizontal distance of a degree. Isobaths corresponding to 900 and 2,000 metres (3,000 and 6,600 ft) are also shown in

2002-481: Is the southern extremity of Goh Puket ( Phuket Island ). Exclusive economic zones in Andaman Sea: The northern and eastern side of the basin is shallow, as the continental shelf off the coast of Myanmar and Thailand extends over 200 kilometres (120 mi) (marked by 300 metres (980 ft) isobath ). About 45 percent of the basin area is shallower (less than 500 metres (1,600 ft) depth), which

2079-591: The Nile and Niger River deltas. Bangladesh is largely underlain by silt deposits of the Ganges delta. Silt is also abundant in northern China, central Asia, and North America. However, silt is relatively uncommon in the tropical regions of the world. Silt is commonly found in suspension in river water, and it makes up over 0.2% of river sand. It is abundant in the matrix between the larger sand grains of graywackes . Modern mud has an average silt content of 45%. Silt

2156-526: The Strait of Malacca further southeast. Traditionally, the sea has been used for fishery and transportation of goods between the coastal countries and its coral reefs and islands are popular tourist destinations. The fishery and tourist infrastructure was severely damaged by the December 2004 Indian Ocean earthquake and tsunami . The Andaman Sea, which extends over 92°E to 100°E and 4°N to 20°N, occupies

2233-490: The Andaman Sea is 120 centimetres (47 in) per year.) It is found that the SSH of the basin is primarily determined by the transport of water through the straits. The contributions from rainfall and rivers become substantial only during summer. Hence, a net inward flow occurs through the straits between April and November, followed by a net outward transport until March. The basin has a very high rate of transport of water through

2310-795: The Andaman Sea, scattered between Ranong and Satun Provinces . These species are sensitive to the degradation of seagrass meadows. Coral reefs are estimated to occupy 73,364 rai (117 km) in the Andaman Sea with only 6.4 percent in ideal condition. The sea has long been used for fishing and transportation of goods between the coastal countries. Thailand alone harvested about 943,000 t (2.079 × 10 lb) of fish in 2005 and about 710,000 t (1.57 × 10 lb) in 2000. Of those 710,000 t (1.57 × 10 lb), 490,000 t (1.08 × 10 lb) are accounted for by trawling (1,017 vessels), 184,000 t (406,000,000 lb) by purse seine (415 vessels), and about 30,000 t (66,000,000 lb) by gillnets . Of Thailand's total marine catch, 41%

2387-404: The Burma plate. The last eruption started on 13 May 2008 and continues. The volcanic island of Narcondam , which lies further north, was also formed by this process. No records exist of its activity. Collectively, the modern Ayeyarwady (Irrawaddy) and Thanlwin (Salween) rivers deliver >600 Mt/yr of sediment to the sea. Most recent studies show: 1) There is little modern sediment accumulating on

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2464-596: The Martaban Canyon; 3) a mud drape/blanket is wrapping around the narrow western Myanmar Shelf in the eastern Bay of Bengal. The thickness of the mud deposit is up to 20 metres (66 ft) nearshore and gradually thins to the slope at −300 metres (−980 ft) water depth, and likely escapes into the deep Andaman Trench; 4) The estimated total amount of Holocene sediments deposited offshore is approximately 1,290 by 109 tonnes (1,270 by 107 long tons; 1,422 by 120 short tons). If we assume this has mainly accumulated since

2541-677: The Thai navy intervened when Burmese vessels tried to intercept Thai fishing boats in the contested sea areas, and Thai fighter aircraft were thought to be deployed by the National Security Council. Thai fishing boats were also frequently confronted by the Malaysian navy to the extent that the Thai government had to caution its own fishers against fishing without license in foreign waters. The 2004 marine production in Thailand

2618-404: The Thai shores of Malay Peninsula whereas seagrass meadows occupy an area of 79 km (31 sq mi). Mangroves are largely responsible for the high productivity of the coastal waters – their roots trap soil and sediment and provide shelter from predators and nursery for fish and small aquatic organisms. Their body protects the shore from the wind and waves, and their detritus are a part of

2695-430: The U.S. Department of Agriculture puts the cutoff at 0.05mm. The term silt is also used informally for material containing much sand and clay as well as silt-sized particles, or for mud suspended in water. Silt is a very common material, and it has been estimated that there are a billion trillion trillion (10 ) silt grains worldwide. Silt is abundant in eolian and alluvial deposits, including river deltas , such as

2772-783: The Western Islands of the Nicobar Group to Sandy Point in Little Andaman Island, in such a way that all the narrow waters appertain to the Burma Sea. On the Northwest. The Eastern limit of the Bay of Bengal [A line running from Cape Negrais (16°03'N) in Burma [Myanmar] through the larger islands of the Andaman group, in such a way that all the narrow waters between the islands lie to the Eastward of

2849-412: The aquatic food chain. A significant part of the Thai mangrove forests in the Andaman Sea was removed during the extensive brackish water shrimp farming in 1980s. Mangroves were also significantly damaged by the 2004 tsunami. They were partly replanted after that, but their area is still gradually decreasing due to human activities. Other important sources of nutrients in the Andaman Sea are seagrass and

2926-403: The basin is suggestive of strong shear in the flow during different times of the year, and further indicates the presence of low frequency geophysical waves (such as westward propagating Rossby waves) and other transient eddies. The coastal areas of the Andaman Sea are characterized by mangrove forests and seagrass meadows . Mangroves cover between more than 600 km (232 sq mi) of

3003-552: The basin, which is 3 kilometres (1.9 mi) wide and 37 metres (121 ft) deep. The International Hydrographic Organization defines the limits of the "Andaman or Burma Sea" as follows: On the Southwest. A line running from " Oedjong Raja " [ "Ujung Raja" or "Point Raja" ] ( 5°32′N 95°12′E  /  5.533°N 95.200°E  / 5.533; 95.200 ) in Sumatra to Poeloe Bras (Breuëh) and on through

3080-513: The crystal structure of the quartz, known as Moss defects. Such defects are produced by tectonic deformation of the parent rock, and also arise from the high-low transition of quartz: Quartz experiences a sharp decrease in volume when it cools below a temperature of about 573 °C (1,063 °F), which creates strain and crystal defects in the quartz grains in a cooling body of granite. Mechanisms for silt production include: Laboratory experiments have produced contradictory results regarding

3157-589: The domain experiences maximum wind intensity. It weakens by March–April and reverses to strong south-westerlies from May to September, with mean wind speeds touching 8 m/s (29 km/h) in June, July, and August, distributed near-uniformly over the entire basin. Wind speeds plummet by October and switch back to north-easterlies from November. Air temperature is stable over the year at 26 °C (79 °F) in February and 27 °C (81 °F) in August. Precipitation

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3234-558: The earthquake damage potential in the silty soil of the central United States in the event of a major earthquake in the New Madrid Seismic Zone . Silt is easily transported in water and is fine enough to be carried long distances by air in the form of dust . While the coarsest silt particles (60 micron) settle out of a meter of still water in just five minutes, the finest silt grains (2 microns) can take several days to settle out of still water. When silt appears as

3311-460: The eastern side of the basin. This is characteristic of the propagation of Kelvin Waves. It is observed that the water level rises in the basin between April and November with the maximum rate of piling up of water during April and October (marked by the steep slope of the curve). The rise in sea surface height (SSH) is attributed to rainfall, fresh water influx from rivers, and inflow of water through

3388-470: The effectiveness of various silt production mechanisms. This may be due to the use of vein or pegmatite quartz in some of the experiments. Both materials form under conditions promoting ideal crystal growth, and may lack the Moss defects of quartz grains in granites. Thus production of silt from vein quartz is very difficult by any mechanism, whereas production of silt from granite quartz proceeds readily by any of

3465-513: The figure to emphasize the steepness of the slope. Further, it may be noted that the deep ocean is also not free from sea mounts; hence only around 15 percent of the total area is deeper than 2,500 metres (8,200 ft). The northern and eastern parts are shallower than 180 meters (590 feet) due to the silt deposited by the Irrawaddy River . This major river flows into the sea from the north through Myanmar. The western and central areas are 900–3,000 meters (3,000–9,800 ft) deep. Less than 5% of

3542-443: The fine silt produced in dust storms and the coarse silt fraction possibly representing the fine particle tail of sand production. Loess underlies some of the most productive agricultural land worldwide. However, it is very susceptible to erosion. The quartz particles in silt do not themselves provide nutrients, but they promote excellent soil structure , and silt-sized particles of other minerals, present in smaller amounts, provide

3619-401: The laboratory using the pipette method, which is based on settling rate via Stokes' law and gives the particle size distribution accordingly. The mineral composition of silt particles can be determined with a petrographic microscope for grain sizes as low as 10 microns. Vadose silt is silt-sized calcite crystals found in pore spaces and vugs in limestone . This is emplaced as sediment

3696-764: The line and are excluded from the Bay of Bengal, as far as a point in Little Andaman Island in latitude 10°48'N, longitude 92°24'E]. On the Southeast. A line joining Lem Voalan (7°47'N) in Siam [Thailand], and Pedropunt (5°40'N) in Sumatra. Oedjong means " cape " and Lem means "point in the Dutch language on maps of the Netherlands East Indies (Indonesia). Lem Voalan [Phromthep Cape]

3773-409: The local currents that are influenced by tides, and seasonally varying monsoons winds and waves. The climate of the Andaman Sea is determined by the monsoons of southeast Asia , as the prevailing winds reverse with the start of either season. The region experiences north-easterlies with an average windspeed of 5 m/s (18 km/h) from November to February. During these months, the western part of

3850-515: The middle Holocene highstand (~6000 yr BP) like other major deltas, the historical annual mean depositional flux on the shelf would be 215 megatonnes (212,000,000 long tons; 237,000,000 short tons) per year, which is equivalent to ~35% of the modern Ayeyarwady-Thanlwin rivers derived sediments; 5) Unlike other large river systems in Asia, such as the Yangtze and Mekong, this study indicates a bi-directional transport and depositional pattern controlled by

3927-520: The month of April. Although the surface flow through PC is generally inward during summer monsoon, the preceding and succeeding months experience outflow (strong outflow in October, but weak outflow in April). During April and October, when the effects of local winds are minimal, Andaman Sea experiences the intensification of meridional surface currents in the poleward direction along the continental slope on

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4004-453: The most important straits (in terms of width and depth) are Preparis Channel (PC), Ten Degree Channel (TDC), and Great Channel (GC). PC is the widest but shallowest (250 metres (820 ft)) of the three and separates south Myanmar from north Andaman. TDC is 600 metres (2,000 ft) deep and lies between Little Andaman and Car Nicobar . GC is 1,500 metres (4,900 ft) deep and separates Great Nicobar from Banda Aceh . Running in

4081-417: The mud bottoms of lagoons and coastal areas. They also create a habitat or temporal shelter for many burrowing and benthic organisms. Many aquatic species migrate from and to seagrass either daily or at certain stages of their life cycle. The human activities which damage seagrass beds include waste water discharge from coastal industry, shrimp farms and other forms of coastal development, as well as trawling and

4158-787: The necessary nutrients. Silt, deposited by annual floods along the Nile River , created the rich, fertile soil that sustained the Ancient Egyptian civilization. The closure of the Aswan High Dam has cut off this source of silt, and the fertility of the Nile delta is deteriorating. Loess tends to lose strength when wetted, and this can lead to failure of building foundations. The silty material has an open structure that collapses when wet. Quick clay (a combination of very fine silt and clay-sized particles from glacial grinding)

4235-514: The only currently active volcano associated with the Indian subcontinent . This island volcano is 3 km (2 mi) in diameter and rises 354 metres (1,161 ft) above sea level. Its recent activity resumed in 1991 after a quiet period of almost 200 years. It is caused by the ongoing subduction of the India plate beneath the Andaman island arc , which forces magma to rise in this location of

4312-513: The past 50 years. With Dutch funding, the Bangladeshi government began to help develop older chars in the late 1970s, and the effort has since become a multi-agency operation building roads, culverts , embankments, cyclone shelters, toilets and ponds, as well as distributing land to settlers. By fall 2010, the program will have allotted some 100 square kilometres (20,000 acres) to 21,000 families. A main source of silt in urban rivers

4389-440: The problem may be the conflation of high rates of production with environments conducive to deposition and preservation, which favors glacial climates more than deserts. Loess associated with glaciation and cold weathering may be distinguishable from loess associated with hot regions by the size distribution. Glacial loess has a typical particle size of about 25 microns. Desert loess contains either larger or smaller particles, with

4466-401: The same period is suggestive of the downwelling nature of Kelvin waves. The waves further propagate along the eastern boundary of the Andaman Sea, which is confirmed by the differential deepening of the 20-degree isotherm along longitudes 94°E and 97°E (averaged over latitudes 8°N and 13°N). These longitudes are chosen so that one represents the western part of the basin (94°E) and the other along

4543-508: The sea floor and the gears themselves and are becoming unpopular. So, the mollusk production has decreased from 27,374 t (60,349,000 lb) in 1999 to 318 tonnes in 2004. While crustaceans composed only 4.5 percent of the total marine products in 2004 by volume, they accounted for 21 percent of the total value. They were dominated by banana prawn , tiger prawn , king prawn, school prawn, bay lobster ( Thenus orientalis ), mantis shrimp, swimming crabs and mud crabs . The total catch in 2004

4620-495: The sea floor generated a massive tsunami with an estimated height of 28 meters (92 feet) that killed approximately 280,000 people along the coast of the Indian Ocean. The initial quake was followed by a series of aftershocks along the arc of the Andaman and Nicobar Islands. The entire event severely damaged the fishing infrastructure. Within the sea, to the east of the main Great Andaman island group, lies Barren Island ,

4697-491: The sea is deeper than 3,000 meters (9,800 feet), and in a system of submarine valleys east of the Andaman-Nicobar Ridge, the depth exceeds 4,000 meters (13,000 feet). The sea floor is covered with pebbles, gravel, and sand. The western boundary of the Andaman Sea is marked by islands and sea mounts, with straits or passages of variable depths that control the entry and exit of water to the Bay of Bengal . There

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4774-591: The shelf immediately off the Ayeyarwady River mouths. In contrast, a major mud wedge with a distal depocenter, up to 60 metres (200 ft) in thickness, has been deposited seaward in the Gulf of Martaban, extending to approximately 130 metres (430 ft) water depth into the Martaban Depression. Further, 2) There is no evidence showing that modern sediment has accumulated or is transported into

4851-475: The south than any other part of the basin. An intense surface outflux through GC, of the order of 40 cm/s (16 in/s), occurs during summers and winters. While this flow is directed westwards in winter, it is southwards along the west coast of Indonesia in summer. On the other hand, the TDC has strong surface influx in summer, which weakens by October. This is followed by a sturdy outflux in winter, which wanes by

4928-509: The steep continental slope on the eastern side of the basin (97°E). It is observed that both these longitudes experience deepening of the isotherms in April and October, but the effect is more pronounced at 97°E (isotherms deepen by 30 metres (98 ft) in April and 10 metres (33 ft) in October). This is a concrete signature of downwelling in the basin and is definitely not forced locally as

5005-423: The straits in April and October. This is a period of equatorial Wyrtki jets, which hit the coast of Sumatra and reflect back as Rossby waves and coastal Kelvin waves . These Kelvin waves are guided along the eastern boundary of Indian Ocean, and a part of this signal propagates into the Andaman Sea. The northern coast of Sumatra is the first to be affected. The 20 °C (68 °F) isotherm which deepens during

5082-470: The term used in the name. The largest terrestrial seas, in decreasing order of area, are: Seas may be considered marginal between ocean and land, or between oceans in which case they may be treated as marginal parts of either. There is no single ultimate authority on the matter. (clockwise from 180°) In addition to the marginal seas listed in the three subsections below, the Arctic Ocean itself

5159-407: The three major straits. The first two of these are quantifiable and are hence expressed in volumes of water for comparison. From this, the expected influx through the straits (= SSH anomaly – Rainfall – River Influx) could be deduced. A possible fourth factor, evaporative losses, is negligible in comparison. (Previous studies show that the annual mean freshwater gain (precipitation minus evaporation) of

5236-458: The two seasons elicits a very strong negative pumping velocity of more than 5 m (16 ft) per day along the north coast of Indonesia from May to September (shown here, June). This may signify coastal downwelling in the summer. It is also observed that the region develops a weak but positive pumping velocity of less than 3 m (9.8 ft) per day at the mouth of GC in winter (here, December). Generally, currents are found to be stronger in

5313-699: The unaided eye. It also corresponds to a Tanner gap in the distribution of particle sizes in sediments : Particles between 120 and 30 microns in size are scarce in most sediments, suggesting that the distinction between sand and silt has physical significance. As noted above, the lower limit of 2 to 4 microns corresponds to the transition from particles that are predominantly broken quartz grains to particles that are predominantly clay mineral particles. Assallay and coinvestigators further divide silt into three size ranges: C (2–5 microns), which represents post-glacial clays and desert dust; D1 (20–30 microns) representing "traditional" loess ; and D2 (60 microns) representing

5390-927: The use of push nets and dragnets. The 2004 tsunami affected 3.5% of seagrass areas along the Andaman Sea via siltation and sand sedimentation and 1.5% suffered total habitat loss. The sea waters along the Malay Peninsula favor molluscan growth, and there are about 280 edible fish species belonging to 75 families. Of those, 232 species (69 families) are found in mangroves and 149 species (51 families) reside in seagrass; so 101 species are common to both habitats. The sea also hosts many vulnerable fauna species, including dugong ( Dugong dugon ), several dolphin species, such as Irrawaddy dolphin ( Orcaella brevirostris ) and four species of sea turtles: critically endangered leatherback turtle ( Dermochelys coriacea ) and hawksbill turtle (Eletmochelys imbricata) and threatened green turtle ( Chelonia mydas ) and olive ridley turtle ( Lepidochelys olivacea ). There are only about 150 dugongs in

5467-413: The very coarse North African loess. Silt can be distinguished from clay in the field by its lack of plasticity or cohesiveness and by its grain size. Silt grains are large enough to give silt a gritty feel, particularly if a sample is placed between the teeth. Clay-size particles feel smooth between the teeth. The proportions of coarse and fine silt in a sediment sample are determined more precisely in

5544-902: The western coast of the Malay Peninsula , and the Andaman and Nicobar Islands of India and Myanmar are rich in coral reefs and offshore islands with spectacular topography. Despite having been damaged by the 2004 Sumatra earthquake and tsunami, they remain popular tourist destinations. The nearby coast also has numerous marine national parks – 16 only in Thailand, and four of them are candidates for inclusion into UNESCO World Heritage Sites . Marginal sea There are several terms used for bulges of ocean that result from indentations of land, which overlap in definition, and which are not consistently differentiated: Many features could be considered to be more than one of these, and all of these terms are used in place names inconsistently; especially bays, gulfs, and bights, which can be very large or very small. This list includes large areas of water no matter

5621-416: The winds are weaker during this period. This confirms unequivocally that the sudden burst of water into the basin through the straits, the intensification of eastern boundary currents and the coincidental deepening of isotherms in April and October are the direct consequence of the propagation of downwelling Kelvin waves in the Andaman Sea, remotely forced by equatorial Wyrtki jets. The evolution of vorticity in

5698-420: Was 333 percent for pelagic and 245 percent for demersal species in 1991. Cephalopods are divided into squid, cuttlefish and molluscs, where squid and cuttlefish in Thai waters consists of 10 families, 17 genera and over 30 species. The main mollusk species captured in the Andaman Sea are scallop , blood cockle ( Anadara granosa ) and short-necked clam. Their collection requires bottom dredge gears, which damage

5775-538: Was 51,607 t (113,774,000 lb) for squid and cuttlefish and 36,071 tonnes (79,523,000 lb) for crustaceans. The sea's mineral resources include tin deposits off the coasts of Malaysia and Thailand. Major ports are Port Blair in India; Dawei , Mawlamyine and Yangon in Myanmar; Ranong port in Thailand; George Town and Penang in Malaysia; and Belawan in Indonesia. The Andaman Sea, particularly

5852-906: Was composed of: pelagic fish 33 percent, demersal fish 18 percent, cephalopod 7.5 percent, crustaceans 4.5 percent, trash fish 30 percent and others 7 percent. Trash fish refers to non-edible species, edible species of low commercial value and juveniles, which are released to the sea. Pelagic fishes were distributed between anchovies ( Stolephorus spp., 19 percent), Indo-Pacific mackerel ( Rastrelliger brachysoma , 18 percent), sardinellas ( Sardinellars spp., 14 percent), scad (11 percent), longtail tuna ( Thunnus tonggol , 9 percent), eastern little tuna ( Euthynnus affinis , 6 percent), trevallies (6 percent), bigeye scad (5 percent), Indian mackerel ( Rastrelliger kanagurta , 4 percent), king mackerel ( Scomberomorus cavalla , 3 percent), torpedo scad ( Megalaspis cordyla , 2 percent), wolf herrings (1 percent), and others (2 percent). Demersal fish production

5929-438: Was dominated by purple-spotted bigeye ( Priacanthus tayenus ), threadfin bream ( Nemipterus hexodon ), brushtooth lizardfish ( Saurida undosquamis ), slender lizardfish ( Saurida elongata ) and Jinga shrimp ( Metapenaeus affinis ). Most species are overfished since the 1970s–1990s, except for Spanish mackerel ( Scomberomorus commersoni ), carangidae and torpedo scad ( Meggalaspis spp.). The overall overfishing rate

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