Halmahera plate has recently (1990s) been postulated to be a microplate within the Molucca Sea Collision Zone of eastern Indonesia .
22-620: The tectonic setting of the Molucca Sea region is unique. It is the only global example of an active arc-arc collision consuming an oceanic basin via subduction in two directions. The Molucca Sea plate has been subsumed by tectonic microplates, the Halmahera plate and the Sangihe plate . The whole complexity is now known as the Molucca Sea Collision Zone . The existence of Halmahera as
44-569: A depth of about 200 km. Seismic tomography suggests that the Halmahera goes deeper to at least 400 km. Both Sangihe and Halmahera are exposed to the surface while the Molucca Sea plate is completely subsumed below these two microplates. The southern boundary of the Molucca Sea plate is also the boundary of the Philippine Sea plate and the Australian plate , and is moving northwards. Since
66-757: A line to the Northern point of Halmahera and down its West coast to Tanjong Libolo, its Southern extreme. On the South. A line from the Southern extreme of Halmahera to the North point of Bisa (Setile) Island, thence to the Northern extreme of Obi Major , through this island to Tanjong Ake Lamo, its Southwestern point, thence to Tanjong Dehekolano, the Eastern extremity of the Soela [ Sula ] Islands, along their Northern coasts to Tanjong Marikasoe,
88-480: A tectonic plate separate from the Molucca Sea plate is not yet entirely agreed upon by paleogeologists. Some see Halmahera as an eastern slab of the Molucca Sea plate, just as they regard Sangihe as a western slab of the Molucca Sea plate. What is apparent to date is that Halmahera was part of the Molucca Sea slab subducted during the Neogene between 45 Ma and 25 Ma. Seismicity shows the east-dipping Halmahera reaches
110-471: A volcanic arc of islands without a tectonic plate base. More recent studies in the 1990s and later, have displaced this theory with the Halmahera plate theory. Molucca Sea The Molucca Sea ( Indonesian : Laut Maluku ) is located in the western Pacific Ocean , around the vicinity of Indonesia , specifically bordered by the Indonesian Islands of Celebes (Sulawesi) to the west, Halmahera to
132-516: Is situated along the western boundary of the Molucca Sea plate. The northwest moving Halmahera plate is situated along the eastern boundary of the Molucca Sea plate. In the western Pacific Ocean , the Molucca Sea is bordered by the Indonesian Islands of Celebes ( Sulawesi ) to the west, Halmahera to the east, and the Sula Islands to the south. The Molucca Sea borders the Banda Sea to the south and
154-434: Is that the Molucca Sea plate has been completely subducted beneath the overriding Halmahera and Sangihe plates . When actively subducting, the crustal collision of the Molucca Sea plate was formed by surface intersection of "oppositely dipping Benioff zones ” (also known as divergent double subduction) which results in the Sangihe and Halmahera volcanic arcs . The force exerted by the thick overlying collision complex of
176-532: The Banda Sea to the south and the Celebes Sea to the west. To the north is Philippine Sea and to the east is Halmahera Sea . The islands bordering the Molucca Sea include Halmahera to the north east, Buru and Ceram in the centre, and Sulawesi to the west. The Talaud Islands to the north are considered to be the northern border the sea, though the Molucca Sea Plate , the tectonic plate named after
198-676: The Celebes Sea at 700–1000 km depth is interpreted as a remnant slab below the Sangihe plate, both remnants having originated from a slab subducted beneath the Philippine-Halmahera Arc 45 Ma to 25 Ma ago. In this model, the Bird's Head and Halmahera plates are separated by the Sorong Fault , a major lateral east–west fault. An earlier model considered the area to be the Halmahera Arc ,
220-460: The Celebes Sea to the west. To the north is the Philippine Sea and to the east is the Halmahera Sea . Situated south of Mindanao , the Molucca Sea is a narrow basin underlined by a north‐south ophiolitic ridge, which uplifts the central region of the basin. While the scientific community has not come to a consensus as to when the Molucca Sea plate became fully subducted, the dominant theory
242-596: The Celebes Sea , which the USGS attributed to the “ deep reverse faulting within the inclined seismic zone defining the deep limit of the Molucca Sea microplate beneath the Celebes Sea Basin. ” The geologic characteristics displayed on the surrounding islands provide insight regarding the complex plate movement of the divergent double subducting plate. Detached ophiolitic series and thick melanges are overlain by forearc deposits; subduction-driven east–west shortening of
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#1732844376532264-411: The Halmahera and Sangihe plates effectively depressed the crust of the Molucca Sea plate. The plate itself features an asymmetrical morphology, configured in an inverted U-shape. The arc-arc collision zone of the Molucca Sea plate is characterized as a thick, low velocity layer, which is highly variable in density. The variable in density of the Molucca Sea plate led to different subduction velocities on
286-551: The Molucca Sea is the 15,780-foot (4,810-meter) Batjan (Indonesian: Bacan ) basin. This region is known for its periodic experiences of earthquakes, which stems from the sea itself being a micro plate, in which the Molucca Sea is being subducted in two opposite directions: one in the direction of the Eurasian Plate to the west and the other in the direction of the Philippine Sea Plate to the east. The Molucca Sea borders
308-458: The Sangihe plate and the Halmahera plate are in continuity with the Molucca Sea plate, this implies all three slabs are moving northward in mantle with the Australian plate . A broad high-velocity zone beneath the Bird's Head plate at 400–600 km depth is interpreted by R Hall and W Spakman as indicating a remnant slab subducted below the Halmahera plate, and another broad high-velocity zone beneath
330-618: The Southern extreme of the Talaud Group , through these islands to their Northeastern extreme ( 4°29′N 126°52′E / 4.483°N 126.867°E / 4.483; 126.867 ) and thence a line to Tanjong Sopi, the Northern point of Morotai Island . On the East. By the West coast of Morotai from Tanjong Sopi as far south as Wajaboela ( 2°17′N 128°12′E / 2.283°N 128.200°E / 2.283; 128.200 ), thence
352-613: The Western extreme, thence a line to the Southeast point of Banggai Island ( 1°43′S 123°36′E / 1.717°S 123.600°E / -1.717; 123.600 ). On the West. The East coasts of Banggai and Peleng Islands to North Bangkalan ( 1°10′S 123°18′E / 1.167°S 123.300°E / -1.167; 123.300 ) thence a line to Tg. Botok (Celebes) ( 1°04′S 123°19′E / 1.067°S 123.317°E / -1.067; 123.317 ) round
374-532: The coast to Tg. Pasir Pandjang ( 0°39′S 123°25′E / 0.650°S 123.417°E / -0.650; 123.417 ) and across to Tg. Tombalilatoe ( 0°18′24″N 123°20′44″E / 0.30667°N 123.34556°E / 0.30667; 123.34556 ) on the opposite coast, thence up the East coast to Tg. Poeisan, the Northeastern extreme of Celebes. The Portuguese , Dutch , British , and Spanish Empires fought each other for control of
396-554: The east, and the Sula Islands to the south. The Molucca Sea has a total surface area of 77,000 square miles (200,000 square kilometres). The Molucca Sea is rich in coral and has many diving sites due to the deepness of its waters. The deepness of the water explains the reasoning behind dividing the sea into three zones, which functions to transport water from the Pacific Ocean to the shallower seas surrounding it. The deepest hollow in
418-520: The only known example of divergent double subduction (DDS), which describes the subduction on both sides of a single oceanic plate. The Molucca Sea plate is one of many tectonic features that compose the Molucca Sea Collision Complex, which refers to the tectonic relationship of the Sangihe plate , Halmahera plate , and the Molucca Sea plate, in addition to the volcanic Halmahera and Sangihe Arcs. The southeast moving Sangihe plate
440-652: The sea, extends further north. The International Hydrographic Organization (IHO) defines the "Molukka Sea" [ sic ] as being one of the waters of the East Indian Archipelago . The IHO defines its limits as follows: On the North. By a line from the Northeast extreme of Celebes [ Sulawesi ] through the Siau Islands to the South point of Sangi ( 3°21′N 125°37′E / 3.350°N 125.617°E / 3.350; 125.617 ) thence to
462-535: The spice islands that can only be accessed through the Molucca Sea. January 6, 2019, measuring 7.0, with no tsunamis resulting. The sea is a very seismically active area due to the Molucca Sea Plate . Molucca Sea Plate Located in the western Pacific Ocean near Indonesia, the Molucca Sea plate has been classified by scientists as a fully subducted microplate that is part of the Molucca Sea Collision Complex . The Molucca Sea plate represents
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#1732844376532484-451: The two sides. Divergent Double Subduction may facilitate various tectonic processes, including closure of ocean basins, accretion and amalgamation of volcanic arcs, and growth of continents. Historically, the Molucca Sea plate has experienced hundreds of earthquakes ranging in magnitude. The most recent large earthquake occurred in January 2017 when a 7.3 magnitude earthquake deep beneath
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