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{{Short description|Small fully subducted tectonic plate near Indonesia}} |
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{{Infobox tectonic plate |
{{Infobox tectonic plate |
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| image = File: |
| image = File:Molucca Sea Plate map-fr.png |
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| alt = The Molucca Sea Plate |
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| type = [[List of tectonic plates#Minor plates|Minor]] |
| type = [[List of tectonic plates#Minor plates|Minor]] |
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| move_direction = |
| move_direction = north |
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| move_speed = 30-40 mm/year<ref name="Socquet_etal_2006">{{Cite journal|last=Socquet A.|last2=Simons W.|last3=Vigny C.|last4=McCaffrey R.|last5=Subarya C.|last6=Sarsito D.|last7=Ambrosius B.|last8=Spakman W.|year=2006|title=Microblock rotations and fault coupling in SE Asia triple junction (Sulawesi, Indonesia) from GPS and earthquake slip vector data|url=https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JB003963|journal=Journal of Geophysical Research: Solid Earth|volume=111|issue=B8|doi=10.1029/2005JB003963|access-date=2018-10-02|archive-date=2019-12-08|archive-url=https://web.archive.org/web/20191208215649/https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2005JB003966|doi-access=free}}</ref><ref name="Bellier_etal_2001">{{Cite journal|last=Bellier O.|last2=Sébrier M.|last3=Beaudoin T.|last4=Villeneuve M.|last5=Braucher R.|last6=Bourlès D.|last7=Siame L.|last8=Outranto E.|last9=Pratomo I.|year=2001|title=High slip rate for a low seismicity along the Palu-Koro active fault in central Sulawesi (Indonesia)|journal=Terra Nova|volume=13|issue=6|pages=463–470|doi=10.1046/j.1365-3121.2001.00382.x|doi-access=free}}</ref> |
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| move_speed = ? |
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| geo_features = [[Molucca Sea]] |
| geo_features = [[Sulawesi]], [[Molucca Sea]] |
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}} |
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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 Zone|Molucca Sea Collision Complex]]. The Molucca Sea plate represents the only known example of [[divergent double subduction]] (DDS), which describes the subduction on both sides of a single oceanic plate.<ref name=":0">{{Cite journal|last1=Zhang|first1=Qingwen|last2=Guo|first2=Feng|last3=Zhao|first3=Liang|last4=Wu|first4=Yangming|date=May 2017|title=Geodynamics of divergent double subduction: 3-D numerical modeling of a Cenozoic example in the Molucca Sea region, Indonesia|journal=Journal of Geophysical Research: Solid Earth|volume=122|issue=5|pages=3977–3998|doi=10.1002/2017jb013991|bibcode=2017JGRB..122.3977Z |s2cid=133371837 |issn=2169-9313}}</ref> |
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==Earlier theory== |
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The '''Molucca Sea Plate''' (also ''Molucca Sea Microplate'') was theorised to be a small [[tectonic plate]] carrying northern [[Sulawesi]], the [[Molucca Sea]] and a portion of the [[Banda Sea]] in a region littered with numerous small plates. The theory suggested a [[subduction zone]] lies along its northern border with the [[Sunda Plate]]. A small [[divergent boundary]] exists along the Sulawesi part of the border with the [[Banda Sea Plate]] and transitions into a convergent boundary as it bisects the [[Banda Sea]]; the rest of the borders being [[Transform boundary|transform boundaries]]. |
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[[File:MoluccaSeaCollisionZone.png|thumb|460x460px|Molucca Sea Collision Zone modified by Zhang et al.<ref name=":0"/> using GeoMapApp]] |
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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 Arc|Halmahera]] and [[Sangihe plate|Sangihe]] Arcs. The southeast moving [[Sangihe plate]] 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 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 [[Ophiolite|ophiolitic]] ridge, which uplifts the central region of the basin.<ref name=":1">{{Cite journal|last1=Silver|first1=Eli A.|last2=Moore|first2=J. Casey|date=1978-04-10|title=The Molucca Sea Collision Zone, Indonesia|journal=Journal of Geophysical Research: Solid Earth|volume=83|issue=B4|pages=1681–1691|doi=10.1029/jb083ib04p01681|bibcode=1978JGR....83.1681S |issn=0148-0227}}</ref> |
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== Plate mechanics == |
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==Current theory== |
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[[File:CrossSection.png|thumb|460x460px|Cross Section of Molucca Sea Collision Zone modified by Zhang et al.<ref name=":0"/>]] |
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While the scientific community has not come to a consensus as to when the Molucca Sea plate became fully subducted, the dominant theory is that the Molucca Sea plate has been completely subducted beneath the overriding [[Halmahera plate|Halmahera]] and [[Sangihe plate]]s.<ref name=":0" /> When actively subducting, the crustal collision of the Molucca Sea plate was formed by surface intersection of "oppositely dipping [[Wadati–Benioff zone|Benioff zones]]” (also known as divergent double subduction) which results in the [[Sangihe plate|Sangihe]] and Halmahera [[volcanic arc]]s.<ref name=":1" /> The force exerted by the thick overlying collision complex of the Halmahera and Sangihe plates effectively depressed the crust of the Molucca Sea plate.<ref>{{Cite journal|last=McCaffre, Silver, Raitt|first=Robert, Eli, Russell|date=1980|title=Crustal Structure of the Molucca Sea Collision Zone, Indonesia|url=http://web.pdx.edu/~mccaf/pubs/mccaffrey_mol_sea_agu_1980.pdf|journal=Geophysical Monograph |series=Geophysical Monograph Series |volume=23|page=161 |doi=10.1029/GM023p0161 |bibcode=1980GMS....23..161M |isbn=0-87590-023-2 }}</ref> 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.<ref name=":0" /><ref>{{Cite book|title=The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands|last1=McCaffrey|first1=Robert|last2=Silver|first2=Eli A.|last3=Raitt|first3=Russell W.|date=1980|publisher=American Geophysical Union|isbn=978-0875900230|location=Washington, D. C.|pages=161–177|doi=10.1029/gm023p0161}}</ref> The variable in density of the Molucca Sea plate led to different subduction velocities on the two sides.<ref name=":0" /> [[Divergent double subduction|Divergent Double Subduction]] may facilitate various tectonic processes, including closure of ocean basins, [[Accretion (geology)|accretion]] and amalgamation of volcanic arcs, and growth of continents.<ref name=":0" /> |
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== Earthquakes == |
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More recent scientific studies suggest the Molucca Sea Plate has been totally subsumed by the [[Halmahera Plate]] and the [[Sangihe Plate]], so that no portion of the Molucca Sea Plate remains exposed to Earth's surface. The tectonic setting of this region is unique in that it is the only global example of an active arc-arc collision consuming an oceanic basin via subduction in two directions, between microplates Halmahera Plate and Sangihe Plate.<ref>[http://earthquake.usgs.gov/eqcenter/recenteqsww/Quakes/us2009cybb.php#summary USGS.GOV:Magnitude 7.2 - KEPULAUAN TALAUD, INDONESIA 2009 February 11 17:34:50 UTC]</ref> |
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[[File:Divergent Double Subduction Zone.png|thumb|460x460px|(Asymmetric) Divergent Double Subduction Zone modified by Zhao et al.<ref name=":0"/>]] |
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To the Southeast is the [[Sorong Fault]], a major lateral east-west fault in the region which separates [[Bird's Head Plate]] and Halmahera Plate. This theory is more fully discussed in the article [[Molucca Sea Collision Zone]]. |
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Historically, the Molucca Sea plate has experienced hundreds of earthquakes ranging in magnitude.<ref name=":1"/> The most recent large earthquake occurred in January 2017 when a 7.3 magnitude earthquake deep beneath 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.''”<ref>{{Cite news|url=https://www.decodedscience.org/philippines-iran-alaska-far-north-earthquakes-5-11-january-2017/60479|title=Philippines, Iran, Alaska (and the Far North): Earthquakes 5-11 January 2017|date=2017-01-11|work=Decoded Science|access-date=2018-06-03}}</ref> |
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Large earthquakes frequently strike this area sometimes triggering [[tsunami]]s. |
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== Geology == |
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==Recent large quakes (>6.0) in region== |
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The geologic characteristics displayed on the surrounding islands provide insight regarding the complex plate movement of the [[Divergent double subduction|divergent double subducting]] plate. Detached [[Ophiolite|ophiolitic]] series and thick [[Mélange|melanges]] are overlain by [[forearc]] deposits; subduction-driven east–west shortening of the Snellius Plateau caused the thrust [[Mélange|melanges]] to reactivate and deform the [[forearc]] series.<ref>{{Cite journal|last1=Bader|first1=Anne Gaëlle|last2=Pubellier|first2=Manuel|date=2008-07-18|title=Forearc deformation and tectonic significance of the ultramafic Molucca central ridge, Talaud islands (Indonesia)|journal=Island Arc|volume=9|issue=4|pages=653–663|doi=10.1111/j.1440-1738.2000.00309.x|s2cid=129639389 |issn=1038-4871}}</ref> Exposed [[Ophiolite|ophiolitic]] rocks can be found on the islands of the submarine Talaud-Mayu Ridge, which bisects the arc-arc collision zone of the Molucca Sea plate; these [[ophiolite]]s provide insight regarding the relationship between earthquakes and uplift surrounding the plate.<ref>{{Cite journal|last=McCaffrey|first=Robert|date=April 1991|title=Earthquakes and ophiolite emplacement in the Molucca Sea Collision Zone, Indonesia|journal=Tectonics|volume=10|issue=2|pages=433–453|doi=10.1029/90tc02553|bibcode=1991Tecto..10..433M |issn=0278-7407}}</ref> |
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* Jan 11, 2016 - 6.4, waters off [[Karakelong]] |
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* Nov 14, 2014 - 7.3 Waters off [[Ternate City|Kota Ternate]] |
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* Sept 9, 2014 - 6.5 South Molucca Sea |
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* June 13, 2011 - 6.2 Molucca Sea |
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* Feb 11, 2009 - 7.2 [[Talaud Islands|Kepulauan Talaud]] |
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* Sep 10, 2008 - 6.6 180 km south of Manado on [[Sulawesi]]. |
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* July 26, 2007 - 6.9 Molucca Sea |
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* Mar 17, 2007 - 6.5 Molucca Sea |
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* Jan 21, 2007 - 7.5 Molucca Sea, 5 deaths |
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* May 19, 2006 - 6.3 Molucca Sea |
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* Dec 21, 2005 - 6.3 190 km south of [[Manado]]. |
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<ref>[http://earthquake.usgs.gov/regional/world/historical_country.php#indonesia NEIC]</ref> |
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== |
== See also == |
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{{ |
{{Portal|Geology}} |
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* [[Molucca Sea Collision Zone]] |
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*{{cite journal|last=Bird|first=P.|year=2003|title=An updated digital model of plate boundaries|journal=Geochemistry, Geophysics, Geosystems|volume=4|issue=3|pages=1027|url=http://peterbird.name/publications/2003_PB2002/2003_PB2002.htm|doi=10.1029/2001GC000252}} |
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* [[Sangihe plate]] |
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* [[Halmahera plate]] |
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* [[List of earthquakes in Indonesia]] |
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== References == |
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{{reflist}} |
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{{Tectonic plates|state=collapsed}} |
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{{SE Asia plates}} |
{{SE Asia plates}} |
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{{DEFAULTSORT:Molucca Sea |
{{DEFAULTSORT:Molucca Sea plate}} |
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[[Category:Tectonic plates]] |
[[Category:Tectonic plates]] |
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[[Category:Geology of the Pacific Ocean]] |
[[Category:Geology of the Pacific Ocean]] |
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[[Category:Geology of Indonesia]] |
[[Category:Geology of Indonesia]] |
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[[Category:Molucca Sea]] |
[[Category:Molucca Sea]] |
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{{tectonics-stub}} |
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Latest revision as of 02:13, 9 November 2024
| Molucca Sea plate | |
|---|---|
 | |
| Type | Minor |
| Movement1 | north |
| Speed1 | 30-40 mm/year[1][2] |
| Features | Sulawesi, Molucca Sea |
| 1Relative to the African 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 the only known example of divergent double subduction (DDS), which describes the subduction on both sides of a single oceanic plate.[3]
Tectonic setting
[edit]
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 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 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.[4]
Plate mechanics
[edit]
While the scientific community has not come to a consensus as to when the Molucca Sea plate became fully subducted, the dominant theory is that the Molucca Sea plate has been completely subducted beneath the overriding Halmahera and Sangihe plates.[3] 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.[4] The force exerted by the thick overlying collision complex of the Halmahera and Sangihe plates effectively depressed the crust of the Molucca Sea plate.[5] 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.[3][6] The variable in density of the Molucca Sea plate led to different subduction velocities on the two sides.[3] Divergent Double Subduction may facilitate various tectonic processes, including closure of ocean basins, accretion and amalgamation of volcanic arcs, and growth of continents.[3]
Earthquakes
[edit]
Historically, the Molucca Sea plate has experienced hundreds of earthquakes ranging in magnitude.[4] The most recent large earthquake occurred in January 2017 when a 7.3 magnitude earthquake deep beneath 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.”[7]
Geology
[edit]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 the Snellius Plateau caused the thrust melanges to reactivate and deform the forearc series.[8] Exposed ophiolitic rocks can be found on the islands of the submarine Talaud-Mayu Ridge, which bisects the arc-arc collision zone of the Molucca Sea plate; these ophiolites provide insight regarding the relationship between earthquakes and uplift surrounding the plate.[9]
See also
[edit]
References
[edit]- ^ Socquet A.; Simons W.; Vigny C.; McCaffrey R.; Subarya C.; Sarsito D.; Ambrosius B.; Spakman W. (2006). "Microblock rotations and fault coupling in SE Asia triple junction (Sulawesi, Indonesia) from GPS and earthquake slip vector data". Journal of Geophysical Research: Solid Earth. 111 (B8). doi:10.1029/2005JB003963. Archived from the original on 2019-12-08. Retrieved 2018-10-02.
- ^ Bellier O.; Sébrier M.; Beaudoin T.; Villeneuve M.; Braucher R.; Bourlès D.; Siame L.; Outranto E.; Pratomo I. (2001). "High slip rate for a low seismicity along the Palu-Koro active fault in central Sulawesi (Indonesia)". Terra Nova. 13 (6): 463–470. doi:10.1046/j.1365-3121.2001.00382.x.
- ^ a b c d e f g h Zhang, Qingwen; Guo, Feng; Zhao, Liang; Wu, Yangming (May 2017). "Geodynamics of divergent double subduction: 3-D numerical modeling of a Cenozoic example in the Molucca Sea region, Indonesia". Journal of Geophysical Research: Solid Earth. 122 (5): 3977–3998. Bibcode:2017JGRB..122.3977Z. doi:10.1002/2017jb013991. ISSN 2169-9313. S2CID 133371837.
- ^ a b c Silver, Eli A.; Moore, J. Casey (1978-04-10). "The Molucca Sea Collision Zone, Indonesia". Journal of Geophysical Research: Solid Earth. 83 (B4): 1681–1691. Bibcode:1978JGR....83.1681S. doi:10.1029/jb083ib04p01681. ISSN 0148-0227.
- ^ McCaffre, Silver, Raitt, Robert, Eli, Russell (1980). "Crustal Structure of the Molucca Sea Collision Zone, Indonesia" (PDF). Geophysical Monograph. Geophysical Monograph Series. 23: 161. Bibcode:1980GMS....23..161M. doi:10.1029/GM023p0161. ISBN 0-87590-023-2.
{{cite journal}}: CS1 maint: multiple names: authors list (link) - ^ McCaffrey, Robert; Silver, Eli A.; Raitt, Russell W. (1980). The Tectonic and Geologic Evolution of Southeast Asian Seas and Islands. Washington, D. C.: American Geophysical Union. pp. 161–177. doi:10.1029/gm023p0161. ISBN 978-0875900230.
- ^ "Philippines, Iran, Alaska (and the Far North): Earthquakes 5-11 January 2017". Decoded Science. 2017-01-11. Retrieved 2018-06-03.
- ^ Bader, Anne Gaëlle; Pubellier, Manuel (2008-07-18). "Forearc deformation and tectonic significance of the ultramafic Molucca central ridge, Talaud islands (Indonesia)". Island Arc. 9 (4): 653–663. doi:10.1111/j.1440-1738.2000.00309.x. ISSN 1038-4871. S2CID 129639389.
- ^ McCaffrey, Robert (April 1991). "Earthquakes and ophiolite emplacement in the Molucca Sea Collision Zone, Indonesia". Tectonics. 10 (2): 433–453. Bibcode:1991Tecto..10..433M. doi:10.1029/90tc02553. ISSN 0278-7407.
