Geodynamics of flat subduction: Seismicity and tomographic constraints from the Andean margin

Tectonics - Tập 19 Số 5 - Trang 814-833 - 2000
Marc‐André Gutscher, Wim Spakman1,2,3,4, Harmen Bijwaard1,2,3,4, E. R. Engdahl1,2,3,4
1Department of Physics, University of Colorado, Boulder
2Laboratoire de Gdophysique, Tectonique et Sddimentation, UMR 5573, Universit• de Montpellier, Montpellier, France
3Vening Meinesz Research School of Geodynamics, Faculty of Earth Sciences, Utrecht University, Netherlands
4•Now at UBO / [UEM, UMR Domaines Ocdaniques, Plouzand, France.

Tóm tắt

The cause and geodynamic impact of flat subduction are investigated. First, the 1500 km long Peru flat slab segment is examined. Earthquake hypocenter data image two morphologic highs in the subducting Nazca Plate which correlate with the positions of subducted oceanic plateaus. Travel time tomographic images confirm the three‐dimensional slab geometry and suggest a lithospheric tear may bound the NW edge of the flat slab segment, with possible slab detachment occurring down dip as well. Other flat slab regions worldwide are discussed: central Chile, Ecuador, NW Colombia, Costa Rica, Mexico, southern Alaska, SW Japan, and western New Guinea. Flat subduction is shown to be a widespread phenomenon, occuring in 10% of modern convergent margins. In nearly all these cases, as a spatial and temporal correlation is observed between subducting oceanic plateaus and flat subduction, we conclude that flat subduction is caused primarily by (1) the buoyancy of thickened oceanic crust of moderate to young age and (2) a delay in the basalt to eclogite transition due to the cool thermal structure of two overlapping lithospheres. A statistical analysis of seismicity along the entire length of the Andes demonstrates that seismic energy release in the upper plate at a distance of 250–800 km from the trench is on average 3–5 times greater above flat slab segments than for adjacent steep slab segments. We propose this is due to higher interplate coupling and the cold, strong rheology of the overriding lithosphere which thus enables stress and deformation to be transmitted hundreds of kilometers into the heart of the upper plate.

Từ khóa


Tài liệu tham khảo

10.1130/0091-7613(1994)022<0937:FTSTIS>2.3.CO;2

10.1130/0091-7613(1976)4<686:SDOEAS>2.0.CO;2

10.1038/323052a0

Bialas J., 1999, GEOMAR Report 94

Bialas J., 2000, GEOMAR Report 96

10.1029/98JB02467

10.1029/TC003i007p00741

10.1126/science.239.4847.1501

10.1029/JB095iB12p19495

Boyd T. M., 1984, High‐resolution determination of the Benioff Zone geometry beneath Southern Peru, Bull. Seism. Soc. Am., 74, 559

10.1029/94JB00111

10.1029/92JB00493

10.1029/91JB01991

10.1038/373600a0

10.1111/j.1365-246X.1995.tb06845.x

10.1029/1999JB900332

10.1130/0016-7606(1993)105<0715:LBACOS>2.3.CO;2

10.1130/0016-7606(1982)93<545:COSGLO>2.0.CO;2

10.1029/GL014i008p00824

10.1016/0025-3227(94)90117-1

10.1038/347662a0

10.1130/0091-7613(1993)021<0547:MSHPEO>2.3.CO;2

Defant M. J., 1993, The geochemistry of young volcanism throughout western Panama and SE Costa Rica: An overview, J. Geol. Soc. London, 149, 569, 10.1144/gsjgs.149.4.0569

10.1111/j.1365-246X.1990.tb06579.x

10.1130/0091-7613(1991)019<1145:ROTWCL>2.3.CO;2

10.1029/96JB03555

10.1029/95GL02013

Engdahl E. R., 1998, Global teleseismic earthquake relocation with improved travel times and procedures for depth relocation, Bull. Seismol. Soc. Am., 88, 722, 10.1785/BSSA0880030722

10.1029/93JB03360

10.1016/S0040-1951(98)00091-2

10.1130/0016-7606(1992)104<0219:QUATAC>2.3.CO;2

10.1029/94JB00129

Gutscher M. ‐A., 2000, An Andean model of interplate coupling and strain partitioning applied to the flat subduction of SW Japan (Nankai Trough), Tectonophysics

10.1046/j.1365-3121.1999.00247.x

10.1016/S0012-821X(99)00153-3

10.1016/S0012-821X(99)00060-6

10.1130/0091-7613(2000)28<535:CSMBCB>2.0.CO;2

Hall M. L., 1985, Volcanotectonic segmentation of the N. Andes, Geology, 13, 203, 10.1130/0091-7613(1985)13<203:VSOTNA>2.0.CO;2

10.1016/0895-9811(91)90035-J

10.1029/JB086iB06p04971

10.1029/JB093iB12p15153

Hey R. N., 1977, Tectonic evolution of the Cocos‐Nazca spreading center, Geol. Soc. Am. Bull., 88, 1414

10.1016/0040-1951(81)90231-6

10.1029/JB093iB04p03211

10.1029/93JB03112

10.1029/JB080i035p04809

10.1130/0016-7606(1983)94<341:ATRTGO>2.0.CO;2

10.1016/0040-1951(96)00032-7

10.1130/SPE295-p75

10.1029/1999JB900394

10.1130/SPE295-p235

10.1046/j.1365-246x.1998.00595.x

10.1130/0016-7606(1978)89<981:SATHOT>2.0.CO;2

10.1007/978-3-0348-9140-0_4

10.1016/0040-1951(85)90039-3

Monzier M., 1997, Les adakites d’Equateur: modele préliminaire, C. R. Acad. Sci., Ser. I, 324, 545

10.1130/0091-7613(1995)023<0395:SMAAEO>2.3.CO;2

10.1016/0040-1951(80)90125-0

10.1130/MEM154-p729

10.1007/s000240050247

10.1029/96GL03971

10.1029/1999JB900060

10.1130/0091-7613(1998)026<0199:ANVITC>2.3.CO;2

10.1016/0012-821X(94)90042-6

10.1029/JB086iB11p10753

10.1016/0040-1951(84)90023-4

10.1130/0016-7606(1981)92<448:PRARAL>2.0.CO;2

10.1144/gsjgs.141.5.0793

10.1016/0040-1951(92)90388-M

10.1016/0031-9201(94)90046-9

10.1130/SPE295-p309

10.1016/0040-1951(95)00034-8

Pubellier M., 1998, Le changement de régime plio‐quaternairedans une zone d’échappement tectonique; controle par des intrusifs syntectoniques (Irian Jaya, Indonésie), Proc. Réunion des Sciences de la Terre (RST Meeting), Brest, France, 179

10.1029/JB088iB04p03355

10.1029/91JB02047

10.1029/JB092iB13p13903

10.1029/92TC01108

10.1029/94JB00988

10.1126/science.277.5334.1956

10.1029/94JB00503

10.1029/JB088iB12p10403

10.1038/345336a0

10.1111/j.1365-246X.1987.tb01644.x

10.1029/JB084iB03p01049

10.1130/0091-7613(1994)022<0451:TIOTIO>2.3.CO;2

10.1029/1999TC900011

10.1016/0012-821X(83)90170-X

10.1007/978-94-009-5450-2_2

10.1016/0040-1951(76)90068-8

10.1029/95TC02618

10.1029/96TC03703

10.1029/90EO00319

10.1144/gsjgs.141.5.0783

10.1016/0031-9201(78)90037-7

Thông tin
Thông tin xuất bản

Tectonics

Tập 19 Số 5

814-833

Thông tin tác giả