Microseismicity evidence for subduction of the Caribbean plate beneath the South American Plate in northwestern Venezuela

Pérez, Omar J.; Jaimes, Martha A.; Garciacaro, Emilio

doi:10.1029/96jb03174

Cited by 26 publications

(20 citation statements)

References 31 publications

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“…These blocks are limited by major strike-slip fault and thrust systems (Audemard and Audemard 2002). Several seismological studies indicate that a continuous slab built as part of the Caribbean lithosphere subduct beneath Northern Colombia and NW Venezuela, and extends along the entire width of Mérida Andes (Colmenares and Zoback 2003;Malavé and Suarez 1995;Perez et al 1997;Van der Hilst and Mann 1994). Another hypothesis assumes a tear fault along San Sebastian-El Pilar fault system (Taboada et al 2000).…”

Section: Geological Settingmentioning

confidence: 97%

“…However, some events have been recorded for depths exceeding 150 km in Eastern and Western Venezuela. They have been attributed by means of focal solutions and seismic tomography to subduction processes (Corredor 2003;Malavé and Suarez 1995;McCann and Pennington 1990;Perez et al 1997;Van der Hilst 1990). Southwest Venezuela, seismicity is characterized by the Bucaramanga Nest composed by intermediate depth events gathering in small volume, eastward the seismicity is dominated by Boconó and Oca-Ancón fault systems with several shallow depths but with some deep seismicity.…”

Section: Constraintsmentioning

confidence: 97%

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A 3-D lithospheric model of the Caribbean-South American plate boundary

Sanchez

Götze

Schmitz

2010

Int J Earth Sci (Geol Rundsch)

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A 3-D structural model of the Caribbean-South American plate boundary was constructed by gravity modeling. The model was constrained by four wide-angle seismic refraction sections, Moho depth estimations from receiver functions, and additionally seismological hypocenters, surface geology, and geodynamic information. Density values were calculated from empirical velocitydensity functions, and mineralogical-chemical composition considering specific P/T conditions. We tested different structural models for Western and Eastern Venezuela. In the final model, the fit of the measured and modeled gravity fields for a long Caribbean slab in Western Venezuela was better than the fit obtained for a short one. This interpretation is consistent with the constraining data. The slab is interpreted to extend further to the south beneath Northern Colombia and culminates in the area of the seismic cluster of the Bucaramanga nest. The modeling estimates a slab dip angle under Maracaibo and Mérida Andes of 15°, which increases to 32°below 100 km depth. The dip direction of approx. N150°E ± 5 increases lightly eastward. In Eastern Venezuela, considering its short wavelength, lineaments analyzed from gravity data (by curvature methods and Euler deconvolution) seem to be related to shallow structures and density contrast in the Serranía del Interior and not from a deep detached slab beneath the continental crust. It is deduced from modeling results that this slab configuration has a very small influence on the gravity field. The slab was modeled according to the subduction-transform propagation model with purely westward subduction and a slab break off along a vertical dip-slip tear through the lithosphere.

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Section: Geological Settingmentioning

confidence: 97%

Section: Constraintsmentioning

confidence: 97%

A 3-D lithospheric model of the Caribbean-South American plate boundary

Sanchez

Götze

Schmitz

2010

Int J Earth Sci (Geol Rundsch)

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“…This fault system is zone of partitioned slip [ Audemard and Audemard , 2002] on subparallel and/or en‐echelon dextral and thrust faults, including the Pallafanga, Algecira, Gualcaramo, Yopal, and Bocono faults [ Taboada et al , 2000; Audemard and Audemard , 2002]. Based on the extent of the subducted CA slab, Perez et al [1997] have interpreted the present CA‐ND‐SA triple‐junction as lying at the intersection of the Bocano fault (ND‐SA), San Sebastian‐El Pilar fault (CA‐SA), and an unnamed but seismically active dextral fault trending NW (ND‐CA). (This would explain why the former Leeward Antilles subduction zone is now seismically quiescent east of Curacao.)…”

Section: Small Platesmentioning

confidence: 99%

“…Meanwhile, the proposal that ND (and/or the Maracaibo block) converges with CA has been confirmed by the discovery of a high-seismic-velocity slab of subducted Caribbean lithosphere which dips 17°toward 150°down to a depth of 275 km [van der Hilst and Mann, 1994]. Perez et al [1997] studied the Benioff zone of seismicity within this slab, and showed that it terminates eastward near Curacao-Aruba. This discovery of subduction proves that CA does not extend (on the surface) south of the South Caribbean deformed belt.…”

Section: Panama Plate (Pm) and North Andes Plate (Nd)mentioning

confidence: 99%

An updated digital model of plate boundaries

Bird

2003

Geochem Geophys Geosyst

2,148

1,761

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[1] A global set of present plate boundaries on the Earth is presented in digital form. Most come from sources in the literature. A few boundaries are newly interpreted from topography, volcanism, and/or seismicity, taking into account relative plate velocities from magnetic anomalies, moment tensor solutions, and/or geodesy. In addition to the 14 large plates whose motion was described by the NUVEL-1A poles (Africa, Antarctica, Arabia, Australia, Caribbean, Cocos, Eurasia, India, Juan de Fuca, Nazca, North America, Pacific, Philippine Sea, South America), model PB2002 includes 38 small plates (Okhotsk, Amur, Yangtze, Okinawa, Sunda, Burma, Molucca Sea, Banda Sea, Timor, Birds Head, Maoke, Caroline, Mariana, North Bismarck, Manus, South Bismarck, Solomon Sea, Woodlark, New Hebrides, Conway Reef, Balmoral Reef, Futuna, Niuafo'ou, Tonga, Kermadec, Rivera, Galapagos, Easter, Juan Fernandez, Panama, North Andes, Altiplano, Shetland, Scotia, Sandwich, Aegean Sea, Anatolia, Somalia), for a total of 52 plates. No attempt is made to divide the Alps-Persia-Tibet mountain belt, the Philippine Islands, the Peruvian Andes, the Sierras Pampeanas, or the California-Nevada zone of dextral transtension into plates; instead, they are designated as ''orogens'' in which this plate model is not expected to be accurate. The cumulative-number/area distribution for this model follows a power law for plates with areas between 0.002 and 1 steradian. Departure from this scaling at the small-plate end suggests that future work is very likely to define more very small plates within the orogens. The model is presented in four digital files: a set of plate boundary segments; a set of plate outlines; a set of outlines of the orogens; and a table of characteristics of each digitization step along plate boundaries, including estimated relative velocity vector and classification into one of 7 types (continental convergence zone, continental transform fault, continental rift, oceanic spreading ridge, oceanic transform fault, oceanic convergent boundary, subduction zone). Total length, mean velocity, and total rate of area production/destruction are computed for each class; the global rate of area production and destruction is 0.108 m 2 /s, which is higher than in previous models because of the incorporation of back-arc spreading.

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“…tectônica atual na parte norte da América do Sul (Figura 2.3)é muito complexa, pela compilação feita por Colmenares e Zoback (2003), e que sintetiza estudos da tectônica ná area Norte feitos por Taboada et al (2000), Gonzalez de Juana et al (1980), Pennington(1981),Robertson e Burke (1989),Mann (1999),Beltran e Giraldo (1989),Perez et al (1997), ECOPETROL (1998) eGutscher et al (1999).…”

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Espessura crustal da parte norte dos Andes usando precursores de pP e sS para telessismos

Camacho¹

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In this work we studied the crustal thickness in northern Andes and northern central Andes (between 10 • N and 9 • S). We analyzed the reflections from the underside of the Moho for six intermediate earthquakes occurred in the study area to estimate the crustal thickness at the bounce point. The pmP and smS phases (reflections at the Moho) are identified as precursors to the depth phase pP and sS, respectively, when recorded at teleseismic distances. This method require events of magnitude > 6 and depth > 100 km.In order to better identify those two reflections, it was necessary to stacking traces from different stations. The study area was divided in three sections: northern area between 6 • N -0 • (Colombia), in this area we analyzed two earthquakes and the crustal thicknesses in four bounce points were found; central area between 2 • S-5 • S (Ecuador), in this area we studied one earthquake and the crustal thicknesses in three bounce points were found; southern area between 6 • S -9 • S (Peru-Brazil border), where we analyzed three earthquakes and the crustal thicknesses in seven bounce points were found. Crustal thickness found in the southern area varied from 35 to 40 km, from 40 to 63 km in the central area and from 26 to 56 km in the northern area. We estimated a V p /V s ratio of 1.79±0.16 for the northern Andes using the time differences sS-smS and pP-pmP relation. Our analysis complements the data base of Moho depths in the Northern Andes and also, it allows a comparison with the model of crustal thickness estimated by Assumpção et al. (2013) confirming the Moho depth on both studies.

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Microseismicity evidence for subduction of the Caribbean plate beneath the South American Plate in northwestern Venezuela

Cited by 26 publications

References 31 publications

A 3-D lithospheric model of the Caribbean-South American plate boundary

A 3-D lithospheric model of the Caribbean-South American plate boundary

An updated digital model of plate boundaries

Espessura crustal da parte norte dos Andes usando precursores de pP e sS para telessismos

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