<i>P</i> wave velocity tomography of the Venezuelan region from local arrival times

Bosch, Miguel

doi:10.1029/96jb03172

Cited by 5 publications

(3 citation statements)

References 46 publications

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“…We show in this paper that subducted aseismic South American oceanic lithosphere lies under northern Venezuela, beneath continental South America, extending along a SW trend 150–200 km from the end of the seismically defined slab beneath Paria to a point near the western edge of the Venezuelan Serranía (approximately 9°N, 65.5°W). Our result is largely consistent with the tomography results of Van der Hilst [1990] and Bosch [1997] and with the analysis of Russo and Speed [1992] regarding tectonic wedging of South American continental lithosphere between overriding Caribbean terranes and underthrust South American oceanic slab. The load this slab places on the lithosphere accounts for the large negative gravity anomalies over the Venezuelan foreland by downwarping South American continental lithosphere and displacement of the mantle below, a suggestion also made by Van der Hilst [1990].…”

Section: Introductionsupporting

confidence: 92%

“…This subducted lithosphere lies far SW of the Caribbean coast, and by inference lies below South American continental lithosphere. Subducted oceanic slab therefore lies beneath the metamorphic coastal terranes and the foreland deformation belt, largely consistent with the analysis of Russo and Speed [1992] and with the larger scale P wave delay‐time tomographies of Van der Hilst [1990] and Bosch [1997].…”

Section: Slab Structure Beneath South Americasupporting

confidence: 80%

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Aseismic continuation of the Lesser Antilles slab beneath continental South America

et al. 2003

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We present results of travel time inversions of teleseismic P and S waves recorded at the SECaSA92 (Southeast Caribbean South America 1992) temporary broadband array in northeastern Venezuela and Trinidad. The inversions reveal the unusual structure of the southern termination of the Lesser Antilles subduction zone: A minimum 2% relatively high‐velocity anomaly trends WSW from the seismically defined Lesser Antilles slab beneath and NW of the Paria Peninsula to a point below the Venezuelan Serranía del Interior, well south of the Caribbean coast. Resolution tests utilizing actual ray geometries and densities of the source data indicate that the regional‐scale structure beneath the study area is reasonably well resolved. Thus a detached and detaching subducted South American slab appears to lie beneath continental South America. We infer that oceanic South American lithosphere has been overridden to a significant degree by continental South America. The detached slab now lying beneath continental South America was driven into its current position after detaching from the former eastward striking Mesozoic ocean‐continent passive margin as this margin entered the subduction zone. Because oceanic and continental South America are still attached without apparent relative motion between them along the Atlantic passive margin southeast of our study region, the slab must be the actively moving element during continental overriding. Thus the slab and its surrounding mantle (both Caribbean and South America) beneath northeastern South America are mobile and have moved ESE relative to the stable Guyana Shield craton.

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Section: Introductionsupporting

confidence: 92%

Section: Slab Structure Beneath South Americasupporting

confidence: 80%

Aseismic continuation of the Lesser Antilles slab beneath continental South America

et al. 2003

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“…Studies have been carried out in many different regions including California (Aki & Lee, 1976;Thurber, 1983;Eberhart-Phillips, 1986;Walck & Clayton, 1987;Walck, 1988;Zhao & Kanamori, 1992;Eberhart-Phillips & Michael, 1993;Scott et al, 1994), Taiwan (Kao & Rau, 1999), Japan (Nakanishi, 1985;, South America (Bosch, 1997;Graeber & Asch, 1999) and the Mediterranean (Chiarabba et al, 1997;Luca et al, 1997;Papazachos & Nolet, 1997;Haslinger et al, 1999). Apart from the source-receiver geometry, one of the distinguishing features of LET compared to the other types of tomography discussed here, is the need to relocate earthquake hypocenters (spatial location and origin time) as part of the image reconstruction.…”

Section: Local Earthquake Tomographymentioning

confidence: 99%