New seafloor map of the Puerto Rico trench helps assess earthquake and tsunami hazards

Brink, Uri S. ten; Danforth, W.W.; Polloni, Christopher F.; Andrews, Brian D.; Llanes, P.; Smith, Shep M; Parker, E. N.; Uozumi, Toshihiko

doi:10.1029/2004eo370001

Cited by 40 publications

(35 citation statements)

References 6 publications

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“…Bathymetry contour interval is 0.5 km. Color bathymetry combines multibeam bathymetry at depths >2500 m, single‐beam bathymetry at shallower depths, and lidar near shore (see ten Brink et al [2004] for details). Dashed line is approximate location of proposed tear in the NOAM plate.…”

Section: Introductionmentioning

confidence: 99%

Vertical motions of the Puerto Rico Trench and Puerto Rico and their cause

Brink

2005

J. Geophys. Res.

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[1] The Puerto Rico trench exhibits great water depth, an extremely low gravity anomaly, and a tilted carbonate platform between (reconstructed) elevations of +1300 m and À4000 m. I argue that these features are manifestations of large vertical movements of a segment of the Puerto Rico trench, its forearc, and the island of Puerto Rico that took place 3.3 m.y. ago over a time period as short as 14-40 kyr. I explain these vertical movements by a sudden increase in the slab's descent angle that caused the trench to subside and the island to rise. The increased dip could have been caused by shearing or even by a complete tear of the descending North American slab, although the exact nature of this deformation is unknown. The rapid (14-40 kyr) and uniform tilt along a 250 km long section of the trench is compatible with scales of mantle flow and plate bending. The proposed shear zone or tear is inferred from seismic, morphological, and gravity observations to start at the trench at 64.5°W and trend southwestwardly toward eastern Puerto Rico. The tensile stresses necessary to deform or tear the slab could have been generated by increased curvature of the trench following a counterclockwise rotation of the upper plate and by the subduction of a large seamount.

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Section: Introductionmentioning

confidence: 99%

Vertical motions of the Puerto Rico Trench and Puerto Rico and their cause

Brink

2005

J. Geophys. Res.

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“…Anegada adjoins the edge of a submarine slope that descends nearly 8 km to the floor of the Puerto Rico Trench, 125 km to the north (ten Brink et al 2004;Grindlay et al 2005).…”

Section: Tectonicsmentioning

confidence: 99%

Geomorphic and stratigraphic evidence for an unusual tsunami or storm a few centuries ago at Anegada, British Virgin Islands

et al. 2010

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Waters from the Atlantic Ocean washed southward across parts of Anegada, east-northeast of Puerto Rico, during a singular event a few centuries ago. The overwash, after crossing a fringing coral reef and 1.5 km of shallow subtidal flats, cut dozens of breaches through sandy beach ridges, deposited a sheet of sand and shell capped with lime mud, and created inland fields of cobbles and boulders. Most of the breaches extend tens to hundreds of meters perpendicular to a 2-km stretch of Anegada's windward shore. Remnants of the breached ridges stand 3 m above modern sea level, and ridges seaward of the breaches rise 2.2-3.0 m high. The overwash probably exceeded those heights when cutting the breaches by overtopping and incision of the beach ridges. Much of the sand-and-shell sheet contains pink bioclastic sand that resembles, in grain size and composition, the sand of the breached ridges. This sand extends as much as 1.5 km to the south of the breached This article is intended for tsunami-geology issue of Natural Hazards edited by Ioan Nistor: inistor@uottawa.ca. Electronic supplementary material The online version of this article

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“…Modern studies of the extremely deep seafloor (.8000 m in the west) of the Puerto Rico Trench, NW of Barbados, by ten Brink et al (2004), reveal it to be 'atypical of oceanic trenches. Subduction (of the North American Plate, which lies to the north, under the Caribbean Plate to the south) is highly oblique to the trench axis with a large component of left-lateral strike -slip motion'.…”

Section: West Indian Corals and More On Barbadosmentioning

confidence: 98%

“…This platform was horizontally deposited over Cretaceous to Paleocene arc rocks (on the Caribbean Plate) starting in the Late Oligocene. Then, at 3.5 Ma, the carbonate platform was tilted towards the trench over a time period of less than 40 ka such that its northern edge is at a depth of 4000 m and its reconstructed elevation on land in Puerto Rico is at þ1300 m (U. ten Brink et al 2004). The dating of these events closely matches Gregory's deductions and although the events in Barbados were quite different from the above, there is a coincidence of timing of now-proven major vertical movements with those erroneously supposed in the late 19th and early 20th centuries, even though there is still no agreement about the history of the Caribbean Plate.…”

Section: West Indian Corals and More On Barbadosmentioning

confidence: 99%

Chapter 6 Home after the African expedition

Leake¹

2011

Memoirs

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New seafloor map of the Puerto Rico trench helps assess earthquake and tsunami hazards

Cited by 40 publications

References 6 publications

Vertical motions of the Puerto Rico Trench and Puerto Rico and their cause

Vertical motions of the Puerto Rico Trench and Puerto Rico and their cause

Geomorphic and stratigraphic evidence for an unusual tsunami or storm a few centuries ago at Anegada, British Virgin Islands

Chapter 6 Home after the African expedition

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