Is the local seismicity in western Hispaniola (Haiti) capable of imaging northern Caribbean subduction?

Abstract

The boundary between the Caribbean and North American plates in the Hispaniola region is the northwestern termination of the North American plate subduction evolving from westward subduction in the Lesser Antilles to southward subduction in the Greater Antilles and oblique collision against the Bahamas platform in Cuba. We analyze P waveforms recorded by 27 broadband seismic temporary stations deployed during the Trans-Haiti project. Seismicity recorded by the temporary network from June 2013 to June 2014 is used to locate the earthquakes. A total of 514 events were identified with magnitudes ranging from 1 to 4.5. Twenty-six moment tensors were calculated by full waveform inversion using the ISOLA software. The analysis of the new moment tensors for the Haiti upper lithosphere indicates that normal, thrust and strike-slip faulting are present but with a majority of thrust faulting. The mean P and T axes for the moment tensors indicated that the current compressional deformation is mainly N-S to NNE-SSW. Moreover, a dozen intermediate-depth earthquakes (>70 km) are located under Haiti, with one event in the south of the island reaching 260 km depth. The seismic data of the Haiti network, over a one-year time period, tend to confirm the existence of a lithospheric slab inherited from southward subduction under the Greater Antilles. The scarcity of the intermediate-depth seismic events in this area may be the effect of the lack of a dense seismic network or may indicate that we image the western slab edge.

Spatial Variations in Crustal and Mantle Anisotropy Across the North American‐Caribbean Boundary on Haiti

“…The fast polarization direction should therefore also be parallel to SH max . Geodetic and seismotectonic studies show that the SH max has a NNE–SSW orientation across much of central Haiti (Calais et al, 2016; Corbeau et al, 2019; Rodriguez et al, 2018), which is generally more consistent with our measurements of shear wave splitting in the crust (Figure 6).…”

The Tectonics and Active Faulting of Haiti from Seismicity and Tomography

“…Further west, moving along strike into the Gulf of Gonâve (300°), offshore seismic data do show active compressional tectonics with north dipping reverse faults and folding perturbing the most recent sediments (Corbeau, Rolandone, Leroy, Meyer, et al, ). Moment tensors determined for this cluster also have a significant thrust component, again with P axis that indicates a NNE‐SSW compression orientation (Corbeau, Clouard, et al, ). We therefore suggest that the active seismicity we observe is linked to a north‐dipping reverse fault structure, similar to those observed in the field and part of the Trans‐Haiti deformation belt (Pubellier et al, ).…”

Along-strike segmentation in the northern Caribbean plate boundary zone (Hispaniola sector): Tectonic implications

“…However, to the west, the margin orientation shifts again to a NE-SW trending and the convergence component becomes more relevant with the development of compressive structures in the Windward Passage Sill and the NE margin of Cuba. Also, Corbeau et al (2019) show an almost pure reverse focal mechanism located in the Windward Passage, evidencing the relevant convergence component in this area. Thus, we can determine that along the entire margin of Hispaniola, the orientation of the margin also influence the structural framework in the overriding plate.…”

“…8 d and g) in Hispaniola might be seismically associated to a slab break-off of an inherited NOAM subducted slab (Calais et al, 1992;Corbeau et al, 2017). New data from Corbeau et al (2019) (Fig. 19).…”

“…r n a l P r e -p r o o f 27Although this area shows a little seismic record, recent studies carried out byCorbeau et al (2017 and2019) reveal that this area is subject to more seismicity than previously believed. Moreover, these studies show a dozen intermediate-depth earthquakes (>70 km) under Haiti, with a 260 kmdepth event in the south of the island Corbeau et al (2019). propose that this intermediate seismicity is the result of deep deformation caused by a remnant lithospheric slab inherited from the southward subduction of the NOAM.…”