Articulo CNS
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- ItemAmbient noise tomography images accreted terranes and igneous provinces in Hispaniola and Puerto Rico.(2018-11-15)The North American-Caribbean plate boundary near the islands of Hispaniola and Puerto Rico is a complex region in which strain is accommodated by different modes of deformation. In 2013, 16 broadband stations were deployed in the Dominican Republic to densify the local permanent network. One goal is to combine their data with those from permanent networks in the Caribbean to develop a better understanding of the crust and upper mantle structure in the Greater Antilles. Here we use the records of 204 stations spanning almost 7 years of data to obtain group velocity maps. We observe at short periods the contacts between accreted terranes and the igneous provinces of Hispaniola and Puerto Rico, at longer periods the collisional boundary between the buoyant Bahamas Carbonate Platform and Hispaniola, and the transition from Hispaniola's accreted terranes to the faster lithosphere of the Venezuelan Basin and Cayman Trough.
- ItemCrustal thickness and bulk Poisson ratios in the Dominican Republic from receiver function analysis(2020-01)The Dominican Republic (DR) comprises the eastern two-thirds of the island of Hispaniola, which is located on the Caribbean-North American plate boundary. Previous studies have described the shallow structure and stratigraphy of the island but, due to a dearth of broadband seismic data, little is known about the lower crust and mantle. Since August 2014, thirteen broadband, three-component seismic stations have been deployed temporarily in the They are combined with four permanent broadband stations in the DR and three in neighboring Haiti to enhance studies of Hispaniola's lower crust and upper mantle. We report results of a receiver function study using teleseismic data recorded by these stations. Specifically, we compute receiver functions and determine crustal properties via H-κ stacking. We propose additional intracrustal and upper mantle layers based on identifications of prominent and coherent P-to-S converted phases observed in receiver function gathers. Our results show that crustal thickness varies beneath the island of Hispaniola over the range 13–47 km with a median of 24 km and bulk Vp/Vs ratios vary over 1.58–1.99 with median 1.79. Receiver function modeling reveals intracrustal discontinuities at station PAPH (Port au Prince, Haiti), at a depth of 8.0 km, station JIDR (Jimaní, DR; 8.8 km depth), and SDDR (Sabaneta, DR; 15.8 km depth). Additional discontinuities appear in the upper mantle beneath PAPH (60.1 km depth), PCDR (Punta Cana; 60 km), SDD (Santo Domingo; 70 km), and SC01 (Santiago; 81 km). Two north-south cross-sections show variations in bulk Vp/Vs ratios that are consistent with expectations based upon surface geology but variations in crustal thickness are more scattered and do not conform to expectations from simple tectonic models of Hispaniola's formation. Our stacking results reveal consistency between Vp/Vs ratios in four distinct regions which are consistent with the compositional domains identified by previous studies.
- ItemSeismic S-wave coda attenuation in the Dominican Republic as a tool for seismic hazard mitigation.(2020-06-20)High-quality waveforms of the vertical and horizontal components of 1356 seismic events recorded from 2013 to 2016 by the Dominican Republic’s seismic network, were analyzed to study the local spatial distribution of the coda frequency-dependent attenuation Qc(f)−1. Qc(f) was estimated at central frequencies of 1.5 (± 0.5), 3.0 (± 1.0), 6.0 (± 2.0), and 12.0 (± 4.0) Hz and interpreted by considering the single backscattering model. Our results of the attenuation of coda waves may explain why some regions of the Dominican Republic (DR) are more prone to suffer damage due to earthquakes than other areas. The majority of the cities and towns in the DR that were severely damaged by earthquakes in the past are located in zones of low and very low coda wave attenuation. In contrast, cities located in zones of high Qc(f)−1 tend to suffer less damage. Our findings identify regions with low seismic attenuation that reflect zones with soft soils that could be impacted by future large events in the DR. These results can be used as a tool for planning seismic hazard mitigation and emergency response as well as for land use regulations.