GPS Geodetic Infrastructure and Current Tectonic Movements within the Caribbean Region
Liu, Hanlin 1989-
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This dissertation first summarizes the current GPS geodetic infrastructure in the Caribbean region and illustrates its applications in tectonics and geological hazard studies. The infrastructure consists of three essential components: 1) a network of over 300 permanent stations that provide continuous observations to the public and several local land deformation monitoring networks, 2) a well-developed stable regional reference frame that is tied to the International GNSS Service reference frame of 2008 (IGS08), and 3) sophisticated GPS data post-processing software packages, such as GIPSY/OASIS (V6.4), GAMIT/GLOBK (V10.5), and software tools developed through the study discussed in the rest of the dissertation. This study developed a stable Caribbean reference frame (CARBRF17) using long-term continuous GPS observations from 13 continuously operating GPS stations located on the margins of the stable portion of the Caribbean plate. The major products from this study include the seven parameters for realizing CARBRF17 and the three-component velocities of 250 continuous GPS stations (> 3 years) with respect to CARBRF17. The frame stability of CARBRF17 is approximately 0.9 mm/year and 1.3 mm/year in the horizontal and vertical directions, respectively. CARBRF17 enables geological hazards monitoring to be conducted using stand-alone GPS, and such hazards include volcanos, landslides, subsidence, sea level changes, and coastal erosion. Applications of CARBRF17 within the Caribbean region discussed within this dissertation include the long-term spatial variation monitoring of the Montserrat Island, observation of tectonic movements on the Hispaniola Island and in the Maracaibo triangular block within the southern Caribbean area, and the analysis of ongoing post-seismic displacement observed within the region after the 2012 Costa Rica earthquake (Mw 7.6). Quantitative results also indicate that the Virgin Islands basin presently exhibits left-lateral motion in an approximate east-west direction and it is opening in a roughly north-south direction. The results from GPS and seismic data, suggest that the Anegada Gap is a typical inactive interseismic segmentation and that strain accumulation is occurring at a rate of 1-2 mm/year. The GPS results also suggest that partial coupling occurred between the Lesser Antilles arc and the rigid Caribbean region.