Relative Motion between the Caribbean and North American Plates and Related Boundary Zone Deformation from a Decade of GPS Observations

Global Positioning System (GPS) measurements in 1986, 1994, and 1995 at sites in Dominican Republic, Puerto Rico, Cuba, and Grand Turk define the velocity of the Caribbean plate relative to North America. The data show eastward motion of the Caribbean plate at a rate of 21 ± 1 mm/yr (1 standard error ) in the vicinity of southern Dominican Republic, a factor of 2 higher than the NUVEL-1A plate motion model prediction of 11 ± 3 mm/yr. Independent measurements on San Andres Island, and an Euler vector derived from these data, also suggest a rate that is much higher than the NUVEL-1A model. Available data, combined with simple elastic strain models, give the following slip rate estimates for major left-lateral faults in Hispaniola: (1) the North Hispaniola fault offshore the north coast of Hispaniola, 4 ± 3 mm/yr; (2) the Septentrional fault in northern Dominican Republic, 8 ± 3 mm/yr; and (3) the Enriquillo fault in southern Dominican Republic and Haiti, 8 ± 4 mm yr. The relatively high plate motion rate and fault slip rates suggested by our study, combined with evidence for strain accumulation and historical seismicity, imply that seismic risk in the region may be higher than previous estimates based on low plate rate/low fault slip rate models and the relatively low rate of seismicity over the last century

Oblique collision and strain partitioning from GPS measurements in the northeastern Caribbean

International audienceGPS data collected in the Dominican Republic from 1994 to 2001 show that oblique convergence between the North American and Caribbean plates is partitioned between 5.2 ± 2 mm.yr−1 of dip‐slip reverse motion on the North Hispaniola thrust (approximately N‐S), and 12.8 ± 2.5 mm.yr−1 and 9.0 ± 9.0 mm.yr−1 of approximately E‐W left‐lateral strike‐slip motion on the Septentrional and Enriquillo faults (95% confidence). The agreement between GPS and paleoseimological slip rates on the Septentrional fault, together with the 770–960 years since the last major earthquake and the 800–1200 years maximum repeat time of major earthquakes, may indicate that the Septentrional fault is currently in the late phase of its rupture cycle

Kinematics of the Nicaraguan Forearc from GPS Geodesy

Campaign GPS data from a network in the Nicaraguan forearc show a strong component of arc-parallel motion indicating northwest translation of a nearly rigid forearc sliver. Our measured mean velocity for forearc sites of 15.1 mm yr−1 agrees well with the arc-parallel sliver motion predicted previously by DeMets (2001) derived from closure constraints on oblique convergence between the Cocos and Caribbean plates. The lack of a northeasterly oriented arc-normal component of motion in forearc velocities indicates that there are complexities involved beyond a simple interpretation of sliver motion being driven by oblique convergence. The forearc is reasonably well-fit by rigid rotation about an Euler pole with a rms misfit of residual velocities of 4.9 ± 2.6 mm yr−1. Current motion of the forearc sliver relative to the stable Caribbean plate yields predominantly boundary parallel NW motion with boundary normal extension in the northwestern region averaging ∼5 mm yr−1

GPS Measurement of Surface Deformation Around Soufriere Hills Volcano, Montserrat from October 1995 to July 1996

Global Positioning System geodesy was used to measure surface deformation on Soufriere Hills volcano, Montserrat from October 6, 1995 to July 1, 1997 during initial dome growth and gravitational collapse. Our data from this period show non-axially symmetric horizontal displacements, and decreasing subsidence as a function of radial distance from the former topographic high of the volcanic edifice. Forward modeling suggests that surface deformation is caused by a shallow vertical dike (\u3c 3 km), which expanded approximately 1 m, coupled with a deflating Mogi source at about 6 km depth. These inferred source parameters are in good agreement with independent observations of regional dike widths and preemption magma storage depth

GPS Geodetic Constraints on Caribbean-North America Plate Motion

We describe a model for Caribbean plate motion based on GPS velocities of four sites in the plate interior and two azimuths of the Swan Islands transform fault. The data are well fit by a single angular velocity, with average misfits approximately equal to the 1.5–3.0 mm yr−1 velocity uncertainties. The new model predicts Caribbean-North America motion ∼65% faster than predicted by NUVEL-1A, averaging 18–20±3 mm yr−1 (2σ) at various locations along the plate boundary. The data are best fit by a rotation pole that predicts obliquely convergent motion along the plate boundary east of Cuba, but are fit poorly by a suite of previously published models that predict strike-slip motion in this region. The data suggest an approximate upper bound of 4–6 mm yr−1 for internal deformation of the Caribbean plate, although rigorous estimates await more precise and additional velocities from sites in the plate interior

Terrane deletion in northern Guerrero state

La evolución tectonoestratigráfica del margen sur de la placa Norteamericana en México es materia de debate. Los escenarios recientemente propuestos muestran la acreción de terrenos oceánicos durante el Campaniano-Eoceno. Aquí presentamos nuevos resultados del mapeo a escala 1:100,000 de un transecto de 30 x 250 km en el norte del Estado de Guerrero, de Huetamo, Michoacán a Papalutla, Guerrero. Nuestro objetivo al mapear esta región fue caracterizar los límites de terrenos que han sido propuestos a lo largo, de este transecto y el análisis de su evolución tectonoestratigráfica. Nuestro mapa, sección estructural y análisis de la sección estratigráfica de 9 km de espesor, son consistentes con información regional. En el área mapeada se desarrolló una cuenca Jurásica-Cretácica temprana (de retro-arco?) en la cual se depositaron rocas volcánicas submarinas predominantemente andesíticas y sedimentarias, sobre un basamento continental Pérmico tardío-Triásico temprano. Una transgresión Aptiana/Albiana propició el depósito de una plataforma carbonatada Cretácica media y facies de cuenca en el margen occidental del ámbito Tetisiano. Esta plataforma fue ahogada por la sedimentación de un flysch Cretácico tardío. La orogenia Laramídica de edad Cretácico tardío-Paleógeno resultó en un acortamiento de aproximadamente 60 km debido al plegamiento y cabalgamiento con dirección ENE. La extensión Terciaria post-orogénica dio paso a un volcanismo terrestre, sedimentación fluvial siliciclástica y a la formación de un graben con dirección norte y con un relieve estructural de 3 km. · Se han propuesto tres diferentes versiones del límite de los terrenos Guerrero-Mixteca y del límite del subterráneo Arcelia-Teloloapan que se ubican en la región cubierta por nuestro transecto. No hemos encontrado incompatibilidades estratigráficas o estructurales que requieran la existencia de ninguno de estos límites. Por lo tanto, estos terrenos y subterráneos deberían de ser eliminados en el área que hemos mapeado. doi: https://doi.org/10.22201/igeof.00167169p.1996.35.4.52

Transpressional rupture of an unmapped fault during the 2010 Haiti earthquake

On 12 January 2010, a Mw 7.0 earthquake struck the Port-au-Prince region of Haiti. The disaster killed more than 200,000 people and caused an estimated $8 billion in damages, about 100% of the country’s gross domestic product1. The earthquake was initially thought to have ruptured the Enriquillo–Plantain Garden fault of the southern peninsula of Haiti, which is one of two main strike-slip faults inferred to accommodate the 2 cm yr−1relative motion between the Caribbean and North American plates2, 3. Here we use global positioning system and radar interferometry measurements of ground motion to show that the earthquake involved a combination of horizontal and contractional slip, causing transpressional motion. This result is consistent with the long-term pattern of strain accumulation in Hispaniola. The unexpected contractional deformation caused by the earthquake and by the pattern of strain accumulation indicates present activity on faults other than the Enriquillo–Plantain Garden fault. We show that the earthquake instead ruptured an unmapped north-dipping fault, called the Léogâne fault. The Léogâne fault lies subparallel to—but is different from—the Enriquillo–Plantain Garden fault. We suggest that the 2010 earthquake may have activated the southernmost front of the Haitian fold-and-thrust belt4 as it abuts against the Enriquillo–Plantain Garden fault. As the Enriquillo–Plantain Garden fault did not release any significant accumulated elastic strain, it remains a significant seismic threat for Haiti and for Port-au-Prince in particular