These are representative sample records from related to your search topic.
For comprehensive and current results, perform a real-time search at

Cenozoic basin development in Hispaniola  

SciTech Connect

Four distinct generations of Cenozoic basins have developed in Hispaniola (Haiti and Dominican Republic) as a result of collisional or strike-slip interactions between the North America and Caribbean plates. First generation basins formed when the north-facing Hispaniola arc collided with the Bahama platform in the middle Eocene; because of large post-Eocene vertical movements, these basins are preserved locally in widely separated areas but contain several kilometers of arc and ophiolite-derived clastic marine sediments, probably deposited in thrust-loaded, flexure-type basins. Second generation basins, of which only one is exposed at the surface, formed during west-northwesterly strike-slip displacement of southern Cuba and northern Hispaniola relative to central Hispaniola during the middle to late Oligocene; deposition occurred along a 5-km (3-mi) wide fault-angle depression and consisted of about 2 km (1 mi) of submarine fan deposits. Third generation basins developed during post-Oligocene convergent strike-slip displacement across a restraining bend formed in central Hispaniola; the southern 2 basins are fairly symmetrical, thrust-bounded ramp valleys, and the third is an asymmetrical fault-angle basin. Fourth generation basins are pull-aparts formed during post-Miocene divergent strike-slip motion along a fault zone across southern Hispaniola. As in other Caribbean areas, good source rocks are present in all generations of basins, but suitable reservoir rocks are scarce. Proven reservoirs are late Neogene shallow marine and fluvial sandstones in third generation basins.

Mann, P.; Burke, K.



Methiini and Oemini of Hispaniola (Coleoptera: Cerambycidae: Cerambycinae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Two new species of Methiini (Tessaropa hispaniolae Lingafelter, Methia dolichoptera) (Coleoptera: Cerambycidae) from Hispaniola are diagnosed, described, and illustrated. The Dominican Republic represents a New Country Record for Malacopterus tenellus (Fabricius) (Oemini), and all hispaniolan local...


Cholera in United States Associated with Epidemic in Hispaniola  

PubMed Central

Cholera is rare in the United States (annual average 6 cases). Since epidemic cholera began in Hispaniola in 2010, a total of 23 cholera cases caused by toxigenic Vibrio cholerae O1 have been confirmed in the United States. Twenty-two case-patients reported travel to Hispaniola and 1 reported consumption of seafood from Haiti. PMID:22204035

Heiman, Katherine E.; Schmitz, Ann; Török, Tom; Apostolou, Andria; Hanson, Heather; Gounder, Prabhu; Bohm, Susan; Kurkjian, Katie; Parsons, Michele; Talkington, Deborah; Stroika, Steven; Madoff, Lawrence C.; Elson, Franny; Sweat, David; Cantu, Venessa; Akwari, Okey; Mahon, Barbara E.; Mintz, Eric D.



Modes of active deformation in Eastern Hispaniola  

NASA Astrophysics Data System (ADS)

Eastern Hispaniola and the Puerto Rico Island are the emerged part of a doubly vergent thrust wedge formed by oblique arc-continent collision with subduction and underthrusting of the North America Plate in the Puerto Rico trench and underthrusting of the Caribbean crust in The Muertos trough (Dolan et al. 1998, Mann et al., 2002, ten Brink et al. 2010). In the relatively small area of Eastern Hispaniola several types of active crustal deformation have been recognized: 1) At the prowedge of the orogene, the rear of the accretionary prism is cut by the strike-slip Septentrional Fault, bounding a sliver plate (Mann et al, 2002). Recent detailed mapping and aeromagnetic surveys in the onshore part of the prism (Samaná Peninsula and Septentrional Cordillera, Sysmin Team) revealed that the internal structure of the sliver is made of parallel bands of sigmoidal, left-lateral, NW-SE thrust splays, bounded by steep strike-slip faults. We interpreted these structures as transpressional strike-slip duplex. It is worth to note the similarity between the strike and dip of the thrust splays and the 303, 62, 74 focal mechanism calculated by Russo and Villaseñor (1995) for the thrust event of the August 4, 1946 Hispaniola earthquake. 2) The uplifted core of the orogen extends between the accretionary prism and the beginning of the Muertos retrowedge. Half of this area is occupied by the Oriental Cordillera, a recent uplift of cretaceous island-arc rocks arching the Late Neogene reef. The rest of the territory is the Caribbean Coastal Plain modelled on the Late Neogene reef. The Oriental Cordillera is made of two en echelon left-stepping uplifts: the domal-shaped Haitises and the rhombohedral-shaped Seibo (García-Senz et al, 2007); the latter share structural similarities and scaling relations with the 90° neutral stepover model of McClay and Bonora (2001). Therefore we interpret it as a restraining stepover developed over a blind splay of the Septentrional Fault, and the main active fault at surface, the Yabón fault, as a trans pop-up strike-slip fault. 3) The contractive faults and folds that form the Oriental Cordillera disappear to the east replaced by a field of NW-SE to WNW-ESE trending normal faults with fresh scarps up to 75 m high depressing the Late Neogene reef (Punta Cana extended area). In plan form, the faults show multiple relays and transverse ramps at the overlaps. A NE-SW section coast to coast across the Punta Cana area show the Late Neogene reef gently arched and cut by normal faults bounding half-grabens, with the main throw directed to the NE. The amount of extension exceeds 3 km (5% of stretching). A very similar system of normal faults has been documented in seismic lines across the Mona Passage (eg. van Gestel et al., 1998, Mondziel, 2007, Chaytor and ten Brink, 2010) and onshore western Puerto Rico (Hippolyte et al., 2005), which are interpreted by a pinning extension model (Dolan et al., 1998, Mann et al., 2002) or by oblique extension (Chaytor and ten Brink, 2010). Whatever the tectonic model may be, our data places an onshore boundary between transpressional and extensional domains. 4) The retrowedge at the southern margin of Hispaniola form an imbricate of E-W segmented thrusts overriding the Muertos trough (ten Brink et al., 2010). These authors suggest that the transport direction within the Muertos thrust system is southward perpendicular to the regional trend of the belt.

García-Senz, J.; Pérez-Estaún, A.



Tertiary serpentinite tectonics in northern Hispaniola  

SciTech Connect

At least 4 types of serpentinite bodies are found in N. Hispaniola, by different inclusion and Tertiary deformation styles: (1) Narrow slivers occurring on Tertiary faults, rarely containing inclusions, which occur throughout the region. (2) Massive fractured serpentinites associated with a Cretaceous volcanic plutonic and metamorphic basement, and containing rodingite dikes, occurs in the Puerto Plata region. (3) Massive, fractured, but coherent bodies containing Tertiary limestone clasts which apparently the same as nearby limestone overlying the serpentinite occur west of Puerto Plata. (4) Diapirically emplaced bodies in the Gaspar Hernandez region containing both brecciated and massive zones and containing a variety of inclusions. Type 4 bodies protrude into the clastic Upper Eocene Altamira Fm. The most common tectonic inclusions in these bodies are rounded cobbles of diorite and gabbro. Amphibolites are also common, but friable greenschists and blueschists are rare, as are blocks of clastic sediments. The authors suggest that large blocks of the Altamira Fm. were incorporated into the serpentinite during their past Eocene diapirism and that these blocks were deformed in a brittle manner into gouge zones by internal movements in the diapir. Type 4 serpentinites may therefore have incorporated inclusions at high crustal levels by brittle processes. Type 2 bodies, in contrast, may have incorporated inclusions by ductile flow of serpentinite at lower crustal levels. Type 33 bodies are the most enigmatic. They may be sedimentary, but alternatively may have incorporated limestone in a gouge (as for type 4), which has later healed to a coherent mass.

Nagle, F.; Draper, G.



Western North Atlantic Humpback Whale Census, Hispaniola - 1980  

Microsoft Academic Search

From 13 January to 20 April 1980, the ORES research vessel, r\\/v REGINA MARIS, conducted visual and acoustic censuses on breeding and calving banks of Western North Atlantic humpback whales (Megaptera novaeangliae) near the island of Hispaniola in the Greater Antilles. Seventy censuses were run and 2949 sightings were made along 672.4 nautical miles of ship's track (4.4 sightings\\/n.m.). The

K. C. Balcomb; N. J. Haenel



Active Faults in Eastern Hispaniola: The Hispaniola-Puerto Rico Microplate Boundary?  

NASA Astrophysics Data System (ADS)

An extensive tract of limestone of mostly Pleistocene-Recent age covers the Eastern part of the Dominican Republic. Numerous distinctive marine terraces outcrop along the southern and eastern coast, the lowest of which has been dated at about 125Ka. In the eastern area, the highest terrace is about 50m asl, is very variable in elevation, and correlates with a terrace of about 50 m asl along the southern coast. This feature might correlate with a feature of similar height on the Island of Marie Galante in the Lesser Antilles, dated at 250Ka. Manipulation of 3 arc-sec grid of SRTM land data and a 12 arc-sec grid of marine data reveals the location of the upper marine terrace as well as numerous scarps with 10's of meters of relief tending WNW across the region. The 2nd derivative of the relief grid is used to objectively identify the location of the upper terrace, which is compared to the elevation grid to develop an along escarpment profile of terrace elevation. If undisturbed, this feature should be contour parallel, that is all at the same elevation. Systematic elevation changes along profile suggest titling and numerous abrupt vertical (~30-50m) and at least one horizontal offset (375m) of this feature. Terrace displacing scarps can be traced many kilometers from offshore, across the coast paralleling marine terraces, and continuing inland as linear features that I interpret as active normal faults cutting the limestone platform. Five systems of normal faults have been identified in this manner, the longest of which may be capable of generating earthquakes of about magnitude 7-7 1/4. If the age of the upper terrace is roughly about 250Ka, then the observed horizontal displacements of about 375 meters suggest a rate of fault motion on the order of mm"s/yr for each of the5 faults. This total rate of deformation of several mm/yr is similar to the rate of deformation calculated from GPS studies for the rate of motion between the Hispaniola and Puerto Rico microplates, suggesting that much of the inter-microplate motion is not contained to the offshore regions of the Mona Passage, but rather passes on shore in the eastern part of the Dominican Republic.

McCann, W. R.



Satellite Sees Tropical Storm Chantal Move Over Hispaniola - Duration: 0:09.  

NASA Video Gallery

This NOAA GOES-East satellite animation from July 6 to July 10 shows the development of Tropical Storm Chantal in the Atlantic Ocean and movement over Hispaniola by July 10. TRT 0:06 Credit: NASA/N...


Bulletin of the Seismological Society of America Significant Earthquakes on the Enriquillo Fault System, Hispaniola, 1500-2010  

E-print Network

Bulletin of the Seismological Society of America Significant Earthquakes on the Enriquillo Fault Earthquakes on the Enriquillo Fault System, Hispaniola, 1500-2010: Implications for Seismic Hazard the past 500 years, particularly on the island of Hispaniola. We use accounts of historical earthquakes

ten Brink, Uri S.



E-print Network

to be extant at the type locality on top of Pic La Selle, Haiti. The juniperscollected from Hispaniola appear la Selle, Haiti. Junipers from the Pelempito region of the Dominican Republicand from northern Haiti existe todavia en su lugar tipico en la cima del Pic La Selle, Haiti. Las sabinas recolectadas en la

Adams, Robert P.


Historical perspective on seismic hazard to Hispaniola and the northeast Caribbean region  

USGS Publications Warehouse

We evaluate the long-term seismic activity of the North-American/Caribbean plate boundary from 500 years of historical earthquake damage reports. The 2010 Haiti earthquakes and other earthquakes were used to derive regional attenuation relationships between earthquake intensity, magnitude, and distance from the reported damage to the epicenter, for Hispaniola and for Puerto Rico and the Virgin Islands. The attenuation relationship for Hispaniola earthquakes and northern Lesser Antilles earthquakes is similar to that for California earthquakes, indicating a relatively rapid attenuation of damage intensity with distance. Intensities in Puerto Rico and the Virgin Islands decrease less rapidly with distance. We use the intensity-magnitude relationships to systematically search for the location and intensity magnitude MI which best fit all the reported damage for historical earthquakes. Many events occurred in the 20th-century along the plate-boundary segment from central Hispaniola to the NW tip of Puerto Rico, but earlier events from this segment were not identified. The remaining plate boundary to the east to Guadeloupe is probably not associated with M > 8 historical subduction-zone earthquakes. The May 2, 1787 earthquake, previously assigned an M 8–8.25, is probably only MI 6.9 and could be located north, west or SW of Puerto Rico. An MI 6.9 earthquake on July 11, 1785 was probably located north or east of the Virgin Islands. We located MI I 7.7) and May 7, 1842 (MI 7.6) earthquakes ruptured the Septentrional Fault in northern Hispaniola. If so, the recurrence interval on the central Septentrional Fault is ~300 years, and only 170 years has elapsed since the last event. The recurrence interval of large earthquakes along the Hispaniola subduction segment is likely longer than the historical record. Intra-arc M ? 7.0 earthquakes may occur every 75–100 years in the 410-km-long segment between the Virgin Islands and Guadeloupe.

ten Brink, U.S.; Bakun, W.H.; Flores, C.H.



Historical perspective on seismic hazard in Hispaniola and the NE Caribbean  

NASA Astrophysics Data System (ADS)

We use 500 years of historical earthquake damages reports from Hispaniola, Puerto Rico, and islands to the east to quantitatively constrain the long-term seismic activity and vulnerability of these islands. A training set of instrumentally-recorded earthquakes with damage reports, was used to derive regional relationships between earthquake intensity, magnitude, and distance from the reported damage to the epicenter. The regional relationship in Hispaniola, the Virgin Islands, and the northern Lesser Antilles is similar to that previously derived for California indicating a relatively rapid attenuation of damage intensity with distance. In Puerto Rico, however, we find higher intensities for a given magnitude and distance. These relationships were applied to historical earthquakes with location, magnitude, and errors evaluated quantitatively. The Septentrional Fault in northern Hispaniola appears to have a 306±26 year recurrence interval based on published paleo-seismic evidence for a 1230 AD earthquake and our determination of additional earthquakes in 1562 (MI 7.7± 0.5) and in 1842 (MI 7.6± 0.2). Earthquakes with these magnitudes and recurrence interval are capable of relieving the accumulated slip rate (12.3 mm/y) on the fault, provided that the rupture length is at least 160 km. The recurrence interval is similar to the 310-year recurrence interval for the Enriquillo Fault in southern Hispaniola. Earthquakes in the Puerto Rico Trench appear to be rare, in agreement with the small convergent component of this oblique subduction zone, and they are not very large. We determined an intensity magnitude of MI7.8 for the Ms7.8-8.1 1946 earthquake in the Dominican Republic and a location close to the consequent tsunami. This location is 90 km NW of the epicenter and likely represents the moment centroid. The 1787 earthquake north of Puerto Rico, which previously was assigned M8, is only MI7.2. Considering that damage was only reported from Puerto Rico, where damage from a given magnitude earthquake is greater than in other islands, the moment magnitude of the 1787 earthquake may have been as small as M5.8. Two large historical earthquakes took place in the northern Lesser Antilles in 1690 and 1843, but it is difficult to determine if they occurred on the subduction interface east of the islands or within the arc. Their respective magnitudes would have been MI7.9 and 8.25 if subduction events or MI7.5 and 7.9 if crustal arc events. No events could be unequivocally placed in the Muertos Trough south of Hispaniola and Puerto Rico, where the arc thrusts over the Caribbean plate interior.

ten Brink, U. S.; Bakun, W.; Flores, C. H.



Neotectonics of Hispaniola - Plate motion, sedimentation, and seismicity at a restraining bend  

NASA Technical Reports Server (NTRS)

The question as to the extent to which earthquake mechanisms define plate motion is addressed in view of the pattern of Neogene faulting, volcanism, and sedimentation in Hispaniola. The structure of two fault systems that approximately define the northern and southern coasts of the island suggest an east-west trend in relative plate motion, which is consistent with previous findings. The intervening area consists of en echelon mountain ranges thrust up at the restraining bend from the early Miocene. A Pleistocene volcanic province within this area is interpreted as defining a diffuse extensional fault termination of the southern strike-slip fault zone.

Mann, P.; Matumoto, T.; Burke, K.



Neotectonics of Hispaniola - Plate motion, sedimentation, and seismicity at a restraining bend  

NASA Astrophysics Data System (ADS)

The question as to the extent to which earthquake mechanisms define plate motion is addressed in view of the pattern of Neogene faulting, volcanism, and sedimentation in Hispaniola. The structure of two fault systems that approximately define the northern and southern coasts of the island suggest an east-west trend in relative plate motion, which is consistent with previous findings. The intervening area consists of en echelon mountain ranges thrust up at the restraining bend from the early Miocene. A Pleistocene volcanic province within this area is interpreted as defining a diffuse extensional fault termination of the southern strike-slip fault zone.

Mann, P.; Matumoto, T.; Burke, K.



Morphostructure at the junction between the Beata ridge and the Greater Antilles island arc (offshore Hispaniola southern slope)  

NASA Astrophysics Data System (ADS)

Oblique convergence between the Caribbean plate's interior and the inactive Greater Antilles island arc has resulted in the collision and impingement of the thickened crust of the Beata ridge into southern Hispaniola Island. Deformation resulting from this convergence changes from a low-angle southward-verging thrust south of eastern Hispaniola, to collision and uplift in south-central Hispaniola, and to left-lateral transpression along the Southern peninsula of Haiti in western Hispaniola. Using new swath bathymetry and a dense seismic reflection grid, we mapped the morphological, structural and sedimentological elements of offshore southern Hispaniola. We have identified four morphotectonic provinces: the Dominican sub-basin, the Muertos margin, the Beata ridge and the Haiti sub-basin. The lower slope of the Muertos margin is occupied by the active Muertos thrust belt, which includes several active out-of-sequence thrust faults that, were they to rupture along their entire length, could generate large-magnitude earthquakes. The interaction of the thrust belt with the Beata ridge yields a huge recess and the imbricate system disappears. The upper slope of the Muertos margin shows thick slope deposits where the extensional tectonics and slumping processes predominate. The northern Beata ridge consists of an asymmetrically uplifted and faulted block of oceanic crust. Our results suggest that the shallower structure and morphology of the northern Beata ridge can be mainly explained by a mechanism of extensional unloading from the Upper Cretaceous onward that is still active residually along the summit of the ridge. The tectonic models for the northern Beata ridge involving active reverse strike-slip faults and transpression caused by the oblique convergence between the Beata ridge and the island arc are not supported by the structural interpretation. The eastern Bahoruco slope an old normal fault that acts as a passive tear fault accommodating the sharp along-strike transition from low-angle thrusting to collision and uplifting.

Granja Bruña, J. L.; Carbó-Gorosabel, A.; Llanes Estrada, P.; Muñoz-Martín, A.; ten Brink, U. S.; Gómez Ballesteros, M.; Druet, M.; Pazos, A.



New Evaluation of Seismic Hazard in Cental America and la Hispaniola  

NASA Astrophysics Data System (ADS)

The results from seismic hazard studies carried out in two seismic scenarios, Central America Region (CA) and La Hispaniola Island, are presented here. Both cases follow the Probabilistic Seismic Hazard Assessment (PSHA) methodology and they are developed in terms of PGA, and SA (T), for T of 0.1, 0.2, 0.5, 1 and 2s. In both anaysis, hybrid zonation models are considered, integrated by seismogenic zones and faults where data of slip rate and recurrence time are available. First, we present a new evaluation of seismic hazard in CA, starting with the results of a previous study by Benito et al (2011). Some improvements are now included, such as: updated catalogue till 2011, corrections in the zonning model in particular for subduction regime taken into account the variation of the dip in Costa Rica and Panama, and modelization of some faults as independent units for the hazard estimation. The results allow us to carry out a sensitivity analysis comparing the ones obtained with and without faults. In a second part we present the results of the PSHA in La Hispaniola, carried out as part of the cooperative project SISMO-HAITI supported by UPM and developed in cooperation with ONEV. It started a few months after the 2010 event, as an answer to a required help from the Haitian government to UPM. The study was aimed at obtaining results suitable for seismic design purposes and started with the elaboration of a seismic catalogue for the Hispaniola, requiring an exhaustive revision of data reported by around 30 seismic agencies, apart from these from Puerto Rico and Dominican Republic Seismic Networks. Seismotectonic models for the region were reviewed and a new regional zonation was proposed, taking into account different geophysical data. Attenuation models for subduction and crustal zones were also reviewed and the more suitable were calibrated with data recorded inside the Caribbean plate. As a result of the PSHA, different maps were generated for the quoted parameters, together with the UHS for the main cities in the country. The obtained values for PGA and return peridod of 475 y. are comparable to the ones of the Dominican Republic Building Code, with maximun PGA around 400 cm/s2 (in rock sites). However, the morphology of the map is quite similar to the previous one by Frankel et al (2011), althought ours presents lower PGA values. The results are available as a basis for the the first Haitian building code.

Benito, B.; Camacho, E. I.; Rojas, W.; Climent, A.; Alvarado-Induni, G.; Marroquin, G.; Molina, E.; Talavera, E.; Belizaire, D.; Pierristal, G.; Torres, Y.; Huerfano, V.; Polanco, E.; García, R.; Zevallos, F.



New myrmecomorphous longhorned beetles from Haiti and the Dominican Republic with a key to Anaglyptini and Tillomorphini of Hispaniola (Coleoptera: Cerambycidae: Cerambycinae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

First records of the tribes Anaglyptini and Tillomorphini (Coleoptera: Cerambycidae: Cerambycinae) are documented for Hispaniola. A new genus of highly myrmecomorphic longhorned beetle (Licracantha, new genus) is described and illustrated based on one species (Licracantha formicaria, new species) a...


Accretionary margin of north-western Hispaniola: morphology, structure and development of part of the northern Caribbean plate boundary  

USGS Publications Warehouse

Broad-range side-scan sonar (GLORIA) images and single- and multi-channel seismic reflection profiles demonstrate that the margin of north-western Hispaniola has experienced compression as a consequence of oblique North American-Caribbean plate convergence. Two principal morphological or structural types of accretionary wedges are observed along this margin. The first type is characterized by a gently sloping (???4??) sea floor and generally margin-parallel linear sets of sea-floor ridges that gradually deepen towards the flat Hispaniola Basin floor to the north. The ridges are caused by an internal structure consisting of broad anticlines bounded by thrust faults that dip southwards beneath Hispaniola. Anticlines form at the base of the slope and are eventually sheared and underthrust beneath the slope. In contrast, the second type of accretionary wedge exhibits a steeper (???6-16??) sea-floor slope characterized by local slumping and a more abrupt morphological transition to the adjacent basin. The internal structure appears chaotic on seismic reflection profiles and probably consists of tight folds and closely spaced faults. We suggest that changes in sea-floor declivity and internal structure may result from variations in the dip or frictional resistance of the de??collement, or possibly from changes in the cohesive strength of the wedge sediments. The observed pattern of thickening of Hispaniola Basin turbidites towards the insular margin suggests differential southwards tilting of the Hispaniola Basin strata, probably in response to North America-Caribbean plate interactions since the Early Tertiary. Based upon indirect age control from adjacent parts of the northern caribbean plate boundary, we infer a Late Eocene to Early Miocene episode of transcurrent motion (i.e. little or no tilting), an Early Miocene to Late Pliocene period of oblique convergence (i.e. increased tilt) during which the accretionary wedge began to be constructed, and a Late Pliocene to Recent episode of increased convergence (i.e. twice the Miocene to Pliocene tilt), which has led to rapid uplift and erosion of sediment sources on the margin and on Hispaniola, generating a submarine fan at the base of the insular slope. ?? 1992.

Dillon, William P.; Austin, J.A., Jr.; Scanlon, K.M.; Terence, Edgar N.; Parson, L.M.



Frequency-dependent attenuation of the Hispaniola Island region of the Caribbean Sea  

USGS Publications Warehouse

We determine frequency-dependent attenuation 1/Q(f) for the Hispaniola region using direct S and Lg waves over five distinct passbands from 0.5 to 16 Hz. Data consist of 832 high-quality vertical and horizontal component waveforms recorded on short-period and broadband seismometers from the devastating 12 January 2010 M 7.0 Haiti earthquake and the rich sequence of aftershocks. For the distance range 250–700 km, we estimate an average frequency-dependent Q(f)=224(±27)f0.64(±0.073) using horizontal components of motion and note that Q(f) estimated with Lg at regional distances is very consistent across vertical and horizontal components. We also determine a Q(f)=142(±21)f0.71(±0.11) for direct S waves at local distances, ?100 km. The strong attenuation observed on both vertical and horizontal components of motion is consistent with expectations for a tectonically active region.

McNamara, D.; Meremonte, M.; Maharrey, J.Z.; Mildore, S-L.; Altidore, J.R.; Anglade, D.; Hough, S.E.; Given, D.; Benz, H.; Gee, L.; Frankel, A.



Significant earthquakes on the Enriquillo fault system, Hispaniola, 1500-2010  

NASA Astrophysics Data System (ADS)

Although the 2010 Haiti earthquake came as a surprise to many, historical records indicate frequent seismic activity along the northeast Caribbean plate boundary over the past 500 years, particularly on the island of Hispaniola. Here we show that a series of devastating earthquakes on the Enriquillo fault system in the 18th century started with an intensity magnitude (MI) of 6.8 earthquake in 1701 near the location of the 2010 Haiti earthquake and that the accounts of the shaking in the 1701 earthquake are similar to those of the 2010 earthquake. A series of large earthquakes migrating from east to west started with the October 18, 1751 MI7.6 earthquake near the eastern end of the fault in the Dominican Republic, followed by the November 21, 1751 MI6.7 earthquake near Port-au-Prince, Haiti, and the June 3, 1770 MI7.7 earthquake west of the 2010 earthquake rupture. We associate no other significant events since 1500 with the Enriquillo fault system. The 2010 Haiti earthquake may mark the beginning of a new cycle of large earthquakes on the Enriquillo fault system after 240 years of quiescence. Future devastating earthquakes should be expected.

Bakun, W.; Flores, C. H.; ten Brink, U. S.



Plate boundary readjustment in oblique convergence: Example of the Neogene of Hispaniola, Greater Antilles  

NASA Astrophysics Data System (ADS)

The Haitian fold-and-thrust belt is the major mountain belt of Haiti (western part of Hispaniola, Greater Antilles) and resembles a compressive restraining bend between the two major faults which have driven the opening of the Cayman Basin since the Eocene. During the rifting stage, from the middle to the late Eocene, this area underwent an extensional evolution with fissural volcanic activity along NE-SW tilted blocks. The Haitian fold-and-thrust belt was constructed from the Early Miocene until the Present by stacking sedimentary units into a collisional wedge perpendicular to the tilted blocks, which was propagating to the southwest. During the construction of the wedge, piggyback basins were formed and progressively uplifted. During the late Neogene, convergence is localized in the Cul-de-Sac-Enriquillo trough where the active front proceeds southward onto the Beata ridge. In this area, Miocene to Quaternary wrench structures of the lower plate, like the Southern Peninsula and the Enriquillo-Plantain Garden faults, are reactivated as normal faults, owing to the loading of the fold-and-thrust belt.

Pubellier, Manuel; Mauffret, Alain; Leroy, Sylvie; Vila, Jean Marie; Amilcar, Helliot



Investigating the relationship between deforestation and changes in hydrology across the island of Hispaniola  

NASA Astrophysics Data System (ADS)

Over recent decades, Haiti and the Dominican Republic have reported changes in reservoir water levels - while some areas have experienced increases others have seen decreasing trends, especially reservoirs located in the Dominican Republic - leading to, among other things, regional flooding and shortages in hydroelectricity output. We investigate whether extensive deforestation, particularly in the western part of Hispaniola - shared by the two nations - is driving these changes by affecting the regional water balance. Due to a lack of available spatiotemporal environmental data, remotely sensed vegetation and precipitation information is used along with estimated evapotranspiration rates to study regional hydro-climatologic fluctuations over three decades. Changes in vegetative cover, precipitation, and evapotranspiration across the island are investigated using 25 years of Normalized Difference Vegetation Index (NDVI) data, historical satellite and gauge precipitation records, and estimated surface temperature and solar radiation. NDVI values are derived from imagery obtained by NOAA's 8 km resolution AVHRR instrument. Monthly precipitation is collected from several different sources, including NASA and NOAA precipitation satellites, as well as local rain gauges. Evapotranspiration is estimated using an energy balance approach. Preliminary results indicate a general decrease in rainfall over the eastern part of the island during the past three decades, with little change observed across the western half. NDVI and precipitation anomalies across the island are not well correlated, suggesting that deforestation is likely not the cause of regional changes in precipitation. The results of this work hold potentially important implications for future land-use and water infrastructure planning for both nations.

Hakimdavar, R.



Paleoseismology in the Caribbean: A Review of Studies in Hispaniola, Puerto Rico and Trinidad  

NASA Astrophysics Data System (ADS)

We have applied paleoseismic techniques to the study of faults on three of the islands in the Caribbean region: Hispaniola, Puerto Rico, and Trinidad. The Septentrional fault zone (SFZ) is the major North American-Caribbean plate-boundary fault in Hispaniola, where it traverses the densely populated and rapidly developing Cibao Valley in northern Dominican Republic. Our studies show that the most recent ground rupture on the SFZ east of Santiago, in the central part of the valley, occurred about 800 years ago, and was associated with a minimum of about 4 m of left-lateral strike-slip displacement. The penultimate event occurred after AD30, suggesting a recurrence interval of 800 to 1200 years. Studies of offset Holocene stream terraces suggest a SFZ slip rate of 6-12 mm/yr, indicating that this structure accommodates about half of the geodetically determined total plate-boundary motion of approximately 19 mm/yr. These paleoseismic data suggest that the seismic hazard associated with the SFZ is high. The major structures of the North American-Caribbean plate boundary are offshore north of Puerto Rico. However, the location of the island within the plate-boundary zone suggests the possibility of onshore Holocene faults, though no faults with Holocene displacement have previously been documented on the island, and current seismic hazard assessments only consider the impact of distant, offshore seismic sources. Our mapping and paleoseismic studies demonstrate that repeated Holocene surface rupture has occurred on a previously unrecognized fault in the Lajas Valley of southwestern Puerto Rico. We identified an approximately east-west trending scarp crossing an alluvial fan on the southern side of the Lajas Valley. A 1.5-meter-deep trench that we excavated exposed two narrow fault zones, about 1m apart, disrupting the alluvial deposits. Structural relations indicate valley-side-down fault slip, with a component of strike-slip motion, though we could not determine whether the horizontal displacement is right or left lateral. The two fault zones terminate at different stratigraphic horizons, indicating at least two surface-rupturing events. Radiocarbon analyses of samples collected from the sediments show that these two earthquakes occurred during the past 7500 years. The earlier event occurred between 5650 and 7550 Cal. yr. B.P. The younger event occurred post 5040 Cal. yr. B.P., but no minimum age has yet been established. Trinidad is located along the transform plate boundary between the South American and Caribbean plates. Analysis and comparison of historic triangulation and GPS data suggest that a significant fraction (14+/-3 mm/yr) of the total plate-boundary motion (about 20 mm/yr) is being accommodated across the Central Range Fault in central Trinidad. Geomorphic evidence of Quaternary faulting along the Central Range Fault includes linear drainages, aligned topographic saddles and troughs, offset ridges, right-laterally deflected streams, and linear scarps, supporting the geodetic evidence for youthful fault slip. We exposed a 6-m-wide shear zone within Pliocene(?) material in a trench cut into a fluvial terrace across the Central Range Fault. The overlying Holocene fluvial gravel is faulted and folded across the shear zone, and Holocene fluvial deposits are faulted against the shear zone on the north side. Our paleoseismic studies demonstrate that surface rupture has occurred within the past 4500 years on this previously unrecognized, active fault.

Prentice, C. S.; Mann, P.; Weber, J.; Crosby, C.



Historical perspective on Caribbean seismic hazard, ten Brink, Bakun, Flores Historical perspective on seismic hazard to Hispaniola and the northeast Caribbean  

E-print Network

interval on the central Septentrional Fault is ~300 years, and only 170 years has elapsed since the last on seismic hazard to Hispaniola and the northeast Caribbean region Uri S. ten Brink1* , William H. Bakun2-American/Caribbean plate boundary from 500 years of historical earthquake damage reports. The 2010 Haiti earthquakes

ten Brink, Uri S.


New records of Caribbomerus from Hispaniola with redescription of C. elongatus (Fisher) and a key to the genus in the West Indies (Coleoptera: Cerambycidae: Cerambycinae: Graciliini)  

Technology Transfer Automated Retrieval System (TEKTRAN)

Three species of Caribbomerus Vitali are newly recorded for the Dominican Republic: C. decoratus (Zayas), C. elongatus (Fisher), and C. asperatus (Fisher). The first two also represent first records for Hispaniola. Caribbomerus elongatus (Fisher) is redescribed based on additional material, includi...


Tree-based delimitation of morphologically ambiguous taxa: A study of the lizard malaria parasites on the Caribbean island of Hispaniola q  

E-print Network

Tree-based delimitation of morphologically ambiguous taxa: A study of the lizard malaria parasites from the Caribbean island of Hispaniola. All six infect lizards in the genus Anolis, but only two for blood parasites from 677 Anolis lizards, representing 26 Anolis spp. from a total of 52 sites across

Mahler, D. Luke


On the role of the Beata Ridge in the structure of southern Hispaniola: new constrains from the correlation between offshore and onshore structures  

NASA Astrophysics Data System (ADS)

The Beata Ridge is a thickened aseismic crust block that forms a NNE-SSW trending bathymetric high located in the interior of the Caribbean Large Igneous Province (CLIP). This ridge is impinging into the Greater Antilles island arc in south-central Hispaniola Island. The impingement has resulted into the following main consequences for the southern region of Hispaniola: uplifting and accretion of part of the CLIP to the island arc, an associated localized strain partitioning and a sharp structural change between both sides of the ridge, with frontal thrusting in the Los Muertos convergent margin (to the east) against dominant left-lateral strike-slip tectonics in the Enriquillo-Plantain Garden fault zone (to the west). Two hypotheses have been suggested to explain the impingement as a result of: 1) the continuous motion of the aseismic ridge toward the NE against the Greater Antilles, at least from the Miocene; or 2) the thickened ridge acting as a fixed obstacle in the foreland area impeding the overthrusting of the island arc over the Caribbean plateau. Several works have tried to restore the situation prior to the impingement of the Beata Ridge into the island arc and to correlate the tectonic units observed on both sides of the region of impingement: the offshore imbricate structures observed in Los Muertos convergent margin with the onshore Peralta fold-and-thrust belt and/or the E-W transcurrent Enriquillo fault system in southern Hispaniola. However as a result of the huge lateral and vertical offset caused by the impingement of the aseismic ridge there is not a tectonic model which can successfully explain this transition. A detailed interpretation of the deep and shallow structure of western Los Muertos convergent margin and northern Beata Ridge has been made using the new data obtained from the CARIBENORTE research cruise carried out in the spring of 2009 in the southern insular slope of Hispaniola. On the other hand a complete geothematic survey of the whole Dominican Republic funded by the EU Sysmin Program has been recently performed including (among others) a detailed 1:50.000 geological and 1:100.000 geomorphological and active processes mappings. The integration and correlation of the onshore and offshore structural data of southern Hispaniola presented here provides valuable information to constrain and evaluate the consequences of the impingement of the Beata Ridge into the island arc and to help understand how the present day sharp transition between frontal thrusting and strike-slip tectonics may take place. These results can be further implemented into the evaluation and assessment of seismic hazard in the densely populated Hispaniola island, and especially, the eastern termination of the Enriquillo-fault zone, that in Haiti was responsible for the deadly event on 12 January 2010.

Granja Bruña, J.; Hernaiz-Huerta, P.; Carbó-Gorosabel, A.; Llanes Estrada, M.; Pérez-Valera, F.; Abad, M.; Gómez Ballesteros, M.; Druet, M.; Munoz Martin, A.; Martín-Dávila, J.; Pazos, A.; Catalan, M.; ten Brink, U. S.



Influence of salinity and temperature on the physiology of Limia melanonotata (Cyprinodontiformes: Poeciliidae): A search for abiotic factors limiting insular distribution in Hispaniola  

USGS Publications Warehouse

We investigated salinity and temperature effects on routine metabolic rate (RMR), temperature tolerance (CTMax, critical thermal maximum), and salinity tolerance of Limia melanonotata, a poecliid fish that occurs in west-central inland waters of Hispaniola. Routine metabolic rate and CTMax were measured in fish acclimated to three salinities (0, 30, and 60 ppt) and temperatures (25??, 30??, and 35??C) for nine temperature-salinity combinations. Salinity and temperature did not significantly interact in their effect on RMR. For combined salinity acclimations, adjusted RMR (ANCOVA) was significantly lower at 25??C than either 30?? or 35??C. For combined temperature acclimations, mean RMR was significantly lower at 60 ppt than either 0 or 30 ppt. Salinity and temperature had a significant interactive effect on temperature tolerance. Mean CTMax was significantly higher at 30?? than 25??C at all salinities, but at 35??C was significantly higher than at 25?? or 30??C only among fish acclimated in fresh water. Fish exposed to a chronic increase in salinity experienced most mortality in a salinity range of 70-107 ppt, with females exhibiting greater salinity tolerance than males. Limia melanonotata approaches the upper extreme in salinity and temperature tolerances known for poeciliids. Our results also suggest that L. melanonotata may reduce energy expenditures at environmental extremes to tolerate harsh conditions for extended periods. Despite its curythermal and euryhaline adaptations, L. melanonotata has a relatively restricted inland range in Hispaniola and is unknown from inshore brackish or marine habitats. The present distribution of this species and congeners may be the result of a combination of factors that include historical zoogeography and ecological requirements.

Haney, D.C.; Walsh, S.J.



Potential fields and seismicity at northern La Hispaniola Island: useful constraints to determine the crustal structure of an oblique convergence area  

NASA Astrophysics Data System (ADS)

The interpretation of aeromagnetic and gravity data together with petrophysical analysis allow characterize the tectonic domains and the determination of the crustal structure up to Moho levels. In order to compare the crustal structure deduced from the potential fields with the seismicity, a set of earthquakes events from the USGS database have been studied (hypocenters shallower than 40 km and magnitude greater than 3.5). This study is focused on the northern part of the La Hispaniola Island, where an oblique subduction and strike-slip collision is taking place since the Mesozoic. The Septentrional Fault Zone (SFZ), an almost WNW-ESE directed strike slip fault, is bounded by a set of earthquakes up to 6 in magnitude whose hypocenter is located from 20 to 30 km in depth, with some deeper events (up to 40 km) in places. Northward of this fault zone, there is an area of mainly shallower hypocenters (up to 20 km) characterized by events of comparatively higher magnitude (up to 7) that deepen slightly again towards offshore where the range of depths is 0 to 30 km clustering around what is believed to be the subduction zone. The Bouguer anomaly shows a sharp gradient that separates the Cibao Valley to the south, characterized by an elongated minimum, from the accretionary prism (Mamey group and Puerto Plata-Rio San Juan Complex) to the north, characterized by a set of relative maxima and minima of higher intensity. Moreover, the accretionary prism presents a well defined magnetic zonation over the Mamey Group and the igneous-metamorphic complexes of Puerto Plata and Rio San Juan. In this area, magnetic anomalies are an order of magnitude higher than in the Cibao Valley, where the magnetic fabric is rather uniform with the exception of three prominent anomalies that can be associated to igneous rocks emplaced to the northern border of La Hispaniola Fault Zone. The Camú Fault, that separates Mamey Group from Puerto Plata Complex, constitutes another clear magnetic boundary, whereas it is not so clear in terms of seismicity or gravity. The potential field data together with the location of the epicentre and hypocenter of the earthquakes helps to define the upper boundary of the subducting slab at cortical levels and the geometry of the accretionary prism, specially the igneous-metamorphic complexes of Puerto Plata and Rio San Juan.

Ayala, C.; García-Lobón, J. L.; Rey Moral, C.; Escuder-Viruete, J.



The genus Leptostylopsis of Hispaniola (Coleoptera: Cerambycidae: Acanthocinini)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The generic differences and similarities between Leptostylus LeConte and Leptostylopsis Dillon (Coleoptera: Cerambycidae: Acanthocinini) are discussed. Leptostylopsis is redescribed and the following species are transferred from Leptostylus to Leptostylopsis: Leptostylopsis annulipes (Fisher 1942)...


Three new phylogenetic and biological Neurospora species: N. hispaniola, N. metzenbergii and N. perkinsii  

E-print Network

by repro- ductive isolation as determined by biological species recognition (BSR) and geographic. crassa and N. intermedia isolates that were either not clearly assignable to species by BSR using tester investigated reproductive isolation with BSR in PS1­3 and the two other most closely related species, N


Historical perspective on seismic hazard to Hispaniola and the northeast Caribbean region  

E-print Network

. If so, the recurrence interval on the central Septentrional Fault is $300 years, and only 170 years has. ten Brink,1 William H. Bakun,2 and Claudia H. Flores1 Received 29 April 2011; revised 7 October 2011 of the North-American/Caribbean plate boundary from 500 years of historical earthquake damage reports. The 2010

ten Brink, Uri S.


Copeia,1988(3),pp. 636-641 A New Diminutive Frog from Hispaniola  

E-print Network

sexed by gonadal examination. Institutional abbreviations are as listed in Leviton et al., 1985 on W end of Pic Macaya ridge, 2310-2320 m; UF-FSU 64209-10, basin N of west end of Morne Ma- caya ridge-71, S slope Morne Formon ridge, 2100 m; UF-FSU 64393,64571- 72, ridge near campsite at Pic Formon, 2130- 2270

Hedges, Blair


A new species of Derancistrus (Coleoptera: Cerambycidae: Prioninae) from Dominican Republic with notes on other species of Prioninae of Hispaniola  

Technology Transfer Automated Retrieval System (TEKTRAN)

Derancistrus hovorei is described from Dominican Republic. A diagnosis is provided to discriminate it from related taxa, in particular Derancistrodes vittatus (Olivier) and Derancistrus elegans (Palisot de Beauvois). Biological, distributional, and/or taxonomic notes are provided for other Hispani...


Seven New Species of Elaphidiini (Coleoptera: Cerambycidae) from the Dominican Republic with Taxonomic Notes, New Country Records, and a Key to Elaphidion Audinet-Serville from Hispaniola  

Technology Transfer Automated Retrieval System (TEKTRAN)

Seven new species, two new combinations, two new synonyms, and four new country records of Elaphidiini longhorned woodborers (Coleoptera: Cerambycidae) from the Dominican Republic are presented. Elaphidion compressipenne Fisher is transferred to Ceresium Newman as C. compressipenne (Fisher), new c...


The effect of sociocultural factors on the quality of relations of the United States with Hispaniola: analysis of the American military occupation of Haiti and the Dominican Republic (1915-1934)  

E-print Network

of Haiti and the Dominican Republic (1915-1934). (May 1988) Fausto B. Alvarez, B. S. , Texas A&M University Chairperson of Advisory Committee: Dr. James H. Copp In this thesis, a 1922 United States congressional record was analyzed to examine.... Barbara Finlay, from whom I have learned important human values; and to my children Michelle, Fausto David, and Michael Alexander, who provide me with reasons for developing my human potential. TABLE OF CONTENTS Page ABSTRACT ACKNOWLEDGEMENTS...

Alvarez, Fausto B.



Magmatic relationships and ages between adakites, magnesian andesites and Nb-enriched basalt-andesites from Hispaniola: Record of a major change in the Caribbean island arc magma sources  

NASA Astrophysics Data System (ADS)

Located in the Cordillera Central of the Dominican Republic, the Late Cretaceous Tireo Fm (TF) records a major change of the magma sources in the Caribbean island arc. It comprises a > 3 km thick sequence of arc-related volcanic and volcano-sedimentary rocks with variable geochemical characteristics. Combined detailed mapping, stratigraphy, geochemistry and U-Pb/Ar-Ar geochronology show that the volcanic rocks of the Tireo Fm include two main volcanic sequences. The lower volcanic sequence is dominated by monotonous submarine vitric-lithic tuffs and volcanic breccias of andesite to basaltic andesite, with minor interbedded flows of basalts and andesites. Fossil and (U-Pb and 40Ar- 39Ar) geochronological data show that arc magmatism in the lower sequence began to accumulate before ˜ 90 Ma, from the Aptian to Turonian. These rocks constitute an island arc tholeiitic suite, derived from melting by fluxing of a mantle wedge with subduction-related hydrous fluids. The upper volcanic sequence is characterized by a spatial and temporal association of adakites, high-Mg andesites, and Nb-enriched basalts, which collectivelly define a shift in the composition of the subduction-related erupted lavas. A dacitic to rhyolitic explosive volcanism with subaerial and episodic aerial eruptions, and sub-volcanic emplacements of domes, characterize mainly this stratigraphic interval. The onset of this volcanism took place at Turonian-Coniacian boundary and continued in the Santonian to Lower Campanian, with minor events in the Late Campanian. Adakites represent melts of the subducting slab, magnesian andesites the product of hybridization of adakite liquids with mantle peridotite, and Nb-enriched basalts melts of the residue from hybridization. We propose a model of oblique ridge subduction at ˜ 90 Ma and possibly subsequent slab window formation, as principal cause of magmatic variations recorded in the Caribbean island arc, above a southwestern-dipping subduction zone.

Escuder Viruete, J.; Contreras, F.; Stein, G.; Urien, P.; Joubert, M.; Pérez-Estaún, A.; Friedman, R.; Ullrich, T.



An extinct monkey from Haiti and the origins of the Greater Antillean primates  

E-print Network

primate dentition yet recorded, demonstrating the likely coexistence of two primate species on Hispaniola 114714 (Florida Museum of Natural History) is a nearly complete dentition including a dP4, examples

Rosenberger, Alfred H.


The Life of Hurricane Irene from Caribbean to Canada - Duration: 1:30.  

NASA Video Gallery

An animation of satellite observations from August 21 through August 29 showing the birth of Hurricane Irene in the Caribbean and her track over Puerto Rico, Hispaniola, the Bahamas, the U.S. East ...


Satellite Movie Shows Bertha Becoming Second Atlantic Hurricane - Duration: 0:48.  

NASA Video Gallery

This animation of NOAA's GOES-East satellite imagery from August 2 through 4 shows the movement of Tropical Storm Bertha over Puerto Rico, Hispaniola and the Bahamas. It became a hurricane on Augus...




... including portions of Central and South America, Hispaniola (Haiti and the Dominican Republic), Africa, Eastern Europe, Southeast ... to parts of Central America, the Dominican Republic, Haiti or some areas of the Middle East, your ...


75 FR 20849 - Notice of Agreements Filed  

Federal Register 2010, 2011, 2012, 2013, 2014

...010977-063. Title: Hispaniola Discussion Agreement. Parties: Crowley Liner Services and Seaboard Marine Ltd. Filing Party: Wayne...America Discussion Agreement. Parties: APL Co. PTE Ltd.; Crowley Latin America Services, LLC.; Dole Ocean Cargo...



Sweet drinks are made of this: Conservation genetics of an endemic palm species from the Dominican Republic  

Technology Transfer Automated Retrieval System (TEKTRAN)

Pseudophoenix ekmanii is a threatened palm species restricted to the Parque Nacional of Jaragua in the southernmost region of Hispaniola. Sap from individual trees is commonly extracted to make a local drink; once they are tapped the plant usually dies. Additionally, adult plants are harvested for...


Establishment of the west indian fruit fly (Diptera: Tephritidae) parasitoid Doryctobracon areolatus (Hymenoptera: Braconidae)in the Dominican Republic  

Technology Transfer Automated Retrieval System (TEKTRAN)

The West Indian fruit fly, Anastrepha obliqua (Macquart), infests numerous fruit species, particularly Anacardiaceae and most importantly mango (Mangifera indica L.). Widespread in the Neotropics, it was first reported in Hispaniola nearly 70 years ago. Continental populations are attacked by the op...


Hispaniolan Hemilophini (Coleoptera: Cerambycidae: Lamiinae)  

Technology Transfer Automated Retrieval System (TEKTRAN)

The Tribe Hemilophini (Lamiinae) is reviewed for Hispaniola and an identification key is provided. Fifteen species are now known from the island, including one new species of Adesmus (A. fortunei from La Vega Province, Dominican Republic), one new species of Oedudes (O. anulatus from Peravia and La...


Historical occurrence and distribution of humpback whales in the eastern and southern Caribbean Sea, based on data from American whaling logbooks  

Microsoft Academic Search

The best-known present-day wintering areas for the North Atlantic population of humpback whales ( Megaptera novaeangliae) are in the northern West Indies, notably off the island of Hispaniola. However, it is known that in the nineteenth century American whaler s hunted humpbacks in the Windward Islands (primarily from Guadeloupe southwards), along the coast of Trinidad, in the Gulf of Paria

Randall R. Reeves; Steven L. Swartz; Sara E. Wetmore; Phillip J. Clapham



Conservation and management of the American crocodile  

Microsoft Academic Search

The American crocodile is a rare and endangered species, the range of which has contracted to disjunct locations such as Hispaniola, Jamaica, Cuba, Panama, and southern Florida. In an attempt to determine what factors might be limiting population growth, an extensive collaborative research program was conducted in 1978–82 in southern Florida. Limiting factors explicitly studied included climate, hurricanes, population dispersion,

James A. Kushlan



Phytologia (April 2008) 90(1) 103 THE EVOLUTION OF CARIBBEAN JUNIPERUS  

E-print Network

; J. lucayana from Cuba, Haiti, Jamaica and the Bahamas; J. gracilior Pilger from Haiti and Dominican Republic; J. ekmanii Florin from Haiti; and J. urbaniana Pilger & Ekman from Haiti. Carabia (1941, Cuba, Jamaica, likely extinct in Haiti), J. gracilior (endemic to Hispaniola), J. gracilior var

Adams, Robert P.


NASA Imagery of Haiti  

NSDL National Science Digital Library

This page includes a collection of NASA images surrounding the Haiti Earthquake. Images include landslide risk maps, photos from the Terra Spacecraft, post-earthquake Port au Prince, Hispaniola topography map, anaglyph (3-D) map of southern Haiti, and 3-D topography of Port au Prince.



Discussion Problem Solutions D1. A good example would involve something that is equally likely to occur on each day  

E-print Network

be skewed right because some countries, such as the United States, have a per capita income that is much should occur less frequently in February. Another possible example is the number of bills paid each day is strongly skewed right. Most islands are quite small; Cuba and Hispaniola are comparatively very large

D'Orsogna, Maria Rita


Oblique collision in the northeastern Caribbean from GPS measurements and geological observations  

NASA Astrophysics Data System (ADS)

Previous Caribbean GPS studies have shown that the rigid interior of the Caribbean plate is moving east-northeastward (070°) at a rate of 18-20 ± 3 mm/yr relative to North America. This direction implies maximum oblique convergence between the island of Hispaniola on the Caribbean plate and the 22-27-km-thick crust of the Bahama carbonate platform on the adjacent North America plate. We present a tectonic interpretation of a 15-site GPS network which spans the Hispaniola-Bahama oblique collision zone and includes stable plate interior sites on both the North America and Caribbean plates. Measurements span the time period of 1994-1999. In a North America reference frame, GPS velocities in Puerto Rico, St. Croix, and the Lesser Antilles indicate that these areas move as a single block in an east-northeast direction (070°) at a rate of 19-20 mm/yr consistent with the movement of the rigid interior of the Caribbean plate. GPS velocities at six sites in central and eastern Hispaniola (Dominican Republic) show drastically different behavior with more eastwardly strikes (080°) and much slower rates (4-17 mm/yr) than areas of the stable Caribbean plate. The boundary between the relatively slower-moving Hispaniola collisional zone and the relatively faster-moving, uncollided Puerto Rico-Virgin Islands area is the Mona Passage where late Neogene rifting occurs in a broad zone. Elastic modeling favors strain partitioning with oblique slip on the outer, low-angle submarine thrust faults (North Hispaniola, Muertos) and strike slip on the inner, subvertical subaerial, strike-slip faults (Septentrional, Enriquillo).

Mann, Paul; Calais, Eric; Ruegg, Jean-Claude; Demets, Charles; Jansma, Pamela E.; Mattioli, Glen S.



Tsunamis triggered by the 12 January 2010 Earthquake in Haiti  

NASA Astrophysics Data System (ADS)

On 12 January 2010 a magnitude Mw 7.0 earthquake occurred 25 km west-southwest of Haiti’s Capital of Port-au-Prince, which resulted in more than 230,000 fatalities. In addition tsunami waves triggered by the earthquake caused at least 3 fatalities at Petit Paradis. Unfortunately, the people of Haiti had neither ancestral knowledge nor educational awareness of tsunami hazards despite the 1946 Dominican Republic tsunami at Hispaniola’s northeast coast. In sharp contrast Sri Lankan UN-soldiers on duty at Jacmel self-evacuated given the memory of the 2004 Indian Ocean tsunami. The International Tsunami Survey Team (ITST) documented flow depths, runup heights, inundation distances, sediment deposition, damage patterns at various scales, and performance of the man-made infrastructure and impact on the natural environment. The 31 January to 7 February 2010 ITST covered the greater Bay of Port-au-Prince and more than 100 km of Hispaniola’s south coast between Pedernales, Dominican Republic and Jacmel, Haiti. The Hispaniola survey data includes more than 20 runup and flow depth measurements. The tsunami impacts peaked with maximum flow depths exceeding 3 m both at Petit Paradis inside the Bay of Grand Goâve located 45 km west-southwest of Port-au-Prince and at Jacmel on Haiti’s south coast. A significant variation in tsunami impact was observed on Hispaniola and tsunami runup of more than 1 m was still observed at Pedernales in the Dominican Republic. Jacmel, which is near the center of the south coast, represents an unfortunate example of a village and harbor that was located for protection from storm waves but is vulnerable to tsunami waves with runup doubling from the entrance to the head of the bay. Inundation and damage was limited to less than 100 m inland at both Jacmel and Petit Paradis. Differences in wave period were documented between the tsunami waves at Petit Paradis and Jacmel. The Petit Paradis tsunami is attributed to a coastal submarine landslide. Field observations, video recordings, satellite imagery and numerical modelling are presented. The team interviewed numerous eyewitnesses and educated residents about the tsunami hazard. Community-based education and awareness programs are essential to save lives in locales at risk from locally generated tsunamis. Petit Paradis landslide scar with tree located 70m offshore

Fritz, H. M.; Hillaire, J. V.; Molière, E.; Mohammed, F.; Wei, Y.



Morphology, structure, and tectonic evolution of the Mona canyon (northern Mona passage) from multibeam bathymetry, side-scan sonar, and seismic reflection profiles  

NASA Astrophysics Data System (ADS)

The submarine Mona Canyon is a rift between Puerto Rico and Hispaniola of the Greater Antilles. An integrated marine geophysical data set, including multibeam bathymetry, side-scan sonar imagery, single channel and multichannel seismic reflection profiles is used to evaluate the morphology, structure, and tectonic evolution of the Mona Canyon. A structural restoration of the central Mona canyon indicates that extension in the rift initiated in the Middle Oligocene, approximately 30 Ma. A minimum total extension of 6.1 km and a minimum longitudinal strain of 11.4% across the central Mona canyon are calculated. The overall extension is proposed to have occurred over two phases. Phase I occurred from the Middle Oligocene to Late Miocene, and was a slow (0.09 mm/yr) stage of at least 1.7 km of opening. Phase II was most likely controlled by the impact of the subducted southeast portion of the Bahamas platform beneath the northeastern Caribbean plate margin. Phase II was a more rapid (0.4 mm/yr) stage of extension of at least 4.4 km that occurred from the Late Pliocene to the Recent as the SE Bahamas collision warped the middle and upper slope of the northern Puerto Rico margin along its advancing path and slowed the eastward movement of Hispaniola relative to Puerto Rico. The upper reaches of the Mona canyon form the trailing edge of the Puerto Rico-Virgin Islands block as it pulls away from a pinned Hispaniola. The Mona reentrant marks the trailing edge of a northern Hispaniola forearc sliver that forms due to increased coupling between the subducting North America plate and the overriding plate.

Mondziel, Steven; Grindlay, Nancy; Mann, Paul; Escalona, Alejandro; Abrams, Lewis



Plant mites of the Dominican Republic, with a description of a new species of Petrobia (Tetranychina) Wainstein, 1960 (Acari, Prostigmata, Tetranychidae) and a key to the species of this subgenus.  


Fourteen mite species of plant-associated mites of the suborder Prostigmata are reported from the Dominican Republic. Four of these refer to new findings for the country, including Petrobia (Tetranychina) hispaniola n. sp. Sánchez & Flechtmann, described from specimens collected from leaves of Citrus sp. (Rutaceae) and Rosa sp. (Rosaceae). A key for the separation of the world species of Petrobia (Tetranychina) is presented.  PMID:25112265

Martínez, Leocadia Sánchez; Flechtmann, Carlos H W; De Moraes, Gilberto J



Actively evolving microplate formation by oblique collision and sideways motion along strike-slip faults: An example from the northeastern Caribbean plate margin  

Microsoft Academic Search

The pattern of folding, faulting, and late Quaternary coral-reef uplift rates in western and central Hispaniola (Haiti and Dominican Republic) suggest that the elongate Gonave microplate, a 190,000-km2 area of the northeastern Caribbean plate, is in the process of shearing off the Caribbean plate and accreting to the North American plate. Late Cenozoic transpression between the southeastern Bahama Platform and

Paul Mann; F. W. Taylor; R. Lawrence Edwards; Teh-Lung Ku



Neotectonics of Puerto Rico and the Virgin Islands, northeastern Caribbean, from GPS geodesy  

Microsoft Academic Search

The boundary between the North American and Caribbean plates is characterized primarily by left-lateral motion along predominantly east-west striking faults. Seismicity and marine geophysical survey data are consistent with at least two, and possibly three, microplates in the diffuse boundary zone in the northeastern Caribbean: (1) the Gonave, (2) the Hispaniola, and (3) the Puerto Rico-northern Virgin Islands (PRVI). We

Pamela E. Jansma; Glen S. Mattioli; Alberto Lopez; Charles DeMets; Timothy H. Dixon; Paul Mann; Eric Calais



Cholera in the United States, 2001-2011: a reflection of patterns of global epidemiology and travel.  


SUMMARY US cholera surveillance offers insight into global and domestic trends. Between 2001 and 2011, 111 cases were reported to the Centers for Disease Control and Prevention. Cholera was associated with international travel in 90 (81%) patients and was domestically acquired in 20 (18%) patients; for one patient, information was not available. From January 2001 to October 2010, the 42 (47%) travel-associated cases were associated with travel to Asia. In October 2010, a cholera epidemic started in Haiti, soon spreading to the Dominican Republic (Hispaniola). From then to December 2011, 40 (83%) of the 48 travel-associated cases were associated with travel to Hispaniola. Of 20 patients who acquired cholera domestically, 17 (85%) reported seafood consumption; 10 (59%) ate seafood from the US Gulf Coast. In summary, an increase in travel-associated US cholera cases was associated with epidemic cholera in Hispaniola in 2010-2011. Travel to Asia and consumption of Gulf Coast seafood remained important sources of US cholera cases. PMID:24865664

Loharikar, A; Newton, A E; Stroika, S; Freeman, M; Greene, K D; Parsons, M B; Bopp, C; Talkington, D; Mintz, E D; Mahon, B E



Late Cenozoic alkaline volcanism in the northwestern Caribbean - Tectonic setting and Sr isotopic characteristics  

NASA Technical Reports Server (NTRS)

The northwestern corner of the Caribbean plate has at least sixteen centers of alkalic volcanism, most of which is Quaternary in age. Sr-87/Sr-86 ratios of the rocks in these centers are used to distinguish three geographical groups: a low-ratio group (0.7026-0.7031) at the Nicaraguan Rise, an intermediate-ratio group (0.7036-0.7038) in northeastern Costa Rica, and a high-ratio group (0.7047-0.7063) in Hispaniola. It is suggested that the increased radiogenic strontium in both Costa Rica and Hispaniola may have come from volatile-rich fluids escaping from adjacent subducting slabs of oceanic crust. The isotopic differences between the two areas is explained by the relative longevity and high rate of subduction in Costa Rica compared to that in Hispaniola. The Costa Rican alkaline rocks cover a segment of the Cocos plate which is being subducted at a smaller angle (about 35 deg) than at the rest of the Central American arc.

Wadge, G.; Wooden, J. L.



Relative motion between the Caribbean and North American plates and related boundary zone deformation from a decade of GPS observations  

NASA Astrophysics Data System (ADS)

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.

Dixon, Timothy H.; Farina, Frederic; Demets, Charles; Jansma, Pamela; Mann, Paul; Calais, Eric



Re-emergence of Cholera in the Americas: Risks, Susceptibility, and Ecology  

PubMed Central

Background: The re-emergence of cholera in Haiti has established a new reservoir for the seventh cholera pandemic which threatens to spread to other countries in the Americas. Materials and Methods: Statistics from this new epidemic are compared to the 1991 Peru epidemic, which demonstrated the speed and complexity with which this disease can spread from country to country. Environmental factors implicated in the spread of Vibrio cholerae such as ocean currents and temperatures, as well as biotic factors from zooplankton to waterfowl pose a risk for many countries in the Americas. Results: The movement of people and goods from Hispaniola are mostly destined for North America, but occur to some degree throughout the Americas. These modes of transmission, and the probability of uncontrolled community spread beyond Hispaniola, however, are completely dependent upon risk factors within these countries such as water quality and availability of sanitation. Although North America has excellent coverage of these deterrents to the spread of infectious gastrointestinal diseases, many countries throughout Latin America and the Caribbean lack these basic services and infrastructures. Conclusions: In order to curb the immediate spread of cholera in Hispaniola, treatment availability should be expanded to all parts of the island and phase II epidemic management initiatives must be developed. PMID:23055647

Poirier, Mathieu JP; Izurieta, Ricardo; Malavade, Sharad S; McDonald, Michael D



Seismological Insights into the Structure of the Lesser Antilles  

NASA Astrophysics Data System (ADS)

Due to an overall eastwards drift of the Caribbean plate of around 2cm/year relative to the Atlantic plate, the type of the subduction along the eastern part of the Caribbean changes. Compared to the simple subduction of the Atlantic plate in the east, the northern plate boundary zone is far more complex, predominantly characterised by a left-lateral east-west strike-slip motion that includes an oblique convergence of the Bahamas carbonate banks and a pull apart basin in the Mona Passage, the sea gate between Hispaniola and Puerto Rico. The island of Hispaniola is decoupled from the Caribbean plate, which leads to a second subduction zone south of Hispaniola where the Caribbean plate subducts beneath the Hispaniola micro plate. Strictly speaking, the arc only extends to the east of the island of Puerto Rico but since most of the northern Caribbean plate boundary zone is directly linked to it the results become more directly comparable. Fed by the Orinoco River the southern part of the Lesser Antilles is a sediment-rich subduction zone, which becomes sediment-poor towards the north as the sediments get blocked by several banks, including the accretionary prism containing the island of Barbados. Here we investigate the crustal and mantle structure variation along the Antilles Arc using measurements of seismic anisotropy and receiver functions. We use data from three component broadband stations that are located from the southern end of the arc to Hispaniola in the north. Seismic anisotropy refers to directional variations in wave speeds and their polarisations. The observation of two independently propagating shear waves (splitting) is the least ambiguous indication of anisotropy. Such observations can be used to constrain mantle flow beneath subduction regions, offering insights into slab dynamics. We generally observed trench parallel orientations around the plate boundary. However, we see significant local deviations in the inferred flow pattern, for example, in the shallow mantle beneath the Mona Passage. Significant variations in sediment load, petrology and volcanism are observed along the arc. We investigate whether there is any correlation with crustal structure using receiver functions to determine Moho depth and Vp/Vs ratio. The receiver functions are computed using the extended-time multitaper frequency domain cross-correlation receiver-function (ETMTRF) by Helffrich (2006). This method has the advantage of resistance to noise, which is helpful since most of the data around the arc will have been collected by stations close to the ocean, thus containing a large amount of noise. Our preliminary results show clear variations in these measurements. There are also regions where the Moho is not very sharp.

Schlaphorst, D.; Kendall, J.; Bastow, I. D.; Baptie, B.



Spatiotemporal Dynamics of Dissemination of Non-Pandemic HIV-1 Subtype B Clades in the Caribbean Region  

PubMed Central

The Human immunodeficiency virus type-1 (HIV-1) epidemic in the Caribbean region is mostly driven by subtype B; but information about the pattern of viral spread in this geographic region is scarce and different studies point to quite divergent models of viral dissemination. In this study, we reconstructed the spatiotemporal and population dynamics of the HIV-1 subtype B epidemic in the Caribbean. A total of 1,806 HIV-1 subtype B pol sequences collected from 17 different Caribbean islands between 1996 and 2011 were analyzed together with sequences from the United States (n?=?525) and France (n?=?340) included as control. Maximum Likelihood phylogenetic analyses revealed that HIV-1 subtype B infections in the Caribbean are driven by dissemination of the pandemic clade (BPANDEMIC) responsible for most subtype B infections across the world, and older non-pandemic lineages (BCAR) characteristics of the Caribbean region. The non-pandemic BCAR strains account for >40% of HIV-1 infections in most Caribbean islands; with exception of Cuba and Puerto Rico. Bayesian phylogeographic analyses indicate that BCAR strains probably arose in the island of Hispaniola (Haiti/Dominican Republic) around the middle 1960s and were later disseminated to Trinidad and Tobago and to Jamaica between the late 1960s and the early 1970s. In the following years, the BCAR strains were also disseminated from Hispaniola and Trinidad and Tobago to other Lesser Antilles islands at multiple times. The BCAR clades circulating in Hispaniola, Jamaica and Trinidad and Tobago appear to have experienced an initial phase of exponential growth, with mean estimated growth rates of 0.35–0.45 year?1, followed by a more recent stabilization since the middle 1990s. These results demonstrate that non-pandemic subtype B lineages have been widely disseminated through the Caribbean since the late 1960s and account for an important fraction of current HIV-1 infections in the region. PMID:25148215

Cabello, Marina; Mendoza, Yaxelis; Bello, Gonzalo



Currents and waters of the upper 1200 m of the eastern Caribbean Sea during winter  

E-print Network

', e. ser Antilles from St Ducia to the south. The Subtropical ~~iater witn a high- salinity core near 2)0 cl/t enters mainly through pas- sages ia the lesser Antilles from Dominica north ard. at Anegada and Mon Passages. Some also may enter between... enter the Caribbean through the Lesser Antilles, particularly between Guadeloupe and Dominica, and through Mona Passage. The acceleration potential indicates in- flow between Jamaica and Hispaniola where the eddy cen- tered south of the passage apps...

Febres Ortega, German Antonio



VIROLOGY: Poliomyelitis Eradication--a Dangerous Endgame  

NSDL National Science Digital Library

Access to the article is free, however registration and sign-in are required. Efforts to eradicate poliovirus from the face of the Earth have been very successful, thanks in large part to the oral poliovirus vaccine developed by Albert Sabin. However, as Nathanson and Fine explain in their Perspective, maintaining a world free from poliomyelitis will not be easy. They discuss the implications of a recent outbreak of paralytic poliomyelitis on the island of Hispaniola from which wild poliovirus was eliminated 10 years previously (Kew et al.).

Neal Nathanson (University of Pennsylvania; Departments of Microbiology and Neurology)



Depression in Caregivers of Status-Naïve Pediatric HIV Patients Participating in a Status Disclosure Study in Haiti and the Dominican Republic: Preliminary Report.  


A pilot study is underway to assess safety and acceptability of an intervention to disclose their HIV infection status to status-naïve pediatric antiretroviral therapy patients in Hispaniola [the island shared by Haiti and the Dominican Republic (DR)]. Of 22 Haiti and 47 DR caregivers recruited to date, 68.2% Haiti and 34.0% DR caregivers had clinically significant depressive symptomatology at the time of enrollment (p = 0.008). Depressive symptom prevalence was higher in Haiti caregivers who were female (81.3% vs. 0 in males; p = 0.02) and in DR caregivers who were patients' mothers (50.0%) or grandmothers (66.7%; 56.0% combined) than others (9.1%), (p < 0.001). Internalized stigma was more commonly reported by Haiti (85.7%) than DR (53.2%; p = 0.01) caregivers; 56.4% of Haiti and DR caregivers reporting internalized stigma vs. 26.1% of caregivers denying it had depressive symptoms (p = 0.02). Depression is common in Hispaniola caregivers possibly affecting disclosure timing. Study participation presents opportunities for addressing caregiver depression. PMID:25389181

Beck-Sagué, Consuelo M; Dévieux, Jessy G; Pinzón-Iregui, María Claudia; Abreu-Pérez, Rosa; Lerebours-Nadal, Leonel; Gaston, Stephanie; Dean, Andrew G; Halpern, Mina; Rouzier, Vanessa; Bertrand, Rachel; Rosenberg, Rhonda; Pape, Jean William; Nicholas, Stephen W; Blasini, Ileana



Untangling intra- and interspecific effects on body size clines reveals divergent processes structuring convergent patterns in Anolis lizards.  


Bergmann's rule-the tendency for body size to increase in colder environments-remains controversial today, despite 150 years of research. Considerable debate has revolved around whether the rule applies within or among species. However, this debate has generally not considered that clade-level relationships are caused by both intra- and interspecific effects. In this article, we implement a novel approach that allows for the separation of intra- and interspecific components of trait-environment relationships. We apply this approach to body size clines in two Caribbean clades of Anolis lizards and discover that their similar body size gradients are constructed in very different ways. We find inverse Bergmann's clines-high-elevation lizards are smaller bodied-for both the cybotes clade on Hispaniola and the sagrei clade on Cuba. However, on Hispaniola, the inverse cline is driven by interspecific differences, whereas intraspecific variation is responsible for the inverse cline on Cuba. Our results suggest that similar body size clines can be constructed through differing evolutionary and ecological processes, namely, through local adaptation or phenotypic plasticity (intraspecific clines) and/or size-ordered spatial sorting (interspecific clines). We propose that our approach can help integrate a divided research program by focusing on how the combined effects of intra- and interspecific processes can enhance or erode clade-level relationships at large biogeographic scales. PMID:25325747

Muñoz, Martha M; Wegener, Johanna E; Algar, Adam C



Earthquake source parameters for the 2010 January Haiti main shock and aftershock sequence  

NASA Astrophysics Data System (ADS)

Previous analyses of geological and geodetic data suggest that the obliquely compressive relative motion across the Caribbean-North America plate boundary in Hispaniola is accommodated through strain partitioning between near-vertical transcurrent faults on land and low-angle thrust faults offshore. In the Dominican Republic, earthquake focal-mechanism geometries generally support this interpretation. Little information has been available about patterns of seismic strain release in Haiti, however, due to the small numbers of moderate-to-large earthquakes occurring in western Hispaniola during the modern instrumental era. Here, we analyse the damaging MW = 7.0 earthquake that occurred near Port au Prince on 2010 January 12 and aftershocks occurring in the four months following this event, to obtain centroid-moment-tensor (CMT) solutions for 50 earthquakes with magnitudes as small as MW = 4.0. While the 2010 January main shock exhibited primarily strike-slip motion on a steeply dipping nodal plane (strike=250°, dip=71° and rake=22°), we find that nearly all of the aftershocks show reverse-faulting motion, typically on high-angle (30°-45°) nodal planes. Two small aftershocks (MW 4.5 and 4.6), located very close to the main shock epicentre, show strike-slip faulting with geometries similar to the main shock. One aftershock located off the south coast of Haiti shows low-angle thrust faulting. We also examine earthquakes occurring in this region from 1977-2009 successful analysis of four such events provides evidence for both strike-slip and reverse faulting. The pattern of seismic strain release in southern Haiti thus indicates that partitioning of plate motion between transcurrent and reverse structures extends far west within Hispaniola. While we see limited evidence for low-angle underthrusting offshore, most reverse motion appears to occur on high-angle fault structures adjacent to the Enriquillo fault. Our results highlight the need to incorporate seismogenic slip on compressional structures into hazard assessments for southern Haiti.

Nettles, Meredith; Hjörleifsdóttir, Vala



Seismic Images of the Crust across the northern Beata Ridge (NE Caribbean)  

NASA Astrophysics Data System (ADS)

The Beata Ridge is a NE-SW trending structure located in the interior of the Caribbean plate, between the extended Colombian and Venezuelan basins. The northern part of the ridge is ~100 km-wide and emerged (Sierra de Bahoruco in the southern Hispaniola Island) and the southern part is ~3500 km- wide and > 4000 m below sea level. It has been suggested that northern part of the ridge is colliding with the E-W tending island arc. In summary, the Hispaniola island arc is being impacted by collision with the Bahamas Bank in the north and by collision with the Beata Ridge in the south. This collision processes jointly with the main E-W component of left-lateral strike-slip have yielded the basin and range physiography observed in the Hispaniola island. To study the macro-structure of the Beata Ridge has likely the key to understand the controversial origin and evolution of the Caribbean plate. A recent combined onshore-offshore CARIBE NORTE survey has been carried out in the Dominican Republic region to study the subduction and collision processes in this area. The marine geophysical cruise aboard the Spanish R/V Hespérides was carried out in spring of 2009. The cruise collected multibeam bathymetry, gravity, magnetic, high-resolution seismic and three-channel seismic reflection data. In the frame of that experiment, a wide angle seismic profile was carried out across the Beata Ridge along a near NW-SE trending line of 200 km length. A set of 5 OBS were anchored along that transect on both sides of the Beata Ridge and 2 seismic land stations at the Beata and Alto Velo Islands, recorded continuously the airgun shots provided by the R/V Hespérides. Processing of the whole dataset is still ongoing, but available results, improve significantly spatial P-wave velocity variations in the upper and middle crust on both sides of the Beata Ridge. In this work, the more recent results from wide angle seismic data across the Beata Ridge are presented.

Nuñez, Diana; Córdoba, Diego; Pazos, Antonio; Martín-Dávila, José; Carbó, Andrés.; Granja-Bruña, José Luis; Payero, Juan; Octavio Cotilla, Mario



Haiti and the Dominican Republic - same island - different climate adaptation strategies  

NASA Astrophysics Data System (ADS)

The two Caribbean states, Haiti and the Dominican Republic, have experienced similar natural forces since the 18th century, such as for instance, hurricanes and earthquakes. Despite this fact, Haiti tends to be more vulnerable to natural forces than the Dominican Republic, while environmental management strategies have been very different in both countries throughout the 19th century. Research findings show that neither atmospheric nor seismic hazards, which directly hit the territory of Haiti, have significant impacts on long-term population densities and growth rates. Conversely, uncontrolled and unregulated urbanization in Haiti between 1850 and 2009 has systematically exposed more people to natural forces. Thus, Haiti is willing to take increasing human security risks, because, it finally matters where people settle. Population growth versus storm occurrence/frequency in different departments/provinces on Hispaniola island between 1850 and 2009.

Klose, C. D.; Webersik, C.



Paleoseismicity of the North American-Caribbean plate boundary (Septentrional fault), Dominican Republic  

USGS Publications Warehouse

The Septentrional fault zone, the major North American-Caribbean plate-boundary fault in Hispaniola, is a likely source of large earthquakes in the Dominican Republic. An excavation into a Holocene alluvial fan deposited across the fault in the central Cibao Valley, Dominican Republic, provides evidence that it has been at least 430 yr and probably more than 740 yr since the last ground-rupturing earthquake along this segment of the fault. On the basis of these data and published estimates of the plate-tectonic slip rate, it is proposed that the Septentrional fault is a source of high seismic potential in the densely populated and rapidly developing Cibao Valley in the northern Dominican Republic. -Authors

Prentice, C.S.; Mann, P.; Taylor, F.W.; Burr, G.; Valastro, S.



Accounts of damage from historical earthquakes in the northeastern Caribbean to aid in the determination of their location and intensity magnitudes  

USGS Publications Warehouse

Documentation of an event in the past depended on the population and political trends of the island, and the availability of historical documents is limited by the physical resource digitization schedule and by the copyright laws of each archive. Examples of documents accessed are governors' letters, newspapers, and other circulars published within the Caribbean, North America, and Western Europe. Key words were used to search for publications that contain eyewitness accounts of various large earthquakes. Finally, this catalog provides descriptions of damage to buildings used in previous studies for the estimation of moment intensity (MI) and location of significantly damaging or felt earthquakes in Hispaniola and in the northeastern Caribbean, all of which have been described in other studies.

Flores, Claudia H.; ten Brink, Uri S.; Bakun, William H.



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

USGS Publications Warehouse

The Puerto Rico Trench, the deepest part of the Atlantic Ocean, is located where the North American (NOAM) plate is subducting under the Caribbean plate (Figure l). The trench region may pose significant seismic and tsunami hazards to Puerto Rico and the U.S.Virgin Islands, where 4 million U.S. citizens reside. Widespread damage in Puerto Rico and Hispaniola from an earthquake in 1787 was estimated to be the result of a magnitude 8 earthquake north of the islands [McCann et al., 2004]. A tsunami killed 40 people in NW Puerto Rico following a magnitude 7.3 earthquake in 1918 [Mercado and McCann, 1998]. Large landslide escarpments have been mapped on the seafloor north of Puerto Rico [Mercado et al., 2002; Schwab et al., 1991],although their ages are unknown.

ten Brink, Uri S.; Danforth, William; Polloni, Christopher; Andrews, Brian; Llanes Estrada, Pilar; Smith, Shepard; Parker, Eugene; Uozumi, Toshihiko



Eremonidiopsis aggregata, gen. n., sp. n. from Cuba, the third West Indian Dioptinae (Lepidoptera, Notodontidae)  

PubMed Central

Abstract A new genus and species of Dioptinae (Lepidoptera, Noctuoidea, Notodontidae) is described from Cuba, this being the third taxon of the subfamily known from the West Indies. Eremonidiopsis aggregata, gen. n., sp. n., appears to be closely related to Eremonidia mirifica Rawlins & Miller from Hispaniola among members of the tribe Dioptini. Eremonidiopsis aggregata is known from two localities in the middle and western portions of the northeastern Cuban mountain range, Nipe–Sagua–Baracoa. The species inhabits low elevations (300–400 m) covered by lowland rainforest and sclerophyll rainforest. The six known specimens, all males, were part of small swarms flying near the top of an unidentified tree during the day at both collecting sites. These localities are included within protected areas, the “Pico Cristal” National Park in the West and the “Alexander von Humbolt” National Park in the East. PMID:24146561

Aguila, Rayner Núñez



An extinct monkey from Haiti and the origins of the Greater Antillean primates  

PubMed Central

A new extinct Late Quaternary platyrrhine from Haiti, Insulacebus toussaintiana, is described here from the most complete Caribbean subfossil primate dentition yet recorded, demonstrating the likely coexistence of two primate species on Hispaniola. Like other Caribbean platyrrhines, I. toussaintiana exhibits primitive features resembling early Middle Miocene Patagonian fossils, reflecting an early derivation before the Amazonian community of modern New World anthropoids was configured. This, in combination with the young age of the fossils, provides a unique opportunity to examine a different parallel radiation of platyrrhines that survived into modern times, but is only distantly related to extant mainland forms. Their ecological novelty is indicated by their unique dental proportions, and by their relatively large estimated body weights, possibly an island effect, which places the group in a size class not exploited by mainland South American monkeys. Several features tie the new species to the extinct Jamaican monkey Xenothrix mcgregori, perhaps providing additional evidence for an inter-Antillean clade. PMID:21282603

Cooke, Siobhán B.; Rosenberger, Alfred L.; Turvey, Samuel



Paleoseismicity of the North American-Caribbean plate boundary (Septentrional fault), Dominican Republic  

NASA Astrophysics Data System (ADS)

The Septentrional fault zone, the major North American-Caribbean plate-boundary fault in Hispaniola, is a likely source of large earthquakes in the Dominican Republic. An excavation into a Holocene alluvial fan deposited across the fault in the central Cibao Valley, Dominican Republic, provides evidence that it has been at least 430 yr and probably more than 730 yr since the last ground-rupturing earthquake along this segment of the fault. On the basis of these data and published estimates of the plate-tectonic slip rate, we propose that the Septentrional fault is a source of high seismic potential in the densely populated and rapidly developing Cibao Valley in the northern Dominican Republic.

Prentice, Carol S.; Mann, Paul; Taylor, F. W.; Burr, G.; Valastro, S.



Twin Tsunamis Triggered by the 12 January 2010 Haiti Earthquake  

NASA Astrophysics Data System (ADS)

On 12 January 2010, a magnitude M w 7.0 earthquake occurred 25 km west-southwest of Haiti's capital Port-au-Prince causing an estimated 316,000 fatalities, thereby exceeding any previous loss of life from a similar size earthquake. In addition, tsunami waves triggered by the earthquake caused at least three fatalities at Petit Paradis due to a complete lack of tsunami awareness. The International Tsunami Survey Team (ITST) was deployed within weeks of the event and covered the greater Bay of Port-au-Prince and more than 100 km of Hispaniola's southern coastline. The collected survey data include more than 21 tsunami heights along with observations of coastal land level change. Maximum tsunami heights of 3 m have been measured for two independently triggered tsunamis.

Fritz, Hermann M.; Hillaire, Jean Vilmond; Molière, Emanuel; Wei, Yong; Mohammed, Fahad



Seismic hazard maps for Haiti  

USGS Publications Warehouse

We have produced probabilistic seismic hazard maps of Haiti for peak ground acceleration and response spectral accelerations that include the hazard from the major crustal faults, subduction zones, and background earthquakes. The hazard from the Enriquillo-Plantain Garden, Septentrional, and Matheux-Neiba fault zones was estimated using fault slip rates determined from GPS measurements. The hazard from the subduction zones along the northern and southeastern coasts of Hispaniola was calculated from slip rates derived from GPS data and the overall plate motion. Hazard maps were made for a firm-rock site condition and for a grid of shallow shear-wave velocities estimated from topographic slope. The maps show substantial hazard throughout Haiti, with the highest hazard in Haiti along the Enriquillo-Plantain Garden and Septentrional fault zones. The Matheux-Neiba Fault exhibits high hazard in the maps for 2% probability of exceedance in 50 years, although its slip rate is poorly constrained.

Frankel, Arthur; Harmsen, Stephen; Mueller, Charles; Calais, Eric; Haase, Jennifer



Variation in dip of the Caribbean Plate along the Muertos Trough  

NASA Astrophysics Data System (ADS)

The M 7.0 Haiti earthquake of 2010 is a reminder that the northeast Caribbean is at high risk for seismic and tsunami hazards. The islands of Puerto Rico and Hispaniola are located between two subduction zones, with the Puerto Rico trench to the north and the Muertos trough to the south. The Puerto Rico trench is caused by southward-directed subduction of the North American Plate, and the Muertos trough is the northern boundary of the Caribbean Plate. There is no active volcanism on Puerto Rico, however earthquake depths and seismic tomography imply that the slab of Caribbean plate continues beneath Puerto Rico. Puerto Rico overlies these two slabs with extensional stress to both the east (Mona Passage) and west (Anacapa Passage). The cause of the extension is unknown, but GPS measurements show that Puerto Rico has anti-clockwise rotation, and the extensional Anacapa Passage may be produced by the rotation. To the west, it is debated whether the Mona Passage is a boundary between two micro-plates. By combining interpreted profiles of gravity data with the locations of earthquakes within the subducting slab on both sides of Mona Passage, we interpret that the subducting slab has a variation in dip along-strike of the Muertos Trough. The subducting slab east of the Mona Passage has a shallow dip angle, whereas the subducting slab west of the Mona Passage has a steep dip angle. This change in dip implies a north to south boundary beneath the Mona Passage, and that this passage is the micro-plate boundary between Puerto Rico and Hispaniola. The shallow dip of the slab to the east of the Mona Passage may cause the rotation of the microplate and the lateral extension.

Xu, X.; Keranen, K. M.; Asencio, E.; Chang, J. C.; Keller, G.



Collisional zones in Puerto Rico and the northern Caribbean  

NASA Astrophysics Data System (ADS)

Puerto Rico is an amalgamation of island arc terranes that has recorded the deformational and tectonic history of the North American-Caribbean Plate boundary. Four collisional zones indicate the contractional events that have occurred at the plate boundary. Metamorphism and deformation of Middle Jurassic to Early Cretaceous oceanic lithosphere during the Early Cretaceous indicate the earliest collisional event. Then, an ophiolitic mélange, mostly comprised of blocks of the metamorphosed oceanic lithosphere, was formed and emplaced in the backarc region during the Turonian-Coniacian deformational event. A possible collision with a buoyant block in the North American Plate caused late Maastrichtian-early Paleocene contraction that created fold-and-thrust belts and the remobilization and uplift of serpentinite bodies in the Southwest Block. Late Eocene-early Oligocene transpression was localized along the Southern and Northern Puerto Rico fault zones, which occur north and south of large granodiorite intrusions in the strong Central Block. The deformation was accommodated in pure shear domains of fold-and-thrust belts and conjugate strike-slip faults, and simple shear domains of large mostly left-lateral faults. In addition, it reactivated faults in the weak Southwest Block. This island-wide transpression is the result of a Greater Antilles arc and continental North American collision. The kinematic model of the structures described in Puerto Rico correlate with some structures in Hispaniola and Cuba, and shows how the northern boundary of the Caribbean Plate was shortened by collisions with continental lithosphere of the North American Plate throughout its history. The tectonic evolution of the Greater Antilles shows a history of collisions, in which the latest collision accretes Cuba to the North American Plate, reorganizes the plate boundary, and deforms with transpression Hispaniola and Puerto Rico. The latest collision in Puerto Rico shows the case in which an arc collides obliquely with buoyant crust producing left-lateral transpression and converges obliquely with dense oceanic lithosphere.

Laó-Dávila, Daniel A.



Actively evolving microplate formation by oblique collision and sideways motion along strike-slip faults: An example from the northeastern Caribbean plate margin  

NASA Astrophysics Data System (ADS)

The pattern of folding, faulting, and late Quaternary coral-reef uplift rates in western and central Hispaniola (Haiti and Dominican Republic) suggest that the elongate Gonave microplate, a 190,000-km 2 area of the northeastern Caribbean plate, is in the process of shearing off the Caribbean plate and accreting to the North American plate. Late Cenozoic transpression between the southeastern Bahama Platform and the Caribbean plate in Hispaniola has inhibited the eastward motion of the northeastern corner of the plate. Transpression is manifested in western and central Hispaniola by the formation of regional scale folds that correspond to present-day, anticlinal topographic mountain chains continuous with offshore anticlinal ridges. Areas of most rapid Quaternary uplift determined from onland coral reefs 125 ka and younger, coincide with the axial traces of these folds. Offshore data suggest recent folding and faulting of the seafloor. Onshore reef data do not conclusively require late Quaternary folding, but demonstrate that tectonic uplift rates of the axial areas of the anticlines decrease from the Northwest Peninsula of Haiti (0.37 mm/yr) to to the central part of the coast of western Haiti (0.19 mm/yr) to the south-central part of western Haiti (0 mm/yr). Formation of the 1200-km-long Enriquillo-Plantain Garden-Walton fault zone as a 'bypass' strike-slip fault has isolated the southern edge of the Gonave microplate and is allowing continued, unimpeded eastward motion of a smaller Caribbean plate past the zone of late Neogene convergence and Quaternary uplift of coral reefs in Hispaniola. Offshore seismic reflection data from the Jamaica Passage, the marine strait separating Jamaica and Haiti, show that the Enriquillo-Plantain Garden fault zone forms a narrow but deep, active fault-bounded trough beneath the passage. The active fault is continuous with active faults mapped onshore in western Haiti and eastern Jamaica; the bathymetric deep is present because the Jamaica Passage fault segment represents a 50-km-wide, transtensional left-step of the fault trace between Haiti and Jamaica. Onshore satellite imagery and field observations suggest that the Enriquillo-Plantain Garden fault forms a continuous trace extending from central Hispaniola east of Lake Enriquillo, Dominican Republic, to the westernmost end of the southern peninsula of Haiti. The regional lineament corresponds to a recent fault scarp in Quaternary alluvium of the Clonard pull-apart basin in the central part of the southern peninsula of Haiti and suggests that at least this part of the lineament has undergone recent slip. Calmus (1983) has suggested a total offset of 30-50 km of the Enriquillo-Plantain Garden fault zone in the southern peninsula of Haiti using the apparent offset of lithologic units. Seismic reflection data from Lake Enriquillo document recent deformation of Quaternary lake sediments where the lineament crosses the lake. Leveling of the crest of a late Holocene coral reef and associated algal tufa around Lake Enriquillo demonstrate late Holocene vertical movement and tilting in a 1500-m-wide zone parallel to the fault trend. Lateral offset is difficult to show in the Enriquillo Valley area because of rapid recent sedimentation into the valley. The pattern of inactive strike-slip faults and fold belts of Cenozoic age in Cuba and the Yucatan basin suggest that two elongate microplates were sheared off the proto-Caribbean plate and accreted to the North American plate by a similar process in Paleocene and Eocene times. Age of terminal deformation in western, central and eastern Cuba is consistent with southeastward younging and migration of arc collision. The similarity of the size and sequence of events in Cuba suggests that the process of oblique collision and sideways motion of the plate along a new strike-slip fault towards a free face may be an important process of microplate formation and interplate transfer in other areas.

Mann, Paul; Taylor, F. W.; Edwards, R. Lawrence; Ku, Teh-Lung



Documentation for Initial Seismic Hazard Maps for Haiti  

USGS Publications Warehouse

In response to the urgent need for earthquake-hazard information after the tragic disaster caused by the moment magnitude (M) 7.0 January 12, 2010, earthquake, we have constructed initial probabilistic seismic hazard maps for Haiti. These maps are based on the current information we have on fault slip rates and historical and instrumental seismicity. These initial maps will be revised and improved as more data become available. In the short term, more extensive logic trees will be developed to better capture the uncertainty in key parameters. In the longer term, we will incorporate new information on fault parameters and previous large earthquakes obtained from geologic fieldwork. These seismic hazard maps are important for the management of the current crisis and the development of building codes and standards for the rebuilding effort. The boundary between the Caribbean and North American Plates in the Hispaniola region is a complex zone of deformation. The highly oblique ~20 mm/yr convergence between the two plates (DeMets and others, 2000) is partitioned between subduction zones off of the northern and southeastern coasts of Hispaniola and strike-slip faults that transect the northern and southern portions of the island. There are also thrust faults within the island that reflect the compressional component of motion caused by the geometry of the plate boundary. We follow the general methodology developed for the 1996 U.S. national seismic hazard maps and also as implemented in the 2002 and 2008 updates. This procedure consists of adding the seismic hazard calculated from crustal faults, subduction zones, and spatially smoothed seismicity for shallow earthquakes and Wadati-Benioff-zone earthquakes. Each one of these source classes will be described below. The lack of information on faults in Haiti requires many assumptions to be made. These assumptions will need to be revisited and reevaluated as more fieldwork and research are accomplished. We made two sets of maps using different assumptions about site conditions. One set of maps is for a firm-rock site condition (30-m averaged shear-wave velocity, Vs30, of 760 m/s). We also developed hazard maps that contain site amplification based on a grid of Vs30 values estimated from topographic slope. These maps take into account amplification from soils. We stress that these new maps are designed to quantify the hazard for Haiti; they do not consider all the sources of earthquake hazard that affect the Dominican Republic and therefore should not be considered as complete hazard maps for eastern Hispaniola. For example, we have not included hazard from earthquakes in the Mona Passage nor from large earthquakes on the subduction zone interface north of Puerto Rico. Furthermore, they do not capture all the earthquake hazards for eastern Cuba.

Frankel, Arthur; Harmsen, Stephen; Mueller, Charles; Calais, Eric; Haase, Jennifer



Interseismic Plate coupling and strain partitioning in the Northeastern Caribbean  

NASA Astrophysics Data System (ADS)

The northeastern Caribbean provides a natural laboratory to investigate strain partitioning, its causes and its consequences on the stress regime and tectonic evolution of a subduction plate boundary. Here, we use GPS and earthquake slip vector data to produce a present-day kinematic model that accounts for secular block rotation and elastic strain accumulation, with variable interplate coupling, on active faults. We confirm that the oblique convergence between Caribbean and North America in Hispaniola is partitioned between plate boundary parallel motion on the Septentrional and Enriquillo faults in the overriding plate and plate-boundary normal motion at the plate interface on the Northern Hispaniola Fault. To the east, the Caribbean/North America plate motion is accommodated by oblique slip on the faults bounding the Puerto Rico block to the north (Puerto Rico subduction) and to the south (Muertos thrust), with no evidence for partitioning. The spatial correlation between interplate coupling, strain partitioning and the subduction of buoyant oceanic asperities suggests that the latter enhance the transfer of interplate shear stresses to the overriding plate, facilitating strike-slip faulting in the overriding plate. The model slip rate deficit, together with the dates of large historical earthquakes, indicates the potential for a large (Mw7.5 or greater) earthquake on the Septentrional fault in the Dominican Republic. Similarly, the Enriquillo fault in Haiti is currently capable of a Mw7.2 earthquake if the entire elastic strain accumulated since the last major earthquake was released in a single event today. The model results show that the Puerto Rico/Lesser Antilles subduction thrust is only partially coupled, meaning that the plate interface is accumulating elastic strain at rates slower than the total plate motion. This does not preclude the existence of isolated locked patches accumulating elastic strain to be released in future earthquakes, but whose location and geometry are not resolvable with the present data distribution. Slip deficit on faults from this study are used in a companion paper to calculate interseismic stress loading and, together with stress changes due to historical earthquakes, derive the recent stress evolution in the NE Caribbean.

Manaker, D. M.; Calais, E.; Freed, A. M.; Ali, S. T.; Przybylski, P.; Mattioli, G.; Jansma, P.; Prépetit, C.; de Chabalier, J. B.



Petrochemistry and tectonic significance of Cretaceous island-arc rocks, Cordillera Oriental, Dominican Republic  

NASA Astrophysics Data System (ADS)

Cretaceous island-arc rocks of the Caribbean island-arc system have been exposed by Cenozoic faulting in the Cordillera Oriental in eastern Hispaniola. High-K 2O intermediate to felsic volcanic rocks (Loma la Vega volcanics) are interbedded with marine epiclastic sedimentary rocks and tuffs (Las Guajabas tuffs) and unconformably overlie pre-Aptian sedimentary rocks, low-K 2O volcanic rocks (Guamira volcanics) and a granodioritic to tonalitic intrusion (El Valle pluton). The petrology and geochemistry of these units, in conjunction with regional stratigraphic data, are used to speculate on the tectonics of the newly developing Caribbean island-arc system during Early and Late Cretaceous time. The Loma la Vega volcanics are characterized by the presence of large phenocrysts of sanidine, and minor amounts of clinopyroxene, opaque oxides, and rare leucite in a devitrified matrix of chlorite and clay. Although the volcanic rocks have undergone some low-temperature alteration/ metamorphism, which redistributed some major elements and large-ion-litho-phile trace elements, the high-field-strength elements, rare-earth elements, and radiogenic isotopes appear to have been minimally affected. Based on abundances of the relatively immobile elements, trace-element enrichment patterns and isotopic compositions, the Loma la Vega volcanics are considered part of the high-K, calc-alkaline (CA) or shoshonitic island-arc volcanic series. In contrast, pre-Aptian (Early Cretaceous?) volcanic and plutonic rocks of the underlying Los Ranchos Formation have chemical characteristics similar to rocks in the island-arc tholeiitic or "primitive island-arc" (PIA) series that form coeval and along-strike sections of the Early Cretaceous Caribbean island arc in other parts of present-day Hispaniola, Cuba, Puerto Rico and the Virgin Islands. An abrupt and regional change in composition from island-arc tholeiites to high-K, calc-alkaline rocks is coincident with a hypothesized reversal in subduction polarity in pre-Aptian time. As inferred from previously published tectonic models, polarity reversal may have been triggered by attempted subduction of the Caribbean oceanic plateau beneath this segment of the Caribbean island arc. The observed magmatic and tectonic effects of the proposed Cretaceous Caribbean arc reversal are similar to the better documented Neogene subduction reversal event in the Solomon Islands arc in the southwest Pacific.

Lebrón, María Cristina; Perfit, Michael R.



Genetic introgression and hybridization in Antillean freshwater turtles (Trachemys) revealed by coalescent analyses of mitochondrial and cloned nuclear markers.  


Determining whether a conflict between gene trees and species trees represents incomplete lineage sorting (ILS) or hybridization involving native and/or invasive species has implications for reconstructing evolutionary relationships and guiding conservation decisions. Among vertebrates, turtles represent an exceptional case for exploring these issues because of the propensity for even distantly related lineages to hybridize. In this study we investigate a group of freshwater turtles (Trachemys) from a part of its range (the Greater Antilles) where it is purported to have undergone reticulation events from both natural and anthropogenic processes. We sequenced mtDNA for 83 samples, sequenced three nuDNA markers for 45 samples, and cloned 29 polymorphic sequences, to identify species boundaries, hybridization, and intergrade zones for Antillean Trachemys and nearby mainland populations. Initial coalescent analyses of phased nuclear alleles (using (*)BEAST) recovered a Bayesian species tree that strongly conflicted with the mtDNA phylogeny and traditional taxonomy, and appeared to be confounded by hybridization. Therefore, we undertook exploratory phylogenetic analyses of mismatched alleles from the "coestimated" gene trees (Heled and Drummond, 2010) in order to identify potential hybrid origins. The geography, morphology, and sampling context of most samples with potential introgressed alleles suggest hybridization over ILS. We identify contact zones between different species on Jamaica (T. decussata × T. terrapen), on Hispaniola (T. decorata × T. stejnegeri), and in Central America (T. emolli × T. venusta). We are unable to determine whether the distribution of T. decussata on Jamaica is natural or the result of prehistoric introduction by Native Americans. This uncertainty means that the conservation status of the Jamaican T. decussata populations and contact zone with T. terrapen are unresolved. Human-mediated dispersal events were more conclusively implicated for the prehistoric translocation of T. stejnegeri between Puerto Rico and Hispaniola, as well as the more recent genetic pollution of native species by an invasive pet turtle native to the USA (T. scripta elegans). Finally, we test the impact of introgressed alleles using the multispecies coalescent in a Bayesian framework and show that studies that do not phase heterozygote sequences of hybrid individuals may recover the correct species tree, but overall support for clades that include hybrid individuals may be reduced. PMID:23353072

Parham, James F; Papenfuss, Theodore J; Dijk, Peter Paul van; Wilson, Byron S; Marte, Cristian; Schettino, Lourdes Rodriguez; Brian Simison, W



Geological interpretation of combined Seabeam, Gloria and seismic data from Anegada Passage (Virgin Islands, north Caribbean)  

USGS Publications Warehouse

The Anegada Passage (sensu lato) includes several basins and ridges from Southeast of Puerto Rico to the corner of the Virgin Islands Platform. Seabeam (Seacarib I) and Gloria long-range sidescan sonar surveys were carried out in this area. These new data allow us to propose an interpretation of the Anegada Passage. Most of the features described are related to wrench faulting: (a) St Croix and Virgin Islands Basins are pull-apart basins created in a right-lateral strike-slip environment based on their rhomboidal shape and seismic data (e.g. the flower structure). These two pull-aparts are divided into two sub-basins by a curvilinear normal fault in the Virgin Islands Basin and a right-lateral strike-slip fault in the St Croix Basin. (b) Tortola Ridge and a 'dog's leg' shaped structure are inferred to be restraining bends between two right-lateral strike-slip faults. (c) We identified two ENE-WSW volcanic lineaments in the eastern area and one volcano lying between Virgin Islands and St Croix Basins. (d) As shown by the seismic activity main wrench motion occurs along the north slope of Virgin Islands Basin and through Anegada Passage. A branching of this main fault transmits the transtensional motion to St Croix Basin. A two-stage story is proposed for the creation of the basins. A first extensional event during Eocene(?)-Oligocene-lower Miocene time created Virgin Islands, St Croix Basins and the tilted blocks of St Croix Ridge. A second transtensional event from Pliocene to Recent gave the present day pattern to this area. However, the displacement along the strike-slip faults is no more than 15 km long. The proposed geodynamic model is based on the separation of the northeastern Caribbean boundary into two blocks. In the West, the indenter of Beata Ridge gives a northeastern motion to Hispaniola Block. In the East, as a result of Hispaniola Block's motion, the Puerto Rico-Virgin Islands Block could escape in an east-northeast direction. ?? 1990 Kluwer Academic Publishers.

Jany, I.; Scanlon, K.M.; Mauffret, A.



Plate interaction in the NE Caribbean subduction zone from continuous GPS observations  

NASA Astrophysics Data System (ADS)

Kinematic similarities between the Sumatra and Puerto Rico Trenches highlight the potential for a mega-earthquake along the Puerto Rico Trench and the generation of local and trans-Atlantic tsunamis. We used the horizontal components of continuous GPS (cGPS) measurements from 10 sites on NE Caribbean islands to evaluate strain accumulation along the North American (NA) - Caribbean (CA) plate boundary. These sites move westward and slightly northward relative to CA interior at rates ?2.5 mm/y. Provided this motion originates in the subduction interface, the northward motion suggests little or no trench-perpendicular thrust accumulation and may in fact indicate divergence north of Puerto Rico, where abnormal subsidence, bathymetry, and gravity are observed. The Puerto Rico Trench, thus, appears unable to generate mega-earthquakes, but damaging smaller earthquakes cannot be discounted. The westward motion, characterized by decreasing rate with distance from the trench, is probably due to eastward motion of CA plate impeded at the plate boundary by the Bahamas platform. Two additional cGPS sites in Mona Passage and SW Puerto Rico move to the SW similar to Hispaniola and unlike the other 10 sites. That motion relative to the rest of Puerto Rico may have given rise to seismicity and normal faults in Mona Rift, Mona Passage, and SW Puerto Rico.

ten Brink, Uri S.; López-Venegas, Alberto M.



Internal Tides in the Mona Passage  

NASA Astrophysics Data System (ADS)

Prior studies have shown that the Mona Passage and the shelf break along the SW coast of Puerto Rico are sites of internal wave generation and these waves have been partially characterized. Joint shipboard and glider-based observations have now allowed more detailed documentation of a tidally-induced internal wave train generated in the Mona Passage between Puerto Rico and Hispaniola. Wave generation occurs in the region of "El Pichincho", a submerged ridge across the passage where tidal action induces hydraulic forcing of the wave. Here, semi- diurnal isopycnal displacement centered at depths around 100 m spans a vertical range of up to 50 m. Shipboard observations show impingement of the wave at Mona Island to the south of the area of formation. Glider observations reveal wave damping as the wave train propagates south along the Mona Passage towards the open Caribbean Sea as well as complex optical effects associated to transient enhancement of phytoplankton photosynthetic activity through vertical displacement of the deep chlorophyll maximum into the shallower high light regime. We derive and discuss critical wave parameters including wavelength, amplitude and phase velocity. These internal wave dynamics may be applicable to other Caribbean Passages where similar phenomena may occur.

Corredor, J. E.; Morell, J. M.; Capella, J. E.; Glenn, S.; Pabst, D.



Antillipeltis, a new genus of Antillean Trogossitidae (Coleoptera: Cleroidea) with a key to the Cleroidea.  


Antillipeltis gen. nov. is described based on the following six new extant species and two new fossil species from Hispaniola and Puerto Rico: A. alleni sp. nov. (Dominican Republic, Miocene), A. darlingtoni sp. nov. (Haiti), A. iviei sp. nov. (Dominican Republic, Miocene), A. maculata sp. nov. (Dominican Republic), A. minuta sp. nov. (Dominican Republic), A. nitida sp. nov. (Puerto Rico), A. portoricensis sp. nov. (Puerto Rico), and A. pubescens sp. nov. (Dominican Republic). The genus is placed in Cleroidea, as currently delimited, based on the presence of a distinctive type of aedeagus occurring primarily in this superfamily, plus a combination of features excluding it from other cucujiform superfamilies. Within Cleroidea, the genus is tenatively placed in the family Trogossitidae and subfamily Lophocaterinae, but it differs from all other Trogossitidae in the presence of ventral membranous lobes with adhesive setae on tarsomeres 1-4 and in a combination of 9-segmented antennae, weak 3-segmented antennal club consisting of slightly elongate antenomeres, lack of postcoxal processes on the pronotal hypomera, and unique leg modifications. A key is provided for major groups of Cleroidea and all described genera of Peltinae and Lophocaterinae, with the exception of Rentoniini, based in part on the literature and in part on dissections of adult males. Antillipeltis is one of three endemic West Indian genera of Coleoptera that is both extant and known from Dominican amber. PMID:24870333

Lawrence, John F; Leschen, Richard A B; Slipi?ski, Adam



Oxygen isotope evidence of Little Ice Age aridity on the Caribbean slope of the Cordillera Central, Dominican Republic  

NASA Astrophysics Data System (ADS)

Climate change during the so-called Little Ice Age (LIA) of the 15th to 19th centuries was once thought to be limited to the high northern latitudes, but increasing evidence reflects significant climate change in the tropics. One of the hypothesized features of LIA climate in the low latitudes is a more southerly mean annual position of the Intertropical Convergence Zone (ITCZ), which produced more arid conditions through much of the northern tropics. High-resolution stable oxygen isotope data and other sedimentary evidence from Laguna de Felipe, located on the Caribbean slope of the Cordillera Central of the Dominican Republic, support the hypothesis that the mean annual position of the ITCZ was displaced significantly southward during much of the LIA. Placed within the context of regional paleoclimate and paleoceanographic records, and reconstructions of global LIA climate, this shift in mean annual ITCZ position appears to have been induced by lower solar insolation and internal dynamical responses of the global climate system. Our results from Hispaniola further emphasize the global nature of LIA climate change and the sensitivity of circum-Caribbean climate conditions to what are hypothesized to be relatively small variations in global energy budgets.

Lane, Chad S.; Horn, Sally P.; Orvis, Kenneth H.; Thomason, John M.



Rio Soliette (haiti): AN International Initiative for Flood-Hazard Assessment and Mitigation  

NASA Astrophysics Data System (ADS)

Natural catastrophic events are one of most critical aspects for health and economy all around the world. However, the impact in a poor region can impact more dramatically than in others countries. Isla Hispaniola (Haiti and the Dominican Republic), one of the poorest regions of the planet, has repeatedly been hit by catastrophic natural disasters that caused incalculable human and economic losses. After the catastrophic flood event occurred in the basin of River Soliette on May 24th, 2004, the General Direction for Development and Cooperation of the Italian Department of Foreign Affairs funded an international cooperation initiative (ICI) coordinated by the University of Bologna, that involved Haitian and Dominican institutions.Main purpose of the ICI was hydrological and hydraulic analysis of the May 2004 flood event aimed at formulating a suitable and affordable flood risk mitigation plan, consisting of structural and non-structural measures. In this contest, a topographic survey was necessary to realize the hydrological model and to improve the knowledge in some areas candidates to be site for mitigation measures.To overcome the difficulties arising from the narrowness of funds, surveyors and limited time available for the survey, only GPS technique have been used, both for framing aspects (using PPP approach), and for geometrical survey of the river by means of river cross-sections and detailed surveys in two areas (RTK technique). This allowed us to reconstruct both the river geometry and the DTM's of two expansion areas (useful for design hydraulic solutions for mitigate flood-hazard risk).

Gandolfi, S.; Castellarin, A.; Barbarella, M.; Brath, A.; Domeneghetti, A.; Brandimarte, L.; Di Baldassarre, G.



Flood mapping of the trans-boundary river Soliette (Haiti and the Dominican Republic)  

NASA Astrophysics Data System (ADS)

Over the last decades, Isla Hispaniola (i.e. the territory shared by Haiti and the Dominican Republic) has been sadly affected by several hydro-geological disasters. In fact, the island has been involuntary protagonist of the international chronicles for being hit by the passage of several devastating hurricanes. Incalculable damages to structures and environment and thousand fatalities are the results of such events. A recent and glaring example is that of May 2004, when extreme and intense precipitations, originated by a tropical depression in the Caribbean Sea, occurred over the island, producing a devastating flash-flooding of the river Soliette trans-boundary catchment. The flooding destroyed most of the cities of Jimaní and Fond Verrettes and killed over 1,000 Haitian and Dominican people. The same event also killed 414 people in the Dominican Republic. This presentation shows the analysis of the hydrological and hydraulic behaviour of the river Soliette aimed at modelling the flood event of May 2004 and formulating a trans-boundary flood mitigation plan.

Brandimarte, L.



Conservation and management of the American crocodile  

NASA Astrophysics Data System (ADS)

The American crocodile is a rare and endangered species, the range of which has contracted to disjunct locations such as Hispaniola, Jamaica, Cuba, Panama, and southern Florida. In an attempt to determine what factors might be limiting population growth, an extensive collaborative research program was conducted in 1978 82 in southern Florida. Limiting factors explicitly studied included climate, hurricanes, population dispersion, nesting habitat, fertility, predation, nest chamber environment, juvenile survivorship, artificial mortality, disturbance, and environmental contamination. No single natural factor limits the population, although in concert various factors result in low adult recruitment rates. Such natural limitations explain the natural rarity of this tropical species at the temperate limits of its range. Two artificial sources of mortality are death of adults on roads and the flooding of nests by high groundwater tables. These sources of mortality are potentially controllable by the appropriate management agencies. Active management, by such means as protection of individuals, habitat preservation and enhancement, nest site protection, and captive breeding, is also appropriate for assuring the survival of a rare species. The American crocodile has survived in southern Florida in face of extensive human occupancy of parts of its former nesting habitat, demonstrating the resilience of a threatened species. This case history illustrates the efficacy of conducting research aimed at testing specific management hypotheses, the importance of considering biographical constraints limiting population status in peripheral populations, the need for active management of rare species, and the role of multiple reserves in a conservation and management strategy.

Kushlan, James A.



Genomic and Phenotypic Characterization of Vibrio cholerae Non-O1 Isolates from a US Gulf Coast Cholera Outbreak  

PubMed Central

Between November 2010, and May 2011, eleven cases of cholera, unrelated to a concurrent outbreak on the island of Hispaniola, were recorded, and the causative agent, Vibrio cholerae serogroup O75, was traced to oysters harvested from Apalachicola Bay, Florida. From the 11 diagnosed cases, eight isolates of V. cholerae were isolated and their genomes were sequenced. Genomic analysis demonstrated the presence of a suite of mobile elements previously shown to be involved in the disease process of cholera (ctxAB, VPI-1 and -2, and a VSP-II like variant) and a phylogenomic analysis showed the isolates to be sister taxa to toxigenic V. cholerae V51 serogroup O141, a clinical strain isolated 23 years earlier. Toxigenic V. cholerae O75 has been repeatedly isolated from clinical cases in the southeastern United States and toxigenic V. cholerae O141 isolates have been isolated globally from clinical cases over several decades. Comparative genomics, phenotypic analyses, and a Caenorhabditis elegans model of infection for the isolates were conducted. This analysis coupled with isolation data of V. cholerae O75 and O141 suggests these strains may represent an underappreciated clade of cholera-causing strains responsible for significant disease burden globally. PMID:24699521

Grim, Christopher J.; Onifade, Tiffiani J.; Cinar, Hediye N.; Tall, Ben D.; Taviani, Elisa; Hasan, Nur A.; Abdullah, AbdulShakur H.; Carter, Laurenda; Sahu, Surasri N.; Kothary, Mahendra H.; Chen, Arlene; Baker, Ron; Hutchinson, Richard; Blackmore, Carina; Cebula, Thomas A.; Huq, Anwar; Colwell, Rita R.



First skull of Antillothrix bernensis, an extinct relict monkey from the Dominican Republic  

PubMed Central

The nearly pristine remains of Antillothrix bernensis, a capuchin-sized (Cebus) extinct platyrrhine from the Dominican Republic, have been found submerged in an underwater cave. This represents the first specimen of an extinct Caribbean primate with diagnostic craniodental and skeletal parts in association, only the second example of a skull from the region, and one of the most complete specimens of a fossil platyrrhine cranium yet discovered. Cranially, it closely resembles living cebines but is more conservative. Dentally, it is less bunodont and more primitive than Cebus, with crowns resembling Saimiri (squirrel monkeys) and one of the oldest definitive cebines, the late Early Miocene Killikaike blakei from Argentina. The tricuspid second molar also resembles the enigmatic marmosets and tamarins, whose origins continue to present a major gap in knowledge of primate evolution. While the femur is oddly short and stout, the ulna, though more robust, compares well with Cebus. As a member of the cebid clade, Antillothrix demonstrates that insular Caribbean monkeys are not monophyletically related and may not be the product of a single colonizing event. Antillothrix bernensis is an intriguing mosaic whose primitive characters are consistent with an early origin, possibly antedating the assembly of the modern primate fauna in greater Amazonia during the La Venta horizon. While most Greater Antillean primate specimens are quite young geologically, this vanished radiation, known from Cuba (Paralouatta) and Jamaica (Xenothrix) as well as Hispaniola, appears to be composed of long-lived lineages like several other mainland clades. PMID:20659936

Rosenberger, Alfred L.; Cooke, Siobhán B.; Rímoli, Renato; Ni, Xijun; Cardoso, Luis



First skull of Antillothrix bernensis, an extinct relict monkey from the Dominican Republic.  


The nearly pristine remains of Antillothrix bernensis, a capuchin-sized (Cebus) extinct platyrrhine from the Dominican Republic, have been found submerged in an underwater cave. This represents the first specimen of an extinct Caribbean primate with diagnostic craniodental and skeletal parts in association, only the second example of a skull from the region, and one of the most complete specimens of a fossil platyrrhine cranium yet discovered. Cranially, it closely resembles living cebines but is more conservative. Dentally, it is less bunodont and more primitive than Cebus, with crowns resembling Saimiri (squirrel monkeys) and one of the oldest definitive cebines, the late Early Miocene Killikaike blakei from Argentina. The tricuspid second molar also resembles the enigmatic marmosets and tamarins, whose origins continue to present a major gap in knowledge of primate evolution. While the femur is oddly short and stout, the ulna, though more robust, compares well with Cebus. As a member of the cebid clade, Antillothrix demonstrates that insular Caribbean monkeys are not monophyletically related and may not be the product of a single colonizing event. Antillothrix bernensis is an intriguing mosaic whose primitive characters are consistent with an early origin, possibly antedating the assembly of the modern primate fauna in greater Amazonia during the La Venta horizon. While most Greater Antillean primate specimens are quite young geologically, this vanished radiation, known from Cuba (Paralouatta) and Jamaica (Xenothrix) as well as Hispaniola, appears to be composed of long-lived lineages like several other mainland clades. PMID:20659936

Rosenberger, Alfred L; Cooke, Siobhán B; Rímoli, Renato; Ni, Xijun; Cardoso, Luis



Rethinking Antillothrix: the mandible and its implications.  


A mandible of the Hispaniolan primate Antillothrix bernensis, virtually complete and providing the only definitive evidence of the species' lower dentition, has been discovered in a submerged Dominican Republic cave. The new specimen enables a more certain assessment of the species' phylogenetic position than previously possible. It belongs to the same individual as the nearly complete young adult cranium and postrcranial elements found earlier at the same site. Of the extinct Caribbean platyrrhines, the jaw compares well with partial mandibles representing Xenothrix mcgregori, from Jamaica. Among living platyrrhines, it closely resembles Callicebus and Aotus, as documented in a biometric analysis employing three-dimensional geometric morphometrics of Callicebus, Aotus, Pithecia, Chiropotes, Cacajao, Cebus, and Saimiri. The jaw falls within the morphological variability of Callicebus and Aotus in this three-dimensional analysis, is otherwise most similar to Pithecia, and is distinct from cebines. Lower molars resemble the Haitian primate, Insulacebus, a genus known by a full dentition and gnathic fragments with a pattern of derived features also present in Xenothrix. Considering the available craniodental and postcranial evidence, we conclude that Antillothrix is not properly classified as cebid but rather is best grouped with Pitheciidae, an idea long central to discussions of the phylogenetic affinities of the Greater Antillean primates. Since Antillothrix and Insulacebus are more primitive anatomically than the highly modified Xenothrix, it is tempting to surmise that the origins of the latter involved a vicariance or dispersal event via Hispaniola isolating it on Jamaica. PMID:23526607

Rosenberger, Alfred L; Klukkert, Zachary S; Cooke, Siobhán B; Rímoli, Renato



Calculation of source and structural parameters at regional and teleseismic distances  

NASA Astrophysics Data System (ADS)

Wave number integration and generalized ray theory methods for computation of synthetic seismograms have been used to model short-period local and near regional seismograms from small (M1 2.5 - 4.0) earthquakes located in Australia and India. When the effect of crustal structure is adequately known, source depth can be determined with an accuracy of 1 km or less from sP and Rg wave arrivals within the observed wave forms. The determination of source depth directly from the wave form data offers a method of discrimination of explosives from earthquakes using sparse station distribution since it is unlikely that explosions will be emplaced below depths of a few kilometers. A method for computing the wavefield for SH and P-SV line sources in an elastic layer-over-halfspace model with corrugated boundaries has been developed to study the effect of imperfections in a crustal waveguide. The formulation allows the computation of the wave field at any point within the model. The formulation is appropriate for the study of scattered high frequency crustal phases such as Pg and Lg and mantle phases such as Pn and Sn. Source parameters of selected earthquakes have been obtained from inversion of teleseismic body wave data for use in regional wave propagation studies. Upper mantle structure was examined using P waves from an intermediate depth earthquake under Hispaniola.

Langston, Charles A.



Earthquake Shakes ``Big Bend'' Region of North America-Caribbean Boundary Zone  

NASA Astrophysics Data System (ADS)

At 12:45 pm on 22 September, a M6.5 earthquake severely shook the northern Dominican Republic on the island of Hispaniola. The earthquake caused extensive damage to buildings in the major cities of Puerto Plata and Santiago, along with landslides in outlying areas. The main shock was followed by a large aftershock of M5.1 1 hr and 45 min later. Unfortunately, one person died due to collapse of a building during the main shock, two elderly people died of heart attacks, and one person jumped out of a building and later died of injuries. Fortunately, two partially collapsed school buildings and several office buildings in Puerto Plata that were severely damaged were unoccupied at the time of the early morning main shock. Aftershocks ranging up to nearly M5 continued for over a month, alarming local inhabitants. The M6.5 earthquake is the strongest shock to affect the northern Dominican Republic since a series of thrust events ranging from M6.1-8.1 occurred offshore and northeast of the Dominican Republic between 1943 and 1953 [Dolan and Wald, 1998]. This article summarizes the tectonic setting of the recent earthquake, its focal mechanism and inferred fault plane, damage, and ongoing research.

Mann, Paul; Calais, Eric; Huerfano, Victor



[Chikungunya: a challenge for the Dominican Republic's health services].  


The Region of the Americas has been affected since December 2013 by a chikungunya epidemic for the first time. Although the first cases were recorded in the French Caribbean, the epidemic quickly spread to the Dominican Republic due to trade and people movements. The Dominican Republic, which shares the island of Hispaniola with Haiti, has a population of 10 million. This article contains information from a range of different publications and official documents about the chikungunya virus infection and epidemic. These papers were extremely helpful for guiding the response to the epidemic in the Dominican Republic and may also be useful for enhancing knowledge of the virus and responses among health workers elsewhere in the region. Particular attention is drawn to the important research undertaken in countries and territories affected by the epidemic in the Indian Ocean area. This is the case, for example, of the island of La Réunion, where the epidemic had an attack rate of more than 30% between 2005 and 2007. Researchers were able to identify risk groups, severe and atypical forms of the infection, cases of vertical transmission, chronic disease causing recurrent pain over three years, and directly- or indirectly-related deaths from the virus. Given its high attack rate, the chikungunya virus has emerged as an exceptional challenge for health ministries and calls for appropriate organized responses from the health services, prioritization of care for risk groups and patients exhibiting severe forms of the disease, and effective social communication and intersectoral actions. PMID:25604103

Moya, José; Pimentel, Raquel; Puello, José



Evolutionary stasis and lability in thermal physiology in a group of tropical lizards.  


Understanding how quickly physiological traits evolve is a topic of great interest, particularly in the context of how organisms can adapt in response to climate warming. Adjustment to novel thermal habitats may occur either through behavioural adjustments, physiological adaptation or both. Here, we test whether rates of evolution differ among physiological traits in the cybotoids, a clade of tropical Anolis lizards distributed in markedly different thermal environments on the Caribbean island of Hispaniola. We find that cold tolerance evolves considerably faster than heat tolerance, a difference that results because behavioural thermoregulation more effectively shields these organisms from selection on upper than lower temperature tolerances. Specifically, because lizards in very different environments behaviourally thermoregulate during the day to similar body temperatures, divergent selection on body temperature and heat tolerance is precluded, whereas night-time temperatures can only be partially buffered by behaviour, thereby exposing organisms to selection on cold tolerance. We discuss how exposure to selection on physiology influences divergence among tropical organisms and its implications for adaptive evolutionary response to climate warming. PMID:24430845

Muñoz, Martha M; Stimola, Maureen A; Algar, Adam C; Conover, Asa; Rodriguez, Anthony J; Landestoy, Miguel A; Bakken, George S; Losos, Jonathan B



Seismic-zonation of Port-au-Prince using pixel- and object-based imaging analysis methods on ASTER GDEM  

USGS Publications Warehouse

We report about a preliminary study to evaluate the use of semi-automated imaging analysis of remotely-sensed DEM and field geophysical measurements to develop a seismic-zonation map of Port-au-Prince, Haiti. For in situ data, Vs30 values are derived from the MASW technique deployed in and around the city. For satellite imagery, we use an ASTER GDEM of Hispaniola. We apply both pixel- and object-based imaging methods on the ASTER GDEM to explore local topography (absolute elevation values) and classify terrain types such as mountains, alluvial fans and basins/near-shore regions. We assign NEHRP seismic site class ranges based on available Vs30 values. A comparison of results from imagery-based methods to results from traditional geologic-based approaches reveals good overall correspondence. We conclude that image analysis of RS data provides reliable first-order site characterization results in the absence of local data and can be useful to refine detailed site maps with sparse local data. ?? 2011 American Society for Photogrammetry and Remote Sensing.

Yong, A.; Hough, S.E.; Cox, B.R.; Rathje, E.M.; Bachhuber, J.; Dulberg, R.; Hulslander, D.; Christiansen, L.; Abrams, M.J.



Seismic zonation of Port-Au-Prince using pixel- and object-based imaging analysis methods on ASTER GDEM  

USGS Publications Warehouse

We report about a preliminary study to evaluate the use of semi-automated imaging analysis of remotely-sensed DEM and field geophysical measurements to develop a seismic-zonation map of Port-au-Prince, Haiti. For in situ data, VS30 values are derived from the MASW technique deployed in and around the city. For satellite imagery, we use an ASTER GDEM of Hispaniola. We apply both pixel- and object-based imaging methods on the ASTER GDEM to explore local topography (absolute elevation values) and classify terrain types such as mountains, alluvial fans and basins/near-shore regions. We assign NEHRP seismic site class ranges based on available VS30 values. A comparison of results from imagery-based methods to results from traditional geologic-based approaches reveals good overall correspondence. We conclude that image analysis of RS data provides reliable first-order site characterization results in the absence of local data and can be useful to refine detailed site maps with sparse local data.

Yong, Alan; Hough, Susan E.; Cox, Brady R.; Rathje, Ellen M.; Bachhuber, Jeff; Dulberg, Ranon; Hulslander, David; Christiansen, Lisa; and Abrams, Michael J.



Hurricane Georges' Landfall in the Dominican Republic: Detailed Airborne Doppler Radar Imagery  

NASA Technical Reports Server (NTRS)

Current understanding of landfalling tropical cyclones is limited, especially with regard to convective scale processes. On 22 September 1998 Hurricane Georges made landfall on the island of Hispaniola, leaving behind a trail of death and devastation, largely the result of excessive rainfall, not sea level surge or wind. Detailed airborne measurements were taken as part of the Third Convection and Moisture Experiment (CAMEX-3). Of Particular interest are the ER-2 nadir X-band Doppler radar (EDOP) data, which provide a first-time high-resolution view of the precipitation and airflow changes as a hurricane interacts with mountainous terrain. The circulation of hurricane Georges underwent an obvious transition during landfall, evident in the rapid increase in minimum sea-level pressure, the subsidence of the eyewall anvil, and a decrease in average ice concentrations in the eyewall. The eye, as seen in satellite imagery, disappeared, but contrary to current understanding, this was not due to eyewall contraction but rather to convective eruption within the eye. The main convective event within the eye, with upper-level updraft magnitudes near 20 m/s and 89 GHz brightness temperatures below 100 K, occurred when the eye moved over the Cordillera Central, the island's main mountain chain. The location, intensity and evolution of this convection indicate that it was coupled to the surface orography. It is likely that surface rain rates increased during landfall, because of effective droplet collection, both in the convection and in the more widespread stratiform rainfall areas over the island. Evidence for this is the increase in radar reflectivity below the bright band of 1-2 dB/km down to ground-level. Such increase was absent offshore. Such low-level rain enhancement, which cannot be detected in satellite images of upwelling infrared or microwave radiation, must be due to the ascent of boundary-layer air over the topography.

Geerts, B.; Heymsfield, G. M.; Tian, L.; Halverson, J. B.; Guillory, A.; Mejia, M. I.



Slip rate and earthquake recurrence along the central Septentrional fault, North American-Caribbean plate boundary, Dominican Republic  

USGS Publications Warehouse

The Septentrional fault zone (SFZ) is the major North American-Caribbean, strike-slip, plate boundary fault at the longitude of eastern Hispaniola. The SFZ traverses the densely populated Cibao Valley of the Dominican Republic, forming a prominent scarp in alluvium. Our studies at four sites along the central SFZ are aimed at quantifying the late Quaternary behavior of this structure to better understand the seismic hazard it represents for the northeastern Caribbean. Our investigations of excavations at sites near Rio Cenovi show that the most recent ground-rupturing earthquake along this fault in the north central Dominican Republic occurred between A.D. 1040 and A.D. 1230, and involved a minimum of ???4 m of left-lateral slip and 2.3 m of normal dip slip at that site. Our studies of offset stream terraces at two locations, Rio Juan Lopez and Rio Licey, provide late Holocene slip rate estimates of 6-9 mm/yr and a maximum of 11-12 mm/yr, respectively, across the Septentrional fault. Combining these results gives a best estimate of 6-12 mm/yr for the slip rate across the SFZ. Three excavations, two near Tenares and one at the Rio Licey site, yielded evidence for the occurrence of earlier prehistoric earthquakes. Dates of strata associated with the penultimate event suggest that it occurred post-A.D. 30, giving a recurrence interval of 800-1200 years. These studies indicate that the SFZ has likely accumulated elastic strain sufficient to generate a major earthquake during the more than 800 years since it last slipped and should be considered likely to produce a destructive future earthquake.

Prentice, C.S.; Mann, P.; Pena, L.R.; Burr, G.



Chronology of the Pueblo Viejo epithermal gold-silver deposit, Dominican Republic: formation in an Early Cretaceous intra-oceanic island arc and burial under ophiolite  

NASA Astrophysics Data System (ADS)

The Pueblo Viejo deposit (production to 1996: 166 t Au, 760 t Ag) is located in the Dominican Republic on the Caribbean island of Hispaniola and ranks as one of the largest high-sulfidation/acid-sulfate epithermal deposits (reserves in 2007: 635 t Au, 3,648 t Ag). One of the advanced argillic ore bodies is cut by an inter-mineral andesite porphyry dike, which is altered to a retrograde chlorite-illite assemblage but overprinted by late-stage quartz-pyrite-sphalerite veins and associated low-grade Au, Ag, Zn, Cd, Hg, In, As, Se, and Te mineralization. The precise TIMS U-Pb age (109.6 ± 0.6 Ma) of the youngest zircon population in this dike confirms that the deposit is part of the Early Cretaceous Los Ranchos intra-oceanic island arc. Intrusion-related gold-sulfide mineralization took place during late andesite-dacite volcanism within a thick pile (>200 m) of carbonaceous sand- and siltstones deposited in a restricted marine basin. The high-level deposit was shielded from erosion after burial under a late Albian (109-100 Ma) ophiolite complex (8 km thick), which was in turn covered by the volcano-sedimentary successions (>4 km) of a Late Cretaceous-Early Tertiary calc-akaline magmatic arc. Estimates of stratigraphic thickness and published alunite, illite, and feldspar K-Ar ages and closure temperatures (alunite 270 ± 20°C, illite 260 ± 30°C, K-feldspar 150°C) indicate a burial depth of about 12 km at 80 Ma. During peak burial metamorphism (300°C and 300 MPa), the alteration assemblage kaolinite + quartz in the deposit dehydrated to pyrophyllite. Temperature-time relations imply that the Los Ranchos terrane then cooled at a rate of 3-4°C/Ma during slow uplift and erosion.

Mueller, Andreas G.; Hall, Gregory C.; Nemchin, Alexander A.; O'Brien, Darren



Late Holocene liquefaction features in the Dominican Republic: A powerful tool for earthquake hazard assessment in the northeastern Caribbean  

USGS Publications Warehouse

Several generations of sand blows and sand dikes, indicative of significant and recurrent liquefaction, are preserved in the late Holocene alluvial deposits of the Cibao Valley in northern Dominican Republic. The Cibao Valley is structurally controlled by the Septentrional fault, an onshore section of the North American-Caribbean strike-slip plate boundary. The Septentrional fault was previously studied in the central part of the valley, where it sinistrally offsets Holocene terrace risers and soil horizons. In the eastern and western parts of the valley, the Septentrional fault is buried by Holocene alluvial deposits, making direct study of the structure difficult. Liquefaction features that formed in these Holocene deposits as a result of strong ground shaking provide a record of earthquakes in these areas. Liquefaction features in the eastern Cibao Valley indicate that at least one historic earthquake, probably the moment magnitude, M 8, 4 August 1946 event, and two to four prehistoric earthquakes of M 7 to 8 struck this area during the past 1100 yr. The prehistoric earthquakes appear to cluster in time and could have resulted from rupture of the central and eastern sections of the Septentrional fault circa A.D. 1200. Liquefaction features in the western Cibao Valley indicate that one historic earthquake, probably the M 8, 7 May 1842 event, and two prehistoric earthquakes of M 7-8 struck this area during the past 1600 yr. Our findings suggest that rupture of the Septentrional fault circa A.D. 1200 may have extended beyond the central Cibao Valley and generated an earthquake of M 8. Additional information regarding the age and size distribution of liquefaction features is needed to reconstruct the prehistoric earthquake history of Hispaniola and to define the long-term behavior and earthquake potential of faults associated with the North American-Caribbean plate boundary.

Tuttle, M.P.; Prentice, C.S.; Dyer-Williams, K.; Pena, L.R.; Burr, G.



Mélanges and olistostromes in the Puerto Plata area (northern Dominican Republic) as a record of subduction and collisional processes between the Caribbean and North-American plates  

NASA Astrophysics Data System (ADS)

The Cordillera Septentrional records the oblique subduction and collisional processes between the Caribbean and North American plates during Late Cretaceous to early Palaeogene times. The Puerto Plata basement complex of this range is considered to represent a fragment of the frontal part of the Great Arc of the Caribbean in Hispaniola that originated during thrusting of the Caribbean plate onto the North American shelf. This paper describes and interprets mélange-type formations spatially related to this basement complex and its associated sedimentary cover, the Imbert Fm. Such formations include the San Marcos olistostromic Fm and a unit of Serpentinic Breccias located at the base and interbedded in the lower section of the former. Both units are Eocene in age, have been mainly deposited by syntectonic subaqueous mass-transport processes and typically host a varied mixture of blocks of known and unknown origin, including high-P metamorphic rocks (knockers). Cartoon models of palaeotectonic reconstructions depicting the final stages of subduction and the onset of collisional process in Early and Middle Eocene times respectively, are proposed in order to show the original relationships among all geological units involved in the study area. The Serpentinic Breccias are interpreted as being the result of extensive sedimentary recycling of peridotite and serpentinite massive bodies or subduction related mélanges when exposed at the surface by return flow during early exhumation stages of the accretionary complex, coevally with the end of island-arc volcanism. This process is inferred to be the triggering mechanism for the feeding of originally deep-sited knockers, probably in combination with strike-slip tectonics and associated mud diapirism The slightly younger San Marcos Fm records the collision event and main exhumation stage, while displaying the typical features present in olistostromes and other mass-wasting, gravitationally-driven deposits recognized in extensive areas of forearc and accretionary complexes involved in arc-continent collisional processes.

Hernaiz Huerta, P. P.; Pérez-Valera, F.; Abad, M.; Monthel, J.; Diaz de Neira, A.



Late-Holocene paleoenvironmental change at mid-elevation on the Caribbean slope of the Cordillera Central, Dominican Republic: a multi-site, multi-proxy analysis  

NASA Astrophysics Data System (ADS)

High-resolution proxy records from the circum-Caribbean region indicate significant variation in Late Holocene climate, especially precipitation, attributed primarily to shifts in the mean annual position of the Intertropical Convergence Zone (ITCZ). The paleoenvironmental and cultural impacts of this Late-Holocene climate variability have been analyzed intensively in the western Caribbean, and to a lesser extent in the southern Caribbean. However, the occurrence and impacts of Late Holocene climate shifts in the eastern Caribbean, especially in island interiors, has not been well documented. Here we present sediment records of Late-Holocene paleoenvironmental change from two lakes located on the Caribbean slope of the Cordillera Central in the Dominican Republic that span the last ?3000 years. Sediment characteristics, pollen, charcoal, biogenic carbonate assemblages and isotopic composition, and bulk sedimentary carbon isotope values in Laguna Castilla and Laguna de Salvador indicate extreme shifts in hydrology, vegetation, and disturbance regimes in response to climate change and human activity in the lake watersheds. Close correspondence between the hydrological histories of the lakes and trace metal concentrations in sediments of the Cariaco Basin indicate that precipitation variability here responds to the same controls, and may similarly reflect shifts in the mean annual position of the ITCZ. Human occupation of the watersheds appears to be closely linked to severe dry periods and may indicate larger scale cultural responses to precipitation variability on the island of Hispaniola. Prehistoric human populations strongly affected vegetation and disturbance regimes in the lake watersheds. Impacts may have lasted several centuries and may have been more severe than impacts of modern populations.

Lane, Chad S.; Horn, Sally P.; Mora, Claudia I.; Orvis, Kenneth H.



Faith based aviation: An ethnographic study of missionary flights international  

NASA Astrophysics Data System (ADS)

The development of faith-based missionary aviation is a post-World War II phenomenon. The war effort demonstrated the value, utility, and global reach of aviation to remote, underdeveloped areas of the world. With the beginnings of a worldwide infrastructure for aviation, Christian aviators realized aviation could increase the range and effectiveness of their efforts to reach the world for Christ (Mellis, 2006). Although individual organizations provide statistical information and data about flight operations there is a lack of external evidence and relevant research literature confirming the scope and value of these faith based aviation organizations and operations. A qualitative, ethnographic study was conducted to document the activities of one faith-based aviation organization to gain an understanding of this little known aspect of civilian aviation. The study was conducted with Missionary Flights International (MFI) of Fort Pierce, FL which has been involved in faith-based, missionary aviation since its inception in 1964. As an aviation organization "MFI strives to offer affiliated missions the kind of efficient service and professionalism expected of an airline operation" (Missionary Flights International, 2013, p.1). MFI is a lifeline for missionaries to Haiti and the Dominican Republic, fulfilling their motto of "Standing in the Gap". MFI provides twice a week service to the island of Hispaniola and the Republic of Haiti. In this in-depth study insight and understanding was gained into the purpose of MFI, their daily routines and operations, and the challenges they face in maintaining their flight services to Haiti. This study provided documentation of the value and utility of such aviation efforts and of the individuals involved in this endeavor.

Cooper, Joseph H.


Reconstructing the Population Genetic History of the Caribbean  

PubMed Central

The Caribbean basin is home to some of the most complex interactions in recent history among previously diverged human populations. Here, we investigate the population genetic history of this region by characterizing patterns of genome-wide variation among 330 individuals from three of the Greater Antilles (Cuba, Puerto Rico, Hispaniola), two mainland (Honduras, Colombia), and three Native South American (Yukpa, Bari, and Warao) populations. We combine these data with a unique database of genomic variation in over 3,000 individuals from diverse European, African, and Native American populations. We use local ancestry inference and tract length distributions to test different demographic scenarios for the pre- and post-colonial history of the region. We develop a novel ancestry-specific PCA (ASPCA) method to reconstruct the sub-continental origin of Native American, European, and African haplotypes from admixed genomes. We find that the most likely source of the indigenous ancestry in Caribbean islanders is a Native South American component shared among inland Amazonian tribes, Central America, and the Yucatan peninsula, suggesting extensive gene flow across the Caribbean in pre-Columbian times. We find evidence of two pulses of African migration. The first pulse—which today is reflected by shorter, older ancestry tracts—consists of a genetic component more similar to coastal West African regions involved in early stages of the trans-Atlantic slave trade. The second pulse—reflected by longer, younger tracts—is more similar to present-day West-Central African populations, supporting historical records of later transatlantic deportation. Surprisingly, we also identify a Latino-specific European component that has significantly diverged from its parental Iberian source populations, presumably as a result of small European founder population size. We demonstrate that the ancestral components in admixed genomes can be traced back to distinct sub-continental source populations with far greater resolution than previously thought, even when limited pre-Columbian Caribbean haplotypes have survived. PMID:24244192

Moreno-Estrada, Andrés; Gravel, Simon; Zakharia, Fouad; McCauley, Jacob L.; Byrnes, Jake K.; Gignoux, Christopher R.; Ortiz-Tello, Patricia A.; Martínez, Ricardo J.; Hedges, Dale J.; Morris, Richard W.; Eng, Celeste; Sandoval, Karla; Acevedo-Acevedo, Suehelay; Norman, Paul J.; Layrisse, Zulay; Parham, Peter; Martínez-Cruzado, Juan Carlos; Burchard, Esteban González; Cuccaro, Michael L.; Martin, Eden R.; Bustamante, Carlos D.



Bivergent thrust wedges surrounding oceanic island arcs: Insight from observations and sandbox models of the northeastern caribbean plate  

USGS Publications Warehouse

At several localities around the world, thrust belts have developed on both sides of oceanic island arcs (e.g., Java-Timor, Panama, Vanuatu, and the northeastern Caribbean). In these localities, the overall vergence of the backarc thrust belt is opposite to that of the forearc thrust belt. For example, in the northeastern Caribbean, a north-verging accretionary prism lies to the north of the Eastern Greater Antilles arc (Hispaniola and Puerto Rico), whereas a south-verging thrust belt called the Muertos thrust belt lies to the south. Researchers have attributed such bivergent geometry to several processes, including: reversal of subduction polarity; subduction-driven mantle flow; stress transmission across the arc; gravitational spreading of the arc; and magmatic inflation within the arc. New observations of deformational features in the Muertos thrust belt and of fault geometries produced in sandbox kinematic models, along with examination of published studies of island arcs, lead to the conclusion that the bivergence of thrusting in island arcs can develop without reversal of subduction polarity, without subarc mantle flow, and without magmatic inflation. We suggest that the Eastern Greater Antilles arc and comparable arcs are simply crustalscale bivergent (or "doubly vergent") thrust wedges formed during unidirectional subduction. Sandbox kinematic modeling suggests, in addition, that a broad retrowedge containing an imbricate fan of thrusts develops only where the arc behaves relatively rigidly. In such cases, the arc acts as a backstop that transmits compressive stress into the backarc region. Further, modeling shows that when arcs behave as rigid blocks, the strike-slip component of oblique convergence is accommodated entirely within the prowedge and the arc-the retrowedge hosts only dip-slip faulting ("frontal thrusting"). The existence of large retrowedges and the distribution of faulting in an island arc may, therefore, be evidence that the arc is relatively rigid. The rigidity of an island arc may arise from its mafi c composition and has implications for seismic-hazard analysis. ?? 2009 Geological Society of America.

ten Brink, U.S.; Marshak, S.; Granja, Bruna J. L.



Slip rate and earthquake recurrence along the central Septentrional fault, North American-Caribbean plate boundary, Dominican Republic  

NASA Astrophysics Data System (ADS)

The Septentrional fault zone (SFZ) is the major North American-Caribbean, strike-slip, plate boundary fault at the longitude of eastern Hispaniola. The SFZ traverses the densely populated Cibao Valley of the Dominican Republic, forming a prominent scarp in alluvium. Our studies at four sites along the central SFZ are aimed at quantifying the late Quaternary behavior of this structure to better understand the seismic hazard it represents for the northeastern Caribbean. Our investigations of excavations at sites near Rio Cenovi show that the most recent ground-rupturing earthquake along this fault in the north central Dominican Republic occurred between A.D. 1040 and A.D. 1230, and involved a minimum of ˜4 m of left-lateral slip and 2.3 m of normal dip slip at that site. Our studies of offset stream terraces at two locations, Rio Juan Lopez and Rio Licey, provide late Holocene slip rate estimates of 6-9 mm/yr and a maximum of 11-12 mm/yr, respectively, across the Septentrional fault. Combining these results gives a best estimate of 6-12 mm/yr for the slip rate across the SFZ. Three excavations, two near Tenares and one at the Rio Licey site, yielded evidence for the occurrence of earlier prehistoric earthquakes. Dates of strata associated with the penultimate event suggest that it occurred post-A.D. 30, giving a recurrence interval of 800-1200 years. These studies indicate that the SFZ has likely accumulated elastic strain sufficient to generate a major earthquake during the more than 800 years since it last slipped and should be considered likely to produce a destructive future earthquake.

Prentice, Carol S.; Mann, Paul; PeñA, Luis R.; Burr, G.



Permo-Triassic reconstruction of western Pangea and the evolution of the Gulf of Mexico&solCaribbean region  

NASA Astrophysics Data System (ADS)

A Permo-Triassic reconstruction of western Pangea (North America, South America, Africa) is proposed that is characterized by (1) definition of the North Atlantic fit by matching of marginal offsets (fracture zones) along the opposing margins, (2) a South Atlantic fit that is tighter than the BuIlard fit and that is achieved by treating Africa as two plates astride the Benue Trough and related structures during the Cretaceous, (3) complete closure of the Proto-Atlantic Ocean between North and South America, accomplished by placing the Yucatan block between the Ouachita Mountains and Venezuela, (4) a proposed Hercynian suture zone that separates zones of foreland thrusting from zones of arc-related magmatic activity; to the northwest of this suture lie the Chortis block and Mexico and most of North America, and to the southeast lie South America, the Yucatan Block, Florida and Africa, and (5) satisfaction of paleomagmatic data from North America, South America, and Africa. Beginning with the proposed reconstruction, the relative motion history of South America with respect of North America is defined by using the finite difference method. Within the framework provided by the proposed relative motion history, an evolutionary model for the development of the Gulf of Mexico and Caribbean region is outlined in a series of 13 plate boundary reconstructions at time intervals from the Jurassic to the present. The model includes (1) formation of the Gulf of Mexico by 140 Ma, (2) Pacific provenance of the Caribbean plate through the North America-South America gap during Cretaceous time, (3) Paleocene-Early Eocene back arc spreading origin for the Yucatan Basin, whereby Cuba is the frontal arc and the Nicaragua Rise-Jamaica-Southern Hispaniola is the remnant arc, and (4) 1200 km of post-Eocene cumulative offset along both the Northern and Southern Caribbean Plate Boundary Zones, allowing large-scale eastward migration of the Caribbean plate with respect to the North and South American Plates.

Pindell, James; Dewey, John F.



Changes in Late Cretaceous-Quaternary Caribbean plate motion directions inferred from paleostress measurements from striated fault planes  

NASA Astrophysics Data System (ADS)

We compiled paleostress analyses from previous research works collected at 591 localities of striated fault planes in rocks ranging in age from Late Cretaceous to Quaternary in the circum-Caribbean and Mexico. The purpose of the study is to quantify a progressive clockwise rotation of the Caribbean plate during its Late Cretaceous to recent subduction of the Proto-Caribbean seaway. Paleostress analysis is based on the assumption that slickenside lineations indicate both the direction and sense of maximum resolved shear stress on that fault plane. We have plotted directions of maximum horizontal stress onto plate tectonic reconstructions of the circum-Caribbean plate boundaries and infer that these directions are proxies for paleo-plate motion directions of the Caribbean plate. Plotting these stress directions onto reconstructions provided a better visualization of the relation of stress directions to blocks at their time of Late Cretaceous to recent deformation. Older, more deformed rocks of Late Cretaceous to Eocene ages yield a greater scatter in derived paleostress directions as these rocks have steeper dips, more pervasive faulting, and were likely affected by large rotations as known from previous paleomagnetic studies of Caribbean plate margins. Despite more scatter in measurements from older rock units, four major events that affected the Caribbean plate and the Great Arc of the Caribbean (GAC) are recognizable from changing orientations of stress directions: 1) Late Cretaceous collision of the GAC with southern Mexico and Colombia is consistent with NE directions of maximum compression in rocks of this age range in southern Mexico and EW directions in Colombia as the GAC approached the Proto-Caribbean seaway; 2) Paleocene-Eocene collision of the GAC with the Bahamas platform in Cuba and Hispaniola and with the South American plate in Venezuela is consistent with CW rotations of stress directions in rocks of these ages in the northern Caribbean and CCW rotations of these rocks in the southern Caribbean ; 3) Late Miocene collision and indentation of the Panama arc with northwestern South America is consistent with EW directions in rocks of these ages; and 4) Oligocene to recent strike-slip faulting along the northern and southern boundaries of the Caribbean shows consistent directions for the northern (NE) and southern (NW) Caribbean. Stress directions document the progressive clockwise rotation of the Caribbean plate and the GAC motion from NE in the Late Cretaceous, to ENE in the Paleogene, to EW in the Neogene.

Batbayar, K.; Mann, P.; Hippolyte, J.



Mass flow in serpentinite-hosted subduction channels: P - T - t path patterns of metamorphic blocks in the Rio San Juan mélange (Dominican Republic)  

NASA Astrophysics Data System (ADS)

Serpentinite mélanges formed in the subduction zone channel of an intra-oceanic arc system are exposed in the Rio San Juan complex of northern Hispaniola. This study presents an array of pressure-temperature paths for 14 metamorphic blocks. The P- T paths were constructed from isochemical P- T phase diagrams ("pseudosections") as well as multi-equilibrium calculations on mineral assemblages, providing for the first time the means to compare P- T paths in both time and space. The study involves metabasic, meta-andesitic and metagranitic lithologies. Subduction was slow, so that the uninterrupted thermal development of the subduction zone can be followed over a time span of more than 60 Myr. Early eclogites mirror "warm" subduction zone gradients (˜18°/km); both clockwise and anticlockwise paths are found. The maximum P- T conditions reached are ˜800 °C and 26 kbar, thus indicating sufficient buoyancy for return flow from depths exceeding the stability of serpentine. As the subduction zone matures, P/ T gradients gradually steepen to ˜6°/km, and the maximum depth from which blocks are exhumed decreases in a regular way from 26 to 17 kbar. The exhumed metamorphic products are initially omphacite-bearing blueschists and evolve to jadeite- and lawsonite-bearing blueschists with veins of jadeitite jade. Lawsonite eclogites are not found, because in the latest history of the subduction zone the predominantly basic geochemistry of the blocks evolved to more intermediate compositions inappropriate for this rock type. There are no indications of systematic differences or episodic variations in subduction/exhumation velocities, so that a continuous cycling of material in the subduction zone channel is indicated. In two blocks of eclogite and garnet blueschist an earlier amphibolite-facies history at 575-700 °C and 7-8 kbar can be documented, suggesting erosion of the base of the overlying intra-oceanic island arc. The fossil subduction zone studied in detail here is part of a much larger feature exposed at intervals around the perimeter of the Caribbean plate where the intra-oceanic arc has collided with North and South America. The continuous history documented here from before 120 Ma to after 60 Ma constrains regional plate tectonic models to incorporate a similarly uninterrupted continuous history of eastward movement of the Caribbean plate with respect to North and South America.

Krebs, M.; Schertl, H.-P.; Maresch, W. V.; Draper, G.



Middle America - Regional Geological Integrity, Hydrocarbon Implications.  

NASA Astrophysics Data System (ADS)

Dogma holds that the Caribbean Plate and its islands formed in the Pacific and comprise oceanic crust and intra- oceanic arc rocks. Middle America, between N and S America, manifests a regional, N35°E and N60°W tectonic fabric. The NE trend results from Triassic-Jurassic reactivation of Palaeozoic convergent structures as extensional faults during Pangean rifting and commencement of N America drift. The NW trend parallels major inter-continental faults and oceanic fractures along which extension and drift occurred. Triassic-Jurassic red beds accumulated in the NE trending, intra-continental rifts of N, S and Central America. Proximal extended continental margins subsided to accommodate thick Cretaceous carbonate sections (Florida - Bahamas, Campeche, Nicaragua Rise). Distal margins formed continental blocks flanked by seaward-dipping wedges. Seismic and drilling in basins along the eastern seaboard of N America (Baltimore Canyon to Blake Plateau) document Triassic-Jurassic red beds overlain by salt and carbonates. Hydrocarbons are present. In Middle America the Gulf of Mexico remained "intra-continental", surrounded by continental blocks (N America, Maya, Florida). The area further south experienced greater extension, manifest by diverging oceanic fracture patterns to the east and west. Seismic data over the Caribbean Plateau reveal deep architecture of NE trending highs flanked by dipping wedges of reflections, similar to eastern N America distal basins. DSDP drilling calibrated the overlying smooth seismic Horizon B" as recording Cenomanian basalts. Smoothness, great lateral extent and coeval exposed sections with palaeosols followed by shallow marine carbonates suggest they were sub-aerial. Adjacent, rough seismic Horizon B" probably records top of submarine, serpentinized mantle. Seismic over the plateau also reveals features identical to drilled Sigsbee salt diapirs of the Gulf of Mexico. The regional tectonic fabric demonstrates a shared geological history of Middle American geographic components, negates rotations of the Maya and Chortis blocks required by Pacific models and shows that the Caribbean Plate formed in place. Regional geologic and seismic data indicate that much of "oceanic" Middle America is in fact underpinned by extended continental crust. Salt is present, and probably Jurassic, Cretaceous and Tertiary source rocks also. Oil is seen on Puerto Rico, Hispaniola, Jamaica, Cuba, Belize, Guatemala, Honduras, Nicaragua, Costa Rica and Panama. Prolific hydrocarbon provinces exist in the Gulf of Mexico and along northern S America. The submarine areas in between have significant hydrocarbon potential.

James, K. H.



Identification of Potential Tsunamogenic Areas From Multibeam and Seismic Data in the Greater Antilles South Slope  

NASA Astrophysics Data System (ADS)

As it is known, tsunamis have various general generating mechanisms associated with earthquakes, landslides/slumps and volcanic processes. Active tectonics along the north-eastern Caribbean plate is the principal cause de tsunami in the eastern Greater Antilles islands. In this area, earthquake and tsunami record suggest that the main tsunami sources are large shallow earthquakes (6.5) in submarine areas, which can yield a significant vertical motion over seafloor, and sudden landslides/slumps maybe triggered by this earthquakes generally in steeped bathymetry areas. In the spring of 2005 was carried out in the north-eastern Caribbean plate the marine geophysical survey GEOPRIO-DO aboard of Spanish R/V Hesp¦rides. This marine survey explored the north-eastern area of Puerto Rico and Virgin Islands and the southern slope of Dominican Republic and Puerto Rico. The survey included diverse geophysical techniques to research from deep to shallow structure, but with special emphasis on multibeam systematic mapping carried out in the Muertos Accretionary Prism and Muertos Trough, in the south of Dominican Republic and Puerto Rico. This accretionary complex is occupying a broad band of active compression regime with an east-west trend. It is limited to the south by the Muertos Trough (>5600 m depth), where the Venezuelan Basin oceanic crust is being underthrusted beneath Puerto Rico and Hispaniola islands. We have used multibeam systematic data to get detailed bathymetry grids in which we have made geothematic mapping (contours, slopes, slope direction, channel network). The processing of multibeam data and their integration with shallower seismic data has allowed us to make a detailed morphotectonic analysis. We have identified many seafloor structures like landslides/slumps and active fault zones with high tsunamogenic potential. Our results suggest that the combination of very active tectonics with steep seafloor slopes in the vicinity of highly populated islands yields high tsunami hazard for the eastern Greater Antilles. We consider the integration of high resolution multibeam data with shallow seismic data essential tools to identify sources with high tsunamogenic potential.

Granja, J.; Carbo, A.; Muñoz-Martin, A.; Martin Davila, J.; ten Brink, U.; Gomez, M.; Cordoba, D.; von Hilldebrandt, C.; Payero, J.



From 2012 HAITI-SIS Survey: thick-skin versus thin-skin tectonics partitioned along offshore strike-slip Faults-Haïti  

NASA Astrophysics Data System (ADS)

The characterization of the deformation along large strike-slip fault-systems like transpressive boundaries between N. Caribbean/N America is a challenging topic, which requires a multi-scale approach. Thanks to Haiti-sis new data, the precise description of the fault segmentation pattern, the sedimentogical distribution, the uplift/subsidence rates, the along-fault and intra-basin fluids circulations, allows to actualize the evolution of the deformation history up to present-day . All the co-seismic surface to near-surface events, have to be also identified in order to integrate geophysical solutions for the earthquake, within the present-day geological and structural pattern. These two approaches, ranging from geological to instantaneous time-scales have been used during multi-tools Haiti-Sis oceanographic survey, allowing to document and image these different aspects at a large scale. The complex strike-slip North Caribbean boundary registered significative stress partitioning. Oblique convergence is expressed by along-strike evolution; from rifted segments (Cayman Through) to transpressive ones (Haiti, Dominican Rep.), to subduction (Porto Rico). In the Haiti-Sis survey, we acquired new offshore data surrounding the active fault areas, in the Gonâve Bay, the Jamaica Channel and along Southern Peninsula. Mapping the sea-floor, and HR seismic acquisition were our main objectives, in order to characterize the fault and fold architecture, with a new delineation of active segments. Offshore piston cores, have been used as representative of the modern basin sedimentation, and to document the catastrophic events (earthquakes, massive flood or sudden destabilization of the platform ) represented by turbiditic or mass-flow sequences, with the objective to track the time recurrence of seismic events by dating some of these catastrophic sediment deposition. At surface, the other markers of the fault activity are linked with along-fault permeability and fluid circulation pathway changes. Geochemical signature and temperature of the fluids and gas, change drastically depending on location and depth provenance. Our first results show that 1) the present-day EPGF geometry results from oblique shortening processes along different segments of the fault. Deep basins previously localized south and north of the fault are inverted at different degrees, 2) the Gonâve Island is only the emerged part of a NW-SE, either growing large " anti-formal stack" or basement inversion responsible for the large present-day fold amplitude, or both of them successively. It separates two sub-basins South and North Gonâve with independant sedimentary and deformation evolution 3) the Jeremie Basin probably has a specific long-living evolution, allowing to precise the geodynamic evolution of the Western Hispaniola Margin.

Ellouz, N.; Leroy, S. D.; Momplaisir, R.; Mercier de Lepinay, B.



Potential of high resolution satellite imagery, remote weather data and 1D hydraulic modeling to evaluate flood areas in Gonaives, Haiti  

NASA Astrophysics Data System (ADS)

We present a feasibility study to explore potential of high-resolution imagery, coupled with hydraulic flood modeling to predict flooding risks, applied to the case study of Gonaives basins (585 km²), Haiti. We propose a methodology working at different scales, providing accurate results and a faster intervention during extreme flood events. The 'Hispaniola' island, in the Caribbean tropical zone, is often affected by extreme floods events. Floods are caused by tropical springs and hurricanes, and may lead to several damages, including cholera epidemics, as recently occurred, in the wake of the earthquake upon January 12th 2010 (magnitude 7.0). Floods studies based upon hydrological and hydraulic modeling are hampered by almost complete lack of ground data. Thenceforth, and given the noticeable cost involved in the organization of field measurement campaigns, the need for exploitation of remote sensing images data. HEC-RAS 1D modeling is carried out under different scenarios of available Digital Elevation Models. The DEMs are generated using optical remote sensing satellite (WorldView-1) and SRTM, combined with information from an open source database (Open Street Map). We study two recent flood episodes, where flood maps from remote sensing were available. Flood extent and land use have been assessed by way of data from SPOT-5 satellite, after hurricane Jeanne in 2004 and hurricane Hanna in 2008. A semi-distributed, DEM based hydrological model is used to simulate flood flows during the hurricanes. Precipitation input is taken from daily rainfall data derived from TRMM satellite, plus proper downscaling. The hydraulic model is calibrated using floodplain friction as tuning parameters against the observed flooded area. We compare different scenarios of flood simulation, and the predictive power of model calibration. The method provide acceptable results in depicting flooded areas, especially considering the tremendous lack of ground data, and show the potential of remote sensing information in prediction of flood events in this area, for the purpose of risk assessment and land use planning, and possibly for flood forecast during extreme events.

Bozza, Andrea; Durand, Arnaud; Allenbach, Bernard; Confortola, Gabriele; Bocchiola, Daniele



Petrology and geochemistry of the Late Cenozoic volcanic rocks of the Dominican Republic  

SciTech Connect

Late Cenozoic rocks of Hispaniola are subdivided into two petrographically and geochemically contrasting series, a calc-alkaline series (CA-series), and a mafic alkaline series (MA-series). The CA-series are basalts, basaltic andesites, trachyandesites, and dacites occurring in several eruptive centers in the southern part of the Cordillera Central of the Dominican Republic. MA-series basalts are alkali-olivine basalts and limburgitic basalts occurring in the San Juan Valley of the Dominican republic and in the Cul de Sac of south central Haiti. Olivine, clinopyroxene, amphibole, mica, feldspar, and titanomagnetite were analyzed for major element chemical composition. MA-series basalts are slightly to moderately silica undersaturated, have high TiO2 (>1.5%) and MgO (>5.0%) and moderately high total alkalis (>2.0%). MA-series basalts are enriched in K, Rb, Sr, Ba, U, Th and LREEs with Ba/La ratios around 0.98. REE patterns are fractionated (chrondrite normalized La/Yb ratios around 62, and La/Sm ratios around 6). HFS elements Zr, Hf, Nb, and Ta are high resembling intraplate basalts. 86SR/87SR ratios are high (0.7060-0.7070) with low Rb/Sr ratios (0.03 to 0.15). Basalts, basaltic andesites, trachyandesites, and dacites of the CA-series show low MgO (<5.0%) and TiO2(<2.0%), and moderately high total alkali contents (2 to 7%). Enrichment is seen in K Rb, Sr, Ba, Th, U, and LREEs with Ba/La ratios as high as 5.6 REE patterns are fractionated to a lesser degree compared to the MA-series (chondrite normalized La/Yb around 23, and La/Sm ratios less than 5). HFS elements are lower resembling typical island arc volcanic rocks. CA-series have 87Sr/86Sr ratios (.7043-.7053), with low Rb/Sr ratios as in the MA-series.

Vespucci, P.D.



Searching for the Blind fault: Haiti Subsurface Imaging Project  

NASA Astrophysics Data System (ADS)

The impact of the 12 January 2010 Haiti earthquake was catastrophic, causing serious damage to infrastructure and more than 200000 deaths. Initially, the Haiti earthquake was assumed to occur with the movement of Enriquillo Plantain Garden Fault Zone (EPGFZ), but recent scientific studies have shown that the primary rupture occurred on an unmapped blind thrust fault in the Léogâne fan (associated as Léogâne fault) near the EPGFZ (Figure 1a and 1b). The main purpose of this project are: characterizing and analyzing subsurface structures and associated hazards, characterizing the physical properties of near-surface, locating and understanding the blind faults theorized to have caused the 2010 earthquake (Léogâne fault). Surveys were conducted by a research group from the University of Houston in 2013 to address some of these goals. Surveys were mainly concentrated on Léogâne fan (Figure 1c) and Lake Enriquillo (Figure 1d). For Léogâne surveys, multiple 2D Seismic lines were deployed with approximately N-S orientation. We performed both P wave and S wave refraction analyses and time-migrated the P wave data. The prominent change in both P wave and S wave velocities are interpreted as the effects of faulting. The CMP stacked section shows a multiple discontinuity profile whose location coincides with the anomalies observed at P wave and S wave refraction velocity profile. Extracted reflection coefficients also support a reflective structure at these offsets. We interpret the anomalous structure as North dipping thrust fault. The dip of the fault is estimated around 60°. Near-surface reflection seismic analysis provided deeper information indicating multiple layers with varying velocities, intersected by a number of faults. Gravity surveys were conducted along the main seismic line over Léogâne fan, with additional surveys conducted from Jacmel to Léogâne and around the Port Au Prince area. The estimated Free air gravity profile suggests that the variation of the gravitational field may be related to the proposed faults. More extensive surveys are expected to be conducted in January, 2014. Figure 1 a- digital elevation map of Hispaniola, b- zoomed view of Léogâne fan and Lake Enriquillo with gravity stations, c- surveys over Léogâne area, d- chirp surveys over Lake Enriquillo

Kocel, E.; Stewart, R.; Mann, P.; Dowla, N.



Seismic Catalogue and Seismic Network in Haiti  

NASA Astrophysics Data System (ADS)

The destructive earthquake occurred on January 10, 2010 in Haiti, highlighted the lack of preparedness of the country to address seismic phenomena. At the moment of the earthquake, there was no seismic network operating in the country, and only a partial control of the past seismicity was possible, due to the absence of a national catalogue. After the 2010 earthquake, some advances began towards the installation of a national network and the elaboration of a seismic catalogue providing the necessary input for seismic Hazard Studies. This paper presents the state of the works carried out covering both aspects. First, a seismic catalogue has been built, compiling data of historical and instrumental events occurred in the Hispaniola Island and surroundings, in the frame of the SISMO-HAITI project, supported by the Technical University of Madrid (UPM) and Developed in cooperation with the Observatoire National de l'Environnement et de la Vulnérabilité of Haiti (ONEV). Data from different agencies all over the world were gathered, being relevant the role of the Dominican Republic and Puerto Rico seismological services which provides local data of their national networks. Almost 30000 events recorded in the area from 1551 till 2011 were compiled in a first catalogue, among them 7700 events with Mw ranges between 4.0 and 8.3. Since different magnitude scale were given by the different agencies (Ms, mb, MD, ML), this first catalogue was affected by important heterogeneity in the size parameter. Then it was homogenized to moment magnitude Mw using the empirical equations developed by Bonzoni et al (2011) for the eastern Caribbean. At present, this is the most exhaustive catalogue of the country, although it is difficult to assess its degree of completeness. Regarding the seismic network, 3 stations were installed just after the 2010 earthquake by the Canadian Government. The data were sent by telemetry thought the Canadian System CARINA. In 2012, the Spanish IGN together with ONEV and BME, installed 4 seismic stations with financial support from the Inter-American Development Bank and the Haitian Government. The 4 stations include strong motion and broad-band sensors, complementing the 8 sensors initially installed. The stations communicate via SATMEX5 with the Canadian HUB, which sends the data back to Haiti with minimum delay. In the immediate future, data transfer will be improved with the installation of a main antenna for data reception and the Seismic Warning Center of Port-au-Prince. A bidirectional satellite communication is considered of fundamental importance for robust real-time data transmission that is not affected in the case of a catastrophic event.

Belizaire, D.; Benito, B.; Carreño, E.; Meneses, C.; Huerfano, V.; Polanco, E.; McCormack, D.



Initiatives of Application of the Bakun-Wentworth's Method for the Estimation of Macroseismic Parameters in the Northern South America and the Caribbean Region  

NASA Astrophysics Data System (ADS)

The assessment of location, magnitude and uncertainties of great historical earthquakes is a key issue for understanding the seismic potential and PSHA of a region. In the last years independent techniques using only macrosesismic data points have been developed as, for example, the approach of Bakun and Wentworth (1997) or BW. This method has been largely applied in different tectonic contexts (Bindi et al., 2013), in different UE international projects and in estimations of location, magnitude and epistemic uncertainties (Bakun et al., 2011). We focus on some regional calibration initiatives in Northern South America and areas of the Caribbean Region. BW has been calibrated by Palme et al. (2005) and Choy et al. (2012) for earthquakes of the Mérida Andes and the Venezuela Central Regions. As well, BW calibrations have been proposed for the interandean Valley in Ecuador (Beauval et al., 2010), in the Hispaniola (Bakun et al, 2012) and for the northeastern Caribbean region (ten Brink et al., 2011). Preliminary BW calibration for the southeastern region of Cuba has been proposed by Gómez-Capera et al. (2012). Applications to historical earthquakes in Cuba have given encouraging results mainly for offshore events and are presented in the present study. We also present preliminary results for some earthquakes that have been recently studied in literature as for example the historical earthquakes of 1743 (Salcedo Hurtado and Gómez-Capera in press) and 1785 (Salcedo Hurtado and Castaño Castaño, 2011) which occurred close to Bogotá, BW method and intensity relationship of the literature were used. We present comparisons and sensibility analysis of the different relationships obtained in the region as well as uncertainty assessment. We also note that the magnitude parameter depends strongly on the regional calibration. Because of the availability of new macroseismic studies in Colombia (Servicio Geológico Colombiano y Universidad Nacional de Colombia, 2013; available online inórica/), Venezuela ( and Caribbean Region, in the future it is expected to propose models for macroseismic intensity attenuations of regional character especially in Colombia and in Venezuela in the Cumaná region. This region has a rich earthquake history. In this topic of the regional calibration of intensity attenuation relationships, the situation is challenging because several historical and recent earthquakes in this region are attributed to subduction zones. It is therefore necessary to involve focal depth. This is still an open problem.

Gomez Capera, A.; Bindi, D.; Cifuentes, H.; Choy, J.; Chuy Rodriguez, T.; Garcia, J.; Massa, M.; Palme, C.; Pierristal, G.; Salcedo Hurtado, E.; Sanchez Vasquez, A.



Rapid Detection of Coseismic Displacements with PALSAR ScanSAR-ScanSAR Interferometry  

NASA Astrophysics Data System (ADS)

On large earthquake disasters, researchers and disaster managers eager to grasp the over-all image of the event immediately with as high resolution as possible. The rapid detection of coseismic deformation enables us to discriminate co- and postseismic deformations and estimate fault parameters, which definitely contributes to the evaluation of stress transfer which leads to aftershock forecast. The ScanSAR-ScanSAR interferometry is one of techniques that can provide information on coseismic displacement field in a wide region. Phased Array-type L-band SAR (PALSAR) onboard Japan’s Advanced Land Observation Satellite (ALOS) is capable to make an observation with ScanSAR mode with as wide swath as 350km. Owing to its long wavelength, coherence is high enough to perform interferometry in vegetated areas and steep mountains. We have applied this technique to images acquired before and after 4 events that occurred this year. We use the full-aperture algorithm to produce single look complex images for each swath and apply usual 2-pass interferometry to SLC’s. It is quite important to synchronize bursts of two ScanSAR images for interferometry, but this could be done only by the Japan Aerospace Exploration Agency (JAXA). Our first trial was the Haiti earthquake of January, 2010. After its occurrence, we requested JAXA to acquire a ScanSAR image of the western Hispaniola Island. On February 11, the acquisition was made. JAXA synchronized its bursts to the image acquired on Sept. 26, 2009. We observed coseismic fringes near the epicenter along the Enriquillo fault similar to those obtained from strip-map mode images. On the other hand, no notable deformation was found near the Septentrional fault, northern Haiti. The second example was the Chile earthquake of February 27, 2010. Post-earthquake observation was made on March 1, 2010. The observed area was as wide as 350km, from the Pacific coast to the eastern frank of the Andes, and as long as 1000km. This image was synchronized to that acquired on April 10, 2008. We found maximum 3m range increases in parallel to the coast line from Valparaiso to the south of Concepcion. Since the acquisition was made from the descending track, this observation implies large oceanward shift or subsidence in this region. We also notify that there are two centers of concentric fringes at 35S and 37S, which suggests there are two asperities. We also analyzed images of consecutive acquisition and detected postseismic deformation as well as coseismic deformation from the largest aftershock during one and half month. We also analyzed images from Baja California, Mexico, and Quinghai, China. These results are also presented in association with necessary conditions on successful interferometry.

Hashimoto, M.; Ozawa, T.; Tobita, M.; Miyawaki, M.; Shimada, M.



The Role of Science and Engineering in Rebuilding a More Resilient Haiti (Invited)  

NASA Astrophysics Data System (ADS)

Rebuilding a more disaster-resilient Haiti is the defining challenge in the wake of the devastating magnitude-7 earthquake that struck in January. The contrasting experience of Chile, which weathered a magnitude-8.8 earthquake in April with casualties in the hundreds, teaches us that building resilience is an achievable and desirable goal given suitable investments and governance. Scientists and engineers have much to contribute, but doing so requires effective mechanisms to enable them to inform the rebuilding process. The international donor community has been a key point of engagement since their funds provide the opportunity to build new schools, hospitals, critical infrastructure and housing that will not fail in the next disaster. In advance of a gathering of international donors at the end of March, the U.S. National Science and Technology Council’s interagency Subcommittee on Disaster Reduction convened a workshop that brought together over 100 scientists, engineers, planners, and policymakers, including a delegation of Haitian government officials and academics. Hosted by the University of Miami and organized by the Incorporated Research Institutions for Seismology, the workshop was co-sponsored by the U.S. Department of State, U.S. Agency for International Development (USAID), and United Nations International Strategy for Disaster Reduction with support from NASA, the National Science Foundation, and the U.S. Geological Survey (USGS). Key findings from the workshop covered the need to adopt and enforce international building codes, to use hazard assessments for earthquakes, inland flooding, and landslides in the planning process, and the central importance of long-term capacity building. As an example of one science agency’s contributions, the USGS informed the initial response by rapidly characterizing the earthquake and delivering estimates of population exposure to strong shaking that were used by humanitarian organizations, aid agencies, and the Haitians themselves. In the ensuing weeks, the USGS tracked aftershocks and issued statements with probabilities of future earthquakes. Early on, the U.S. Southern Command made it possible to put an advance team of engineers and a USGS seismologist on the ground in Haiti. That initial team was followed by the first major deployment of a USGS/USAID Earthquake Disaster Assistance Team, which evolved from the long-standing partnership between these two agencies. EDAT activities included field assessment of faulting, coastal uplift, and landslides; seismometer deployments for aftershock recording and characterization of ground shaking amplification; and development of a probabilistic seismic hazard map for Haiti and the whole island of Hispaniola. The team’s efforts benefited greatly from collaboration with Haitian colleagues with knowledge transfer occurring in both directions. The effort also benefited from significant remote sensing acquisitions, which helped to target field activities and constrain fault rupture patterns. Although the products have been put to use in Haiti, it still remains to turn hazard assessments into tools that can be used for effective planning, building code development and land-use decisions.

Applegate, D.



Map pattern and paleostress analysis of extensional faults deforming the Quaternary coral-reef deposits of the southeastern Dominican Republic: Implications for earthquake hazard  

NASA Astrophysics Data System (ADS)

In this study, we document a fault system in southeastern Dominican Republic that constitutes the onland continuation of the Mona Passage fault array. Fault-slip analysis has been carried out on 60 stations and paleostress ellipsoids were computed from striae orientations on faults using inverse methods. The CMT-catalog was also consulted to compare the moment tensor solution of earthquakes with the obtained results. Faults cut the 65-90 m raised coral-reef platform (Pliocene?-Pleistocene) that form the bulk of the Caribbean coastal plain, the 27-30 m reef terrace (247.2+26.3-20.05 ka, Middle Pleistocene), and the 6-7 m reef terrace (~125ka, Middle-Late Pleistocene boundary). Cumulative fault activity in the 65-90 m reef produced half-grabens with north polarity that controls the tributary water drainage. Their bounding faults attain 10-20 km wide and are segmented with transverse ramps developed at relay areas. The maximum throw calculated from fault scarps is about 75m. When represented in a length vs strike diagram, line scarps oriented in a prominent WNW set and a subordinate ENE set, in good agreement with field measurements of 540 fractures, that group into WNW, NNE and ENE sets. Paleostress analyses in tensional and hybrid fractures that affect the lower reef terraces indicate a SW-NE trend of subhorizontal extension. In the 65-90 m reef platform, the fault analysis establishes a stress ellipsoid characterized by a near-subvertical ?1 axis and a near-subhorizontal SSW to SW-trending ?3 axis. Therefore, the resulting type of brittle deformation in the Pleistocene ranges from (near) pure normal to normal strike-slip. In contrast, focal mechanisms solutions of generally deep (>65 km) earthquakes are characteristic of reverse, reverse oblique and strike-slip faulting, though shallow normal mechanisms also occur. The main stress axes determined by right-dihedra diagrams reveal a dominant N-trending subhorizontal compression and a subvertical extension. Assuming uniform stress in the source region, the obtained regional stress ellipsoid that best fit these focal mechanisms is characterized by ?1: 06/348 (plunge, trend) and ?3: 68/172. These results suggest that a compressional to reverse strike-slip type of deformation affects the deep lithosphere of the southeastern Dominican Republic. In conclusion, the studied system of extensional faults is active and differs from the transpressive structures present in western, central and northern Hispaniola. Field evidences point to an extensional stress field affecting the uppermost crustal level, as in the Mona Passage. In contrast, the interpretation of seismicity, fault plane solutions and deep seismic reflection data suggests a compressional to reverse strike-slip stress regime affecting the deep subducting lithospheres. Historical description of destructive earthquakes, field evidences of seismites in the Late Pleistocene reef terraces, and the almost daily seismic activity are indicative of a seismic risk still not yet assessed in southeastern Dominican Republic.

Garcia-Senz, J.; Escuder-Viruete, J.; Perez-Estaun, A.



The dynamics of intra-oceanic subduction zones: A direct comparison between fossil petrological evidence (Rio San Juan Complex, Dominican Republic) and numerical simulation  

NASA Astrophysics Data System (ADS)

Dispersed blocks of various types of metamorphic rocks in serpentinite mélanges of the northern Dominican Republic (Hispaniola) provide fossil evidence for the dynamics of the subduction zone channel in the intra-oceanic Caribbean subduction zone system between 120 and 55 Ma. Comprehensive petrological and geochronological data on three exemplary samples of eclogite and blueschist are presented that allow a series of different but interrelated pressure-temperature-time paths to be delineated. Eclogites indicate a low P/T gradient during subduction and record conditions in the nascent stages of the subduction zone. Lu-Hf data yield 103.6 ± 2.7 Ma for peak metamorphic conditions of 23 kbar/750 °C. An anticlockwise P-T path is defined. Other blocks record the continuous cooling of the evolving subduction zone and show typical clockwise P-T-paths. Omphacite blueschists reach maximum P-T-conditions of 17-18 kbar/520 °C at 80.3 ± 1.1 Ma (Rb-Sr age data). The mature subduction zone is typified by jadeite blueschists recording very high ("cold") P/T gradients. A Rb-Sr age of 62.1 ± 1.4 Ma dates peak metamorphic P-T conditions at 16-18 kbar/340-380 °C. The array of P-T-t data allows overall cooling rates of the subduction zone at depths of c. 60 km to be constrained at 9 °C/Ma. Cooling rates and exhumation rates (i.e., vertical component of retrograde trajectories) of the metamorphic blocks are 9-20 °C/Ma and 5-6 mm/a, respectively. The derived P-T-t array is compared with a 2-D numerical subduction-zone model published by Gerya et al. [Gerya, T.V., Stöckhert, B. and Perchuk, A.L., 2002. Exhumation of high-pressure metamorphic rocks in a subduction channel: a numerical simulation. Tectonics 142, 6-1-6-19.; 45° slab dip, 40 Ma lithosphere age, convergence rates of 10-40 mm/a], which incorporates weakening of lithospheric mantle of the hanging wall by fluids emanating from the downgoing slab, resulting in an increasingly more funnel-shaped subduction channel system with time. The numerically derived array of simulated P-T-t paths as well as the calculated rates of exhumation and cooling agree well with the P-T-t data derived from the metamorphic blocks of the Rio San Juan serpentinite mélanges when convergence rates of 15 to 25 mm/a are chosen. This value is also in accord with available paleogeographic reconstructions calling for a long-term average of 22 mm/a of orthogonal convergence. On the basis of the comparison, the onset of subduction in the Rio San Juan segment of the Caribbean Great Arc can be constrained to approximately 120 Ma. This segment was thus obviously active for more than 65 Ma. An orthogonal convergence rate of 15-25 mm/a requires that a minimum amount of 975-1625 km of oceanic crust must have been subducted. Both petrological/geochronological data and numerical simulation underscore the broad spectrum of different P-T-t paths and peak conditions recorded by material subducted at different periods of time as the subduction zone evolved and matured.

Krebs, M.; Maresch, W. V.; Schertl, H.-P.; Münker, C.; Baumann, A.; Draper, G.; Idleman, B.; Trapp, E.



Radar Observations of Convective Systems from a High-Altitude Aircraft  

NASA Technical Reports Server (NTRS)

Reflectivity data collected by the precipitation radar on board the tropical Rainfall Measuring Mission (TRMM) satellite, orbiting at 350 km altitude, are compared to reflectivity data collected nearly simultaneously by a doppler radar aboard the NASA ER-2 flying at 19-20 km altitude, i.e. above even the deepest convection. The TRMM precipitation radar is a scanning device with a ground swath width of 215 km, and has a resolution of about a4.4 km in the horizontal and 250 m in the vertical (125 m in the core swath 48 km wide). The TRMM radar has a wavelength of 217 cm (13.8 GHz) and the Nadir mirror echo below the surface is used to correct reflectivity for loss by attenuation. The ER-2 Doppler radar (EDOP) has two antennas, one pointing to the nadir, 34 degrees forward. The forward pointing beam receives both the normal and the cross-polarized echos, so the linear polarization ratio field can be monitored. EDOP has a wavelength of 3.12 cm (9.6 GHz), a vertical resolution of 37.5 m and a horizontal along-track resolution of about 100 m. The 2-D along track airflow field can be synthesized from the radial velocities of both beams, if a reflectivity-based hydrometer fall speed relation can be assumed. It is primarily the superb vertical resolution that distinguishes EDOP from other ground-based or airborne radars. Two experiments were conducted during 1998 into validate TRMM reflectivity data over convection and convectively-generated stratiform precipitation regions. The Teflun-A (TEXAS-Florida Underflight) experiment, was conducted in April and May and focused on mesoscale convective systems mainly in southeast Texas. TEFLUN-B was conducted in August-September in central Florida, in coordination with CAMEX-3 (Convection and Moisture Experiment). The latter was focused on hurricanes, especially during landfall, whereas TEFLUN-B concentrated on central; Florida convection, which is largely driven and organized by surface heating and ensuing sea breeze circulations. Both TEFLUN-A and B were amply supported by surface data, in particular a dense raingauge network, a polarization radar, wind profilers, a mobile radiosonde system, a cloud physics aircraft penetrating the overflown storms, and a network of 10 cm Doppler radars(WSR-88D). This presentation will show some preliminary comparisons between TRMM, EDOP, and WSR-88D reflectivity fields in the case of an MCS, a hurricane, and less organized convection in central Florida. A validation of TRMM reflectivity is important, because TRMM's primary objective is to estimate the rainfall climatology with 35 degrees of the equator. Rainfall is estimated from the radar reflectivity, as well from TRMM's Microwave Imager, which measures at 10.7, 19.4, 21.3, 37, and 85.5 GHz over a broader swath (78 km). While the experiments lasted about three months the cumulative period of near simultaneous observations of storms by ground-based, airborne and space borne radars is only about an hour long. Therefore the comparison is case-study-based, not climatological. We will highlight fundamental differences in the typical reflectivity profiles in stratiform regions of MCS's, Florida convection and hurricanes and will explain why Z-R relationships based on ground-based radar data for convective systems over land should be different from those for hurricanes. These catastrophically intense rainfall from hurricane Georges in Hispaniola and from Mitch in Honduras highlights the importance of accurate Z-R relationships, It will be shown that a Z-R relationship that uses the entire reflectivity profile (rather than just a 1 level) works much better in a variety of cases, making an adjustment of the constants for different precipitation system categories redundant.

Heymsfield, G.; Geerts, B.; Tian, L.



Near-field tsunami inferred from numerical modeling of medieval overwash at Anegada, British Virgin Islands  

NASA Astrophysics Data System (ADS)

In a comparison among numerical models of storms and tsunamis, only tsunami waves of nearby origin manage to wash over an area where coral heads of medieval age are scattered hundreds of meters inland from the north shore of Anegada, British Virgin Islands. This low-lying island faces the Puerto Rico Trench 120 km to the north. The island's north shore, fringed by a coral reef 100-1200 m offshore, displays geological evidence for two levels of overwash. The medieval overwash, dated to AD 1200-1450, was the higher one. It is evidenced by scores of coral boulders scattered hundreds of meters inland. Some of them crossed the area of the modern storm berm at Soldier Wash, continued across a broad limestone rise 3-4 m above sea level, and came to rest on lower ground farther inland. Coral heads in four other areas, also medieval or older, came to rest hundreds of meters inland from beach ridges now 2-4 m above sea level. The later, lower-elevation overwash, dated to AD 1650-1800, laid down a sheet of sand and shell that extends as much as 1.5 km inland. The hypothetical causes for each event, tested by numerical modeling, include (1) category IV and V hurricanes that differ in surge and wave heights; (2) the 1755 Lisbon earthquake or hypothetical medieval predecessor, at M 8.7 and M 9.0; (3) M 8.4 thrust earthquake along the Puerto Rico Trench between Hispaniola and Anegada; (4) M 8.7 thrust along the Puerto Rico Trench between Tortola and Antigua; (5) M 8.0 earthquake from normal faulting on the outer rise north of Anegada. The model output includes extent of onshore flooding, depth and velocity of overland flow, and energy lost by tsunami and hurricane waves as they cross the reef and continue across a shallow subtidal flat to Anegada's north shore. For the medieval overwash, the modeling is most conclusive in testing various explanations for the coral boulders inland of Soldier Wash. The simulated hurricane waves do not wash inland of the storm berm; the height of storm surge level is limited by deep water offshore, and the waves lose energy by breaking on the reef. As for the hypothesized tsunami sources, the Soldier Wash evidence is explained only by the M 8.7 interplate-thrust source along the eastern Puerto Rico Trench (4) or the outer-rise source north of Anegada (5). The M 8.7 interplate-thrust source may be inconsistent with recent GPS measurements [1], in which case the likely source is normal faulting on the outer rise (L = 132 km, W = 45 km, depth = 7.5 km, dip = 60°, strike = 110°, rake = -90°, slip = 7.1 m). The 1755 Lisbon tsunami may explain the sand-and-shell sheet from 1650-1800, with two caveats: (1) the sheet extends farther inland than does the modeled inundation from a Lisbon source smaller than M 9.0; and (2) neither of the Lisbon sources tested corresponds to mapped faults offshore Iberia (the modeled Lisbon sources strike NNW-SSE to account for flooding and damage elsewhere in the Caribbean [2]). In the hurricane models, the reef and the subtidal flats behind it dissipate too much wave energy from the storms to explain even the low-elevation overwash of 1650-1800. COMPANION ABSTRACTS: Geological evidence overview (Atwater), coral-boulder ages (Weil Accardo). REFERENCES: [1] GRL 39 (2012), L10304. [2] Marine Geology (2009), 264, 109-122.

Wei, Y.; Ten Brink, U. S.; Atwater, B. F.; Tuttle, M. P.; Robert, H.; Feuillet, N.; Jennifer, W.; Fuentes, Z.



Late Cretaceous to Middle Eocene Geological Evolution of the Northwestern Caribbean - Constraints from Cuban Data  

NASA Astrophysics Data System (ADS)

Cuba acts as the northwestern boundary of the Caribbean Sea. However it is not part of the Caribbean plate, its geological development is deeply related to the plate history. In fact, its Cretaceous volcanic arc rocks tightly correlate with coeval sections in Hispaniola and Puerto Rico, and the same probably occurs with the ophiolites. The early Palaeogene events in Cuba were also involved in the Caribbean plate history. In general, two principal structural levels can be distinguished in the geological structure of Cuba. The rocks belonging to the upper level (Eocene to Quaternary) are little disturbed and can be referred to as the cover. Below it occurs the great complex of the Cuban orogenic belt, which consists mainly of rocks of Jurassic to Eocene age. In addition, small outcrops of Proterozoic metamorphic rocks also occur in north central Cuba. The Palaeocene-Eocene section contains volcanic arc sequences in SE Cuba and northward thrusted piggy back and foreland basins in central and western Cuba. The Mesozoic rocks lies unconformably below. The contacts between the major Mesozoic elements are always tectonic. With the exception of the rocks of the passive Mesozoic margin of North America in northern Cuba, the remaining units represent tectonostratigraphic terranes extending parallel to the axis of the present main island of Cuba. The northernmost unit is the Mesozoic passive continental margin of North America. It consists of a Jurassic- Cretaceous mainly marine sedimentary sequence now exposed as a thrust and fold belt along the northern edge of the Cuban mainland. The other units are, from north to south: the Northern Ophiolitic Belt, the Volcanic Arc Terrane and the Southern Metamorphic Terranes. The ophiolites and the Cretaceous volcanic arc terranes belong to the Proto-Caribbean plate and were accreted to the palaeomargin during Late Cretaceous and early Palaeogene episodes. Some constrains to Caribbean plate origin and evolution according to data from Cuba: Ophiolites: 1- The age of the rocks of the northern ophiolite belt is Upper Jurassic-Albian. Oceanic lithosphere formation, at least in the "Cuban" Proto-Caribbean, ended in the Albian. Cretaceous volcanic arcs: 2- At least two volcanic arc Cretaceous sections are present in Cuba, separated in several regions by a mainly sedimentary Albian-Cenomanian section. The lower arc is probably of Aptian-Albian age. The Cenomanian (or Turonian?) -Campanian upper arc is calcalkalic and contains abundant sedimentary marine interbeds. 3- Some thin tuff beds are present in the southernmost deep water deposits of the North American palaeomargin in western and central Cuba in the Aptian-Cenomanian. This fact could be explained by a volcanic arc located several hundred km to the south of the NA palaeomargin. 4- Cretaceous volcanism ended during the early Campanian all along Cuba. Sedimentary upper Campanian and Maastrichtian sections rest on top of the older Cretaceous sections. Volcanism is only reassumed in SE Cuba (Turquino volcanic arc) late in the Danian. Southern metamorphic terranes: 5- The southern metamorphic terranes are a main feature in the geology of Cuba. They are continental blocks sharing many stratigraphic features with the NA palaeomargin of western Cuba (Guaniguanico mountains). As the last one area seems related to the Yucatan (Maya) block, some authors consider the metamorphic terranes as fragments of the Maya block that travelled to the west.

Cobiella, J.; Hueneke, H.; Meschede, M.; Sommer, M.



Some Aspects of the Physical Variability of the Caribbean Sea Relevant to Regional Climate Variability  

NASA Astrophysics Data System (ADS)

The Caribbean Sea is the least studied portion of the Intra-Americas Sea (IAS), which is the combined Caribbean Sea, Gulf of Mexico, Straits of Florida, and the adjacent western North Atlantic. The upstream elements of the Gulf Stream System are the dominant features of the upper ocean circulation in the Caribbean Sea. The Trade Winds superimpose a coastal upwelling regime along the northern coast of South America and a coastal downwelling regime along the southern coasts of Cuba and Hispaniola. The inflow from the Atlantic through several Antillean passages is derived from tropical and subtropical sources and is relatively weak, shallow, and variable; the outflow to the Gulf of Mexico through the Yucatan Channel is relatively strong, deep, and variable. The variability includes mesoscale eddies and meanders as well as the seasonal cycle and year-to-year variability; it also includes lengthy plumes from the Orinoco and other rivers and lengthy filaments from coastal upwelling centers. Some of the mesoscale variability originates in the Eastern Caribbean; other components originate in the Western Caribbean, especially in the cyclonic Panama-Colombia Gyre. The upper ocean of the Caribbean Sea is not only under the influence of the Trade Winds and their seasonal and longer term variability but also two other, not mutually exclusive, sources of variability: the seasonal heating and precipitation cycles on one hand, and synoptic scale and mesoscale phenomena on the other hand. For example, there are wet and dry seasons, and the Eastern Caribbean is typically dry and the Western Caribbean typically wet, with a heavy rainfall zone off the coast of Central America. And the patterns of atmospheric deep convection and subsidence apparently account for the summertime intensification of an extensive "warm pool" concentrated in the Northwestern Caribbean, which is exported to the Gulf of Mexico. As another example, the weekly Tropical Easterly Waves (TEWs) are the predominant synoptic atmospheric systems in the summertime, while weekly cold front passages are predominant in wintertime. Some of the TEWs develop into tropical cyclones and hurricanes, a subset of which commonly pass over the warm pool that may foster their further development. The atmospheric regime includes the Caribbean Low Level Jet (CLLJ) embedded in the Trade Winds and which may play a critical role in the summertime transport of moisture into the American Midwest. How these synoptic scale systems affect air-sea transfers in the IAS has yet to be quantified. Some of the above points are illustrated with numerical simulations using IAS-POM, an implementation of the Princeton Ocean Model with eddy-admitting resolution. Others are illustrated using information from climatology and recent observations. A challenging potential application is the scientific design of Marine Protected Areas, especially their separation distances taking into account the probable Lagrangian pathways (and rates) linking nearest neighbors through hypothetical larval transports, as illustrated by IAS-POM.

Mooers, C. N.



Overview of Collaborative Project to Develop Tsunami Hazard Assessments for the US Atlantic and Gulf Coasts  

NASA Astrophysics Data System (ADS)

In response to the 2004 Indian Ocean Tsunami, and in anticipation of new license applications, the United States Nuclear Regulatory Commission (US NRC) initiated a long-term research program to improve understanding of tsunami hazard levels for coastal facilities on the U.S. Atlantic and Gulf Coasts. For this effort, the US NRC organized a collaborative research program with researchers at the United States Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA). Key researchers from universities and other groups have also made important contributions to this program. The work undertaken represents the combined effort of a diverse group of marine geologists, geophysicists, geotechnical engineers, and hydrodynamic modelers. The Atlantic and Gulf coasts are the focus of this program due to the number of existing and proposed nuclear facilities located on these coasts and because less is generally known about tsunami hazard on these coasts. Because the US NRC is interested in understanding hazard associated with the rare large tsunami that may occur over long time periods (in excess of 10,000 years), the research program considers both seismic and landslide tsunamigenic sources. It also includes the study of both large far-field sources and near-field sources. The study of tsunamigenic landslides is a key difference between this research program and other tsunami hazard assessment programs. In the initial phase, significant effort was focused on identifying and characterizing offshore near-field landslides and on understanding their regional distribution along the coasts. Once early results were obtained, modeling of one of the larger slides was initiated to better understand the hazard posed by the slides identified. Important properties of the slide, such as flow velocity, were characterized through work that included analysis of the dynamic elements. The research related to far-field tsunamigenic landslides has similarly focused on collecting existing information and assessing the potential impact to the coasts. The focus of seismic sources focused on the Hispaniola-Puerto Rico-Lesser Antilles subduction zone and the enigmatic zone of large earthquakes west of Gibraltar. These source areas were investigated, an evaluation of their tsunamigenic potential was undertaken, and the potential for hazard to the U.S. coastline was considered. As part of the current phase, the USGS will conduct field investigations in key locations for the purpose of filling existing data gaps. Investigations will also continue to assess landslide potential in the Gulf of Mexico and to determine the source of the 1755 Lisbon earthquake. The potential for developing tools and data to undertake probabilistic tsunami hazard assessments (PTHA) will also be a key focus of later phases of the program. Simultaneously, the NOAA MOST tsunami generation and propagation model is being enhanced to include landslide-based initiation mechanisms and is being validated with case studies. The enhanced MOST model will be used to investigate the tsunamigenic sources characterized by the USGS, with the goal of creating an estimation of deterministic tsunami hazard levels for the length of Atlantic and Gulf Coasts.

Kammerer, A. M.; ten Brink, U. S.; Titov, V. V.



Two-stage Extensional Opening of the Mona Passage as Revealed by New Multibeam Bathymetry and Seismic Reflection Data  

NASA Astrophysics Data System (ADS)

The Mona Passage, located between Puerto Rico (P.R.) and the Dominican Republic (D.R.), has long been considered a region of significant extensional deformation resulting from the oblique subduction system active along the northern Caribbean plate boundary. Published analyses of GPS data show that extension in this region continues today, with P.R. moving northeasterly away from Hispaniola at a rate of between 3-4 mm/yr, maintaining the active extensional environment between these islands. High-resolution EM 1002 swath bathymetry and multi-channel seismic reflection profiles collected in the Mona Passage in March 2007 and October 2006 respectively have for the first time clearly revealed the nature of extensional deformation within this seismically active region. These new data, combined with data from several recent bathymetry surveys in the region show a complex morphostructural terrane, comprising a mix of fault-, erosional-, and landslide-related morphologies. Flat-lying and northward- and southward-backtilted fault blocks, capped by Oligocene to Holocene aged carbonate units, dominate the seafloor and sub-seafloor landscape. At the seafloor, the fault blocks are in places eroded by the powerful bottom currents passing through the passage, while in the subsurface, they form extensional basins, covered by variable thicknesses of young sediments. The most prominent of these fault blocks is the north-dipping Desecheo Ridge, where as much as 700 m of carbonate and Cretaceous-lower Oligocene volcanic and basement units are exposed on its southern side along the multi-stranded southward- dipping Desecheo Ridge fault. The Desecheo Ridge fault extends from near Punta Higuero on the west coast of P.R. to Desecheo Island, where is steps approximately 1.5 km south and continues westward. Exposed on the seafloor and in the shallow subsurface are two dominant fault sets of differing orientations; a N- to NNW-oriented set and a W- to WNW-oriented set. The N- to NNW-striking faults are typically shorter, deeply eroded, and in many places such as at the southwest corner of Mona Canyon, curve along strike. Faults in the W- to WNW-oriented set, cross-cut the N- to NNW-set and in many places cut the overlying sediment cover, indicating that they are the younger, active faults. To date, no definitive piercing-points or other evidence of lateral or oblique movement have been identified along any of the faults in the passage, suggesting that most if not all of the current motion on these faults may be extensional. The perpendicular direction to the active fault set (NNE-SSW), while similar to the relative motion between the eastern D.R. and western P.R. given from GPS, is at odds with the E-W extension direction implied by the Mona Rift. Several of the long E-W striking faults extend along much of the approximately 125 km width of the passage, some of which appear to be continuations of sub-aerially exposed faults identified in western P.R., such as Cerro Goden and Mayaguez faults. The length of these faults and the presence of other major, and likely active, faults in close proximity to the coasts of P.R. and the D.R., make an understanding of these individual faults and wider structural fabric of the region important for seismic hazard analysis. In terms of the tectonic history of the region, the presence of two distinct fault orientations of differing ages in the passage may reflect a moderate shift in plate motion during the current stage of extensional opening or a record of the current and an earlier (Miocene-Pliocene?) stage of deformation.

Chaytor, J. D.; ten Brink, U. S.



Seismic rupture process of the 2010 Haiti Earthquake (Mw7.0) inferred from seismic and SAR data  

NASA Astrophysics Data System (ADS)

On January 12th 2010 at 21:53, the Port-au-Prince - Haiti region was struck by an Mw7 earthquake, the second most deadly of the history. The last seismic significant events in the region occurred in November 1751 and June 1770 [1]. Geodetic and geological studies, previous to the 2010 earthquake [2] have warned to the potential of the destructive seismic events in that region and this event has confirmed those warnings. Some aspects of the source of this earthquake are nonconsensual. There is no agreement in the mechanism of rupture or correlation with the fault that should have it generated [3]. In order to better understand the complexity of this rupture, we combined several techniques and data of different nature. We used teleseismic body-wave and Synthetic Aperture Radar data (SAR) based on the following methodology: 1) analysis of the rupture process directivity [4] to determine the velocity and direction of rupture; 2) teleseismic body-wave inversion to obtain the spatiotemporal fault slip distribution and a detailed rupture model; 3) near field surface deformation modeling using the calculated seismic rupture model and compared with the measured deformation field using SAR data of sensor Advanced Land Observing Satellite - Phased Array L-band SAR (ALOS-PALSAR). The combined application of seismic and geodetic data reveals a complex rupture that spread during approximately 12s mainly from WNW to ESE with average velocity of 2,5km/s, on a north-dipping fault plane. Two main asperities are obtained: the first (and largest) occurs within the first ~ 5sec and extends for approximately 6km around the hypocenter; the second one, that happens in the remaining 6s, covers a near surface rectangular strip with about 12km long by 3km wide. The first asperity is compatible with a left lateral strike-slip motion with a small reverse component; the mechanism of second asperity is predominantly reverse. The obtained rupture process allows modeling a coseismic deformation which is in agreement with the deformation field measured by InSAR. [1] Bakun W, Flores C, Brink U, 2012 Significant Earthquakes on the Enriquillo Fault System, Hispaniola, 1500-2010: Implications for Seismic Hazard. Bul. Seis. Soc. of America, 102(1):18-30. [2] Dixon, T. et al., 1998. Relative motion between the Caribbean and North American plates and related boundary zone deformation based on a decade of GPS observations. J. Geophys. Res. 103, 15157-15182. [3] Mercier de Lépinay, B., Deschamps, A., Klingelhoefer, F., Mazabraud, Y., Delouis, B., Clouard, V., Hello Y., Crozon, J., Marcaillou, B., Graindorge, D., Vallée M., Perrot, J., Bouin, M., Saurel, J., Charvis, Philippe, C. and St-Louis, 2011. The 2010 Haiti earthquake: A complex fault pattern constrained by seismologic and tectonic observations, Geoph. Res. Let., 30, L22305 [4] Caldeira B, Bezzeghoud M, Borges JF., 2009 DIRDOP: a directivity approach to determining the seismic rupture velocity vector. J. of Seis.. 2009;14(3):565-600.

Santos, Rúben; Caldeira, Bento; Borges, José; Bezzeghoud, Mourad



Recommendations for the establishment of the seismic code of Haiti  

NASA Astrophysics Data System (ADS)

Haiti, because of his seismicity associated with plate boundary and several faults that cross the island of Hispaniola (Haiti-Dominican Republic), has been affected in the past by major earthquakes, which have caused loss of life and damage or considerable structural collapses (ex. 1771, 1842), sometimes the destruction of the cities. The recent earthquake of January 12, 2010, was the most destructive earthquake that any country has experienced in modern times, when we measure the number of people killed with respect to the population of a country (Cavallo et al. 2010). It's obvious that the major causes of theses losses are the lack of awareness of the population about the earthquakes, the absence of seismic code and quality control of the building. In this paper, we propose some recommendations for the establishment of the seismic code of Haiti in order to decrease physical and social impacts of earthquakes in the future. First of all, we present a theoretical part of concepts and fundamental elements to establish a seismic code, such as: description of the methodology for seismic hazard's assessment, presentation of the results in terms of acceleration maps for the whole country (in rock sites) and Uniform Hazard Spectrum (UHS) in the cities, and the criteria for soil classification and amplification factors for including site's effects, equivalent forces, etc. Then, we include a practical part where calculations and comparisons of five seismic codes of different countries (Eurocode 8, Spain, Canada, United States and Dominican Republic) are included, in order to have criteria for making the proposals for Haiti. Using the results of Benito et al (presented in this session S10) we compare the UHS in different cities of Haiti with the response spectrum derived from the application of the spectral shapes given by the aforementioned codes. Furthermore, the classification of soils and buildings have been also analyzed and contrasted with local data in order to propose the more suitable classification for Haiti. Finally, we have proposed a methodology for the forces estimation providing the values of the relevant coefficients. References: EN 1998-1:2004 (E): Eurocode 8, Design of structures for earthquake resistance, Part 1(General Rules, seismic actions and rules for buildings), 2004. -MTPTC, (2011). Règles de calcul intérimaires pour les bâtiments en Haïti, Ministère des Travaux Publics, Transports et Communications, Février 2011, Haïti. -NBCC 2005: National Building Code of Canada, vol1, National Research Council of Canada 2005. -NCSE-02: Norma de construcción sismorresistente de España. BOE num.244, Viernes 11 Octubre 2002. -NEHRP, 2009. Recommended Provisions for Seismic Regulations for new Buildings and Other Structures, FEMA P-750, February, Part 1 (Provisions) and Part 2 (Commentary). -R-001 (2011): Reglamento para el análisis y diseño sísmico de estructuras de República Dominicana. Decreto No. 201-11. Ministerio de Obras Públicas y Comunicaciones.

Pierristal, G.; Benito, B.; Cervera, J.; Belizaire, D.



On the Changes of the Hydrological Balance of Caribbean Lakes - Modeling and Observations  

NASA Astrophysics Data System (ADS)

The Enriquillo and Sumatra are saltwater lakes located in a rift valley that is a former marine strait created around 1 million years ago when the water level fell and the strait was filled in by river sediments, they are the largest lakes in the Dominican Republic and Haiti, respectively, with Lake Enriquillo being the lowest point in the Caribbean. The lakes, part of the Enriquillo closed water basin in the southwestern region of the island of La Hispaniola, have been experiencing dramatic changes in total lake-surface area coverage during the period 1980-2012. The size of the lakes was determined using remote sensing images (NASA-LANDSAT) analyzed with geographic information system (GIS) at different times during the available record. The size calculation for Lake Enriquillo shows a lake surface area of approximately 276 km2 in 1984 that gradually decreased to 172 km2 in 1996. After a period of fluctuations between 1996 and 2001, the surface area of the lake reaches its lowest point in 2004, at 165 km2. Beginning in 2004, the recent growth of the lake begins and reaches its 1984 size in 2006. Based on surface area measurement for December 2009, the lake size is 333 km2, 17% larger than in 1984 and almost double than in 2004. Sumatra sizes at both ends of the record are 115.96 km2 in 1984 and 134.26 km2 in 2011, an overall 15.8% increase in 27 years. Because the lakes are mostly latitudinally restricted by topography, most of the size changes occur on the southeastern side of Lake Enriquillo, with some growth on the western tip. Determining the causes of lake surface area changes is of extreme importance due to the environmental, social, and economic consequences. The goal of this study is to quantify the changing water balance in these lakes using satellite and ground observations and regional atmospheric modeling. Analyses of environmental variables in the region reflect a hydrological unbalance of the lakes due to changing regional hydro-climatic conditions. Historical data show precipitation, land surface temperature and humidity, and sea surface temperature (SST), increasing all over the past decades. Salinity levels have also been decreasing by more than 30% from baseline levels. We hypothesized that the increases in SSTs may be leading to increases in regional moisture content which leads to decreases in evaporation capacity from the lakes, and simultaneously to increases in fresh water production in the neighboring sierras. A network of rain and fog gauges along the high sierras reflects growing cloud montane forests, with significant increase in water production. Results from a high-resolution mesoscale atmospheric modeling clearly reflect increases in the amount of liquid water content in the vertical column as function of changing regional climate conditions.

Comarazamy, D.; Gonzalez, J.; Glenn, E.; Leon, Y.; Brito, D. R.



MOTION UNDER THE OCEAN: Determining mantle flow of the Northeast Caribbean with seismic anisotropy  

NASA Astrophysics Data System (ADS)

Active plate boundaries in the Northeast Caribbean have formed a complex tectonic environment which includes transform and subduction zones. The Caribbean-North America plate boundary is one such active margin, where subduction transitions from arc- to oblique-type off the northeast coast of Puerto Rico. Several lines of evidence support the notion of a slab tear within the subducting North American plate at this transition zone, including the counter-clockwise rotation of the Puerto Rico microplate over the past 10 Ma and clusters of small seismic events. Understanding mantle flow in this region will not only help determine the nature of tectonic activity controlling these margins, but will also aid our understanding of anomalies, such as slab tears. Mantle flow and crustal deformation are believed to be the main controls of anisotropy in the lithosphere and asthenosphere. When a shear-wave passes through an anisotropic medium, it is split into a fast and slow component, with the fast shear-wave polarized along the fast direction of that medium. Shear-wave splitting is a tool used to determine the strength and direction of such anisotropy. Previous studies in the Caribbean have generally shown fast shear-wave polarization directions parallel to trenches and/or plate boundaries, indicating mantle flow around the plate (Growdon et al. 2009; Masy et al. 2011; Piñero-Feliciangeli and Kendall 2008). We have focused a detailed investigation of seismic anisotropy from 31 stations across six networks in the Northeast Caribbean to better constrain mantle flow in this region. Shear-wave splitting measurements of teleseismic core phases (e.g., SKS and SKKS) were completed using SplitLab, a Matlab° based environment created by Wüstefeld et al. (2008). This program enables the user to compare the quality of results from three splitting methods: rotation correlation (Bowman and Ando, 1987), minimum energy (Silver and Chan, 1991) and eigenvalue (Silver and Chan, 1991). Noisy seismic data is common to these island-based stations due to energy generated by ocean wave action. To overcome this limitation, we stacked error diagrams obtained from our split analyses to produce more robust solutions (Wolfe and Silver, 1998; Monteiller and Chevrot, 2010). A regional synthesis of our results reveals fast shear-wave polarizations that are generally oriented parallel to the plate boundary with intermediate to high split times. For example, polarization directions are oriented roughly N-S along the bulk of the Lesser Antilles, E-W along the Puerto Rico Trench and the northern Lesser Antilles, and NW-SE beneath Hispaniola. Beneath the U.S. and British Virgin Islands, however, the fast polarization direction differs markedly from the regional pattern, becoming almost perpendicular to the plate boundary. Stations on Anegada and St. Croix show a fast polarization direction that is oriented nearly N-S and smaller delay times than surrounding stations. These results suggest that mantle flow is redirected N-S at this location through a gap in the subducted lithosphere of the North American plate. This new understanding of plate geometries and mantle flow provides insight into the controls of Northeast Caribbean tectonism and to other regions around the world with proposed slab tears and gaps.

Mintz, H. E.; Pulliam, J.



Geochemistry of jadeitites and jadeite-lawsonite rocks in a serpentinite mélange (Rio San Juan Complex, northern Dominican Republic): Constraints on fluid composition in a subduction channel environment  

NASA Astrophysics Data System (ADS)

Jadeitites are excellent rock types for obtaining information on fluid composition in subduction zones. Recent studies indicate that many jadeitites appear to have formed by direct precipitation from a fluid [1]. In almost all localities worldwide (see e.g. Harlow and Sorensen, 2005) jadeitites are found either as allochthonous blocks or as veins and lenses directly within the serpentinite country rock of serpentinite mélanges. In the Rio San Juan Complex on the other hand jadeitite also frequently occurs as veins (cm to some dm in thickness) within lawsonite-blueschist blocks [2,3,4] entrained in the serpentinite mélange. The mélange of the Rio San Juan Complex also contains blocks (m to 10m scale) of different metamorphic grade and lithology (eclogites, blueschists, orthogneisses and very low grade rocks) showing contrasting but interrelated P-T-t paths. The consistency of such interrelated P-T-t paths with those obtained by numerical models led Krebs et al. [5] to interpret the mélange of the Rio San Juan Complex as a former subduction channel. So far, two types of jadeitite have been found in the blueschist blocks: either as discordant veins cutting the foliation, or as concordant layers. In some cases the jadeitites contain large amounts of lawsonite and should then better be called jadeite-lawsonite rocks. The latter rock type may form a network of thin (< 1cm) veinlets that are folded. In both jadeitite and jadeite-lawsonite rocks XJd in clinopyroxene ranges between 0.80 and 0.99. The contact between vein and host rock is very sharp and petrographically no sign of a depletion zone near the vein can be recognized, indicating that the infiltrating fluid originated from an external source and was not released from the adjoining host rock. A mineralogical center-to-rim zonation has been identified in the jadeitite veins. Near the contact to the blueschist, lawsonite is the dominant mineral phase and towards the center the amount of jadeite increases. Major and trace element concentrations also change from centers to rims. Ca/Na varies from 0.75-0.77 in the center to 1.03-1.29 in the rim; the rims are enriched in Rb, Ba, Pb, Eu and have slightly higher REE concentrations than the centers. This may be explained by the lower solubility of lawsonite compared to that of jadeite [6], causing lawsonite to crystallize first during precipitation. Lawsonite crystallization leads to a decrease of the Ca/Na ratio in the fluid. When the Ca/Na ratio becomes low enough jadeite starts to crystallize. Based on chemical data, jadeitites and jadeite-lawsonite rocks can be subdivided into two groups. The chondrite-normalised REE pattern of the first group shows decreasing normalized values from LREE (40-10 times) towards HREE (8-1 times). The second group has a U-shaped pattern with a strong positive Eu (5 times) anomaly. Even though no depletion zone in the adjoining host rock of the jadeitite is petrographically visible, there are lower REE concentrations in blueschists directly adjacent to the veins as compared to homogeneous blueschists without any veins. This clearly indicates some fluid-rock interaction during formation of the veins. References 1) Harlow G.E., Sorensen S.S. (2005) Jade (nephrite and jadeitite) and serpentinite: Metasomatic connections. International Geology Review 47:113-146. 2) Schertl, H.-P., Maresch, W.V., Krebs, M., Draper, G. (2007) The Rio San Juan serpentinite complex and its jadeitites (Dominican Republic). In: Martens U., García-Casco A. (eds) High-pressure belts of Central Guatemala: the Motagua suture and the Chuacús Complex. IGCP 546 Special Contribution, 1. 3) Schertl, H.-P., Krebs, M., Maresch, W.V., Draper, G. (2007) Jadeitite from Hispaniola: a link between Guatemala and Antigua? 20th Colloquium on Latin American Earth Sciences, Kiel, Germany, Abstract Volume, 167-168 4) Baese, R., Schertl, H.-P., Maresch, W.V. (2007) Mineralogy and petrology of Hispaniolan jadeitites: first results. In: Martens U., García-Casco A. (eds) High-pressure belts of Central Guatemala: the Motagua suture and the

Baese, Rauno; Maresch, Walter V.; Schenk, Volker; Schertl, Hans-Peter



Diachronous uplift and recycling of sedimentary basins during Cenozoic tectonic transpression, northeastern Caribbean plate margin  

NASA Astrophysics Data System (ADS)

Four marine sedimentary sequences of Late Cretaceous to Pleistocene age crop out in the 320 km long, 1 to 30 km wide Peralta-Rio Ocoa belt of Hispaniola (Haiti and Dominican Republic). The four sedimentary sequences are dominated by marine turbiditic rocks ranging up to 11.5 km in apparent thickness and exhibit mainly northwest to southeast, belt-parallel paleocurrents. The three younger sequences are generally in fault or unconformable contact with the underlying sequence. From northwest to southeast, the four belts become progressively wider, younger, less metamorphosed, less folded and faulted, and lower in topographic elevation. We interpret the three younger sequences as a syn-tectonic stratigraphic record of diachronous, northwest to southeast transpressional closure of a Coniacian-Danian back-arc basin represented by the oldest exposed sedimentary sequence at the northwest end of the belt and inferred at depth beneath the three younger sequences. Using the stratigraphic record, we infer the following three stages in the closure of the back-arc basin and the overlying younger basins. Stage One: latest Cretaceous to early Late Eocene closure. A minimum of 11 km of Paleocene turbidites and limestone in the Padre las Casas area and a minimum of 11.5 km of Early Eocene to early Late Eocene pelagic limestone, mudstone, sandstone, and siltstone in the Peralta and Sierra El Numero areas was deposited in an elongate basin derived from the first stage of latest Cretaceous-early Late Eocene closure and erosion of the Coniacian-Danian back-arc basin to the northwest. Paleocene-Eocene turbidites in both areas contain large amounts of reworked Campanian-Paleocene microfauna and exhibit northwest to southeast belt-parallel paleocurrents. Syn-deformational features in Eocene sedimentary rocks in the Peralta and Sierra El Numero area indicate that convergent deformation accompanied sedimentation (Witschard and Dolan, 1990). Stage Two: Middle Eocene to Early Miocene closure. Up to 8.6 km of Middle Eocene to Early Miocene turbidites, debris flows, and olistostromes of the Rio Ocoa Group of the Dominican Republic were deposited in an elongate basin derived from Middle Eocene to Early Miocene closure, uplift, and erosion of the Peralta Group to the west and northwest. Turbidites contain reworked Eocene faunas and lithologies similar to those in the underlying Peralta Group and exhibit northwest to southeast, belt-parallel paleocurrents. Erosion of Late Cretaceous island arc and overlying Paleogene carbonate rocks of the Cordillera Central provided additional belt-perpendicular sources of coarser-grained conglomerate and olistostromes. Following deposition of the Rio Ocoa Group, both the Peralta and the Rio Ocoa Group were deformed in a southwest-verging fold-and-thrust belt during the Early Miocene. Stage Three: Middle Miocene to Recent closure. Up to 1.5 km of Middle Miocene to Pleistocene sandstone, conglomerate, and reefal limestone of the Ingenio Caei Group of the Dominican Republic were deposited in an elongate basin above a pronounced angular unconformity developed on the older, deformed rocks of the Rio Ocoa Group. Sediments of the Ingenio Caei Group were derived from Middle Miocene to Recent closure, uplift, and erosion of the Rio Ocoa and Peralta Groups to the northwest. Onshore exposures of the Ingenio Caei Group can be correlated with submerged strata seen on seismic reflection profiles across the offshore San Pedro basin. Recent submarine clastic sedimentation in the San Pedro basin is dominated by northwest to southeast influx of clastic turbidites derived from active erosion of onshore exposures of the Rio Ocoa and Ingenio Caei Groups. Middle Miocene (?) to Recent sediments of the San Pedro basin are being actively shortened by northward to northeastward-directed underthrusting along the Muertos trench. Underthrusting at the Muertos trench is suggested to represent ongoing closure of the back-arc basin thought to be deeply buried beneath the San Pedro basin. Tectonic transpression along the closing back-arc basin marks o

Heubeck, Christoph; Mann, Paul; Dolan, James; Monechi, Simonetta