Segmentation and kinematics of the North America‐Caribbean plate boundary offshore Hispaniola

Abstract

Highlights: 27• We explored submarine portions of fault systems bounding the Gonâve microplate 28• Structures are a series of delineated left--lateral strike--slip fault segments 29• The distinct segments 50 to 100 km--long cut across pre--existing structures 30• A 16.5km total strike--slip displacement on the northern system estimated since 1.8 Ma 38Haiti and Jamaica (EPGFZ) and 300--km between Dominican Republic and Cuba (SOFZ). The primary 39 plate--boundary structures are a series of strike--slip fault segments associated with pressure ridges, 40restraining bends, step--over, and dogleg offsets indicating very active tectonics. Several distinct 41 segments 50 to 100 km--long cut across pre--existing structures inherited from former tectonic 42 regimes or bypass recent morphologies formed under the current strike--slip regime. Along the most 43 recent trace of the SOFZ, we measured a strike--slip offset of 16.5 km that indicates steady activity for 44 the past ~1.8 Ma if its current GPS--derived motion of 9.8 ±2 mm/yr has remained stable during the 45 entire Quaternary. 47 48 -Introduction 49 50Following the 2010 Mw 7.0 Haiti earthquake, an international effort was initiated to investigate the 51 corresponding fault system and to constrain both the individual fault slip rates and their seismic 52 history. Such an effort depends critically on knowledge of the detailed geometry of the fault system 53 delineating the northern boundary of the Caribbean domain (Fig. 1). The Caribbean plate is currently 54 moving eastward relative to North America and the plate motion is accommodated along a complex, 55200 km--wide deformed zone, the Northern Caribbean plate Boundary (NCarB). The NCarB is a 56 seismogenic zone extending over 3000 km along the northern edge of the Caribbean Sea ( Fig. 1) and 57 a deforming region that includes two large strike--slip fault systems, the Septentrional--Oriente fault 58 zone (SOFZ) in the north and the Enriquillo--Plantain--Garden fault zone (EPGFZ) in the south (Mann et 59 al., 1991; Calais and De Lépinay, 1995). The SOFZ extends from the Mid Cayman spreading center, 60 initiated 50 Ma ago (Leroy et al., 2000), runs along the Southern coast of Cuba to cut across the 61 northern Hispaniola (Calais and Mercier de Lépinay, 1989; Mann et al., 1998). The EPGFZ, the 62 prolongation to the east of Jamaica of the Walton fault, cuts across the Southern Peninsula in Haiti 63and dies out eastwards in the vicinity of the Muertos trough south of Hispaniola, delimiting the 64Gonâve microplate (DeMets and Wiggins--Grandison, 2007) (Fig. 1). Between the two strike--slip 65 systems, the middle to late Eocene East Cayman margin is described offshore Jamaica (Leroy et al., 66 1996) and the early Miocene to Present collisional wedge of Haiti, well--described onshore (Pubellier 67 et al., 2000), continues offshore in the Gonâve Gulf ( Figs. 1 and 2). 68Destructive earthquakes are reported along the NCarB both onshore and offshore (Ali et al., 2008; 69 96 -Geometry and segmentation o...

How transpressive is the northern Caribbean plate boundary?

“…In December 2012, the cruise HAITI‐SIS on board the R/V L ' Atalante of Institut Français de Recherche pour l'Exploitation de la Mer (Ifremer) carried out mapping of the offshore Haitian area including acquisition of high‐resolution multibeam bathymetry data and multichannel seismic reflection profiles [ Leroy et al ., ]. In this paper, we focus on the Gulf of Gonâve and the Jamaica Passage where we obtain a total of 190 seismic profiles.…”

“…Segmentation of the EPGFZ is from Leroy et al . []. Bathymetric background is the superposition of the HAITI‐SIS cruise data (DOI: ) and the GEBCO 1 min arc grid.…”

The northern Caribbean plate boundary in the Jamaica Passage: Structure and seismic stratigraphy

“…The magnitude of this fault-normal component varies between the models depending on the geometry of the blocks and the data set, but suggests significant transpression on the EPGFZ. In the Jamaica Passage, the primary structures of the EPGFZ are a series of strike-slip fault segments associated to geomorphic features highlighting a primary strike-slip motion (Leroy et al, 2015). Our seismic and structural study of the Jamaica Passage evidences an asymmetrical strike-slip related basin (the Navassa Basin, Fig.…”

“…High-resolution swath bathymetry data was acquired with a maximum precision of 25 m using a hull-mounted multibeam echosounder system. The overall geometry of the active offshore fault system, including a full coverage bathymetric map, and one seismic profile collected are presented in Leroy et al (2015). In this study, we focus on the Jamaica Passage and the interpretation of 60 seismic reflection profiles sampling the EPGFZ between Jamaica and Hispaniola ( Fig.…”

“…For example, our knowledge of the Jamaica Passage between Jamaica and Hispaniola, which is crossed by the EPGFZ, was formerly based on widely-spaced and low resolution seismic reflection profiles and bathymetry (Robinson and Cambray, 1971;Horsfield and Robinson, 1974;Case and Holcombe, 1980;Mann et al, 1995). During November-December 2012, a marine geophysical survey (HAITI-SIS) was carried out aboard the Research Vessel L'Atalante around the northern Caribbean plate boundary to unravel the detailed geometry of the active fault system (Leroy et al, 2015).…”