New multi-scale geophysical data in the northern Hispaniola offshore margin (GEOMARHIS experiment): Preliminary results on oblique tectonics, strain partitioning and associated geological hazards.

Geophysical and geological records attest that the Northern Hispaniola margin poses major earthquake and tsunami hazards for the Greater Antilles. Along this margin it is located the oblique boundary between the Caribbean and the North American plates. This boundary plate is characterized by the coexistence of seismogenic compressive deformed belts and the strike-slip fault zones that represent a strain partitioning model. Between December 3rd of 2025 and January 3rd of 2026, we carried out a multi-scale controlled-seismic source marine survey between Puerto Rico and Cuba (GEOMARHIS experiment). During the marine cruise we acquired multi-channel seismic reflection profiles along- and across-strike of plate boundary using several experimental setups: 1) 2000 km seismic profiles using a 3 km-long streamer of 240 channels (12.5 m-interval) and a 1760 ci airgun array, 900 km of high-resolution seismic profiles using a streamer of 40 channels (6.25 m-interval), and a 420 ci airgun array and a 3.6 kJ sparker sources. In addition, we acquired systematic continuous ultra-high-resolution seismic data, swath bathymetry-backscatter, gravity and magnetics. Here, we show a preliminary interpretation of the tectonic structure based the new data that will provide key information to assess the seismic and tsunami hazard for Puerto Rico, Dominican Republic, Haiti and Cuba.