Structural Analysis of Bonaire, Netherlands Leeward Antilles-A Seismic Investigation

Abstract

We show that the island of Bonaire, Netherlands Antilles exhibits strain indicative of local deformational processes and regional tectonics. We acquired ~172 km of 2D multichannel seismic reflection profiles in the nearshore environment on the west side of Bonaire to evaluate the geology for structural deformation. By integration of previous geological and geophysical studies with our data, we ascertained what tectonic stress and local processes affect the island of Bonaire. Our analysis reveals: 1) a large anticline that extends from onshore the north of Bonaire to at least ~17 km offshore, and is the result of regional Pliocene-Quaternary compression; 2) a feature in the seafloor off the SW coast of Bonaire that is either the result of antecedent topography or late Paleogene NW-SE-directed compression; 3) a rotational slump of the seafloor due to either uplift of the entire island or subsidence of the south of the island; 4) NW-SE-striking faults related to a present regional NE-SW-directed extension, which indicates that footwall uplift of reactivated normal faults is the mechanism for recent uplift of the ABCs.

This study highlights the utility of a localized inexpensive high-resolution seismic study to fill in knowledge gaps and further constrain the tectonics of the Caribbean-South American plate interaction. Additionally, this study shows what factors potentially influence material failure on unsedimented hard rock marine slopes. Finally, understanding what deformation is present on Bonaire and what stresses are imparting the observed strain, can serve as an aid to the inhabitants of the island to mitigate risk.