Overview of the oblique Northern Lesser Antilles subduction zone and the influence onto the partitioning deformation
About the Event:
The geometry of subduction zones is thought to be a key parameter for the control of margin tectonic deformation, interplate coupling, and seismogenic behavior. These subjects remain controversial or unresolved in the Northeastern Caribbean subduction (Barbuda-Virgin Islands) where the convergence obliquity increases northward. Moreover, the seismic activity and particularly the number of events with thrust focal mechanism compatible with subduction earthquakes is sparse and increases northward. One of the major questions in this area is thus to analyze the influence of the increasing convergence obliquity and the slab geometry onto tectonic deformation of the subduction zone. During the ANTITHESIS cruises (2013-2016), we recorded wide-angle seismic, multichannel reflection seismic and bathymetric data along this zone in order to constrain the nature, the geometry and the deformation of the subducting and upper plate. Where the obliquity increase drastically, this experiment highlights:
- a decrease of the slab deepening toward the north at shallow scale (35-km-depth),
- a tectonic partitioning system occurring across the 450-km long Anegada Passage, a structure oblique to the deformation front,
- the continuity of the 850-km-log left-lateral strike-slip Bunce Fault; a structure parallel to the deformation front located 30 km from the trench.
About the Speaker:
Dr Laurencin Muriel is a Research Fellow at the Earth Observatory of Singapore (EOS), Nanyang Technological University (NTU), Singapore since January 2019. She received her bachelor in Geology in 2012 and Master in Marine Geosciences in 2014 at the Université de Bretagne Occidentale (UBO) in Brest (France). She obtained her PhD in Marine Geosciences in 2017 at UBO (Brest, France). During her PhD, she worked on the deformation and tectonic structure of the northern Lesser Antilles subduction zone using reflection and refraction seismic data. Subject that she will present today. During her PhD, she was also involved as geology teacher, president of the PhD student association and as member of the research comity at the University. After her PhD, she did a 9-months post-doc in the Marine Geoscience team at Institut Physique du Globe in Paris (IPGP) working on the Mirage reflection seismic data processing and have joined EOS in January 2019 to continue to work on this data. In EOS, she is involved as the organisation of the Friday seminars and the Postdoc professional development sessions.