Periodic Reporting for period 1 - CAYMAN (Illuminating Ultra-Slow Spreading Centres: a seismic approach to the Cayman Trough)
Reporting period: 2019-09-01 to 2021-08-31
The main objectives of CAYMAN project are:
O1) To test the hypothesis that properties should change significantly from the centre of the Mid-Cayman spreading axis towards the segment ends, using the seismic crustal structure to characterise the mantle melting process along the MCSC and estimate the relative importance of mantle temperature, upwelling rate and magma plumbing for crustal accretion.
O2) To test widely discussed hypotheses and their alternatives for the OCCs formation –Cannat et al.  end-members– mapping crustal velocity to characterise the physical properties and structure of the crust and uppermost mantle over the MCSC.
O3) To characterise phases of predominantly magmatic accretion versus phases of amagmatic accretion, by means of temporal variations in crustal thickness and spreading rate.
The main results achieved during CAYMAN are 1) a 3D model of the crust and mantle structure on the Cayman Trough area and 2) a high-resolution image of the crust along the MCSC axis. These results have been achieved using state-of-the-art tomographic methods, including 2D and 3D tomographic inversion.
The first results of the 3D image of the crust have been presented at national and international conferences. The high-resolution image obtained along the MCSC has been used to relocate the seismicity in the area, and contribute to a broader analysis of the seismogenic structure of ultra-slow spreading centres worldwide. The innovative methodology applied (3D tomographic inversion of real datasets), the further analysis of the 3D image of the crust and the insights of the seismogenic structure of ultra-slow spreading regions will have an impact on the scientific community.