OFFSHORE EMSLAB: objectives, experimental phase and early results
Abstract
A large electromagnetic (EM) experiment dedicated to the exploration of lithosphere and asthenosphere associated with a spreading oceanic plate over its various tectonic regimes, from ridge accretion to subduction, was carried out during the second half of 1985 over an area extending from the Juan de Fuca Ridge, eastward across the coastal zone, the Cascade area and beyond. Referred to by the acronym 'EMSLAB', for 'EM Sound of Lithosphere and Asthenosphere Beneath' the Juan de Fuca Plate, the experiment involved two principal arrays, one on land, the other on the adjacent seafloor. We report here on the outcome of the oceanic portion of EMSLAB, named OFFSHORE EMSLAB for convenience. The OFFSHORE EMSLAB array of seafloor instrumentation included 40 self-contained and free recording units including magnetometers, electrometers and other oceanographic devices. The latter were intended to provide information on the EM fields generated by the interaction of oceanic motions with the main Earth's field, so as (1) to decontaminate ionospheric signals prior to magnetotelluric interpretation, and (2) to illustrate the beneficial contributions that EM observations may provide to ocean studies. The collected database is described and assessed, and an early illustration of its information content is given.
- Publication:
-
Physics of the Earth and Planetary Interiors
- Pub Date:
- March 1989
- DOI:
- 10.1016/0031-9201(89)90027-7
- Bibcode:
- 1989PEPI...53..422F