Building a community project: the experience of the Eastern North America Margin (ENAM) Community Seismic Experiment
M. Beatrice Magnani, Southern Methodist University
The arrival of the Earthscope Transportable Array (TA) stations to the US east coast in 2013, and the coincident choice of the Eastern North American Margin (ENAM) by GeoPRISMS as a primary site presented the scientific community with a unique opportunity to take advantage of the synergy between the two efforts, and to address some of the prominent research questions regarding the structure and evolution of the ENAM. The cooperation between the two programs was particularly appropriate for the ENAM region because a 3D approach that spans multiple scales, and a footprint that crosses the shoreline is best suited to address the role of preexisting lithospheric weakness in the evolution of the margin, from the geometry of the continental rupture to the location and volume of the syn-rift magmatism, the east-west transition from craton to continental and oceanic crust, the distribution of magmatism and associated depletion throughout the lithosphere and the along strike segmentation of the margin.
In the Summer of 2012, a proposal was submitted to the US National Science Foundation for an ambitious plan for seismic data acquisition on a 400-km-wide section of the mid-Atlantic East Coast margin around Cape Hatteras. The study area encompasses the rifted margin, from the continental lithosphere onshore to mature oceanic lithosphere offshore and two major fracture zones that are associated with significant offsets at the modern Mid-Atlantic Ridge. The study also covers several features representing the post-rift modification of the margin by slope instability and fluid flow. The experiment augmented the Earthscope TA with 30 broadband ocean bottom seismometers (OBS) offshore North Carolina and Virginia in a 400 x 500 km area. Embedded in this onshore/offshore passive seismic array, the plan proposed to acquire seismic reflection and refraction data offshore with the R/V Marcus Langseth and the R/V Endeavor, and refraction data onshore with a land-explosion seismic experiment. This onshore/offshore acquisition plan included two major active-source seismic lines in the rift direction from the Carolina Terrane onto oceanic crust. Additional multichannel seismic (MCS) data acquisition in this region enable characterization of crustal and sedimentary structure of the continent-ocean transition zone, as well as the structural setting and architecture of the Cape Fear Slide, Cape Lookout Slide, and Currituck Slide on the adjacent shelf and slope. The seismic experiment was proposed in the context of a community-driven effort, with completely open data access upon completion of the data acquisition. To maximize the educational impact the project included a multifaceted syn- and post-data acquisition plan involving young scientists and students. Data were acquired during several field campaigns in 2014 and 2015, and are now available to the community.
The webinar will describe how the experiment was first conceived and then implemented through community input, and discuss the challenges and opportunities presented by a community-driven project.
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