New-Old Potential Field Data in the Alaska OCS
More than 15MM gravity and magnetic data points were collected in Alaska between 1960 and 1996. These potential field data were collected by public agencies, academic groups, and industry in multiple areas during multiple campaigns. Multiple permittees collected marine gravity, marine magnetic, aeromagnetic, and/or aerogravity data (collectively, potential field data) in nearly 100 permits across all 15 Alaska Outer Continental Shelf (OCS) planning areas. After collection, much of the data acquired by industry in the OCS under permits were selected by BOEM (previously the MMS and USGS - Conservation Division). Much of the public data were released by the USGS, and the academic data are available from various sources. However, the data collected by industry under the OCS permitting process and held by BOEM has not previously been assembled into a complete dataset, or made available publicly.
The potential field data previously collected in the Alaska OCS were identified, collected, preprocessed, and loaded to a GIS system. This enabled comparison of adjacent data from different permits (surveys), highlighting different processing assumptions between surveys, as well as varying interpretation methodologies. Data fields varied greatly for each permit, with some datasets having only limited values (i.e. only Bouguer corrected density values) while others were nearly complete, with original field data, Eötvös corrected, Free Air, and Bouguer values. Processing assumptions applied to the data also vary significantly between permit datasets; wherever possible, raw (field) data were used to integrate each permit dataset into the greater, regional dataset. An iterative process was applied to organizing and preprocessing the data, using learnings from permit data supplied by the same permitee in a similar timeframe to attempt to reconstruct as much information as possible. These data were then merged to minimize misties between permit datasets, and create a regional OCS dataset. This OCS dataset was then integrated with the public on-shore potential field datasets to create an Alaska-wide, regional set of gravity, magnetic, and aeromagnetic data.
Under federal regulation (30 CFR 551.14), such data are available for release 25 years after issuance of the permit authorizing their collection. This regional integration of potential field data from multiple permits will provide a framework for further exploration and scientific study in the Alaska OCS and the Arctic.
AAPG Datapages/Search and Discovery Article #90350 © 2019 AAPG Annual Convention and Exhibition, San Antonio, Texas, May 19-22, 2019