oa Restoring a National Treasure: Recovering Airborne Geophysical Data from Antiquated Data Tapes for Geosurv Iraq

The State Company of Geological Survey and Mining (GEOSURV) is the ministry in Iraq responsible for the development of natural and mineral resources. As part of a Department of Defense initiative by the Task force for Stabilization and Business Operations in Iraq, the U.S. Geological Survey partnered with GEOSURV scientists to modernize GEOSURV’s geophysical capabilities. the objectives of the geophysical component were two-fold: train GEOSURV personnel in the use of state-of-the-art data processing techniques; and recover digital data from a 35-year old tape archive so that GEOSURV can use it to guide their exploration program. This talk focuses on the data recovery effort.<br>A national aeromagnetic and radiometric survey was flown in 1974 by Compagnie General de Geophysique (CGG). the data were of excellent quality, as evident from the detailed paper contour maps that were originally produced. A comparable survey today would cost millions of dollars. the digital data were stored on 9-track magnetic tapes. Over time, as computing equipment evolved, GEOSURV lost the capability to access the data on the tapes. GEOSURV agreed to convey the tape archive to the USGS for possible data recovery. We worked closely with a company near Denver, Colorado that specializes in reading old magnetic tapes using legacy equipment, in this case a 1970’s vintage Raytheon mainframe computer with original Kennedy tape drives. After a lengthy cleaning and conditioning process, the company managed to read Information from the tapes in the original EBCDIC format. the USGS converted the data to standard ASCII and painstakingly corrected innumerable data errors caused by drop-outs and bit-flips, achieving in the end 99.999 percent recovery. the data were imported into Geosoft Oasis montaj for filtering, gridding, and mapping. the final total field anomaly map is superior to the original magnetic field contour maps, as it reveals structural features not previously detected. GEOSURV can now access the CGG survey data and utilize it to benefit the economic development of Iraq. the money saved by not re-surveying the entire country can be redirected for field Investigations of targets of economic importance.