REMOTE SENSING AND GEOPHYSICAL CONSTRAINTS ON THE DISTRIBUTION AND DEFORMATION ASSOCIATED WITH SALT DOME INTRUSIONS ALONG THE SOUTHERN RED SEA COASTLINE, SAUDI ARABIA

A salt diapir (dome) structure, hereafter referred to as the Jazan salt dome (JSD), crops out within the Jazan City in the Jazan Province, Saudi Arabia. The JSD occupies an area of 6 km² and stands approximately 20-40 meters above the surrounding coastal plain. The JSD is seemingly undergoing uplift, creating uneven topography, and is compromising the integrity of buildings and structures. In the neighboring (50 km offshore from the JSD) Farasan Islands, another salt dome, hereafter referred to as the Farasan Salt Dome (FSD), was detected in the near subsurface using geophysical methods. Using these two areas as our test sites, we extracted observations from geophysical and remote sensing data to investigate the following: (1) distribution and deformation rates of salt domes along the southern Red Sea coastal plain, (2) genesis of the salt structures with respect to the regional and local geologic and tectonic setting, and (3) locations of areas prone to salt dome intrusions. The utilized geophysical data included a regional 10 km nominal spacing relative gravity and magnetic surveys. The remote sensing data included optical remote sensing (DigitalGlobe’s WorldView-3 high-resolution imagery [1.24m], Landsat 8 [30m] and ASTER [30m]), C-band radar (ESA’s ERS-2 and Envisat), and DEM (TanDEM-X [12m]). Findings include: (1) a radial pattern of increasing elevations towards the center of the JSD was detected from the TanDEM-X DEM data, (2) a radial pattern of uplift (~2-4 mm/yr) was detected over the JSD from radar data acquired over a time span of 12 years using the Stanford Method for Persistent Scatterers (StaMPs), (3) salt minerals and lithologies typical of salt dome cap rocks were identified over the JSD and the northern section of the FSD using VNIR satellite data, band ratio images, spectral libraries, and supervised classification techniques, (4) localized negative anomalies (~30 mGals) from a contoured Bouguer anomaly map and boundaries of potential salt domes were located on tilt derivative (TDR) over the FSD. From the above criteria, preliminary selections were made for three potential locations of previously unrecognized salt dome locations. Field investigations (high-resolution gravity and magnetic surveys and field reflectance data) and drilling will be conducted to test, verify and refine the results.