The Garmsar salt nappe and seasonal inversions of surrounding faults imaged by SAR interferometry, Northern Iran
Shahram Baikpour, Christopher J. Talbot, 2012. "The Garmsar salt nappe and seasonal inversions of surrounding faults imaged by SAR interferometry, Northern Iran", Salt Tectonics, Sediments and Prospectivity, G. I. Alsop, S. G. Archer, A. J. Hartley, N. T. Grant, R. Hodgkinson
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The allochthonous Tertiary salt of the Garmsar salt nappe extruded from where the most southerly point of the Alborz Mountain front is offset by the Zirab–Garmsar strike-slip fault. We used eleven descending Advanced Synthetic Aperture Radar (SAR) images, acquired by the European Space Agency's ENVISAT satellite from 2003 to 2006, to map surface displacement over 23 increments ranging in time from 30 to 2 months. A 30 month SAR interferogram of the area shows that the regional folds and faults are active south of the mountain front, but are dampened by the allochthonous salt that otherwise appears to be merely degrading at rates that vary with the season. Interferograms for shorter epochs display different patterns of fault blocks in the country rocks that rose and fell with the seasons. By relating surface displacements mapped in these interferograms to the contemporaneous seismic record, we find that seismic faults reactivate repeatedly while their kinematics may have inverted on remarkably short timescales. Seismic disturbances propagate very slowly and faults are longer than expected for earthquakes with ML<3.5, indicating that the regional strains are more aseismic than anticipated by earlier studies.
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Salt Tectonics, Sediments and Prospectivity
In this timely volume, geoscientists from both industry and academia present a contemporary view of salt at a global scale. The studies examine the influence of salt on synkinematic sedimentation, its role in basin evolution and tectonics, and ultimately in hydrocarbon prospectivity. Recent improvements in seismic reflection, acquisition and processing techniques have led to significant advances in the understanding of salt and sediment interactions, both along the flanks of vertical or overturned salt margins, and in subsalt plays such as offshore Brazil. The book is broadly separated into five major themes covering a variety of geographical and process-linked topics. These are: halokinetic sequence stratigraphy, salt in passive margin settings, Central European salt basins, deformation within and adjacent to salt, and salt in contractional settings and salt glaciers.