Active deformation within the Zagros Mountains deduced from GPS measurements

Abstract

We present and interpret the results of Global Positioning System (GPS) measurements at 35 stations in and beside the Zagros Mountain belt, SW Iran, for three campaigns ending March 1998, December 1999 and June 2001. Preliminary motion estimates show clearly the change in character along the strike of the belt. Stations to the SE move at 13–22 ± 3 mm a −1 towards N 7 ± 5°E with respect to Eurasia. Most of the shortening indicated by the GPS velocities seems to occur in the SE Zagros along two major seismic zones and along the Zagros front. To the NW, stations move oblique to the trend of the belt towards N 12 ± 8°W, at 14–19 ± 3 mm a −1 . Most of the shortening in the NW Zagros seems to occur along the Mountain Front Fault with its major earthquakes as well as along the Zagros front. The change in direction and magnitude of the velocity vectors across the north–south-trending Kazerun and Karebas faults involves extension of up to 4 mm a −1 along the strike of the Zagros belt.

Neogene sediments and modern depositional environments of the Zagros foreland basin system

“…Taking an age of 15 Ma for the Guri Member deposits in the north would imply a southward depozone migration rate of about 27 mm yr −1 . Interestingly, this rate is comparable to the present-day motion of the Arabian plate relative to the Iranian microplate (Hessami, Nilforoushan & Talbot, 2006;Tatar et al 2002). An important point of this simple calculation and of this conceptual model in general is that it predicts significant differences in age (in a N-S direction) for units that were deposited within a single depozone (Fig.…”

The 18 August 2014 Mw 6.2 Mormori, Iran, Earthquake: A Thin-Skinned Faulting in the Zagros Mountain Inferred from InSAR Measurements

“…Both thickskinned deformation (Jackson, 1980b;Berberian, 1995) and thin-skinned deformation (Hessami et al, 2006;Walpersdorf et al, 2006) models have been proposed for geodynamic evolution of Zagros orogeny; in the former model, the shortening is accommodated by reverse basement faulting that is separated from shallow sedimentary rocks by the infra-Cambrian Hormuz salt sequence, and, in the latter model, active folding of the shallow sediments is the main deformation mechanism. The rate of shortening in the basement is estimated to be an order of magnitude lower than that in the sedimentary cover (Sherkati et al, 2006).…”

Slope Stability Assessment of the Sarcheshmeh Landslide, Northeast Iran, Investigated Using InSAR and GPS Observations

“…It is worth nothing that computed formal errors by GPS software are usually over-optimistic [39]. Therefore a scale factor was computed and applied to the formal GPS errors based on the average of the weighted root-mean-square residual to the linear fit, computed for all stations [40][41][42]. Figure 8 illustrates several differential interferograms with good coherency in geographical coordinates after removing the orbital and topography effects.…”