Introduction Background
The mountain frontal fault (MFF)
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- The Zagros Foredeep Fault (Z F F)
- Result and analysis
The mountain frontal fault (MFF)The MFF marks the south-southwest boundary of ZSFB. The MFF is believed to have controlled the sedimentation of the Zagros foreland basin since the early tertiary period (Sepehr and Cosgrove, 2004; Sherkati and Letouzey, 2004) (Figure 3.2 a). The Zagros Foredeep Fault (Z F F)The Mountain Front Fault (MFF) bound the Zagros Foredeep from the northeast and the Zagros Foredeep Fault (ZFF) from the southwest (Figure 3.2a). Symmetrical and elongated folds characterize the fault. The ZFF separates the Zagros Foredeep (to the north and northeast) from the Zagros Coastal Plain (to the south and southwest). This region forms the northeastern edge of the alluvial Coastal Plain of the Persian Gulf and is primarily a reverse-slip system (Berberian, 1995). Figure (3.2): Regional geologic (a) cross-sections across northeast Iran showing major tectonic divisions and major tectonic boundaries (Modified after Al-Qayim et al. 2018). (b) active faults in the Lurestan arc and earthquake focal mechanisms of the Zagros in an oblique. Black lines are faults surface projections of Berberian's (1995) “master blind thrusts” are dashed (DEF = Dezful Embayment Fault; MFF = Mountain Front Fault; ZFF = Zagros Foredeep Fault). Chapter Four Result and analysisLOS surface displacement measuringTwo deformation components can be inferred from the interferogram phases if you obtain ascending and descending radar passes over a single area at different times. Figures 4.1 a, b, and 4.2 a, b are the DInSAR interferograms depicting the surface deformation caused by the M7.3 Sarpol Zahab quake. The high fringe indicates that the area has widespread and complex deformation. The surface deformation pattern reveals ground movements in the two lobes, as evidenced by its strong coherence. The first lobe is located roughly southwest of the earthquake's epicenter in ascending and descending data. The horizontal movement shows that this ground area underwent uplift, and this lobe has significant positive LOS displacement. On the LOS, the maximum displacement was 100 and 50 cm (Figures 4.1a and 4.2a, respectively). The second lobe is located roughly northeast of the earthquake's epicenter, with maximum displacements on the LOS of 15 and 35 cm, respectively (Figures 4.1b and 4.2b). The coseismic ground displacement data obtained by SAR clearly shows coseismic slip. The descending DInSAR data shows larger surface displacements (Figure 4.2b) than the ascending data (Figure 4.1b). The trace fault extends from northwest to southeast. Strong decorrelation bands have been observed near the spreading center, possibly due to the ground's high fringe rate and ground disturbances, such as plastic deformation and inversion faulting. They are defined by the strike-slip component compatible with the Zagros Mountains Front Fault. The fringe density of the interferogram of ALOS-2 data (L-band) is lower than that of Sentinel-1 data (C-band), though the second one contains noise (Figures 4.1, 4.2 c). Figure (4.1): The images show the observed co-seismic deformation of ALOS-2 SAR images (a,b) ascending orbit,(c,d) descending orbit). (a) Shows differential interferogram image, and (b) shows LOS co-seismic deformations image. The colorized images of wrapping intervals are 0.03 cm Figure (4. 2): The image shows the observed co-seismic deformation of Sentinel-1A images(a,b) ascending orbit, (c,d) descending orbit) . (a) shows differential interferogram image, and (b) shows LOS co-seismic deformations image. The colorized images of wrapping intervals are 0.03 cm. Download 0.84 Mb. Share with your friends:
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