A. Rastbood; B. Vosooghi
Abstract
In this research, fracture mechanic concepts and dislocation modeling is used to examine the velocity field of GPS observables on the oblique collision zone of Arabia-Eurasia plates. For this purpose, the significant active faults in the study area were selected and proper boundary conditions applied. ...
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In this research, fracture mechanic concepts and dislocation modeling is used to examine the velocity field of GPS observables on the oblique collision zone of Arabia-Eurasia plates. For this purpose, the significant active faults in the study area were selected and proper boundary conditions applied. Numerical boundary element method with green functions obtained from Okada analytical solution were used to distribute strike slip rates among selected active faults. Velocity field obtained from the model was compared with GPS velocity field of Iranian campaign global geodynamic network and by changing boundary conditions using try and error a better coincidence were generated between model and GPS velocity field. At the final stage the difference of most of GPS observations from model results were inside of 95% confidence ellipse. Regarding accordance among model and geological slip rates, in continue of estimates we tried to get better accommodation between model and GPS velocity fields. For this purpose we tried to get better accordance between deduced slip rates by two methods with changing of boundary conditions and introducing some of geological slip rates as boundary conditions. Slip rates of other faults obtained by initial modeling were considered as boundary conditions for final modeling. These boundary conditions were changed by try and error to get close and close to geological slip rates such that the accommodation of model with GPS velocity field were retained and even get better too. Modeling results show that most of faults modeled slip rates are consistent with slip rates obtained by geological methods. The numerical results also show that most of strike slip faults in Iran are dextral. Regarding that final modeled slip rate for North Tabriz fault (6.4 mm/yr) is more than modeled slip rate for Main Recent Fault (2.2 mm/yr), the model shows that North Tabriz Fault is continuation of North Anatolian Fault in Iran.
B. Vosooghi; A. Rastbood
Abstract
In this research, the role of various existing tectonic plate and faulting motions in the middle-east region has been investigated on the geodetic data and its purpose is to estimate the contribution of these motions in the GPS velocity field of campaign global geodynamic network in the region of Iran ...
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In this research, the role of various existing tectonic plate and faulting motions in the middle-east region has been investigated on the geodetic data and its purpose is to estimate the contribution of these motions in the GPS velocity field of campaign global geodynamic network in the region of Iran using fracture mechanics concepts and dislocation modeling. For modeling the faulting data in the Middle-East region were decomposed to various categories by considering the tectonics of the region and were included in the model and the induced velocity field due to them were modeled and compared with GPS velocity field. Obtained results show that the contribution of Arabian plate in observational GPS velocity field is more than the contribution of Anatolian plateau faultings and inside faultings of Iran create an internal north-south compression component and a counterclockwise rotation component in the modeled velocity field. According to modeling results about 30% of GPS velocity field components are produced by Iranian inside faults, 60% by Arabian plate and 10% by Anatolian plate.
Y. Amerian; B. Vosooghi
Abstract
The methodology of geometrical modeling of the earth surface deformation [surface deformation tensor of the first kind (tensor of strain), linearized surface rotation tensor, and surface deformation tensor of the second kind (tensor of change of curvature)] is done using different kind of space geodetic ...
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The methodology of geometrical modeling of the earth surface deformation [surface deformation tensor of the first kind (tensor of strain), linearized surface rotation tensor, and surface deformation tensor of the second kind (tensor of change of curvature)] is done using different kind of space geodetic data (VLBI, SLR, GPS, DORIS, Levelling). In this study the tensor of change of curvature and its invariants and the change of the mean and Gaussian curvature in the Lagrangian portrayal was computed using GPS observation to monitor the subsidence of Mashhad and Neyshabour area. For this purpose, coordinates and displacement rates (velocities) of Iranian Permanent GPS Network (Khorasan area) in Eurasian frame derived in 2007 were analyzed. The maximum value of the rate of mean and Gaussian curvature difference are and respectively in study area. The patterns of numerical analysis confirm land subsidence induced by over explosion of ground water in study area
H. R. Nankali; B. Vosoughi; F. Soboutie; K. Hessami; M. Talebian
Abstract
A three-dimensional lithosphere model with horizontal dimensions of 1500 km×600 km and a depth extent of 70 km for the Zagros is constructed from available geophysical data to find out strength of the outermost layers in this area. The structural boundaries of the model are based on the results ...
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A three-dimensional lithosphere model with horizontal dimensions of 1500 km×600 km and a depth extent of 70 km for the Zagros is constructed from available geophysical data to find out strength of the outermost layers in this area. The structural boundaries of the model are based on the results from the deep seismic sounding profiles. First the finite element model for the temperature is solved in order to obtain initial temperature and the geotherm, after that structural viscoelastic problem is solved using the same mesh as in the thermal initial condition. Preliminary results for wet and dry rheology indicate that the depth of the BDT is about 8 km and 11 km for hot geotherm and 10.5 km to14 km for cold geotherm. The results are in good agreement with focal depth in the Zagros that most earthquakes occur in 8 to 15 km depth (Tatar et al., 2004 and Jackson et al., 2008), that the long-term strength of the continental lithosphere resided only in its upper part, which was contained wholly within the crust.
L. Karimi Dehkordi; B. Vosoughi; Y. Djamour
Abstract
In this study work the idea of the optimal design of GPS monitoring network is extended in order to estimate the parameters of a single strike slip fault: i.e. slip rate and locking depth. By using some numerical examples, the influence of the GPS station distances from the fault trace has been investigated. ...
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In this study work the idea of the optimal design of GPS monitoring network is extended in order to estimate the parameters of a single strike slip fault: i.e. slip rate and locking depth. By using some numerical examples, the influence of the GPS station distances from the fault trace has been investigated. The results show that far GPS stations have more advantages for estimating of slip rate. In contrast, the near stations are important for locking depth.
