Density modeling and elastic parameters calculation in Iran with focus on the Lut Block zone (Eastern Iran)

We propose a new density model in Iran, with a particular focus on the Lut Block zone, in eastern Iran, through inversion of the gravity field starting from a high-resolution seismic tomography model (Kaviani et al, 2020). The density and seismic velocity model allow us to obtain rheological parameters, as shear modulus, and the physical state, like pressure and pressure gradient. We realize a first density model, using known velocity-density relations for crust and mantle (Brocher et al., 2005; Connolly, 2005) optimized with the gravity data. Then we calculate the final 3D density model from constrained inversion of the gravity field with a Bayesian approach. The density model, together with velocities from tomography, allows to calculate principal elastic parameters, using empirical relations (Telford et al., 1976). The area analyzed is tectonically active and presents numerous right-lateral strike-slip faults, that cause the slipping of the East-Iran and the Lut blocks. We observe a high-density crustal anomaly, beginning in an upper crust zone and increasing in density as it descends to the mantle. This is located in an area in the center of the Lut Block, around which we know a part of the East-Iran Block, the Birjand block, is rotating. We analyze the zone in terms of physical parameters, searching for a relation between the density anomaly and the rotation of the Birjand block around it.