Spatial distribution of seismicity parameters in the Persian Plateau

In this paper, seismicity parameters in the Persian Plateau are estimated and represented as colored maps. We depict the b-value variations as an indication of either changing material properties, or the heterogeneity of the stress field in this region. The lower b-values in some regions indicate that the seismic energy release in these areas is mostly provided by large magnitude earthquakes. Yet the b-value around northern Central-Iran and Eastern Alborz seems to be near unity, which implies that the seismic energy release is compatible for larger and smaller earthquakes. We also compared our results with some existing seismological information on Iran. Regarding attenuation: low-Q (high attenuation) regions approximately correspond to relatively lower b-value regions, and areas with nearly medium/high b-values correspond to high-velocity anomaly zones inferred from tomographic inversions. Meanwhile, regions associated with thrust and strike-slip faulting was associated with low/medium b-values. The higher b-values in NW Iran agree with the regional extensional tectonics and low/medium b-values were in agreement with regional compressional/strike-slip tectonics. In terms of geodynamics, this may be interpreted as an indication of a weak crust in NW Iran versus stronger crust (zones under stress) in other parts.