Seismicity and Tectonic Activity of the Lut Block: Investigating Fault Landforms, Earthquake Characteristics, and Stress Distribution

Tectonics of the Iranian plateau is especially characterized by active faulting and destructive earthquakes. About 180,300 human fatalities have been reported due to 217 earthquakes in this region since 1900. Seventeen of these earthquakes, each of which resulted in more than 1000 victims, and 15 of them were greater than MW=7. A substantial part of earthquake fatalities is due to tectonic activities along the eastern and western margins of the Lut Block, which is considered a rigid micro-plate with a thin crustal structure. The eastern border of this block is the Nehbandan fault system, which overprints the Sistan suture zone. The Sistan suture zone represents the closure of the N-S branch of the Neotethys Ocean in the east of Iran. The western border of Lut is separated from Central Iran by several N-S and NNW-SSE striking right-lateral fault systems such as Nayband, Gowk, Shahdad, and Lakarkuh. Thirteen destructive earthquakes from 1977 were accompanied by about 207 km2 surface rupture in the western border of the Lut Block. These earthquakes resulted in ~ 44,700 human losses, with ~36,640 injured and more than 100,000 homeless. In this research, the relationship between the landforms of the active faults on the western border of the Lut desert and the characteristics of earthquakes has been investigated to determine the stress map for the West and South of the Lut block. We investigate the role of the seismic and the geodetic strain and moment rates in the seismicity of the study area. Moreover, based on our field observations and the results of seismic data analysis, we highlight the dominant tectonic regimes in this area.