عنوان مقاله [English]
Most of the areas of the Iranian plateau are high seismicity regions and there is a considerable difference between them. These differences in the eastern Iranian plateau including the Lut block concerning the surrounding areas are so substantial, that can be studied independently. A brief look at the seismic maps of this region shows that around Lut block, the activity of strike-slip and reverse faults has caused many and devastating earthquakes, and relative stability is established in the inner parts of the block, so that it can be considered as a small rigid plate. In this research, the catalog provided by Mousavi-Bafrouei and Babaei-Mahani (2020) is used as the main source. All the historical and instrumental earthquakes until 2018 related to the study area, which is bounded in 56.5 - 61 E and 28 - 35.5 N in eastern Iran, have been separated from this catalog. Earthquakes from 2019 to 2022 have been collected based on the priorities introduced in Mousavi-Bafrouei and Babaei-Mahani (2020), and based on the relationships introduced in Mousavi-Bafrouei and Babaei-Mahani (2020), the magnitude of earthquakes has been unified to Mw. In order to remove dependent events for the data of the last 4 years leading to 2022, the solution of conjugated windows presented in Mousavi-Bafrouei et al. (2014) has been used. In total, a catalog of 1760 historical and instrumental declustered earthquakes has been provided for the area. The data has been divided into a historical part and 4 instrumental parts 1900 to 1963, 1964 to 1999, 2000 to 2005 and 2006 to 2022, and using the maximum curvature method for each of the 4 time intervals, the data completeness threshold have been determined to be 5.7, 4.7, 4 and 3.1 respectively. The seismicity parameters have been estimated taking into account the uncertainty of the magnitudes. Substantially, the estimated b-value is equal to 1.06 and the mean annual occurrence rate for magnitude ≥ 3.1 is 58, and the maximum magnitude of the earthquake is estimated to be 7.9, which indicates the high seismicity of the region. The probability of annual exceedance for different magnitudes is estimated for the return periods of 50, 475, and 2475 years. Comparing the results of this study with the results of the other study that performed based on the same data and using the same method for the seismotectonic province Central East of Iran, it confirms that the seismicity of Lut block and its margin can be determined independently from the other parts of the seismotectonic province Central East of Iran.