A. Rashidi; M. M. Khatib; S. M. Mosavi; Y. Jamor
Abstract
In the S,W Lut Block, geodetic moment rate is more than seismic and geological moment rates. Depending on the type of deformation and geometry of the faults, the study area divided to the 4 parts : northern, central, southern and southeastern (South Lut Block) parts. Values of three types of moment ...
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In the S,W Lut Block, geodetic moment rate is more than seismic and geological moment rates. Depending on the type of deformation and geometry of the faults, the study area divided to the 4 parts : northern, central, southern and southeastern (South Lut Block) parts. Values of three types of moment rates in these area are comparing with each other. The most of geodetic moment rate was obtained respectively in northern, central, southern, southeastern parts of the study area. Geodetic moment rate in the northern part is 2.28E+18 Nm.yr, the central part is 1.86E+18 Nm.yr, the southern part is 1.20E+18 Nm.yr and in the southeastern is 1.10E+18 Nm.yr. The most of seismic moment rate was obtained respectively in central, southeastern, southern, northern parts of the study area. Seismic moment rate in the central part is 5.62316E+17 Nm.yr, in the southeast part is 2.05331E+17 Nm.yr, in the southern part is 1.18984E+17 Nm.yr and in the northern part is 1.03408E+17 Nm.yr. According to Seismic map, maximum seismic moment, respectively is along Gowk, Shahdad, Davaran, East Kerman, Mahan, Bam, Kuhbanan, Dahueiyeh, North Faryab Faults. These faults are responsible for large earthquakes in the study area. The most of geological moment rate was obtained respectively in southern, northern, central, southeastern parts of the study area. Values of geological moment rate for the southern part is 4.16246E+15 Nm.yr, northern part is 2.74157E+15 Nm.yr, centra part is 2.5895E+15 Nm.yr and in the southeastern is 1.08894E+15 Nm.yr. In the study area, maximum geological moment rate is respectively related to west Sabzevaran, Jiroft, Raver, Dalfard, Kuhbanan, Naybandan, Bam, Gowk, Davaran faults. According to values of geological and geodetic moment rates in the four parts of study area and based on the value of the release seismic energy in the central and southeastern parts, it seems that in the next time, the most of seismic potential and seismic hazard are respectively in the northern, southern, central, southeastern parts of the study area. In study area, maximum seismic moment are at years 1981, 1998, 2003, 2010, 2011, 1999, 2005 respectively. Ratio of the geodetic moment rate to the seismic moment rate obtained more than 7.9. This ratio reflects the important role of interseismic deformation in this area. According to the ratio seismic moment rate to geodetic moment rate, in four parts of the study area, can be conclude that the northern and southern parts with ratio: 0.04 and 0.09 are slow strain areas and the central and southeastern parts with ratio 0.30 , 0.18 are fast strain areas. Ratio of seismic moment rate to geological moment rate is 0.93%. This value indicates that 0.93% potential of the faults for seismic energy has been released and not been released a big part of the elastic energy in the area.
M. Talebian
Abstract
The north east of Iran, extending from central Alborz to Kopeh Dagh Mountains, is one of the most seismically active regions of Iran. Several large and ancient cities are located in this region and thus provide relatively reach documented history of earthquakes. Numerous active faults have been known ...
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The north east of Iran, extending from central Alborz to Kopeh Dagh Mountains, is one of the most seismically active regions of Iran. Several large and ancient cities are located in this region and thus provide relatively reach documented history of earthquakes. Numerous active faults have been known in this area, some of them have already been under geological investigations, yet many needs to be studied. However, recent geodetic measurements provide a general view about rates of strike slip and shortening across the region. This study evaluates potential of implementing geologic and geodetic data in seismic hazard assessment in this part of Iran. To achieve this, the region of study has been divided to 5 structural zones. The moment accumulating rate was then calculated for each zone using both geological and geodetic measurements. This moment has been compared with moment released by earthquakes. Comparison of seismic moment released by instrumental and historical earthquakes with moment accumulating rate along major active faults suggest that geologic and geodetic data can be considered as a reliable source of information in seismic hazard analysis, especially where there is no sufficient record of earthquakes in the catalogs.
