Tajikistan: The seismic lull in the Rogun reservoir is alarming

June 14. Uzbek scientists led by the head of the Laboratory of the Institute of Seismology seismotectonics of the Republic of Uzbekistan, the candidate of physical and mathematical sciences Ulfat Nurmatov believe that long-term seismic quiescence in the construction of the Rogun reservoir is very disturbing.

In a study of Uzbek scientists' Seismic situation of the construction site of Rogun reservoir and adjacent territories ", published in the latest issue of the journal" Ecology Xabarnomasi-Ecological Bulletin, "states that the territory of Central Asia is one of the most earthquake-prone regions of the globe.

"Within it there are a number of strong and devastating earthquakes that have led to numerous casualties and destruction of settlements. An analysis of seismological data shows that over the past 150 years within the region have more than 17 cows (with a focal depth of 30 km) and more than 20 deep (with a focal depth of 280 km) earthquakes with magnitudes M? 7.0, with the intensity of J = 9 and more points. District Rogun reservoir is confined to the junction of the Pamir and Tien Shan. These two major tectonic structures delineated Southern Tien Shan and Hissar-Kokshaal regional faults. Vahsh fault, which is dated Rogun reservoir is part of the above-mentioned regional faults and combined them, and controls all the seismic activity of the extended zone collision between two mountain ranges. The total width of the dynamic influence of faults of the order of 30-40 km. Seismic potential of the area is the highest in Central Asia. Of the 17 above mentioned strongest crustal (focal depth of 30 km.) Earthquake with an intensity of 9 and 8 points occurred within the zone, 6 of them have emerged over the last 110 years of the period, "- explains the Uzbek seismologists.

See also: Tajikistan: On the Rogun dam of a crack

According to them, the average frequency of occurrence of 9 magnitude earthquake in the area equal to 15-20 years.

"Last Markansuyskoe strong earthquake with M = 7.3 and an intensity of 9 points emerged in 1974. Over the past 38 years within the area major earthquakes are not registered. Long-term seismic quiescence is very worrying because the conditions are created for the accumulation of more stress in the earth's crust. This situation indicates that at the present time within the zone have accumulated sufficient voltage for the emergence of a stronger earthquake. In connection with the onset of the next period of global seismic activity since the beginning of this century, the likelihood of a major earthquake in the area has increased significantly, "- say the authors of the study.

According to them, the district Rogun reservoir is located between the sites of paired Karatag Hait 1907 and 1949 earthquakes.

"Within this area until an earthquake with an intensity of 9 points or more occurred. Until now, at a distance of 20 km from the location of the Nurek hydroelectric station and 30 km from the Rogun hydroelectric power station there were three strong 8 magnitude earthquake — Faizabad in 1930 and 1943 and Kafdonskoe 1943.

Zone of the South Tien Shan, Hissar-Kokshaal, Vahsh and other faults of the area were of high seismic activity in historical times. This is evidenced by the numerous traces of ancient earthquakes (paleoseismodislocations) found O.G.Kuchaem. Within the above fault zones found 12 paleoseismodislocations resulting from the occurrence of 10-11 ballroom and one as a result of 9 magnitude earthquake "- reminiscent of researchers at the Institute of Seismology of the Academy of Sciences of the Republic.

Source: 12new.uz

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