Аннотация. Каталог землетрясений Таджикистана за 2013 г. содержит 4997 землетрясений с К Р =8.6-15.0, из них 3865-глубокофокусные Памиро-Гиндукушские землетрясения с h=70-250 км и 1132-мелкофокусные, разбросанные по всей территории. Суммарная сейсмическая энергия, выделившаяся в очагах всех землетрясений, составила Е=1.4610 15 Дж. Непосредственно в границах Республики с наибольшей интенсивностью I 0 =6 баллов (К Р =12.4, Mw=4.7) произошло землетрясение 10 ноября в Вахдатском районе, в 24 км юго-восточнее столицы Душанбе. Наиболее сильно пострадали три селения-70 % жилых домов этих селений стали непригодными для жилья. Максимальное среди глубоких землетрясений 2013 г. зарегистрировано в Афганской подзоне 4 апреля с К Р =14.0, Mw=5.4, h=250 км. Из-за большой глубины оно вызвало сотрясения небольшой (I3) интенсивности в эпицентральной зоне и ощущалось в Таджикистане, Афганистане и Пакистане. Однако в целом сейсмический процесс в Республике протекал в фоновом режиме. Ключевые слова: сейсмичность территории Таджикистана, сейсмическая сеть, каталог землетрясений.
The seismic monitoring system consisting of seven digital stations continued to operate in Tajikistan in 2015. This network has registered 9071 earthquakes with KR=8.6–17.0, 6427 of which were Pamir-Hindu Kush earthquakes with intermediate depths (h=70–300 km), and 2644 were shallow events. The total seismic energy released was E=1.8151017 J. The strongest for 2015 was the Hindu Kush earthquake on Octo-ber 26 with Mw=7.5, h=230 km (hpP=217 km) that occurred near the southern borders of the Republic. This earthquake caused significant damage and the death of at least 115 people. It was felt on the territory of 14 states, with a total shaking area of more than 14106 km2. A detailed isoseismal map of this earthquake is given for the Tajikistan territory only. The earthquake was accompanied by a series of over 1400 aftershocks with KR=8.6–12.8, unexpectedly numerous for a deep earthquake. Within the borders of the Republic, the Sarez-II earthquake occurred near the Lake of Sarez on December 7 with Mw=7.2, h=20 km, I0=8, was the strongest one. Undoubtedly, it was triggered by the Hindu Kush earthquake on October 26. In total, more than 500 houses were damaged, dozens of people were injured, and there were human casualties. A detailed isoseismal map of this earthquake was made for four levels of intensity – I=7, 6, 5 and 4. The number of its aftershocks for 24 days only was 1342, with KR=8.6–13.9. As a result the level of seismicity in Tajikistan in 2015, both in terms of the number of earthquakes and the level of released seismic energy, was the highest during the period of instrumental observations.
In 2014, a seismic monitoring system, restored with the participation of the Swiss government, continued to operate in Tajikistan. Seven digital stations Trident+Trillium-40 devices, provide registration of events located in Tajikistan and hundreds of kilometers beyond. This network recorded 5306 earthquakes with КР=8.6–14.5, of which 4308 are deep-focus Pamir-Hindu Kush earthquakes with h=70–270 km and 998 are shal-low, scattered throughout the territory. The total seismic energy released in the sources of all earthquakes amounted to Е~6.61014 J. Within the borders of the Republic, the most powerful earthquake (with КР=13.3) was on September 13. The earthquake located in the southern spurs of the RushanRange at the end of the system of dual Karakul-Sarez faults dividing the Pamirs into Western and Eastern parts. It was felt with an intensity of Ii=4–5 in Khorog and Roshtkal, Ii=4in Rushan and on the lake Sarez. Shocks with Ii=4–5 from the November 1 earthquake with KP=12.1 were also felt in Rogun, at the site of Rogun hydropower plant under construction. The maximum deepest earthquake (КР=14.5, Mw=5.4, h=200 km) occurred on June 14 in the Afghan subzone. Due to the great depth, the area of its perceptibility Ii=3 amounted to 220 thousand km2 in Tajikistan, Afghanistan, Pakistan and Kyrgyzstan. However,in general the seismic process in the Republic proceeded in the background.
In 2016–2017, seismic monitoring of the territory of Tajikistan and adjacent areas was carried out by a network of 7 seismic stations of the Geophysical Survey of the National Academy of Sciences of Tajikistan. In total for 2 years, 17855 earthquakes were registered in the range of KR=8.6–15.9, of which 4882 were small–focus shocks with h<70 km scattered throughout the territory of Southwestern Tien Shan (zone I), Southern Tien Shan (II), Pamir-Hindukush zone of crustal earthquakes (III), and 12973 – with intermediate depths h=70–400 km, located in the Pamir-Hindukush zone IV. 140 earthquakes were felt, for two of them (Gazorchashma earthquake of July 1, 2016 with KR=12.5, I0=6–7 and Karamyk earthquake of May 3, 2017 with KR=14.2, I0=7) the isoseismal maps were constructed and described in separate articles. The strongest earthquakes with a foci in the Earth's crust were grouped in 2016 in the northeast of zone III, on the border with China (June 26, KR=15.3, Mw=6.4 and November 25, KR=15.9, Mw=6.6) and in 2017 – in zone II, on the border with Kyrgyzstan (May 3 and 5 with KR=14.2, Mw=6.0 and 14.1, Mw=5.8 respectively). The strongest earthquake with an intermediate depth of h=230 km occurred on April 10, 2016 with KR=15.1, Mw=6.6 near the southern border of Tajikistan, on the territory of Pakistan. It was felt on the territory of Tajikistan, Kazakhstan, Afghanistan, Pakistan and India. A rare instrumental fact of the seismic field of the Pamir-Hindu Kush earthquakes in 2017 was the registration of the May 6, 2017 earthquake with KR=12.6 (Mw=5.3) with maximum depth of 400 km according to the regional network and 411 km according to the exchange pP-waves in ISC decision. Earlier, only in 1971 a close depth of 405 km was recorded for the November 14 earthquake with KR=9.0. For the region as a whole, in 2016 the maximum seismic energy (E=1.021016 J) was released in zone III, in 2017 – in zone II (E=3.291014 J).
On October 26, 2015, a strong Hindu Kush earthquake with KR=17.0, Mw=7.5 occurred in the Afghan Pamir-Hindu Kush subzone at a depth of hpP=217 km. Shakes of varying intensity caused by this earthquake were recorded in settlements of 14 states: Afghanistan, Tajikistan, Pakistan, Turkmenistan, India, Kyrgyzstan, Uzbekistan, Kazakhstan, China, Iran, Nepal, United Arab Emirates, Russia, Qatar and Bangladesh with a total area of S=14106 km2. The earthquake was preceded by three large (KR=12.5, 12.1, 14.0) foreshocks and was accompanied by a series of more than 1400 aftershocks unprecedented for aftershocks of deep earthquakes with KR=9–13. The energy step between the mainshock and the maximum foreshock is Kfor=3.0, between the mainshock and the maximum (KR=12.8) aftershock – Kaft=4.2. The aftershock recurrence graph has a slope =–0.67, which in absolute value is higher than the average value in the region =0.50. The attenuation para-meter of the Omori law in the initial phase of attenuation, =–1.26, in absolute value is also higher than the average =1.0 for strong earthquakes in the World. Based on the results of a joint analysis of the focal me-chanism solutions of different agencies and vertical sections along and across the aftershock cloud, it was con-cluded that an upthrust movement occurred in the source along a steep east-south-east nodal plane, dipping to the south. The reason for the activity at the site of the earthquake is the movement of the Indian continent to the north and its collision with Eurasia, as a result of which the separation and subduction of the Hindu Kush plate continue. The Hindu Kush earthquake on October 26, 2015, and its aftershocks are just one of the events of successive deformation and stress relief in the latitudinal zone, marked in 2015 by the migration of earthquake epicenters with KR=13–17 from east to west.
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