First results of the analysis of GPS measurement data obtained from 18 sites of two local networks in the vicinity of Ulaanbaatar (Mongolia) for the period 2010–2015 have been presented. Horizontal velocity vectors are consistent with each other in the ITRF2014 system and with the velocities of the IGS permanent station ULAB. The sites move in the E–SE direction at a rate of 25–30 mm/yr, with the displacement azimuth averaging 105°. With respect to Eurasia, the vectors for most of the sites are slighly turned to the south, but they are still of SE orientation with the azimuth range of 130°–150° and magnitude values of 2–4 mm/yr. Relative horizontal velocities tend to decrease towards southeast that determines a zonal distribution of different type of relative strain patterns. The western part of the Ulaanbaatar network is characterized by the W–E oriented extension with the elongation rate ε1 = 12–16 × 10–8 yr–1. The shortening NW–SE trending strain with calculated value ε2 = 22.4 × 10–8 yr–1 characterizes the network’s eastern part. The highest values of the maximum shear strains (εmax = 10–14 × 10–8 yr–1) form an extended area in the center of the testing ground, which is elongated in the northeastern direction, conformably with the strike of the major geologic structures. The strain distribution pattern of the Emeelt network located within the eponymous seismogenic structures is characterized by the crustal elongation (5 × 10–6 yr–1) trending SE–NW and less pronounced shortening in the SW–SE directions. The axial part of the fault crossing the network in the NW direction exhibits maximum deformations.
Based on the results of a laboratory simulation of the seismic fault reactivation by "stick-slip" process, it was shown that the system of two blocks just before an impulse offset goes through the meta-instable dynamic state, with early and late stages of meta-instability [Ma et al., 2012]. In the first stage the offset begins in slow stationary mode with slow stresses relaxation on contact between blocks. In the second stage of the "accelerated synergies" strain rate increases and, subsequently, the deformation process through a process of self-organization came to dynamic impulse offset. The experimental results were used for interpretation of the results of spectral analysis of the deformation monitoring data. The data were held within the southern part of Lake Baikal, where Kultuk earthquake (27.08.2008, Ms=6.1). took place. Its epicenter was located in the South end zone of the main Sayan fault. Monitoring of deformations of rocks was carried out from April to November 2008 in tunnel, located at 30 km from the epicenter of the earthquake. The time series data was divided into month periods and then the periods were processed by the method of spectral analysis. The results showed that before the earthquake has ordered view spectrogram, whereas in other time intervals, both before and after the earthquake such orderliness in spectrograms is missing. An ordered view spectrograms for deformation monitoring data can be interpreted as a consequence of the self-organization of deformation process in the transition of seismically active fault into meta-unstable before the Kultuk earthquake.Key words: seismically active fault; meta-instability; earthquake; strain monitoring; spectral analysis; synergism et al., 2012] показано, что нагруженная система из двух блоков непосред-ственно перед реализацией импульсной подвижки проходит через метанестабильное динамическое состоя-ние, со стадиями ранней и поздней метанестабильности. В первую стадию процесс смещения одного блока относительно другого начинается в квазикриповом стационарном режиме с медленной релаксацией накоп-ленных на межблоковом контакте напряжений. Во вторую стадию «ускоренного синергизма» скорость сме-щения существенно возрастает и впоследствии через процесс самоорганизации и лавинообразного объеди-нения многочисленных активизированных сегментов межблокового контакта переходит в динамическую импульсную подвижку. С учетом этих экспериментальных выводов анализируются результаты спектрально-го анализа данных деформационного мониторинга, проведенного в пределах южной оконечности оз. Байкал, где 27.08.2008 г. произошло Култукское землетрясение (Ms=6.1). Его эпицентр располагался в южном окон-чании зоны Главного Саянского разлома. Мониторинг деформаций горных пород проводился с апреля по ноябрь 2008 г. в штольне, расположенной в 30 км от эпицентра землетрясения. Временной ряд данных был разделен на тридцатидневные интервалы, которые обрабатывались методом спектрального анализа. Ре-зультаты расчетов показали, что перед землетрясением спектрограмма имее...
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