Vulkanologia i sejsmologia

Measured values are given - slant distances and elevations between geodetic marks on the northeast slope of Klyuchevskaya volcano for 1978–2014. As a rule, a rise was observed before the secondary and summit eruptions, and the end of the eruptions was accompanied by the lowering of the volcano slope. According to the longest series of observations of vertical displacements from 1979 to 2014. on the “Kirgurich” radial profile, the rise of the volcano slope is determined to increase as it approaches its crater. The maximum displacements occurred two years before the start of the “Predskazannuy” side breakthrough in 1983, and before the summit eruptions of 2003–2004 and 2007. At a distance of 27 km from the crater of the volcano, the vertical displacements become insignificant. It is shown that points located at altitudes from 2000 meters to 3000 meters are subject to deep creep, i.e. sliding down. The displacement rates of such points reached 5–20 cm/year. Significant horizontal displacements of geodetic points occurred near incidental breaks on March 6, 1980 and March 8, 1983. From 1989–1993. until 2014, reductions of all lengths of lines from 5 to 20 mm were observed, which indicated compression of the northeast slope of Klyuchevskaya volcano.

We have studied paleoseismicity along a zone of the Kokonadyr-Tegerek adyr (foothill) fault in SW Issyk-Kul Lake region. It was shown that, although seismic movements continue along a zone of the tectonic contact of Paleozoic rocks of the Kokonadyr-Tegerek uplift and Quaternary deposits of the Alabash-Konurolyong depression, main number of appearance of seismogenic ruptures in the surface shift southward on hundreds of meters from the adyr fault mentioned above. This process leads to a formation of multiple fault scarps and compensation grabens in their back parts. According to data of radiocarbon dating along the Kokonadyr-Tegerek fault zone there were 4 strong Holocene earthquakes occurred during time intervals: 1771–1785 AD, 1440–1515 AD, and also possibly in 2310–745 BC and 640–5300 BC. Judging by parameters of the fault scarps their magnitudes were M ≥ 7, and seismic intensity I₀≥ IX. Strong seismic activity along the Kokonadyr-Tegerek fault zone continues at least from Mid-Pleistocene. Evidences of this statement are uplifted and abandoned river valley of that time in the uplift with the same name as well as significant accumulation of the lacustrine sediments in northern part of the Alabash-Konurolyong depression. Large thickness of the sediments is tied with glaciers melting in the northern slope of the Terskey Ala-Too Range, and abandoned valleys testify on significant tectonic damming. Most proper model explaining formation of the adyrs (foothills) in the southern part of the Issyk-Kul Depression is a model of a gently dipping main fault flattening out northward, which is complicated by the underthrusts. All obtained data can be used at compilation of a new Map of Seismic Hazard of Kyrgyz Republic.

The article considers the conditions of formation of Au–Ag epithermal mineralization of the Amguemo-Kanchalan volcanic field (AKVP), located on the Western closure of the East Chukchi flank zone of the Okhotsk-Chukchi volcanic belt (OCHVB). In the AKVP potentially large Au–Ag Valunisty mine and several perspective deposits and ore occurrences (Zhilnoye, Shah, Gornoye, Ognennoye and Osennee) are localized. The results of thermo- and cryometric studies of fluid inclusions in quartz and calcite of epithermal veins showed that the solutions was dominated by chlorides Na and K. Epithermal mineralization was deposited by heterogeneous hydrothermal fluids with low salt concentrations (0.2–3.6 wt. % equiv. NaCl, in medium-temperature conditions – 174–354°C). The fluid pressure reached 30–160 bar, which corresponds to the formation depth of 0.1–0.6 km, under hydrostatic conditions. The obtained results allow us to attribute the studied epithermal mineralization to the low sulfidation class. The magmatic hearth of andesitic magmas and meteoric waters are the most probable sources of ore-forming fluids. The information given in the article is of practical importance for regional forecast-metallogenic constructions, prospecting and evaluation of epithermal Au–Ag deposits.