Abstract This paper is devoted to the age, stratigraphic position, and structure of the ignimbrite that occurs in NW Armenia, which is locally named “Leninakan tuff.” The massive structure of the tuff with no internal discontinuities, similar chemical composition and K–Ar ages of all the samples let the authors to deduce that the ignimbrite was formed due to a huge single explosive eruption of the

Abstract The main subject of this article is research on the genetic relationships in the K–Na subalkaline series that occurs in the Belogolovsky volcanic center located in the back part of Sredinny Range. The differentiated rock series includes trachybasalts, trachyandesites, trachytes, comendite, trachytes, and comendites. Mass balance calculation and trace element modeling show that crystal fractionation

Abstract The Klyuchevskoi stratovolcano is one of the largest and most active volcanoes in the world; changes of varying sizes have affected the morphology of its surface during historical time. These rock failures mostly occur in long-lived geologic features, namely, volcano-tectonic chutes. Several researchers have made forecasts of failures based on the relief and morphology of the volcano, the

Abstract This paper describes a method for calculating the earthquake energy class for the Kamchatka region from coda records in the 0.8–1.8 Hz frequency band. The method is based on an empirical correlative relationship between the coda level and the Fedotov earthquake class. The coda level is found as the mean power of the ground velocity in an interval of 30 s. Five seismic dipping zones have been

Abstract The geysers and paleo-geysers that exist in Kamchatka are situated in volcanogenic artesian basins composed of products of recent acid volcanism. This is in accord with the worldwide patterns for the occurrence of geyser fields. The results of a TOUGHREACT simulation of flow-through ascending circulation of thermal waters, which have chemical compositions in agreement with that of the water

Abstract An M 7.4 earthquake occurred near the town of Izmit on August 17, 1999 causing enormous casualties and economic losses: over 15 000 victims and several thousand irreparably damaged buildings and structures. The earthquake produced a set of fractures and fissures in the ground extending for more than 70 km from the Gulf of Izmit, with a new tectonic fault being formed that is more than 150-km

Abstract We show that volcanic activity was occurring in the NW Pacific seafloor areas adjacent to Japan, the Kuril Islands, Kamchatka, and the Commander Islands during Pliocene to Pleistocene time. The activity was highest in two areas. At least three major volcanoes originated and were active in the southern area behind the Japan trench off Honshu and Hokkaido. Lava-dominated Pleistocene stratovolcanoes

Abstract The early 21st century saw increased eruption activity of major volcanoes in the Northern Group of Kamchatka, namely, Sheveluch, Klyuchevskoy, Bezymianny, and the Tolbachik Fissure Zone. The growth of an extrusive dome on Sheveluch andesitic volcano has occurred, with the dome reaching a height of 600 m after 38 years of nearly uninterrupted eruption activity. An 8-year period of relative

Abstract Previous publications by this author (Rodkin, 2008a, 2008b, 2012; Rodkin and Tikhonov, 2016; Rodkin and Rundkvist, 2017) proposed and actually used a method for constructing and analyzing the generalized vicinity of large earthquakes (GVLE). The GVLE method provides an enormous increase in the amount of data that is used and, hence, a much more detailed description of the typical features

Abstract An extended and improved model of the origin and evolution of marginal seas in the strike-slip megazone due to the lateral interaction of the Eurasian and Pacific lithospheric plates is proposed. In the megazone, fragmentation of continental and oceanic plates, mantle upwelling, and ascending and descending lithospheric seismic vortexes occur. As a proof of the validity of the proposed model

Abstract The paper assessed the predictability of the seismic energy rate and large earthquakes in southern Europe and the Mediterranean according to the data from the United States Geological Survey catalog for 1900–2016. A nonlinear second-order differential equation is used as a mathematical model, and optimization and predictability estimation algorithms are this author’s. The estimates show a

Abstract The Omori law for repeated underground shocks after a large earthquake is written here in the form of a nonlinear differential equation. We define a coefficient of deactivation for the rupture zone after the main shock. Two advantages of the new formulation are pointed out. First, there is now an interesting possibility for a natural incorporation of exogenous and endogenous factors that affect

Abstract The probable geothermal reserves of Kamchatka are sufficient to produce 3900 MW of electrical energy. Analogous reserves for heat production are estimated as 1350 MWT (thermal units). The TOUGH2 thermohydrodynamic simulation of extraction for the identified productive geothermal reservoirs with established permeability–capacity and energy properties allows us to predict the following: (1)

Abstract The explosive atmospheric electrogenic paragenesis we studied was found to contain over 100 mineral species, varieties, and non-crystalline phases (carbonaceous minerals, phases and compounds, native metals and alloys, carbides, silicides, nitrides, halides, chalcogenides, oxides, silicates and alumosilicates, and oxysalts. The paragenesis is characterized by an abnormally low level of mineralogical

Abstract This paper discusses currently interesting aspects of metallogeny at the Pacific volcanic belts (PVBs); these consist of complex volcanogenic–plutonic features related to the evolution of the marginal-sea lithosphere, which exhibits a remarkable mineralization peculiarity. We show that as time has passed, the ideas of a metallogenetic homogeneity of the PVBs received a new substantiation from

Abstract This paper is concerned with results from ongoing work using the method of long-term earthquake prediction (LTEP) for the Kuril–Kamchatka island arc based on the seismic gap and seismic cycle patterns. We highlight the most important lines of research in the LTEP method during the preceding decade. A long-term forecast is provided using the basic method for the next 5 years, June 2019 through

Abstract An analysis of deep structure for the East Greenland margin (Blosseville Kyst – Liverpool Land) and the Jan Mayen microcontinent yielded a common crustal model for the time before their dispersal. The joint model presents a visual picture of the net result from the Paleozoic, Mesozoic, and Cenozoic rifting phases. Beginning from the Devonian, a graben-like depression approximately 180 km wide

Abstract This paper discusses the conditions of generation for the Au–Ag epithermal mineralization in the Amguema–Kanchalan Volcanic Field (AKVF), which is situated at the western termination of the East Chukchi flank zone of the Okhotsk–Chukchi Volcanogenic Belt (OChVB). The AKVF contains the potentially large Valunistoe Au‒Ag deposit and several promising deposits and ore occurrences (Zhilnoe, Shakh

Abstract This paper gives measured quantities, inclined distances, and elevations between geodetic monuments on the northeastern slope of Klyuchevskoi Volcano for the period from 1978 through 2014. Parasitic and summit eruptions were generally preceded by uplifts of the slope, while the termination of an eruption was accompanied by subsidence. The data from the longest series of observations of vertical

Abstract This paper is concerned with spatial relationships between seismic zones in the eastern Priamurye region (М ≥ 5) on the one hand and, on the other, regional faults and zones of hidden faults as indicated by axes of gravity and magnetic anomalies. The seismoactive zones where М ≥ 5 earthquakes occurred are mostly confined to regional faults, while there are two cases where no such relationship

Abstract Ejecta of recent volcanic eruptions were found to contain a carbonaceous mineral phase paragenesis of explosive atmospheric electrogenic origin. The paragenesis involves diamonds of octahedral habitus with non-aggregated nitrogen defects (without signs of mantle burning), disordered graphite, shungite-like bitumen (kerite–anthraxolite), carbonaceous globules (clustered allotropes of dicarbon

Abstract We have studied paleoseismicity along the adyr (piedmont) Kokonadyr–Tegerek fault zone in the SW Issyk-Kul region. We have shown that although earthquake slip continues in the tectonic contact zone between the Paleozoic rocks of the Kokonadyr–Tegerek uplift and the Quaternary deposits of the Alabash–Konuroleng trough, still most earthquake-generating ruptures visible at the surface are moving

Abstract The relationship between the chemical composition of plants and the active volcanism of Kamchatka is determined by the fact that the dominant chemical elements for the plants, volcanic ashes, and soils are invariably Ca, Mg, Mn, P, Cu, Zn, and Sr. We have found an increased geochemical background for Kamchatka plants relative to the bulk chemical composition of the soils in the peninsula.

Abstract To highlight the importance of small earthquakes in seismic hazard, we present a study of the 11 May 2016, Mw 4.9, Tesistan earthquake. According to historical data from instrumental seismicity, this earthquake represents the largest event recorded near Guadalajara. Due to the close proximity of the event to the city, accelerations were considerable higher than those caused by historical severe

Abstract The edifices of many active volcanoes on the Kuril Islands contain hydrothermal systems whose surface manifestations include springs with diversity in their chemical compositions and in their physical and chemical parameters. Thermal waters of Kuril Islands were found to exhibit four main isotopic shifts relative to the local meteoric water line. The ultra-acid Cl–SO4 (SO4–Cl) waters show

Abstract This paper reviews high precision measurements of distances by geodimeters and elevations by first-order leveling between permanent geodetic monuments in local strain measurement patches on the coast of the Avacha Bay in order to detect strain precursors of a probable large (М > 7.0) near earthquake and to obtain quantitative characteristics of coseismic strain. We report the results of all