Chemical composition of precipitation in the southern part of the Russian Far East

Distribution of macro-and microelements, found in precipitation in dissolved and suspended forms (solid material) is considered. Contribution of the main sources of substance input in the precipitation on the investigated area is assessed.     

The relation of seismicity to lithospheric density inhomogeneities in the Russian Far East

A well-defined relationship has been identified between the belts, zones and areas of higher seismicity in the Russian Far East on the one hand and, on the other, maxima in the gradient of surface density of spherical sources that give rise to gravity anomalies (μ _z ) equivalent to quasi-isometric density inhomogeneities in the lower crust and upper mantle. The highest epicenter density is observed in the marginal parts of maxima of the μ _z parameter, these parts being interpreted as boundaries of rigid (sialic metamorphic and oceanic mafic) tectonic blocks and plates. The overwhelming majority of crustal seismicity is spatially related to uplifts of the asthenospheric layer reflected in the minima of the μ _z parameter, and is concentrated in uplifted crustal blocks. In addition to the linear type of seismicity due to deep-seated faults, the crust shows a concentrically zonal type of epicenter location associated with plume-generated central-type features (the Olekma-Stanovoi seismic zone). It is shown that seismic fields can be ranked by the depths of earthquake source zones using 3D models, μ _z (x,y,z).     

The Early Cretaceous coal‐forming plants of southern part of East Siberia and Russian Far East

For the first time the plants that gave rise to the Early Cretaceous coals of Transbaikalia (Khilok, Chita‐Ingoda, Bukachacha, and Turga‐Kharanor basins), Amur River region (Bureya Basin), and Primorye region (Razdolnaya River and Partizansk River basins) have been obtained. The plants that produced coals mainly belong to the ginkgoaleans (Pseudotorellia, Sphenobaiera, and Baierella), bennettites, and conifers having pinaceous, taxodiaceous, araucariaceous affinity, as well as extinct cheirolepidiaceous and miroviaceous plants. A parallel palynological study has identified a number of the same elements in addition to the cyatheaceous, gleicheniaceous, osmundaceous, and schizaeaceous ferns.     

Concept for developing a seismologic observation system for tsunami warning in the Russian Far East

The initial information and requirements for developing a seismologic observation system and data-processing and transfer tools for a tsunami warning system and its functions and tasks are considered. The structure of the seismologic observation system for the tsunami warning service (TWS) in the Russian Far East is proposed. A study of general technical and methodological problems is carried out to increase the efficiency for urgent tsunami prediction from continuous seismic monitoring data of territories of the Russian Far East and the world. Special attention is paid to the problem of tsunami prediction from seismologic data on strong earthquakes in near zone of a protected territory (up to 200 km).     

Intergranular trace elements in mantle xenoliths from Russian Far East: Example for mantle metasomatism by hydrous melt

Based on both major and trace element chemistry, the occurrence of the intergranular component in mantle-derived xenoliths from far eastern Russia has been constrained. Whole-rock trace element measurements of one xenolith show apparent negative anomalies in Ce, Th, and high field strength elements on normalized trace element patterns. The trace element pattern of the whole rock differs from those of constituent minerals, indicating that the anomalies in the whole rock are attributable to the presence of an intergranular component. That assumption was confirmed using in situ analysis of trace elements in the intergranular substance and melt inclusion using laser ablation inductively coupled plasma–mass spectrometry. Both the intergranular component and the melt inclusions have identical trace element patterns, which mean that these materials are a cognate metasomatizing agent. The anomalies are regarded as mantle metasomatism related to an aqueous fluid. Hydrous minerals were observed on the wall of the melt inclusions using micro-Raman spectroscopy, indicating that the melt inclusions contained a large amount of water. Thus, this study reveals a trace element composition of a hydrous metasomatizing agent in the mantle.     

Kema terrane: A fragment of a back-arc basin of the early Cretaceous Moneron–Samarga island-arc system, East Sikhote–Alin range, Russian Far East

Abstract The Kema terrane is a suite of Barremian(?)–Aptian to Albian volcano-sedimentary rocks of Sikhote–Alin that are interpreted as deposits of the back-arc basin of the Moneron–Samarga island-arc system. Compositional features of the different-type deposits indicate a near-slope depositional environment influenced by volcanic processes. Studies of slump fold orientation testify to the accumulation of material from southeast to northwest by gravitational sliding. Compositional characteristics of terrigenous rocks suggest the major provenance for detrital material was an ensialic volcanic island arc. Petrochemical characteristics of basaltic rocks indicate that the formations studied were confined to the back part of the arc.     

On the cold wave of January 1954 in the Far East

Summary A synoptic study is made based primarily on 10-day and 5-day mean maps on an unusually cold spell which appeared all over the Far East in the end of January, 1954, following an abnormal warmth. It is found that while it is warm in Japan, cold air is accumulated in Siberia to the north of the climatological jet stream and is confined in the northern latitudes by the latter as long as the high index pattern prevails. But once the index drops, with the southward displacement of the jet stream, the permanent trough of the Far East deepens and the cold air so far accumulated is allowed to penetrate into southern latitudes. Some characteristic features of contour pattern and frontal activity preceding and following the cold air outbreak are described. Further, it is shown that the blocking wave directly related to the cold air outbreak in the Far East can be traced from as far east as North America or possibly the eastern Atlantic.     

Space-time variations of river water chemistry in RF southern Far East

Concentrations and seasonal variations of water chemistry, including dissolved and particulate forms of Fe, Mn, Zn, Cu, Pb, Cd, and Ni in rivers of Primorskii Krai are determined. It is shown that, unlike the macrocomposition, the effect of hydrological regime on the concentration of dissolved metal forms is controversial and depends on anthropogenic load, watershed landscapes, and pH variations. Elevated concentrations of dissolved metal forms are recorded in the beginning of spring flood and during low-water period. Beyond the limits of local impact of wastewater, the concentrations of dissolved forms of Cu, Zn, Ni, Pb, and Cd in river waters of the region insignificantly differ from the clearest rivers of the World.     

Late Jurassic (Tithonian) radiolarians from a clastic unit of the Khabarovsk complex (Russian Far East): Significance for subduction accretion timing and terrane correlation

A well-preserved radiolarian fauna from a clastic unit of the Khabarovsk accretionary complex (southern part of the Badzhal accretionary wedge terrane in the Russian Far East) is assigned to the basal part of the Pseudodictyomitra carpatica zone. The age of the fauna is most likely late Tithonian. This is the first reliable dating of the clastic unit and makes it possible to constrain the timing of subduction accretion in the Badzhal terrane. The Khabarovsk complex is correlated chronologically with the Bikin and Samarka terranes (Russian Far East), Mino, Southern Chichibu and North Kitakami terranes (Japan), and Nadanhada terrane (northeast China).     

远东地区近期强震系列及其相关性研究

远东地区的强震系列可以分为板间强震系列与板内强震系列。研究了它们的分类、特征及其适用的公式，得出远东地区板间强震系列与板内强震系列的相关性十分明显、板内强震系列常发生在板间强震系列之后的结论。     

The development of the system of integrated instrumental monitoring of volcanoes in the Far East Region

This work presents the project of the first stage of implementation of the integrated instrumental system of volcanic activity monitoring in Kamchatka and the Kuril Islands. The system of monitoring was designed for the purpose of ensuring public safety, aviation safety, and reducing economic losses caused by volcanic eruptions. The most active and dangerous volcanoes in Kamchatka (North and Avacha groups of volcanoes) and the Kuril Islands (volcanoes on the islands of Kunashir and Paramushir) are of first priority for monitoring. For this purpose, special observation points are planned to be installed on the volcanoes. The system of monitoring will include a complex of observations (broadband seismic station with a large dynamic range, tiltmeter, devices for gas, acoustic, and electromagnetic observations, and video camera). All the data will be passed to information processing centers in real time. New methods and algorithms of automatic and automated identification of the volcanic activity level and the probabilistic volcano hazard assessment have been developed.     

Gravity and Displacement Variations in the Areas of Strong Earthquakes in the East of Russia

The modern gravimetry methods are capable of measuring gravity with an accuracy of up to 10^–10 of the normal value, which is commensurate with the accuracy of the up-to-date methods of displacement measurements by satellite geodesy. Significant changes, e.g., in the coseismic displacements of the Earth’s surface are recorded in the zones of large earthquakes. These changes should manifest themselves in the variations of gravity. Absolute measurements have been conducted by various modifications of absolute ballistic gravimeters GABL since the mid-1970s at the Klyuchi point (Novosibirsk) in the south of the West Siberian plate. Monitoring observations have been taking place in the seismically active regions since the 1990s. In this paper we consider the results of the long-term measurements of the variations in gravity and recent crustal displacements for different types of earthquakes (the zones of shear, extension, and compression). In the seismically active areas in the east of Russia, the longest annual series of absolute measurements starting from 1992 was recorded in the southeastern segment of Baikal region. In this area, the Kultuk earthquake with magnitude 6.5 occurred on August 27, 2008, at a distance of 25 km from the observation point of the Talaya seismic station. The measurements in Gornyi (Mountainous) Altai have been conducted since 2000. A strikeslip earthquake with magnitude 7.5 took place in the southern segment of the region on September 27, 2003. The effects of the catastrophic M = 9.0 Tohoku, Japan, earthquake of March 11, 2011 were identified in Primor’e in the far zone of the event. The empirical data are consistent with the results of modeling based on the seismological data. The coseismic variations in gravity are caused by the combined effect of the changes in the elevation of the observation point and crustal deformation.     

A synsedimentary structure formation model for the Far East Jurassic-Early Cretaceous basins and uplifts,Russia

This article is to reveal and corroborate the geodynamic conditions for the formation of Cretaceous sedimentary basins of the Russian Far East. The conclusions are based on the comprehensive analysis of the extensive mapping materials and special structural field studies. It has been found that sedimentary basins developed as rift-grabens were synchronous with formation of horsts separating the basins. The imbricated-thrust structures, which are morphologically similar to the subduction-related accretionary prisms but nevertheless different in nature, were formed within the transition zone between the uplifted structures and basins. A synsedimentary supply of a mantle-derived material into basins points to a temporarily continual extension of continental lithosphere. The lithospheric plates moved apart during the strike slip faulting with the subsequent involvement of convective mantle flows and plume diapirism (continental spreading?). Because of horizontal movement of lithospheric plates, horstlike uplifts were formed in the frontal zones. In sedimentary formations overlapping the lithospheric plates, the synsedimentary imbricated-thrust structures were developed, favouring a growth of the uplifts in lateral direction toward the axial zones of rift-grabens. Synchronously with basaltic volcanic activity in the rift-graben zones, basic-ultrabasic intrusive magmatism occurred within the limits of the contiguous uplifts.     

Automatic real time parameter determination of tsunami earthquakes in the Far East of Russia: Algorithms and software

A system of algorithms and software modules is described for automatic real time determination of epicenters and magnitudes of potential tsunami earthquakes. Modules are compiled into a single software system called Tsunami Source Quick Location (SS TSQL). The TSQL complex was successfully tested on dozens of real digital recordings. Currently, the TSQL complex is continuously operated in a test mode within the first phase of the seismic subsystem of the Tsunami Warning System (SS TWS) in the Far East of Russia.     

南海北部新生界地层的远偏移距折射波速度特征

南海北部为张裂大陆边缘,在新生代时期经历了复杂的地质演化,具有良好油气勘探前景.本文首次利用南海北部某区域长排列地震数据的远偏移距折射波速度计算方法获得南海北部地层层速度,并进行了分析,此外,还提出了非初至折射波的概念.本方法在共偏移距剖面上识别、拾取折射波层位,得到折射波走时的横向连续变化数据,利用不同共偏移距同一折射波层位的到达时差计算该折射层位的速度结构.该方法在南海北部陆坡某区域地震资料的应用,揭示了新生界地层层速度的整体结构,反映了新生代不同时代地层的速度变化特征,为进一步利用折射层速度资料探讨南海新生代地质演化提供了新的视角.研究表明,与常规初至折射波法相比,远偏移距折射波能够提供更多的地质信息;该方法的初步应用能够对远偏移距折射波的研究提供进一步的视角.     

应用重力资源估算东海冲绳海槽地壳厚度

利用东海地区的重力资源，并参考在该地区进行的地震测深结果，应用线性公式估算了研究区的地壳厚度，分析了研究区地壳结构特征，根据与中国东部地球物理场、地壳结构的对比，指出东海大陆架地区应是中国大陆的自然延伸，对冲绳海槽的地壳性质进行了探讨，指出冲绳海槽应该为东海大陆架的自然终结。     

应用重力资料估算东海冲绳海槽地壳厚度

利用东海地区的重力资料,并参考在该地区进行的地震测深结果,应用线性公式估算了研究区的地壳厚度,分析了研究区地壳结构特征,根据与中国东部地球物理场、地壳结构的对比,指出东海大陆架地区应是中国大陆的自然延伸.对冲绳海槽的地壳性质进行了探讨,指出冲绳海槽应该为东海大陆架的自然终结.     

Regional Geothermal Characterisation of East Anatolia from Aeromagnetic,Heat Flow and Gravity Data

East Anatolia is a region of high topography made up of a 2-km high plateau and Neogene and Quaternary volcanics overlying the subduction-accretion complex formed by the process of collision. The aeromagnetic and gravity data surveyed by the Mineral Research and Exploration (MTA) of Turkey have been used to interpret qualitatively the characteristics of the near-surface geology of the region. The residual aeromagnetic data were low-pass filtered and analyzed to produce the estimates of magnetic bottom using the centroid method and by forward modelling of spectra to evaluate the uncertainties in such estimates. The magnetic bottom estimates can be indicative of temperatures in the crust because magnetic minerals lose their spontaneous magnetization at the Curie temperature of the dominant magnetic minerals in the rocks and, thus, also are called Curie point depths (CPDs). The Curie point depths over the region of Eastern Anatolia vary from 12.9 to 22.6 km. Depths computed from forward modelling of spectra with 200–600 km window sizes suggest that the bottom depths from East Anatolia from the magnetic data may have errors exceeding 5 km; however, most of the obtained depths appear to lie in the above range and indicate that the lower crust is either demagnetized or non-magnetic. In the interpretation of the magnetic map, we also used reduction-to-pole (RTP) and amplitude of total gradient of high-pass filtered anomalies, which reduced dipolar orientation effects of induced aeromagnetic anomalies. However, the features of the RTP and the total gradient of the high-pass filtered aeromagnetic anomalies are not highly correlated to the hot spring water locations. On the other hand, many high-amplitude features seen on the total gradient map can be correlated with the ophiolitic rocks observed on the surface. This interpretation is supported by Bouguer gravity data. In this paper, we recommend that the sources of the widespread thermal activity seen in East Anatolia must be investigated individually by means of detailed mapping and modelling of high resolution geophysical data to assess further the geothermal potential of the region.     

Assessing rheological properties of fluid mud samples through tuning fork data

Ocean Dynamics - At the nautical bottom approach, part of the fluid mud layers can be included in the available depth if they present favorable rheology. As it is difficult to perform in situ...