G. M. Steblov

Russian Academy of Sciences | RAS

In this National Report are given major results of researches conducted by Russian geodesists in 2015-2018 on the topics of the International Association of Geodesy (IAG) of the International Union of Geodesy and Geophysics (IUGG). This report is prepared by the Section of Geodesy of the National Geophysical Committee of Russia. In the report prepa...

The approach is proposed for modeling deformations in the subduction zones from the surface displacement data recorded by the methods of satellite geodesy. The technique is developed for revealing spatial and temporal variations in the deformations in the subduction zones. Based on the suggested approach, the variations in the deformation processes...

In this National Report are given major results of researches conducted by Russian geodesists in 2015–2018 on the topics of the International Association of Geodesy (IAG) of the International Union of Geodesy and Geophysics (IUGG). This report is prepared by the Section of Geodesy of the National Geophysical Committee of Russia. In the report prepa...

Multiyear satellite geodetic measurements along the Kuril island arc provided data for studying the condition of the Benioff seismic zone and the occurrence of various deformation mechanisms that are responsible for surface displacements. Factors have been determined whose combination can explain the diverse character of observed movements: space–t...

The data of multiannual satellite geodetic observations before, during, and after the 2011 Tohoku earthquake are interpreted on the basis of the keyboard model of the structure of the subduction region. The inhomogeneities in the field of displacement rates of the Earth’s surface are revealed in the directions of both to the inside of Japan Islands...

The 17 July 2017 Komandorsky Islands MW 7.8 earthquake involved arc-parallel right-lateral patchy strike-slip faulting along ~400 km of the Bering Fracture Zone (BFZ) in the westernmost Aleutian Islands back-arc. The large size of the earthquake indicates that the BFZ serves regionally as the primary plate boundary extending from the Near Islands t...

The interpretation of multiannual satellite geodetic observations after the 2010 Maule earthquake is given on the basis of the keyboard concept of the subduction region structure. It is shown that this concept, combined with the models of viscoelastic relaxation in the asthenosphere and nonstationary convection system in the upper mantle, completel...

Рассмотрены проблемы и перспективны интеграции базовых станций глобальных навигационных спутниковых систем на территории России в рамках единой координатной осно-вы для повышения эффективности высокоточного координатно-временного обеспечения. Намечены масштабные задачи, решение которых необходимо для достижения указанной це-ли: гармонизация законод...

A geodetic network of Global Satellite Navigation System (GNSS) observation sites was organized in 2014–2015 for studying the contemporary crustal motions in the zone of the Vladikavkaz deep fault (Milyukov et al., 2014; 2015). The measurements were conducted and the first velocity estimates obtained testifying to the consistency of crustal motions...

For more than a decade, the global network of GPS stations whose measurements are part of the International GPS Service (IGS) have been recording cyclic variations in the radius vector of the geodetic ellipsoid with a period of one year and amplitude of ~10 mm. The analysis of the figure of the Earth carried out by us shows that the observed variat...

The author analyzed the relationship between variations of the Earth's rotation rate and the geodynamic processes within the Earth's body, including seismic activity. The rotation rate of a planet determines its uniaxial compression along the axis of rotation and the areas of various surface elements of the body. The Earth's ellipticity variations,...

The Aleutian and Kuril-Kamchatka arcs meet at a triple junction of the Pacific (PAC), Bering (BER), and North American (NAM) plates. We invert GPS observations from the westernmost Aleutian (Komandorsky) Islands and Kamchatka for the fault locking depth and block motion in the far western Aleutian transform boundary. Three boundary models were cons...

We analyzed long-term satellite geodesic observations after the Simushir earthquakes of 2006–2007. Application of a key model of the structure of the island arc regions combined with a model of nonstationary convective system in the upper mantle allowed us to find a consistent explanation of the motion of the Earth’s surface and distinguish the seg...

This paper contains a brief review of the Russian geodesists’ activity in 2011–2014 in the field of geodynamics mainly based on the analysis of the literature on the subject. The main research topics were investigations of active tectonic regions in Russia and surrounding regions such as Fennoscandia, Baltic Region, North Caucasus, Far East, Baikal...

The Greater Caucasus overall and its Ossetian segment are parts of the neotectonically active Alpine-Himalaya mobile belt. This region, complex from the geodynamical standpoint, is traditionally treated as resulting from interaction between two large lithospheric plates, the Eurasian and Arabian ones. In 2010, a geodetic network for periodical repe...

The velocity field of the Northern Caucasus based on the results of observations at the Northern Caucasus Geodetic Network (NCGN) stations is represented in the paper. Appreciable horizontal displacement to the northeast with velocity of 26-28 mm/yr relative to the International Terrestrial Reference Frame (ITRF2008) is established. General shorten...

We analyze the first ever GPS observations of static surface deformation from a deep earthquake: the 24 May 2013 MW 8.3 Sea of Okhotsk event. Previous studies of deep earthquake sources relied on seismology, and might have missed evidence for slow slip in the rupture. We observed coseismic static offsets on a GPS network of 20 stations over the Sea...

The main body of the paper deals with the problem of establishing and developing the Regional Terrestrial Reference Frame for North East Eurasia (North East Eurasia Reference Frame - NEEREF). The problem solving suggests the creation of the International Scientific Organization. The initiative for establishment of the International Commission on th...

The ionospheric response to the transit of acoustic waves from a number of the strongest submarine earthquakes with magnitudes M w ≥ 7.7, which occurred during the past few years, is analyzed. The amplitude of the response in the detrended TEC is studied as a function of the magnitude and vertical component of the surface deformation. It is shown t...

International Commission on Regional Terrestrial Reference Frame of North East Eura-sia (North East Eurasia Reference Frame - NEEREF) is organising by the initiative of the Geodesy Section of the National Geophysical Committee of Russian Academy of Sciences. It is voluntary association of the organisations of various form of ownership and of the va...

[1] The 2006–2007 doublet of Mw > 8 earthquakes in the Kuril subduction zone caused postseismic transient motion in the asthenosphere, which we observed on the Kuril GPS Array in 2007–2011. Here we show that the Maxwell asthenospheric viscosity that best fits the geodetic data increased by nearly an order of magnitude over the interval of 4 years,...

The question concerning the integrity of major tectonic plates is still unclear for several regions covering the plate junction zones. The Northeast Asia is one such region, where there is no common concept of the configuration of plate boundaries. From the classical viewpoint, the dynamics of Northeast Asia is determined by the superposition of th...

The effects that the two Kuril undersea earthquakes of November 15, 2006, and January 13, 2007, had on the ionosphere are considered on the basis of the results of measurements of variations in the ionosphere’s total electron content obtained from the network of Russian GPS stations. Owing to a favorable location of the stations, the ionosphere’s r...

Great subduction earthquakes are usually followed by postseismic deformation which may be observed for years and decades since the earthquake. Often the coseismic stress caused by slip on the rupture is released by distributed viscoelastic relaxation in the weak upper mantle. Coseismic and postseismic surface displacements recorded by GPS observati...

Using available Russian and international Global Positioning System (GPS) network data, we studied the ionospheric response to the M = 8.9 submarine earthquake of March 11, 2011, on the northeastern coast of Honshu Island, Japan, both near and far (about 2000 km away) from the epicenter. In the region over the epicenter, 8.7 min after the event, we...

In 2006-2007, a doublet of M>8 earthquakes occurred in the central segment of the Kuril subduction zone (KSZ), the region with no great earthquakes for a century. Surface displacements observed on the Kuril GPS Array comprise the postseismic transient motion and the interseismic motion at a constant speed. The postseismic motion triggered mostly by...

The three-dimensional geomechanical model of Southern California was created, including a mountain relief, fault tectonics and characteristic internal borders such as the roof of the consolidated crust and Moho surface. The initial stress state of the model under action of gravitational forces and the horizontal tectonic movements established on ba...

The Bering Sea region is bounded by the Aleutian Arc on the south, by Alaska on the east, and by Chukotka (Siberia) on the west. The northern boundary is where Alaska and Chukotka meet at the Bering Strait. Seismicity around the Bering Sea allowed Mackey et al. [1997] to discriminate the Bering plate (BERI) from the North American plate (NOAM), alt...

Continuous measurements at the Kuril GPS network since 2006 have revealed anomalous coseismic and postseismic displacements of the Earth’s crust, which accompanied the great 2006–2007 earthquake doublet in the central Kuriles and were observed during 2.5 years after the events. Prior to the earthquakes, all observation sites of the Kuril network we...

In 2006–2007, a doublet of great earthquakes (Mw > 8) struck in the center of the Kuril subduction zone, a thrust event followed by an extensional event. Our observations of the Kuril GPS Array in 2006–2009 outline a broad zone of postseismic deformation with initial horizontal velocities to 90 mm/a, and postseismic uplift. We show that most of the...

This report submitted to the International Association of Geodesy (IAG) of the International Union of Geodesy and Geophysics (IUGG) contains results obtained by Russian geodesists in 2007-2010. In the report prepared for the XXV General Assembly of IUGG (Australia, Melbourne, 28 June – 7 July 2011), the results of principal researches in geodesy, g...

In June 2009, one of the greatest eruptions of the Sarychev Peak volcano in Matua Island (48°06′ N, 153°12′ E) for the recent historical period occurred. With the help of satellite sounding methods, the first signs of volcanic activity were recorded and all the stages of the explosive eruption were traced. During the expeditionary investigations in...

The Kuril-Kamchatka subduction zone is the most mobile and seismically active region in Northeast Eurasia. The Kuril island arc is one of the few tectonically active regions, where until recently there had been no space geodetic network. The first GPS stations were installed on the Kamchatka Peninsula in 1997, and on the islands of the Kuril arc fr...

На примере шести камчатских землетрясений 1997-2004 гг. с Мw=6.2-7.8, произошедших на расстояниях 128-316 км от скважины ЮЗ-5, представлен способ точечной оценки косейсмической объемной деформации по амплитудам скачков уровня воды во время землетрясений и величине приливной чувствительности уровня. Получена согласованность по амплитудам и знаку оце...

A method for point estimation of coseismic volume deformation from amplitudes of earthquake-induced jumps in the water level and from the tidal sensitivity of the water level is presented. Application of this method is illustrated by six Kamchatka earthquakes of 1997–2004 with M w = 6.2–7.8 that occurred 128–316 km from the YuZ-5 well. Estimates o...

На примере шести камчатских землетрясений 1997-2004 гг. с Мw=6.2-7.8, произошедших на расстояниях 128-316 км от скважины ЮЗ-5, представлен способ точечной оценки косейсмической объемной деформации по амплитудам скачков уровня воды во время землетрясений и величине приливной чувствительности уровня. Получена согласованность по амплитудам и знаку оце...

The Bering Sea is bordered by Chukotka and Kamchatka on the west, Alaska on the east, and the Aleutians on the south. The Bering plate (BER), distinct from the North American plate (NAM), was earlier hypothesized judging from seismicity [Mackey et al., 1997]. Recent analysis of GPS observations in western Alaska, on islands in the Bering Sea interi...

From the onset of plate tectonics, the existence of most of the plates was never put in doubt, although the boundaries of some plates, like Africa, were later revised. There are however, two microplates in northeast Asia, the Amurian and Okhotsk, whose existence and the sense of rotation was revised several times. The rms value of plate-residual GP...

At convergent plate boundaries, the accumulated elastic strain is released mostly in great shallow thrust earthquakes. Understanding which fraction of the elastic strain due to plate motion is released in earthquakes is important in assessing the seismogenic potential at convergent boundaries where most of great earthquakes occur. Conventionally, a...

In 2006-2007, two great earthquakes ruptured the center of the Kuril subduction zone: first, the interplate thrust event, then the intraplate extensional event on the outer rise. The affected region was a seismic gap since 1915. Published patterns of slip differ for various seismic and tsunami inversions. The surface offsets that we measured with G...

We present the vectors of rotation of 10 major lithospheric plates, estimated from continuous GPS observations at 192 globally distributed stations; 71 stations were selected as representing stable plate regions. All days for the period 1995.0-2007.0 were included in the analysis. In contrast to previous GPS plate models, our model is independent o...

Our study is based on the vectors of rotation of ten major lithospheric plates, that we estimated from continuous GPS observations at 192 globally distributed stations; 71 stations were selected as representing stable plate regions. The time series in the analysis span all days in the interval 1995-2007. In contrast to previous GPS plate models, we...

The 1200-km long Kuril arc is the last subduction zone never previously explored by space geodetic methods. In 2006, we installed the continuous GPS network (CGPS) over the whole arc and added several survey-mode stations (SGPS). In 2006-2007, the paired great earthquakes near the central Kurils happened several months after we installed the networ...

In this work, we developed computer models for the study regions to analyze the influence of the atmospheric pressure on the stressed state of the Earth’s crust. The distributions of distortions in the Earth’s crust to a depth of 100 km determined at four levels were used as the basis of the model: layer 1 0‐20 km; layer 2 20‐40 km; layer 3 40‐60 k...

Horizontal and vertical station velocities in GPS solutions are affected by uncertainties in translation rate of the Earth center (EC). In conventional reference frames such as ITRF2000 usually applied to constrain a GPS solution, EC is mostly constrained by SLR. Our global GPS solution GPS2006.5 for velocities of 226 stations, observed for at leas...

1] Independent Okhotsk and Amurian microplate motions are tested using velocities from 123 GPS sites (80 from within the proposed OKH and AMU plate boundaries) used to constrain the plate kinematics of northeast Asia. A block modeling approach is used to incorporate both rigid block rotation and near-boundary elastic strain accumulation effects in...

Here we analyze the rigidity of eight major lithospheric plates using our global GPS solution GPS2006.0. We included all daily observations in interval 1995.0 to 2006.0 collected at IGS stations, as well as observations at many important stations not included in IGS. Loose multiyear solution GPS2006.0 is based on daily solutions by GAMIT software,...

The 2,200-km Aleutian megathrust demonstrates a rapid change in the sense of relative motion of the Pacific and North American plates, from nearly trench normal at Alaska to nearly trench parallel at Kamchatka, where the Aleutian and Kamchatka megathrusts connect making a cusp. This change is accompanied by an increase in the relative plate velocit...

Meaningful GPS station velocities should not depend on the choice of a specific reference frame since the origin translation rate (OTR) can be estimated from velocities in stable plate interiors, and an appropriate correction can be applied (R.W. King, private communication). A conventional approach is to translate and rotate the initial, loosely c...

GPS measurements of interseismic horizontal surface velocities reveal the degree of kinematic coupling of the plate boundary thrust along the Kamchatka subduction zone from about 51° to 57°N latitude. Inversions for the distribution of aseismic slip rate along the ~15°NW dipping underthrust suggest a nonslipping plate interface in southern Kamchatk...

The drift of regions in northeast Eurasia was studied using the precise satellite geodesy method (Global Positioning System (GPS)). Observational data were analyzed invoking the International Database. Despite the rather short observations (similar to 6 years), the drift directions of the basic Eurasia and Northern America regions were detected and...

The possibility of Okhotsk plate motion independent of the North American plate and Amurian plate motion independent of Eurasia were tested rigorously using velocities from 106 GPS sites (58 from within the proposed Okhotsk and Amurian plate boundaries) in order to constrain the plate kinematics of East Asia. A block modeling approach was used to i...

The aim of this paper is to analyze the potential resources of GPS monitoring during the recording of potential earthquake precursors using the Hector Mine earthquake that occurred in California, USA, in October 16, 1999. This event was chosen because at the time of this fairly large earthquake (M=7.1) a dense network of ground-based GPS stations w...

Global coverage of landmass by a network of reference GPS stations has principally changed the interpretation of the observation of active processes on the Earth using modern space geodesy. The problem of realization of the unified reference frame became one of the main factors for the correct processing of GPS measurements and their interpretation...

The modern cosmic geodesy methods were effectively used in studying structure and processes in earth crust and upper mantle, that is interesting for seismo-active zones. The net of GPS stations working since 1997 within North Eurasia territory (NEDA) enabled investigation of tectonic blocks boundary geometry in East Siberia and Far East regions, wh...

Since 1995, the Russia/US collaborative Project RUSEG provided GPS observations over the vast landmass of east Asia including the Arctic region. Project participants are: RDAAC/GSRAS (G. Steblov) on the Russian side; Columbia U. (M. Kogan and C. Scholz), MIT (R. King), and U. of California - Berkeley (R. Burgmann) on the US side. The authors of thi...

[1] Interseismic GPS velocities in Sakhalin indicate that the island moves to the west at 3–4 mm/yr with respect to the Eurasian plate, which is about half of the relative Eurasia - North America plate convergence rate. GPS measurements across the central Sakhalin fault system provide evidence of compressive and strike-slip strain accumulation at a...

The velocities of 16 stations extending from Svalbard Island in the north Atlantic to eastern Siberia define the Eurasian plate with a root-mean-square (rms) less than 1 mm/yr. Using these stations as a frame of reference, we have estimated velocities for 58 stations in east Asia from the Arctic to southern China and combined these with the results...

Model inversions of displacements of continuously operating GPS stations in Kamchatka show that aseismic afterslip during 2 months following the Mw=7.8, 5 December, 1997 Kronotsky subduction earthquake released as much moment as the earthquake itself. The rapidly decaying transient slip on the subduction underthrust occurred near the downdip edge o...

GPS observations in northeastern Asia, when combined with observations from the global network for the period 1992-1999, yield an angular rotation vector between Eurasia and North America consistent with and a factor of two more precise than estimates derived using GPS or VLBI data previously available from only western Eurasia. The new vector impl...

High-quality digital data from the temporary Leeds Tararua broad-band array, North Island, New Zealand and the station SNZO at Wellington often record long-period oscillations within the body wave train from large, shallow events in the Tonga-Kermadec and Macquarie seismic zones at regional distances (8 deg-25 deg) along the Australasian/Pacific pl...

In the framework of global plate tectonics, a system of major north-south trending faults in Sakhalin is regarded as the Eurasia - North America tectonic plate boundary (1). According to continuous GPS measurements performed since 1995 at reference stations in the north, middle, and south of the island, Sakhalin moves at a speed of 3 - 4 mm/yr to t...

GPS observations in Siberia combined with global observations, collected in 1995-2003, allow us to improve constraints on the geometry and relative motion of the Eurasian (EUR), North American (NAM), and Pacific (PAC) plates [1]. In contrast to our earlier work and to other published studies, we estimate simultaneously both the relative plate rotat...

1] GPS observations in east Siberia combined with global observations, collected 1995– 2002, place constraints on the geometry and motions of the Eurasian, North American, and Pacific plates in east Asia. By comparing velocities relative to Eurasia and to North America, we conclude that east Siberia to the east of the Cherskiy Range belongs to the...