Recent Vertical Crustal Movements Research Articles

Геодезические измерения в регионах интенсивного движения земной коры

Abstract: Reviewed studies on the oil fields, calculated the volume of crude oil performed and the volume of injected water produced to maintain reservoir pressure. These data were compared with the results of repeated leveling measurements. Numerous repetitive instrumental geodetic measurements in the oil fields in different regions have shown that the area where the oil is extractedisnot bearing recent vertical crustal movements manmade. On the basis of numerous repeated leveling measurements in a seismically active region established pattern of recent vertical crustal movements during the catastrophic earthquake.

Geomorphological evidence of recent tilting in the Central Amazonia Region

Geomorphometric techniques applied to remote sensing data represent powerful tools as an aid for detecting terrain features produced by recent vertical crustal movements in a variety of landscapes. In this work, geomorphometric analysis of the Central Amazonia drainage network using Shuttle Radar Topography Mission (SRTM) data was carried out to determine surface water loading and tectonic influence on the development of the Uatumã and Urubu river basins since the Miocene. The main objective was to detect geomorphological domains of lateral stream migration and channel sinuosity changes that could indicate recent vertical crustal movement. To achieve this, the Transverse Topographic Symmetry Factor and Sinuosity Index were applied to analyze the study area drainage network. Comparison of the geomorphological domains with structural field data and records of seismicity suggests that they are influenced by subsurface fault reactivation, which coincides in space with faults mapped in outcrops that have activated since the Miocene. This interpretation is corroborated by the spatial correspondence between these faults with domain boundaries and shapes, by river sinuosity change when crossing these boundaries, and by a high concentration of seismic activity along one of these limits. The crustal movement caused by hydrological loading can also influence such geomorphological features. Such is the case of lateral stream migrations of a domain in the opposite sense to the Amazon River flow. This may be a consequence of the more pronounced expression of hydrological loading in the Negro and Solimões river confluence region.

Recent vertical crustal movements and resulting surface deformation within the North German Basin (Schleswig-Holstein) derived by GIS-based analysis of repeated precise leveling data

Recent vertical crustal movements and resulting surface deformation within the North German Basin (Schleswig-Holstein) derived by GIS-based analysis of repeated precise leveling data

Recent and Late Holocene vertical crustal movements in the Southeast Baltic—The transition zone between the Fennoscandian shield and the Russian plate

The paper analyzed recent vertical crustal movements and compared them with Late Holocene ones (over several thousands of years) with the case study of the transition zone between the Fennoscandia shield and the Russian plate. The study of recent and young movements is based on long-term sea level and repeated geodetic measurements and on geologic geomorphic data, respectively. The data set makes it possible to establish that a weak uplift of the territory gives way with regularity to a weak subsidence after going across the zone of zero movements that agrees with the modern geodynamic constructions and can serve as the basis of long-term prognostic estimations. The results are compared with the newest GPS measurements and with the theoretical model of viscoelastic deformations in the periphery of the past glaciation area during its postglacial isostatic adjustment

Recent vertical crustal movements of a part of the Balkan Peninsula derived from levelling data

The historical levelling data of the epoch of 1950-1960 were used along with the levelling data of the epoch of 1970-1973 for the derivation of the vertical velocity field on the territory of the Republic of Serbia. The methodology was based on the construction of a kinematic network and least squares adjustment and aimed at obtaining the vertical velocities of representative benchmarks. Being the first attempt of this kind for the area under investigation, no further interpretation of the result is given, apart from a couple of remarks concerning the correlation between the gradient surface and the general geophysical features.

Pattern of recent vertical crustal movements in Canada

Abstract We used the method of smooth piecewise algebraic approximation to automatically compute a smooth approximation of large functional scattered re-levelling data and historical tide gauge records given over Canada and northern US to thereby compile a unified map of vertical crustal movements (VCM). The area of study is divided into pieces and piecewise algebraic surfaces are fitted to the tide gauge trends and to the height difference differences, computed from monthly mean sea-level and re-levelling segments, respectively. When the surfaces are fitted to the data, a set of continuity and smoothness constraints is imposed in such a way that rather than the surfaces being fitted sequentially, they are fitted simultaneously, using the constraints as a set-conditions which the parameters of the surfaces must also satisfy. The VCM model obtained in this research gives enough details of the movements. It highlights the long wavelength spatial and temporal variations of the crust in Canada, mainly due to postglacial rebound (PGR). In Eastern Canada, the PGR hinge line appears from Gulf of St. Lawrence in the map of VCM. It follows the Atlantic coast line to the south of the country. In the Great Lakes, the relative movements or the tilt varies slightly between 0.5 and 1.5 mm/year per hundred kilometers) along northeast–southeast direction, which is toward the maximum ice center in Hudson Bay. The computed tilt is in a relatively good agreement with the tilt obtained from the glacial isostatic adjustment (GIA) model of ICE-3G (VM2) in this region (∼1 mm/year per hundred kilometers). The predicted rate of tilt in eastern prairies in Manitoba from VCM is in the range of 1.5–2 mm/year per hundred kilometers toward Hudson Bay. This solution is in good agreement with the results of previous studies for subsidence in southern Lake Athabaska in Saskatchewan and for uplift in southern prairies. However, GIA models do not agree with such findings. The zero line in the map of VCM nearly follows the Pacific coastal line, which is consistent with the PGR zero line in the prairies.

Density inhomogeneity of the lithosphere in the southeastern periphery of the North Asian craton

The study addresses the space distribution of lithospheric density contrasts in 3D and 2D surface (spherical) sources of gravity anomalies to depths of 120 km below the geoid surface and their relationship with shallow deformation and Archean, Early Paleozoic, and Late Mesozoic geodynamic environments. The lithospheric section in northeastern Transbaikalia and the Upper Amur region includes two layers of low-density gradients attendant with low seismic velocities and low electrical resistivity. The lower layer at depths of 80–120 km is attributed to an asthenospheric upwarp that extends beneath the North Asian craton from the Emuershan volcanic belt and the Songliao basin. The concentric pattern of density contrasts in the middle and lower crust beneath the Upper Amur region may be produced by the activity of the Aldan-Zeya plume, which spatially correlates with the geometry of the asthenospheric upwarp as well as with the regional seismicity field, magnetic and heat flow anomalies, and stresses caused by large earthquakes and recent vertical crustal movements. The relationship between shallow and deep structures in the crust and upper mantle bears signature of horizontal displacement (subduction) of the lower crust of the Baikal-Vitim and Amur superterranes beneath the North Asian craton.

Compilation of a Map of Recent Vertical Crustal Movements in Eastern Canada Using Geographic Information System

In this paper, we use geographic information system as a useful tool in compiling vertical crustal movement (VCM) over Eastern Canada. For modeling linear VCM, we employ tide gauge records and precise releveled segments, which reflect the glacial isostatic submergence of the coasts, as well as other global, regional, and local effects. The area of study is divided into two zones: Maritimes and South St. Lawrence zones. Piecewise polynomial surfaces of different orders are calculated by the method of least squares for each region to obtain representations of the recent vertical movements. This work provides the framework for multidisciplinary studies of geodynamics in the region, allowing different selection of zones for vertical crustal movements and simplifying the incorporation of more data in future investigations. We use ArcGIS to visualize the theoretical approaches, and to integrate and analyze different spatially distributed data. This powerful tool helps us to produce a more physically meaningful VCM map for the region. The map reflects the most significant geophysical phenomenon in the region, postglacial rebound, and it is in good agreement with the 2004 glacial isostatic adjustment model of Peltier [ICE-5G(VM2)].

A comparative analysis of maps of vertical crustal movements for European Russia

A comparative analysis has been carried out for maps of recent vertical crustal movements (RVCM) for the European territory of Russia published at various times. We present maps for differences of rates of RVCM (1963–1971, 1971–1986). Considerable discrepancies have been detected for the rates of RVCM shown in the maps as regards the sense of movement, its magnitude and distribution. We point out possible causes of these discrepancies and question the validity of RVCM maps as reflecting tectonic crustal movements.

The relationship of recent vertical movements to the morphostructural pattern of the Kazakh shield

The geodetic data on recent vertical crustal movements within the Kazakh shields is in good correlation with its development in the Holocene (according to a study of juvenile river terraces); they point to gradual transition of the shield to the platform morphostructures of Western Siberia and a contrasting joining with the Central Asia orogenic belt. Small gradients of recent vertical movements dominate the shield. Moderate gradients are typical of local structures, whereas increased and extremely high gradients belong to active deep fault zones.

MAGKAT - A high resolution marine magnetic survey of the Kattegat area

Spatial distribution of isobases of recent vertical crustal movements displayed by the map indicates certain predominant directions (lineaments). The directions coincide with main regional structural directions of the Alpine and Hercynian structural stage in Poland. The movements are concentrated along deeply seated discontinuities and weakness zones of the crust perpendicular to the main direction of tensional normal stress (NW-SE) or parallel to the direction of maximum shear stresses (WNW—ESE, NNE-SSW). The recent vertical crustal movements of Poland are mainly of taphrogenic or block-wave nature. Local halokinetic and orogenic (tangential) movements are also of some importance. Subsidence taking place in a broad meridional zone of the Polish Lowland peripheral to areas glaciated during the last Pleistocene ice stage seems to be at least partly related to glaciisostasy. The wave nature of the recent vertical movements of the earth's crust is confirmed by results of their harmonic analysis. The movements may be described as the net result of overlapping waves of different length and frequency. There are no data which would indicate that recent crustal movements in Poland are directly related to sea-floor spreading of the northern Atlantic Ocean, but it is admitted that this relationship is suggested by some indirect evidence.

Recent fault tectonics and their relations to the seismicity of East Germany

The prominent features of the map of recent vertical crustal movements of East Germany are NW-SE striking faults which divide the whole country into tilted blocks. Some of the faults are known from geological mapping, others, especially in Mecklenburg-Vorpommern and Brandenburg are known only from geophysical investigations or are unknown except for geodetic evidence. The recent mobility of all faults was proved by typical geodetic indications. There are almost no conformities with morphologic structures. The movements along these faults are aseismic and creeping. The difference in the velocity of movement between the blocks on either side of the fault is not more than 0.18 mm/yr, and the direction of movement changes after short periods of time (not geological periods). In some cases, the continuation of faults show no recent mobility in the above described sense, but along the fault planes the epicentres of small earthquakes can be found, especially in southwest Saxony (Vogtland). That seems to be an explanation for areas of very low seismicity and for the relationship between recent crustal movements along faults and the seismic activity along faults.

Recent Vertical Crustal Movements in Shikoku District, Japan and Their Time-Space Representation

Recent Vertical Crustal Movements in Shikoku District, Japan and Their Time-Space Representation

Recent Vertical Crustal Movements in Shikoku Disrict, Japan and Their Time-Space Representation

Recent Vertical Crustal Movements in Shikoku Disrict, Japan and Their Time-Space Representation

Recent tectonic movements and the stability of geodetic signs

Recent vertical crustal movements are functions of several factors: endogenous, exogenous and technogenous. Therefore, when using relevelling data to analyse recent geodynamics, it is necessary to eliminate the exogenous the technogenous effects on the position of geodetic signs. With this purpose in view, an engineering-geomorphological inspection of relevelling lines is carried out. The inspection methods are discussed in the paper, as also are some of the results of inspections and the problems of the elaboration of the types and construction of geodetic sign and principles of their installation.

Some general regularities in the relation between recent vertical dynamics and long-term seismic activity in Bulgaria

The dependence of the maximum magnitude Y of expected tectonic earthquakes upon the velocity X of recent vertical crustal movements in Bulgaria is studied. The two-dimensional random variable (X, Y) is treated as a physical system to which an inner degree of indefiniteness is inherent. With the help of the theory of information, utilizing the possible states A i of the system A and their probabilities p i, the entropy of the partial physical systems X and Y and of the composed system (X, Y) is determined. It is demonstrated that X and Y are not independent and the degree of indefiniteness of X is smaller than that of Y, i.e., that the better known system X could be used as a source of efficient information when studying the state of the less-known (and statistically dependent on it) system Y. This conclusion is further corroborated, by the investigation of the joint sampling distribution of (X, Y) in Bulgaria, made with the help of a new variant suggested by the Chi-Square test of significance aimed at checking a family of statistical hypotheses. A not very close, but statistically significant correlation, of a curvilinear type, between X and Y is established. For the whole country, and especially for its most seismoactive region, the best-fitting regression equations of fourth order, aimed at an express and relatively reliable forecast of Y by means of X, are deducted and experimented. The space structure and the significance of the correlation between X and Y in this region is studied and their regional background surfaces are determined. The results obtained are analysed and a good complex interpretational relation to earlier independent geological, geomorphological and geophysical investigations for this country is established.

Recent vertical crustal movements in Romania: Spatial and temporal variations

Recent vertical crustal movements in Romania: Spatial and temporal variations

Some general regularities in the relation between recent vertical dynamics and long-term seismic activity in Bulgaria

The dependence of the maximum magnitude Y of expected tectonic earthquakes upon the velocity X of recent vertical crustal movements in Bulgaria is studied. The two-dimensional random variable (X, Y) is treated as a physical system to which an inner degree of indefiniteness is inherent. With the help of the theory of information, utilizing the possible states Ai of the system A and their probabilities pi, the entropy of the partial physical systems X and Y and of the composed system (X, Y) is determined. It is demonstrated that X and Y are not independent and the degree of indefiniteness of X is smaller than that of Y, i.e., that the better known system X could be used as a source of efficient information when studying the state of the less-known (and statistically dependent on it) system Y. This conclusion is further corroborated, by the investigation of the joint sampling distribution of (X, Y) in Bulgaria, made with the help of a new variant suggested by the Chi-Square test of significance aimed at checking a family of statistical hypotheses. A not very close, but statistically significant correlation, of a curvilinear type, between X and Y is established. For the whole country, and especially for its most seismoactive region, the best-fitting regression equations of fourth order, aimed at an express and relatively reliable forecast of Y by means of X, are deducted and experimented. The space structure and the significance of the correlation between X and Y in this region is studied and their regional background surfaces are determined. The results obtained are analysed and a good complex interpretational relation to earlier independent geological, geomorphological and geophysical investigations for this country is established.

The ties between recent crustal movements and fault tectonics in the Caraptho-Balkan region

To identify the faults controlling the intensity of recent tectonic processes in the region and to study their geometry and dynamics, one of the variants of the statistical method was used-trend analysis. The map of recent vertical crustal movements in the Carpatho-Balkan region (1:2.000.000) published in Budapest in 1979 was used as initial data for establishing these faults.

A new version of the map of recent vertical crustal movements in the Carpatho-Balkan region based on the collocation method

The paper is concerned with the problem of adequate mapping of resulting discrete values of the movement velocity as a field. The authors used a statistical method (collocation) to represent measurement results for the Carpatho-Balkan region as a field of recent crustal movement velocity. The collocation method gives a possibility of avoiding a strong influence that the available geomorphological and geological knowledge of the area and individual notions of map-makers have on the drawing of isolines of velocity movements. The new version of the map of recent vertical movements in the Carpatho-Balkan region shows some notable differences from the 1979 version.