Empirical data obtained by studying the Earth’s surface deformations in the fault zones induced by exogenous, endogenous, and manmade processes are presented. It is suggested to analyze...

The comparative analysis of the Earth’s surface deformations measured by ground-based and satellite geodetic methods on the regional and zonal measurement scales is carried out. The displacement velocities and strain rates are compared in the active regions such as Turkmenian–Iranian zone of interaction of the Arabian and Eurasian lithospheric plates and the Kamchatka segment of the subduction of the Pacific Plate beneath the Okotsk Plate. The comparison yields a paradoxical result. With the qualitatively identical kinematics of the motion, the quantitative characteristics of the displacement velocities and rates of strain revealed by the observations using the global navigational satellite system (GNSS) are by 1–2 orders of magnitude higher than those estimated by the more accurate methods of ground-based geodesy. For resolving the revealed paradoxes, it is required to set up special studies on the joint analysis of ground-based and satellite geodetic data from the combined observation sites.

This paper addresses the evolution of the views on the subject and methods of geodynamics over the past fifty years. The problems of the metrological provision of the results of repeated...

The results of long-term repeated levelling observations with increased spatial and temporal resolution (distance between benchmarks of 0.3–0.5 km or less and intervals between measurements of 0.5–1.0 years) at oil and gas fields and underground gas storage in Russia and Turkmenistan are considered. Various forms of deformations were found: a weak general uplift or absence of subsidence of the within oil fields, the absence of subsidence during long-term development of a gas field, cyclic deformations (uplift and subsidence) during injection and withdrawal at underground gas storage, and local subsidence in fault zones at all facilities (including underground gas storage during the period of gas injection). Three-dimensional analytical models of deformations of the surface of a weightless elastic half-space with prismatic poroelastic inclusions and inhomogeneous mechanical properties (bulk elastic moduli) are constructed. To assess the total subsidence in oil and gas fields caused by a decrease in reservoir pressure, the solution for a weightless medium was modified to take into account the weight of the overlying rocks, the dynamics of changes in poroelastic parameters, and the genesis of the field formation. It is shown that superposition of solutions for displacements of the half-space containing inclusion and inhomogeneity may explain paradoxical phenomena such as the absence of subsidence during the long-term development of a gas field and the presence of local subsidence under conditions of gas injection into an underground storage. The calculations are compared with the data of repeated geodetic observations to obtain consistent parameters of the development and operation of the underground gas storage.

The time series of the uniquely long geodetic observations of recent geodynamic processes in the Kopet-Dag region are analyzed. The regional observations of contemporary vertical movements cover a 75-year period; the zonal and local systems of leveling measurements, which provide an increased degree of spatiotemporal detail (the distance between the benchmarks is less than 1 km and the measurements are repeated with a frequency of once per month to two times per annum), have been functioning for 50 years. It is shown that during the last 40–50 years, the regional stress field in the forefront of the Main Kopet-Dag thrust and collision zone of the Turanian and Iranian plates is quasi static. The annual average trend rate of strains estimated from a set of the time series of uniquely long geodetic observations is (3–5) × 10⁻⁸ yr⁻¹, which is only one to two amplitudes of tidal deformations of the solid Earth. The local deformations in the fault zone reach the rates that are by 1.5–2 orders of magnitude higher than in the block part of the region. It is found that the segments of the Earth’s surface within the axial part of the depression experience persistent uplifting, which indicates that they do not follow the scheme of inherited evolution characteristic of the fault-block structures of the region. It is demonstrated that these anomalous uplifts can be caused by the variations in the weak seismicity in the zone of the North Ashgabat Fault.

Topical problems of the formation of slow deformation waves and their connection with recent geodynamic (deformational) processes are discussed. It is shown that the term “diffusion of stresses (displacements, strains)” is ill defined from the standpoint of physics of transfer phenomena because in the case of diffusion, mass transfer takes place, whereas the wave processes transfer energy. It is noted that the existing models describing the “diffusion of stresses” are solved based on the mathematical formalism of heat conduction theory which relies on the phenomenon of energy transfer. It is demonstrated that applying the term “wave” to the “stress diffusion” processes is untenable because in the classical sense, wave processes describe undamped (sustained, continuous) oscillations propagating in a homogeneous medium at constant velocity. The processes describing the “diffusion of stresses” form strongly damped oscillations whose propagation velocity substantially decreases with time. As a mechanism corresponding to the wave canonical concepts, a model of autowave deformation processes is proposed that implement the relay-race transfer and successive re-initiation of deformation activity from a fault to a fault or from one activated segment of a fault to another segment. Problematic issues of identifying the slow deformation waves are discussed, and the recommendations are proposed for constructing a network of observation points for the in situ measurements of spatiotemporal migration of the Earth’s surface deformations. It is substantiated that the existence of slow deformation waves does not explain the entire observed spatiotemporal spectrum of recent movements of the Earth’s surface.