Tectonic Forces Research Articles

Cloud Computing is Ushering in a Paradigm Shift in Business Models; Can Management Accounting Stay Unaffected?

Cloud services are just not a Technology but a major strategic shift inducing new business models and it unleashes tectonic forces affecting the very traditional business assumptions. It is an outcome of the rapid changes wrought by digital technologies and may be considered as a major facilitator of Digital Transformation. It drastically changes the expectations of customers, partners, and employees and thus, leads to major changes in the conditions under which business is done. Viewed from a strategic lens, it brings about a radical shift in the way in which a business create, delivers and captures value. Management Accountants should understand the strategic implications of the cloud approach and should appropriately modify the costing, valuation and decision making methodologies.

Yellowstone Plume Drives Neogene North American Plate Motion Change

AbstractPlate motion changes provide powerful constrains on plate tectonic forces. North America is ideal to explore these forces. We use recently published high‐temporal resolution plate reconstructions of North America, which reveal a velocity slow‐down at 17 Ma, roughly coeval with the eruption of the Yellowstone plume, together with a stratigraphic analysis of hiatus surfaces across the continent, which provides proxy information for paleotopography. Using a simple Couette/Poiseuille flow models we estimate asthenosphere flow beneath North America and its impact on Neogene plate motion. We find that North America's Neogene plate motion change can be explained by Poiseuille flow in the asthenosphere generated upon the arrival of the Yellowstone plume and that the flow length‐scale matches the extent of hiatus surfaces. While plume driven upper mantle flow constitutes a geodynamically viable model to explain North America's Neogene plate motion change it provides an intrinsic link between vertical and horizontal plate motions.

THE PHYSIOGRAPHY OF INDIA: AN OVERVIEW

Physiography is a field of geography that studies the physical patterns and processes of the Earth, such as geomorphology, hydrology, soil, rocks, biogeography, and the effects of tectonic forces on landscapes. This paper aimed to discuss the physiographic characteristics of India due to its diverse geographical features by using a systematic search and collection of publications and secondary data. The characteristics of India's physiography were discussed descriptively and visually. This study highlights the fundamental physiographic divisions, sub-divisions, and socioeconomic functions of each type of terrain in India, including the northern mountain range, northern plains, peninsular plateau, coastal plains, and islands (the eastern and western coastal plains, Andaman and Nicobar islands). This overview concluded that the physiography of India is complex, heterogeneous and could be categorized into four divisions with distinct characteristics. In detail, the Himalayan Range is a mountainous region in the northern part of the country which produced by the fold mountain processes. Meanwhile, the Indo-Gangetic Plain was well recognised for its extensive agricultural activities contributed by the Ganges River. India's diverse landforms had a profound impact on the country's cultural and economical development. On the other hand, this study also demonstrated that the plateau region in the country's southern and central regions was geographically diversified. The different landscapes of India influenced the socioeconomic characteristics of the Indian society and consequently supported national development of India.

High resolution architecture of neotectonic fault zones and post-8-Ma deformations in western Hungary: Observations and neotectonic characteristics of the fault zone at the Eastern Lake Balaton

Lake Balaton (Hungary), the largest lake in Central Europe, formed by the interplay of tectonic and external forces. Its shallow water and young soft sediments together allow to carry out ultra-high resolution reflection seismic surveys to investigate shallow tectonic structures and near surface stratigraphy at depth of ca. 0–30 m. To document neotectonics of the eastern lake basin and its onshore surroundings to the East, we have integrated new ultra-high-resolution seismic-reflection data with deeper penetrating multichannel lake and land seismic profiles, regional geological, geophysical and seismicity data, and geomorphological observations. Combined use of these different data sets provided an opportunity to understand better, how these different types and scales of structural features are linked. In our study area, late middle to late Miocene formations compose a deepening than shallowing sedimentary cycle from terrestrial clastic through offshore marl and deltaic sequence filling up the basin between ca. 8.6 to 7.5 Ma. The deltaic sequence is unconformably overlain by erosional remnants of late Pleistocene fluvial deposits and a mantle of latest Pleistocene to Holocene lake mud. Post-early Miocene deformation history involved two phases; a latest middle to early late Miocene transtension and a dominantly strike-slip regime with locally transpressional or transtensional character. The latter neotectonic phase reactivated the earlier faults and resulted in the propagation of 4 major fault zones across the complete late Miocene sequence. The resulting young faults show segmented geometry, stepovers, and connecting splays. The deformation also induced the modest but penetrative folding of the highest preserved Miocene deltaic sequence. The change in deformation style could happen during the late-stage of delta formation, at ca. 8 Ma although a slightly younger timing is not excluded. Faults imaged offshore apparently do not offset the Holocene lacustrine mud by discrete fractures, but the improved distribution map of recent seismicity and morphotectonic indices along their onshore continuations suggests that several segments of the fault pattern are still active, and might be capable of generating earthquakes. Integration of these different data provided an opportunity to understand better, how these different types and scales of structural features are linked and evolved one after another. • 4 fault zones and 4 types of folds were mapped below Lake Balaton. • Post-8-Ma neotectonic faults are the reactivation of earlier Miocene structures. • The mapped fault pattern serves as an example for the complexity of segmented fault zone. • Faults below the lake continue onland form a coherent structural pattern. • Recent fault activity is suggested by the new seismicity map.

The assessment of possible deformations in the fault zone

One of the most relevant aspects for engineering geology regarding faults is the characterization of the changes induced by a fault and the assessment of possible fault movements. This zone cannot be clearly and well observed in field studies. However, it plays a negative role in the construction and operation of structures. In this zone, unfavorable phenomena, such as rock collapses, displacements, etc., may occur. The purpose of the present study is to estimate the size of fault changes, to reveal the peculiarities of stress distribution within the fault influence zone and to characterize free surface movements. The site of the Rogun HPP was chosen as the object of the study. Rogun HPP is located on Vakhsh River (Tajikistan) in a gorge of 400 - 500 m deep. The site of the dam, which will be about 350 m high, is located in a single tectonic block bounded by sub-parallel Ionakhsh and Gulizindan Regional Faults. The complex of Jurassic-Cretaceous sediments in this block lies monoclinically. According to the results of complex inclinometer-deformographic observations at the Rogun HPP site, the faults are tectonically active, with vertical displacements in 1-3 mm per year. In the scheme of numerical simulation, the width of the Ionakhsh Fault together with the crushing zone was taken as 20 m. For all rocks it was accepted: Young modulus – 3000 MPa; Poisson’s ratio - 0.3; density - 2.6 g/cm3. Horizontal compressive tectonic force was given as 12 MPa. The simulation showed that the dynamic influence zone is limited to 200 m on the side of the lying wing and 70 m on the side of the hanging wing, and the concentration zones are located at the mouth and in the middle part of the fault on the side of the lying wing and between the hanging side of the fault and the bottom of the valley. The analysis of the movements of eight points of the surface showed that the direction of movement corresponds to observed in nature. The total amplitude of vertical displacements of two points at the valley is 0.51 m. The values of the resulting displacements on the different sides of the fault are 0.22 and 0.49 m. According to geological data, the width of tectonic breccia zone of the Ionakhsh Fault is 120 m. However, according to numerical simulation the influence zone is about 270 m. Thus, the simulation showed that the size of real fault influence zone is more than twice as large as that measured in nature.

The stress distribution around the mining excavations under different tectonic loads

The article studies the fatures of stress distribution around the mining excavations under different tectonic loads on the case study of the Zhdanovskoe copper-nickel ore deposit, Murmansk region, Russia. The deposit is located in the Arctic zone on the Russia-Norway state boundary and is excavated by the Severny underground mine using simultaneously the sublevel caving and the open stoping methods. The combination of these mining methods in the same area affects the geomechanical conditions; moreover, the highest level of stresses is identified between the opposing excavation fronts. The deepening of mining increases the geodynamic risks caused by the stress state in the rock mass. In this regard, the study of the Zhdanovskoe deposit rock mass stress state and its transformation due to the mining progress is urgent. To address the issues a numerical geomechanical 3D model was created. To specify the correct boundary conditions, the results of the in-situ measurements were compared to visual observation results. To achieve the most accurate result, the direction and ratio of the tectonic loads were varied and the results were analyzed. The authors have analysed the modelling results in the form of the stresses and deformations distribution in the area around the excavations under different directions of tectonic loads. Based on this analysis, the authors have substantiated a relevant variant of direction of tectonic forces relatively the ore body strike. The results have been applied to forecast the changes in perspective stress-strain state during the mining progress.

Oceanic Plateau and Subduction Zone Jump: Two‐Dimensional Thermo‐Mechanical Modeling

AbstractOceanic plateaus are characterized by overthickened crust and rheologically strong and chemically depleted mantle root with respect to normal oceanic lithosphere. The buoyant nature makes them have a great potential to resist subduction and initiate a new subduction zone behind the plateaus, yet the geodynamic process remains enigmatic. Here, we use 2D thermo‐mechanical modeling method to investigate the role of an oceanic plateau in subduction zone reorganization. We systematically examine the rheological strength and compositional density of oceanic plateau mantle and the size of oceanic plateau. Three distinct subduction styles are observed: (a) steep subduction without subduction zone reorganization, favored by a small‐sized (≤150 km) or lowly depleted oceanic plateau; (b) breakoff of subducting slab followed by flat‐slab subduction, which is conditional on a moderate‐sized (≥300 km) oceanic plateau with high degree depletion but relatively low strength; and (c) initiation of a new subduction zone behind the plateau (subduction zone jump), facilitated by a moderate‐sized oceanic plateau with a strongly depleted mantle root. The geodynamic results demonstrate that the overriding lithosphere undergoes a tectonic force switch from compression to tension in ∼5 Myr as the subduction zone is reorganized. This can be reflected in the crustal deformation of the overriding plate and used as an indicator to identify past subduction zone jumps. The spatial relationship predicted by the subduction zone jump models explains the Jurassic closure event of the accretion on southern Qiangtang at ∼175 Ma and the intraoceanic infant arc magmatism in the Meso‐Tethys at ∼165 Ma.

Insights into the structure and surface geology of balanced and retrodeformed geological cross sections from the Nizampur basin, Khyber Pakhtunkhwa, Pakistan

The current research work is an attempt to apply the basic geological procedures, methods of geological mapping, surface and subsurface interpretation and restoration of balanced and retrodeformed cross sections from the Nizampur basin, Khyber Pakhtunkhwa, Pakistan. The work also includes the documentation of several surface structural features, i.e., anticlines, synclines and different types of folds and faults exposed in the vicinity of study area. Four central thrust faults were recognized named as Kahi Thrusts along the cross sections. These thrust faults carried the older sequences of rocks over the younger sequences in different portion along the measured cross section. The folded and faulted rocks in the area show that stratigraphic framework comprises of Eocene, Paleocene, Cretaceous and Jurassic succession of rocks. There are Eocene rocks existing in the extreme South of the mapped area with addition of older Cretaceous and Jurassic succession and contains simple and large-scale folds, faults and back thrust. Two structural transect were mapped which encounter different folds and faults, i.e., X-sections AB oriented NS and CD oriented NE-SW. Restoration of the structural transects was calculated and assumed that at the formation of Main Boundary Thrust, the study area was exposed to the tectonic forces which prognosticated 19.5% shortening in rock sequences from Jurassic to Eocene succession along the measured cross section A_B.

Topographic stress control on bedrock landslide size

Landslides are a major natural hazard and act as a primary driver of erosion, chemical weathering and organic carbon transfer in mountain ranges. Evaluating the impact of landslides on Earth systems requires knowledge about the controls on their size, which are not well understood. Here we show that topographic stress, resulting from the interaction between tectonic stress and topography, influences bedrock landslide size at landscape scales by modulating the subsurface material strength through fracturing and weathering. Using a three-dimensional topographic stress model, we characterize the spatial pattern of subsurface open-fracture zones in a crystalline-rock terrain of the eastern Tibetan mountains. Then, we compare the predicted open-fracture zones with 982 mapped bedrock landslides. The results show that areas with deeper subsurface open-fracture zones tend to accommodate larger landslides. This is probably due to the influences of topographically induced fractures on the material strength and groundwater flow paths and rates. We conclude that the extent of hillslope failure depends on both distant tectonic forces and local topography, which has implications for hazard mitigation, landscape evolution and the global carbon cycle. Stress from tectonics and topography may be the primary control on the size of bedrock landslides, according to a comparison of a stress model with landslide inventories for a mountainous area in eastern Tibet.

A probabilistic method for mapping earth fissure hazards

Earth fissures caused by tectonic forces, human activities, or both seriously threaten the safety of people’s lives and properties. The Taiyuan Basin, a Cenozoic downfaulted basin located in the centre of the Fen-Wei Basin tectonic belt, in northwestern China, presents the ideal study area for a hazard assessment of earth fissures. A total of 104 earth fissures have been observed in the Taiyuan Basin, with a total length of approximately 128 km. In this paper, we proposed a probabilistic method for mapping earth fissure hazards by integrating the analytic hierarchy process (AHP), the area under the curve (AUC), and the certainty factor model (CFM). Geomorphic units, geologic formations, active faults and land subsidence zones of the Taiyuan Basin were mapped in detail. Correlations between these factors and earth fissures were evaluated through spatial modelling in ArcGIS. The AUC was introduced into the AHP to weight each factor and thus, to derive an earth fissure susceptibility map. Finally, the modelled earth fissure susceptibility was compared with a digital inventory of earth fissures to develop a probability function and map the spatial variability in failure probability through the CFM. The study indicates that active faults have the greatest contribution to the generation of earth fissures. Earth fissures are prone to develop in the piedmont alluvial-diluvial clinoplain and the transitional zone near the geomorphic boundary. This mapping procedure can assist in making rational decisions regarding urban planning and infrastructure development in areas susceptible to earth fissures.

Structures in Shallow Marine Sediments Associated with Gas and Fluid Migration

Geological structure changes, including deformations and ruptures, developed in shallow marine sediments are well recognized but were not systematically reviewed in previous studies. These structures, generally developed at a depth less than 1000 m below seafloor, are considered to play a significant role in the migration, accumulation, and emission of hydrocarbon gases and fluids, and the formation of gas hydrates, and they are also taken as critical factors affecting carbon balance in the marine environment. In this review, these structures in shallow marine sediments are classified into overpressure-associated structures, diapir structures and sediment ruptures based on their geometric characteristics and formation mechanisms. Seepages, pockmarks and gas pipes are the structures associated with overpressure, which are generally induced by gas/fluid pressure changes related to gas and/or fluid accumulation, migration and emission. The mud diapir and salt diapir are diapir structures driven by gravity slides, gravity spread and differential compaction. Landslides, polygonal faults and tectonic faults are sediment ruptures, which are developed by gravity, compaction forces and tectonic forces, respectively. Their formation mechanisms can be attributed to sediment diagenesis, compaction and tectonic activities. The relationships between the different structures, between structures and gas hydrates and between structures and authigenic carbonate are also discussed.

A 3D Full Stress Tensor Model for Oklahoma

AbstractThe stress tensor is an important property for upper crustal studies such as those that involve pore fluids and earthquake hazards. At tectonic plate scale, plate boundary forces and mantle convection are the primary drivers of the stress field. In many local settings (10–100 s of km and <10 km depth) in tectonic plate interiors, we can simplify by assuming a constant background stress field that is perturbed by local heterogeneity in density and elasticity. Local stress orientation and sometimes magnitude can be estimated from earthquake and borehole‐based observations when available. Modeling of the local stress field often involves interpolating sparse observations. We present a new method to estimate the 3D stress field in the upper crust and demonstrate it for Oklahoma. We created a 3D material model by inverting multiple types of geophysical observations simultaneously. Integrating surface‐wave dispersion, local travel times and gravity observations produces a model of P‐wave velocity, S‐wave velocity, and density. The stress field can then be modeled using finite element simulations. The simulations are performed using our simplified view of the local stress field as the sum of a constant background stress field that is perturbed by local density and elasticity heterogeneity and gravitational body forces. An orientation of N82°E, for the maximum compressive tectonic force, best agrees with previously observed stress orientations and faulting types in Oklahoma. The gravitational contribution of the horizontal stress field has a magnitude comparable to the tectonic contribution for the upper 5 km of the subsurface.

Three Dimensional Terrain Modeling for Tectonic Geomorphology of Chinara Anticline, Northern Iraq

Analysis of the terrain using three-dimensional models offers a deep insight view of ground surface topography and terrain representation. The Chinara anticline is one of the main structures of NW-SE trends for the highly folded zone in northeastern Iraq. The objective of this study is to understand the interrelationship between topography and morphotectonic features using three-dimensional models. This research employed fourth generates principal raster derivative products from the DEM using ArcGIS. To understand the undulating of this anticline with the morphotectonic style, the adaptive equation has been suggested to determine the direction and amount of the main tectonic forces, which can be applied to other undulated anticlines. The values of northeastern and southwestern limbs undulating index UI are 11.7 and 7.8 respectively that indicates the strong tectonic force towards the northeast. Two listric faults have been conducted via the field survey that confirmed by remotely sensed interpretation and DEM products. These listric faults had an intensive impact in comparison with concluded strike-slip faults, and then the Chinara anticline would be less structural undulating in a region of vicinity syncline to Perat undulation. The morphotectonic landscapes reveal that the listric fault has branched into two parts, the first one extending to form the anticline and the other comprises the structural dilemma.

Vertebrate Life, 10th edition

Vertebrate Life, 10th edition

Time Distribution of Strong Seismic Events in the Fore-Sudetic Monocline in Context of Signals Registered by Water-Tube Gauges in Książ Geodynamic Laboratory

Changes in the stress field in Świebodzice Depression (ŚU) unit area are the reason of complex kinematics of the rock blocks consisting of rotations and horizontal/vertical displacements. The measurement system of the Geodynamic Laboratory in Książ, associated with rock blocks which are separated by faults, is a natural detector of tectonic activity. Installed in laboratory long water-tube gauges allowing to determine the functions of tectonic activity—TAF, and their derivatives. A comparison of the TAF with the seismic activity of the Fore-Sudetic Monocline showed that the strong seismic shocks (magnitude ≥3.6) occur in the Monocline only during defined and repeatable phases of the kinematic activity of the ŚU. Observed concordance proves the thesis of the existence of a large-scale, and largely homogeneous field of tectonic forces which, at the same time, cover the ŚU and the Fore-Sudetic Monocline units. The results of comparison between seismic events temporal distribution and phases of tectonic activity of the ŚU orogen indicate existence of the time relation between function of derivative of the tectonic activity (TAF) and seismic events.

Optimal design of shape of a working in cracked rock mass

A criterion and a method for solving a problem on the prevention of mine working fracture under the action of tectonic and gravitational forces are offered. Based on minimal criterion, theoretical analysis of the definition of the optimal shape of working in the rock mass weakened by arbitrarily located rectilinear cracks was carried out. A closed system of algebraic equations allowing to minimize the stress state and stress intensity factors depending on mechanical and geometrical characteristics of the rock, is constructed. The relation between the shape of the working and the stress intensity factors and also location and sizes of the cracks is obtained. The found optimal shape of working increases load-bearing capacity of the rock.

External signal preservation in halokinetic stratigraphy: A discrete element modeling approach

Abstract Subsurface salt movement in the absence of external tectonic forces can affect contemporaneous sediment deposition, mask allocyclic signals, and deform older strata. We used a discrete element model (DEM) to better understand salt-related modification of a sedimentary sequence with an increasing sedimentation rate. This permitted quantification of thinning rates and analysis of the lateral extent of synkinematic layers. Results show realistic evolution of salt-related faults, defining two salt-withdrawal basins, beyond which strata are undeformed. Thinning of stratigraphy is four times greater between the salt flank and crest than between the undeformed zone and flank, confirming an intense zone of halokinetic modulation adjacent to the diapir. Early, slowly aggrading layers are isolated within the salt-withdrawal basin and strongly influenced by salt growth, whereas later, quickly aggrading layers are more laterally extensive, matching inferences made from subsurface and outcrop data. Halokinetic modulation reduces up the stratigraphic section, mirroring observations around the Pierce diapirs, in the North Sea, offshore UK. Our DEM provides quantitative insights into the dynamic interplay between halokinetic and allocyclic controls on salt-stratigraphic relationships.

New sequence stratigraphic framework on a ‘passive’ margin: implications for the post-break-up depositional environment and onset of glaciomarine conditions in NE Greenland

Detailed sequence stratigraphic frameworks have been produced for most of the Cenozoic deposits around the North Atlantic and Greenland Sea. However, the sequence stratigraphic evolution of the NE Greenland shelf, a significant part of the Atlantic Ocean margin, has so far never been interpreted. This study provides, for the first time, a detailed sequence stratigraphic interpretation of the NE Greenland shelf since the late Eocene. The tectonic evolution, eustatic sea-level change and the impact of glaciations are integrated into a consistent geological history. Based on the identification of pronounced unconformities and their correlative conformities, ten stratigraphic sequences are identified. The onset of deposition is defined by a pronounced erosional event, where late Paleocene tectonic activity caused mass wasting of the uplifted footwall of the Danmarkshavn Ridge along a c. 200 km section of the ridge. A second pronounced unconformity developed across the margin during the mid-Miocene, which caused forced regressive submarine fans to prograde across the margin. The following tectonic quiet period is overlain by glaciomarine deposits, with evidence of ice deformation reaching the present day shelf break. Unknown super-regional plate tectonic forces are suggested as a driver of sequence formation based on correlation with the Canadian Arctic.

Geomorphology and geochemistry of the Late Cenozoic volcanoes in the Halaha River–Chaoer River volcanic fields, western Greater Hinggan Mountain Range, NE China

Abstract The Halaha River–Chaoer River (HC) volcanic field in the Greater Hinggan Mountain Range (NE China) consists of at least 41 monogenetic basaltic volcanoes. Strombolian, violent Strombolian and phreatomagmatic eruptions, as well as the transitional eruptions, generated simple volcanic cones (single vent) and composite volcanic cones (multiple vents). The simple elongated cone is the most abundant geomorphology type. By analysing the elongated crater and coalescent aligned circular crater, cone breaching and depression, and aligned vents, we identified a number of magma-feeding fissures. The majority of these fissures strike NE–ENE. Accordingly, we infer that the regional stress field affected volcanism in the HC field. The lavas in this field are alkali basalts that are enriched in light rare earth elements (La/Yb N = 7.9–24.5). Their ocean island basalt-like rare earth element and spider-diagram patterns, high Nb/U ratios and high TiO 2 contents (>2 wt%) indicate that the basalts were derived from the asthenosphere mantle. Both the asthenosphere upwelling and the tectonic forces are the key controlling factors of the volcanism in the HC field.

Slip Tendency Analysis, Fault Reactivation Potential and Induced Seismicity in the Val d'Agri Oilfield (Italy)

AbstractThe Val d'Agri basin hosts an oil‐field, the largest in onshore Europe, and it is one of the areas of highest seismic hazard in Italy. In an unproductive marginal portion of the reservoir, wastewater is re‐injected by a high‐rate well. Since the beginning of re‐injection in June 2006, a spatio‐temporal correlation between microseismicity (ML ≤ 2.0) and wastewater injection has been observed (suggesting induced seismicity). In this study, we perform a slip‐tendency analysis on the fault system involved in the induced seismicity through a coupled fluid‐flow and geomechanical numerical model simulating the stress partitioning due to the tectonic forces and to the fluid injection. The model results show that the fluid diffusion is strongly dependent on the active stress field and the geological structure in which fluids are injected, which conditioned the occurrence of seismicity that aligned on a small portion of a NE‐dipping fault. However, another fault located closer to the injection well and where no seismicity was detected, is the better well‐oriented fault with the active stress field and, also, the one more susceptible to the pore pressure increase. These results suggest different types of fault deformation acting in the Val d'Agri oilfield as response to the fluid injection (i.e., a mixed‐mode fault slip behavior). Understanding the stress partitioning in tectonically active regions where underground activities such as fluid injection are ongoing is fundamental to give strong constraints for the discrimination between natural and induced seismicity, and finally for a more reliable and robust definition of seismic hazard.