Search Results (462)

The Pearl River Mouth Basin (PRMB) is a significant offshore petroleum basin located in the northern South China Sea, characterized by its complex structural features and well-developed boundary faults. Despite its importance, several critical questions regarding fault growth, evolution models, and genesis mechanisms remain unresolved. This study aims to address these gaps by discussing the evolution of the boundary fault system and its associated stratigraphic record. This study utilizes high-resolution 3D seismic reflection data interpretation and fault displacement profiles to investigate the Zhu I depression, the largest hydrocarbon-bearing depression in the northern rifted zone of the PRMB. The findings indicate that the syn-rift growth of boundary faults within the Zhu I depression exhibits three distinct patterns, along-strike linkage, transverse linkage, and oblique linkage, which are formed under the action of the pre-existing basement fault systems. These patterns describe how individual fault segments connect and evolve during the rifting process, influencing the overall structural development of the basin and hydrocarbon accumulation. Although transverse linkage includes three development stages, consistent with previous studies, these stages are isolated normal faults, overlapping faults, and hard linkage. The study reveals a unique example of how transfer faults within a relay ramp connect the normal boundary faults on both sides. The break progression of the relay ramp can also be classified into three stages, similar to the transverse linkage. This study proposes a new approach, through the inversion of fault evolution by sequence migration, for the reconstruction of fault connection processes and complex fault linkage models developed in southern China and similar areas worldwide. Full article

Ferdinandea Island, part of a shallow-water submarine volcanic field, emerged in the Sicily Channel between Italy and Tunisia in July 1831 and was eroded below sea level within months; its submerged remnant forms the shallowest water depth region of Graham Bank. Here, we review nearly two centuries of historical accounts, geological interpretations and geomorphological data analysis and reassess them against high-resolution multibeam bathymetry, sub-bottom profiles (CHIRP) and published multichannel seismic data. The field comprises six volcanic edifices (V1–V6), 100–170 m high, located along structural trends characteristic of the Sicily Channel Rift. V3, the shallowest edifice, is the remnant of Ferdinandea Island formed during the 1831 Surtseyan eruption. Its flat summit, wave-reworked terrace and steep flanks record rapid post-eruptive modification. Historical observations and hydrographic surveys document the destruction of the emergent island and a further ~6 m lowering of its shallowest point between 1883 and 2012–2015; the separate contributions of wave erosion, subsidence and gravitational adjustment cannot be resolved from the available data. The same regional structural framework appears to have governed the distribution of the other volcanic centres, pockmarks, erosional escarpments and mass-transport deposits of the study area. Seventeen pockmarks, up to ~540 m wide and 22 m deep, occur as isolated, clustered and locally aligned depressions; they are associated with subsurface concave-upward reflectors and local water-column acoustic anomalies, consistent with focused fluid escape. Failures of volcanic and sedimentary slopes are widespread, with the largest debris-avalanche deposit covering ~2.2 km². Taken together, these observations indicate that tectonics, volcanism, fluid migration, wave- and bottom-current reworking, and gravitational instability have operated over different timescales to shape Graham Bank. Ferdinandea thus offers a rare historical and geological reference for investigating the rapid construction, degradation and long-term evolution of shallow-water volcanic edifices and highlights the still-open questions regarding the evolution and fate of ephemeral volcanic islands. Full article

This paper presents findings from a comprehensive assessment aimed at identifying deep geological storage formations suitable for the secure isolation of chemically active gases, including anthropogenic CO₂. Although Kazakhstan currently lacks operational industrial-scale CO₂ storage sites, high annual emissions exceeding 2 million tonnes are concentrated in its southern region, specifically Almaty city and the surrounding Almaty Region. Despite this pressing need, the precise location, availability, and capacity of potential storage sites in this area remain poorly understood. By synthesizing legacy geological, geophysical, and hydrogeological datasets compiled within the eastern Ili Depression, this study evaluates regional deep saline aquifers for potential CO₂ geological storage under favorable techno-economic conditions. It must be clearly emphasized that this study focuses exclusively on deep groundwater aquifers (saline aquifers). Leveraging historical seismic, drilling, and well-logging data originally acquired for petroleum and water resource exploration, we constrain the stratigraphic architecture and structural framework of prospective storage units. The lithostratigraphic framework of the sedimentary cover in the Ili Basin is established, identifying key reservoir intervals and effective sealing formations. The results indicate that the eastern Ili Depression offers highly favorable conditions for geologic storage, with Permian, Triassic, and Jurassic sedimentary successions reaching thicknesses of up to 1200 m. Reservoir intervals are identified across major stratigraphic units, with potential storage formations accounting for up to 60% of the stratigraphic volume. Specifically, the Miocene–Paleogene and Jurassic intervals host sandstone reservoirs exceeding 10 m in thickness, with porosities reaching up to 30%. Upper Jurassic clayey successions function as effective intraformational seals for Middle Jurassic reservoirs, while Upper Cretaceous clay sequences provide regional caprock integrity for the overlying Neogene–Paleogene sandy intervals. These geological settings satisfy rigorous containment criteria required for secure gas sequestration. These insights into the deep architecture of the Ili Depression elucidate key geological controls governing prospective storage sites, paving the way for future carbon capture and storage (CCS) initiatives in one of Kazakhstan’s most vital economic regions. Full article

Persistent Scatterer Interferometry (PSI) provides dense and temporally continuous measurements of ground deformation, offering a robust framework for investigating, among other phenomena, earthquake-related surface deformation. However, most satellite-based investigations of large earthquakes remain focused on coseismic interferograms, source inversions, and short post-seismic observation windows. In this study, we propose a PSI-based parametric approach that, given a Persistent Scatterer (PS) time series, uses a piecewise linear regression with an imposed coseismic step at the earthquake origin time to estimate the pre-event line-of-sight (LOS) velocity, the coseismic displacement step, and the post-event LOS velocity using ascending and descending satellite observations. The methodology is applied to the 7 January 2025 M_w 7.1 Dingri earthquake (southern Tibet), a recent large normal-faulting event for which previous studies have documented complex rupture behavior and significant co- and post-seismic surface deformation. The results show that our PSI-based approach enables, within a single framework, the isolation of the coseismic jump, the quantification of post-event velocity patterns, and the systematic comparison of pre- and post- event deformation. In addition, the combination of ascending and descending datasets yields a first-order reconstruction of the vertical and east–west deformation components. The proposed approach complements physics-based source modeling by offering a scalable, observation-driven, and point-wise characterization of deformation evolution. Full article

The design of curved surface sliders hides some pitfalls that can affect the effectiveness of the isolation system, as pointed out by past theoretical and experimental studies. In this paper, the basic relationships of curved surface sliders are rewritten, defining a characteristic parameter. This relates the design parameters, i.e., the friction coefficient, the equivalent radius, and the seismic displacement, with each other but depends on the damping ratio only. As is well known, a high value of friction could prevent the onset of motion. The self-centering capacity depends on the equivalent radius. Finally, the seismic displacement affects the dimensions and, therefore, the material consumption and the required gap. The design procedure proposed here is organized in two main phases. In the first one, the feasibility of a base isolation system, consistent with the fixed building seismic capacity and maximum displacement, is analyzed. An admissible area, i.e., the couples of values of the effective period and damping ratio, is individualized on the acceleration–displacement (capacity) spectrum plane. To do that, the outcomes of a previous study are used. In the second phase, the iso-R and iso-μ curves are plotted in this area. These allow a suitable choice of the design parameters and, therefore, a performance-oriented design. A flowchart summarizes the method. Finally, some examples show practical applications and allow the verification of the effectiveness of the proposed procedure. Full article

Three-dimensional concrete printing (3DCP) is an emerging additive manufacturing technology that has attracted significant international interest as a potential alternative to conventional construction methods. Existing research has largely focused on isolated technical domains, resulting in fragmented assessments of the technology and inconsistencies between the construction systems evaluated. This review addresses that gap through a holistic review from technical, architectural, environmental, and economic perspectives, with particular emphasis on its applicability within the New Zealand context. The review found that the multifunctional benefits of 3DCP often cause interdependencies between performance domains, which creates evaluation challenges for individual discipline assessments. Several key barriers to adoption within New Zealand were identified, such as limited evidence of the seismic performance of 3DCP structures, a lack of specific regulatory acceptance pathways, and economic scalability. Nevertheless, 3DCP construction was found to demonstrate suitable technical performance to comply with the New Zealand Building Code (NZBC), though this often involved supplementary construction that failed to fully capitalise on the benefits of 3DCP. Economic, regulatory, and social pressures may be driving re-standardisation in built residential projects, reducing the technology’s architectural differentiation from conventional construction and relinquishing one of the technology’s principal value propositions. Life-cycle assessments suggest environmental performance may be comparable with conventional light timber framing (LTF) where low-carbon strategies are adopted, though this should be re-evaluated as seismically resilient wall typologies are developed. Economic viability remains strongly dependent on deployment scale, with breakeven occurring at approximately eleven dwellings, suggesting the technology will be best suited for large-scale developments and prefabrication facilities. Full article

Small-scale excavations with depths of approximately 1 to 3 m are widely conducted for purposes such as the repair of underground pipelines. In confined construction spaces, earth-retaining systems consisting of lightweight sheet-piles with struts and walers are frequently used. However, comprehensive investigations of the influence of ground conditions on member forces have not yet been conducted. Furthermore, since these temporary structures are generally not designed with seismic considerations, they may suffer damage during earthquakes depending on the soil conditions. Accordingly, this study conducted a comprehensive parametric numerical investigation to evaluate how differences in soil type, such as sandy and cohesive soils, and loading conditions during excavation and earthquake loading affect the internal forces in the supporting members. Excavation analyses using PLAXIS 3D confirmed that as the soil strength parameters (cohesion and internal friction angle) decreased, the demand on the supporting members increased and larger internal forces developed. Dynamic analyses using LIQCA 3D revealed complex behavior in which (i) earth pressure acting on the wall generated compressive forces in the struts, (ii) lateral deformation of the excavation face reduced axial forces in the struts, and (iii) when the ground liquefied, it exhibited a vibration-isolation effect, and the vibration components generated in the structural members became smaller. Full article

Rocking foundations reduce seismic force demand through controlled uplift and rotation, but their application remains limited by uncertainty in residual settlement and recentring capacity. Grouting is often employed to reduce these serviceability concerns, yet uncertainty in the geometry of the improvement and seismic demand constrains confident adoption. This paper examines whether strength- and serviceability-related responses of jet-grouted rocking foundations exhibit comparable epistemic uncertainty when motion amplitude and grouting layout are represented by bounded Random Set inputs. A sparse deterministic response database was generated using three-dimensional finite-difference modelling for isolated columns, directional walls, and intersecting walls beneath a 3 × 3 m² foundation supporting a bridge-pier-type structure. The grouting layout was represented by a directional stiffness isotropy index. Motion demand was represented through bounded peak ground acceleration intervals. The deterministic results indicate that walls aligned with the excitation direction provide greater settlement reduction and energy dissipation than isolated columns or perpendicular walls. Variation in the depth of intersecting walls further reveals a trade-off between settlement reduction and recentring capacity. Random Set propagation was then used to construct uncertainty bounds for maximum moment, residual settlement, and recentring ratio. The results show that moment demand is comparatively well constrained, whereas serviceability indicators exhibit wider epistemic uncertainty. Full article

The analysis of earthquake-induced damage scenarios at the urban scale is a fundamental tool for seismic risk assessment and mitigation and the management of urbanized areas exposed to seismic hazards. This paper presents a methodology for simulating earthquake damage scenarios over large urban territories that explicitly accounts for the cumulative effects of seismic sequences. The proposed approach models the progressive accumulation of structural damage and the resulting evolution of building vulnerability under repeated seismic loading. From a complex systems perspective, the methodology describes urban areas as collections of buildings whose vulnerability evolves through memory-dependent processes. Under this framework, the final damage scenario emerges from the cumulative effects of the entire seismic history rather than from the contribution of individual earthquakes considered in isolation. The study extends previous work by the authors, in which instrumentally derived macroseismic intensity maps were integrated with observed building damage data from the 2009 L’Aquila seismic sequence. The results demonstrated that the methodology could successfully reproduce the spatial distribution of observed damage when considering not only the mainshock but also all seismic events exceeding a selected magnitude threshold. In this contribution, new developments of the calibration procedure are presented, together with applications to the 2013 Garfagnana-Lunigiana and the 2016–2017 Central Italy seismic sequences. Through a comparative analysis of these case studies, the influence of different seismic sequence characteristics and building stock features on damage evolution is investigated. The results provide further insight into the capabilities and limitations of the proposed methodology, highlighting its potential as a tool for interpreting post-earthquake damage patterns and supporting seismic risk assessment and mitigation strategies. Full article

Isolated drowned carbonate platforms in the Xisha Area represent critical research archives for deciphering the evolutionary mechanisms of carbonate systems and paleoenvironmental changes within the marginal sea of the northern South China Sea. Nevertheless, existing academic research lacks comprehensive investigations into the sedimentary processes and episodic demise signatures of typical drowned platforms in this region. This study targets the Ganquan Isolated Drowned Carbonate Platform—the largest and best-preserved drowned carbonate platform in the Xisha area. Based on high-resolution 2D multi-channel seismic data and multibeam bathymetric data, this research systematically characterizes the stratigraphic architecture and sedimentary differentiation of the Ganquan Carbonate Platform, and reconstructs its complete Cenozoic evolutionary history via interval velocity inversion, seismic sequence stratigraphic interpretation, sedimentary facies identification, and geomorphological feature analysis. The results reveal that the carbonate succession of the Ganquan Carbonate Platform exhibits prominent vertically zoned interval velocity variations, with two sharp velocity discontinuities identified at the seabed surface and the contact boundary between carbonate rocks and metamorphic basement. Four stratigraphic units are distinguished from top to bottom: seawater column, loose Upper Miocene carbonate deposits, compact Lower–Middle Miocene carbonate strata, and metamorphic basement. Five key Cenozoic seismic boundaries are recognized within the study area, which divide the evolutionary history of the Ganquan Carbonate Platform into four successive episodes: incipient initiation during the Early Miocene, vigorous expansion in the Early–Middle Miocene, transitional decline in the late Middle Miocene, and drowning reworking since the Late Miocene. This study establishes a comprehensive evolutionary model for isolated drowned carbonate platforms in the Xisha region, and advances the theoretical framework governing carbonate platform evolution in marginal seas. Full article

Seismic-while-tunneling signals acquired during coal-mine excavation are typically characterized by strong nonstationarity, intense mechanical noise, weak reflection responses, unstable inter-trace phases, and complex waveform fluctuations. These characteristics make conventional energy- or amplitude-based picking methods susceptible to false triggers and missed detections. To reveal the local complexity mutation of mine seismic signals under strong-noise backgrounds, this study proposes a multiscale fractal-dimension-constrained coherent phase processing method for signal enhancement, first-arrival picking, and fault prediction. First, the raw seismic-while-tunneling records are reorganized into shot gathers, windowed, and downsampled to preserve the effective early-arrival information. A damped multichannel singular spectrum analysis method is then used to extract coherent low-rank components and suppress incoherent random noise. Second, short-window and long-window box-counting fractal dimensions are calculated to characterize local and background waveform complexity, and a fractal-dimension mutation index is constructed to identify abrupt complexity transitions associated with effective seismic arrivals. On this basis, the fractal mutation index is incorporated into a coherent phase picking function that combines multichannel phase consistency and stacked amplitude, forming a fractal-dimension-constrained CCPP detection criterion. This criterion enhances true coherent arrivals while suppressing isolated noise spikes and unstable local amplitude disturbances. Finally, phase-weighted stacking is applied to further strengthen phase-consistent reflection responses and improve the interpretability of seismic-while-tunneling imaging profiles. Field application at the WII02040503 working face of Tunbao Coal Mine demonstrates that the proposed method can effectively improve the continuity of coherent events, stabilize automatic picking results, and enhance anomalous reflection bands under complex underground noise conditions. During the engineering trial, a total of 2558 m of ahead prospecting was completed, and 29 faults were predicted. The field-confirmation rates of the predicted faults with throws greater than 3 m, between 1 and 3 m, and less than 1 m were 100%, 87.50%, and 81.25%, respectively. Overall, 25 of the 29 predicted faults were confirmed by field exposure, corresponding to an overall field-confirmation rate of 86.21%. After velocity-synchronization time-difference correction, the average planar positioning deviation of the confirmed fault predictions decreased from 7.86 m to 5.08 m, corresponding to a 35.37% reduction in positioning error. These results indicate that the proposed fractal-dimension-constrained coherent processing framework provides an effective approach for complexity-aware signal enhancement and robust fault prediction in seismic-while-tunneling monitoring. Full article

This paper presents an analytical solution for near-field cylindrical P-wave scattering by a circular tunnel. A comprehensive elastic–slip interface model is incorporated to capture localized discontinuous deformations and frictional sliding. Employing the wave function expansion method and Graf’s addition theorem, the dynamic stress concentration factor (DSCF) of both soft and stiff linings is systematically investigated. The results reveal that near-field wavefront curvature severely amplifies stress concentration on the illuminated side, degenerating into a plane-wave response only when the dimensionless source distance exceeds 50. Furthermore, within the parameter range considered, the imperfect interface exhibits a dual “flexible barrier” effect heavily influenced by impedance matching: it tends to act as a seismic isolator that reduces the DSCF for stiff linings, but can weaken boundary confinement and exacerbate stress concentration for soft linings. These findings provide crucial theoretical insights for the blast-resistant design of underground structures. Full article

Monitoring the vertical progress of reinforced-concrete buildings supports construction management, urban analytics, and seismic exposure classification, yet camera-based floor counting faces two obstacles: public datasets depict almost exclusively completed structures, and the number of structurally finished floors is visually ambiguous while a building is still being erected. We reformulate building-height estimation as discrete floor-count classification from a single street-level facade image and assemble a 29,049-image multi-source corpus centered on the reinforced-concrete urban stock of Kazakhstan, including a 12-month, fixed-viewpoint sequence of 2255 frames that isolates invariance to construction stage, illumination, weather, and season. We formalize a reproducible annotation protocol for three recurring structural ambiguities—incomplete upper floors, rooftop superstructures, and open ground-level pilotis—and propose DINOv2-MSTS, a dual-branch architecture that aggregates multi-scale patch-token statistics from a frozen self-supervised backbone, trained with an Ordinal-Aware Annotation-Uncertainty (OAU) loss for which its Gaussian spread is learned rather than fixed. On the 5359-image Korter + Mendeley 21-category benchmark, the model attains 80% top-1 accuracy, 94% within $\pm 1$ floor accuracy, and 0.28-floor mean absolute error on this saturated 21-category task (a lower bound for buildings of 21 or more floors) using only 1.84 M trainable parameters, 165× fewer than a fully fine-tuned Vision Transformer, which it outperforms by eight accuracy points. On the separate 2255-frame IITU fixed-label robustness probe, it preserves the correct six-floor prediction in 91% of frames (0.09-floor MAE). The corpus, protocol, architecture, and loss together provide a reproducible benchmark for construction-stage building monitoring. Full article

Mass-timber rocking-wall systems are designed to limit residual deformation by concentrating lateral response in controlled uplift, recentering, and replaceable energy-dissipation mechanisms. Full-scale shake-table records provide a rare opportunity to evaluate this design concept using reproducible physical descriptors rather than isolated peak-response quantities. The public NHERI TallWood two-story mass-timber rocking-wall experiment is reanalyzed using fourteen sequential earthquake records, measured table accelerations, floor and roof accelerations, and instrumented deformation channels. A physics-informed workflow extracts input-intensity, transfer-function, coherence, modal-frequency, equivalent-damping, residual-deformation, self-centering, and deformation-weighted inertial-demand descriptors. An experiment-updated equivalent elastic Abaqus model converts selected identified states into three-dimensional displacement and stress-transfer fields. The identified dominant frequency decreases from approximately 2.11 Hz in the initial low-level event to approximately 0.70 Hz after the final maximum-level excitation, corresponding to a frequency-squared stiffness-loss index near 0.89. Despite this pronounced modal softening, measured residual deformation remains small in absolute terms, and the self-centering index remains moderate to high over most of the sequence. The results indicate that the tested system evolves mainly through changes in contact, uplift, diaphragm compatibility, and interface stiffness rather than through a conventional cumulative plastic-damage mechanism. The descriptor set and calibrated finite-element visualization provide a transferable basis for comparing future mass-timber shake-table datasets and for linking open experimental repositories, modal identification, and finite-element state visualization in performance-based seismic assessment of low-damage timber buildings. Full article

A novel two-stage friction damper (semi-metal composite material) proposed and tested in the paper, some of which can be connected in parallel with regular isolation bearing to form a new composite type combined isolation bearing. It can significantly improve the matching of isolation parameters under multi-level earthquakes (helping to improve the applicability and sustainability of the structure) and enhance the isolation effect. Traditional methods, such as adding lead cores to laminated rubber bearings (LNR) to obtain LRB, or adding metal dampers, viscous dampers, etc., often encounter problems such as insufficient matching of isolation parameters (such as excessive slice force under frequent earthquakes and insufficient damping ratio under rare earthquakes), or space limitations due to the addition of dampers. To address these limitations, this paper proposes this new structure and uses the theory of elasticity mechanics to establish a set of methods for calculating the internal force and deformation of the damper, which can be used for the compact design of the internal structure and connecting components of the damper. After assembly and testing, it shows the damper can ensure reliable operation with a compact size and providing satisfactory damping performance. Independent mechanical performance tests confirm the shape characteristics of the force–displacement hysteresis curve, the appropriate preload torque value, and the technical parameters under variable displacement and variable speed loading conditions. The full-scale combined isolation bearing (LNRF) test verifies the working principle of the damper and the stable bone-shaped force–displacement hysteresis curve output, and compared with LNR, the equivalent viscous damping ratio increases by −14.8% (due to the increase in stiffness), 7.1%, 20.2%, and 24.0% at shear angles of 100%, 200%, 250%, and 300%, respectively. This indicates that the new combined isolation bearing structure and damper design method proposed in this paper can assist in the design of combined bearing structures and the development of products of various specifications, and suits for application in isolation buildings, bridges, and other engineering projects. Full article