Lateral Propagation Research Articles

Terrane Boundary Reactivation, Barriers to Lateral Fault Propagation and Reactivated Fabrics: Rifting Across the Median Batholith Zone, Great South Basin, New Zealand

AbstractProminent preexisting structural heterogeneities within the lithosphere may localize or partition deformation during tectonic events. The NE‐trending Great South Basin, offshore New Zealand, formed perpendicular to a series of underlying crustal terranes, including the dominantly granitic Median Batholith Zone, which along with the boundaries between individual terranes exert a strong control on rift physiography and kinematics. We find that the crustal‐to‐lithospheric scale southern terrane boundary of the Median Batholith Zone is associated with a crustal‐scale shear zone that was reactivated during Late Cretaceous extension between Zealandia and Australia. This reactivated terrane boundary is oriented at a high angle to the faults defining the Great South Basin. We identify a large granitic laccolith along the southern margin of the Median Batholith, expressed as subhorizontal packages of reflectivity and acoustically transparent areas on seismic reflection data. The presence of this strong granitic body inhibits the lateral southwestward propagation of NE‐trending faults, which segment into a series of splays that rotate to align along the margin as they approach. Further, we also identify two E‐W‐ and NE‐SW‐oriented basement fabrics, likely corresponding to prominent foliations, which are exploited by small‐scale faults across the basin. We show that different mechanisms of structural inheritance are able to operate simultaneously, and somewhat independently, within rift systems at different scales of observation. The presence of structural heterogeneities across all scales needs to be incorporated into our understanding of the structural evolution of complex rift systems.

3D slab breakoff in laboratory experiments

We study slab breakoff of subducting plates with variable orientations of passive margins (ocean-continent transition: OCT) using three-dimensional laboratory experiments. Our results show that the initial obliquity of the OCT with the trench determines the depth and timing of slab breakoff. The reference model involves a straight OCT parallel to the trench. Slab breakoff first starts in the central section of the subduction zone at a depth equivalent to ∼250km and then propagates rapidly towards the edges of the subduction zone where it develops at slightly higher depths (∼280km). In the models where passive margin arrives first at the edges of the subduction zone, slab breakoff starts at that location and propagates laterally towards the center of the subduction zone. It results in higher slab breakoff depths at the edges of the subduction zone than at the center (maximum difference of 170km). In models where the passive margin arrives first in the center of the subduction zone, slab-breakoff starts at that location and propagates towards the edges of the subduction zone over a period that can be as large as 31 Ma and with a large range of depths (maximum difference of 170km). The rate of lateral propagation of slab breakoff decreases with the increasing initial obliquity of the OCT with the trench. The model with the maximum obliquity shows a correlation between the surface topography and the slab breakoff at depth. The plate surface is uplifted after the oceanic and continental slab segments are mechanically decoupled, and in the final stage of the experiment, when the slab is educted, subsidence develops as the isostatic and dynamic support diminish.

Gravimetric study of the shallow basaltic plumbing system of Tenerife, Canary Islands

Recent studies on intraplate volcanic islands reveal that magma ascends sub-vertically through these volcanic edifices, following well-defined zones in the lithospheric mantle and oceanic crust, and occasionally suffering lateral propagation along rift zones when it reaches very shallow depths. Visualizing the internal structure of the shallowest part of such magma plumbing systems is crucial to understanding magma transport and the location of basaltic volcanism in these volcanic environments. Tenerife (Canary Islands) is a very good example of an intraplate volcanic island, in which the distribution of basaltic volcanism includes well-defined rift systems, and wider monogenetic fields where cinder cones form clusters along different tectonic alignments. In order to characterize the structure of the uppermost part of the basaltic plumbing system of Tenerife, we conducted a detailed gravimetric study of the north-western, central, and southern sectors of the island. We developed a 3D density contrast model of the subsoil based on the application of a genetic algorithm for the inversion of gravity data. The results of our inverse modelling suggest that the observed gravimetric anomalies below the northwestern rift zone are shallow and aligned parallel to this structure. This is consistent with a shallow character for the rift system and a lateral migration of magma along it that comes from a deeper zone located towards the east of this rift zone. Conversely, the anomalies located in the south are also shallow but are distributed along more than one alignment and are connected to much deeper sub-vertical similar density anomalies. These results support the existence of several main channels at the north and south of the island that allow the ascent of deep basaltic magma to shallower zones of Tenerife. There, magma may be either caught by the rifts systems, being distributed laterally and occasionally erupting, or may continue its ascent to the surface using a secondary system of shallow fractures that dominates the southern part of Tenerife. The results of our inverse model also offer new insights on others aspects of the internal structure of Tenerife, such as the distribution of the basaltic shield or that of Las Cañadas caldera.

A Late Neogene framework and transpressional system within the Yingxiongling Range, western Qaidam Basin, Northeast Tibetan Plateau: Insights from seismic reflection profiles and active tectonics

The Yingxiongling Range is a topographically unique and active tectonic belt in the western Qaidam Basin that has recorded the structural evolution and interactions between itself and surrounding ranges throughout the Late Cenozoic. Although a large scale fault-fold system within this region accommodates transpressive deformation, the overall kinematic pattern remains highly debated. Regional seismic reflection profiles, earthquake distributions, focal mechanisms, and displacement vector results are used in this study to rebuild a northern verging thrust and wedge tectonic system in a perpendicular direction. Interpretations of newly acquired three-dimensional seismic data, the timing of growth strata, and the kinematics of active structures strongly support lateral structural deformation propagation and evolution of the southern Yingxiongling Range in the Late Neogene. A novel analysis of active tectonic and seismic profiles enables us to rebuild the framework, kinematics, and evolutionary pattern of the Yingxiongling Range. We also provide a new interpretation of lateral differentia along the Yingxiongling Range based on critical taper theory and suggest that this overall structure is an integrated part of the Qimen Tagh Wedge. Since the Late Neogene, rapid uplift in this area occurred in response to northward propagation of the Qimen Tagh Wedge.

A Novel Meander Split Power/Ground Plane Reducing Crosstalk of Traces Crossing Over

In this paper, a novel meander split power/ground plane is proposed for reducing crosstalk between parallel lines crossing over it. The working mechanism of the meander split scheme is investigated by simulations and measurements. The LC equivalent circuit and transmission line model are developed for modeling interactions between the meander split and the signal lines. The proposed meander structure enhances electromagnetic coupling between split planes. The capacitive coupling across the split ensures signal integrity and magnetic coupling between adjacent finger shaped structures suppresses lateral wave propagation along the split gap, which in turn helps suppress the crosstalk. The effectiveness of the meander split remains valid over very wide frequency ranges (up to 9 GHz). Experimental results show that the proposed structure improves the signal quality and reduces the near/far end crosstalk over 30 dB and 50% in the frequency domain and time domain, respectively.

Cyclic behaviour of expanded polystyrene (Eps) sandwich concrete walls

Precast concrete walls become increasingly utilized due the rapid needs of inexpensive fabricated house especially as traditional construction cost continue to climb. Moreover, particularly at damaged area due to natural disaster when the requirement of a lot of fast-constructed and cost-efficient houses are paramount. However, the performance of precast walls under lateral load such as earthquake or strong wind is still not comprehensively understood due to various type of reinforcements and connections. Additionally, the massive and solid wall elements also increase the total weight of building and hence increase the earthquake base shear force significantly. Therefore, the precast polystyrene reinforced concrete walls which offers light weight and easy instalment became the focus of this investigation. The experimental test on two RC wall specimens using EPS (Expanded Polystyrene) panel and wire mesh reinforcement have been conducted. Quasi-static load in the form of displacement controlled cyclic tests were undertaken until reaching failure. At each discrete loading step, lateral load-deflection behavior, crack propagation and collapse mechanism were measured which then were compared with theoretical analysis. The findings showed that precast polystyrene reinforced concrete walls gave sufficient seismic performance reaching up to 1% drift at failure point against lateral.

DETECTION AND DELINEATION OF SUBSURFACE COAL MINE FIRE FROM SPACEBORNE THERMAL INFRARED DATA IN JHARIA COALFIELD, DHANBAD, INDIA

Abstract. Coal fire has been found to be a major problem worldwide in coal mining areas. The surrounding areas get hugely affected, and significant amount of reserves are wasted due to the burning of coal. This severely affects the environment condition, which leads to a rise in temperature of the region, which is a major reason for climate change. Greenhouse gases like CO2 SO2 NO CH4 are also emitted from the cracks and fissures. Large masses of the burning of coal also causes land subsidence and collapse. Underground coal fires ignited by natural causes or human error leads to atmospheric pollution, acid rain, land subsidence, and increased coronary and respiratory diseases. They consume a valuable energy resource, destroy floral and faunal habitats, and promote human suffering because of heat, subsidence, and pollution. Jharia Coalfield, Jharkhand, India, is well known for being the storehouse of prime coking coal and for accommodating the maximum number of coal fires among all the coalfields in the country. In this paper, some of the important issues of coal fire mapping from satellite thermal infrared data have been addressed in particular reference to Jharia Coalfield. Namely, these are: retrieval of spectral radiance from raw digital satellite data using scene-specific calibration coefficients of the detectors from metadata, thermal emissivity of surface to obtain kinetic temperature at each ground resolution cell of satellite data, field-based modelling of pixel-integrated temperature for differentiating surface and subsurface fire pixels in Landsat 8 thermal IR data, identification of surface coal fire locations from infrared data and lateral propagation of coal fire.

Lateral Fault Growth in the Kashi Anticline (Chinese Tian Shan): Insights From Seismic Interpretation, Shortening Distribution, and Trishear Methods

AbstractDeciphering the relationship between lateral growth of faults and along‐strike deformation (i.e., shortening and uplift) in the Earth's upper crust remains a challenge. Here we gain insight into the relation between these processes by studying the Kashi anticline, an asymmetric, doubly plunging thrust‐fault‐related fold located in the southwest Tian Shan, China. We use seismic interpretation and field observations, together with 2‐D trishear and excess area methods, to quantify the distribution of shortening along this structure. The shortening distribution along strike of the Kashi anticline is nonlinear and has a peaked, asymmetric, bell shape, with a maximum value of 5.9 ± 0.2 km. After comparing the 3‐D structural model of the Kashi anticline and our trishear models, we propose that lateral propagation‐to‐maximum shortening ratio, initiation fault length, and lateral propagation rate control the lateral fault propagation process and the fold terminations. Moreover, the 3‐D fault morphology and the ages of the growth strata suggest that the Kashi anticline experienced two stages of lateral growth with propagation rates of 60 km/Ma between 1.4 ± 0.2 Myr and 0.9 ± 0.3 Ma, and ~67 km/Myr from 0.9 ± 0.3 Ma to present. These observations highlight the relation between the evolution of lateral fault growth and the along‐strike shortening distribution, allowing us to use the latter (which we can measure) to infer the former (which we cannot). These novel insights from the Kashi anticline can be used to understand lateral growth of thrust and normal faults worldwide.

Biphasic Impact of Prenatal Inflammation and Macrophage Depletion on the Wiring of Neocortical Inhibitory Circuits

SummaryThe etiology of neurodevelopmental disorders is linked to defects in parvalbumin (PV)-expressing cortical interneurons and to prenatal immune challenges. Mouse models of maternal immune activation (MIA) and microglia deficits increase the postnatal density of PV interneurons, raising the question of their functional integration. Here, we show that MIA and embryonic depletion of macrophages including microglia have a two-step impact on PV interneurons wiring onto their excitatory target neurons in the barrel cortex. In adults, both challenges reduced the inhibitory drive from PV interneurons, as reported in neurodevelopmental disorders. In juveniles, however, we found an increased density of PV neurons, an enhanced strength of unitary connections onto excitatory cells, and an aberrant horizontal inhibition with a reduced lateral propagation of sensory inputs in vivo. Our results provide a comprehensive framework for understanding the impact of prenatal immune challenges onto the developmental trajectory of inhibitory circuits that leads to pathological brain wiring.

Tectonic geomorphology and structural architecture of eastern Sulaiman Fold Thrust Belt (SFTB) and adjacent Sulaiman Foredeep (SF), northwest Pakistan

This investigation combines a number of datasets to provide an enhanced and improved tectono-geomorphological framework with which to identify new possible structural lineaments in northwest Pakistan. The dataset includes satellite images and geographic information system (GIS) methods. The present study was carried out using the USGS ASTER DEM (30 m), Landsat 8 (OLI/TIRS) and surface field geology of the study area. Different band combinations, directional filters and principle component analysis (PCA) methods were used to identify the major structural styles and tectonic geomorphological pattern. The panchromatic band (Band-8) was applied to the Landsat 8 satellite images in order to increase the spatial resolution from 30 m to 15 m which aided in the investigation and comparative analysis of tectonic geomorphology and structural styles. Drainage patterns of Zindapir Anticline (ZA), Sakhi Sarwar (SS), Sulaiman Foredeep (SF) and Kingri Fault (KF) areas were generated using Strahler order of streams. The results suggested a combination of the dendritic network with a minor component of trellis pattern for ZP and SF areas, hence proposing a combined structural and stratigraphic/lithological control, whereas the KF area indicated an element of a rectangular pattern suggesting a more structural influence in the western part in comparison to the eastern region. The presence of water gaps (WaGs) and active drainage network indicate lateral growth and propagation directions of the ZP and SS frontal anticlines following the Paleocene Epoch. The geomorphic evidence coupled with satellite data show that the SFTB is tectonically active along with the adjacent SF. The stream courses are deflected or guided due to active folds and tectonics in the area characterized by the distinct fluvial erosional pattern on the flanks/limbs of ZA. Evidence from the study suggests that compressional deformation, uplift and erosion played a significant role in the shaping of the structural and depositional architecture of the basin. It is proposed that the deformation in the SFTB during the late Paleogene is related to the Indian-Eurasian oblique collision, while the subsequent late Tertiary collision of Indian Plate with the Afghan Block (an accreted part of southern Eurasia) further ensued compressive deformation. The results from this study elucidate the possible models proposed for this compressional regime with prevailing wrenching by presenting new data. The findings from this research reveal new tectono-geomorphological features and lineaments in the area that were not documented previously.

Holocene Sedimentary Record and Coastal Evolution in the Makran Subduction Zone (Iran)

The western Makran coast displays evidence of surface uplift since at least the Late Pleistocene, but it remains uncertain whether this displacement is accommodated by creep on the subduction interface, or in a series of large earthquakes. Here, we address this problem by looking at the short-term (Holocene) history of continental vertical displacements recorded in the geomorphology and sedimentary succession of the Makran beaches. In the region of Chabahar (Southern Iran), we study two bay-beaches through the description, measurement and dating of 13 sedimentary sections with a combination of radiocarbon and Optically Stimulated Luminescence (OSL) dating. Our results show that lagoonal settings dominate the early Holocene of both studied beach sections. A flooding surface associated with the Holocene maximum transgression is followed by a prograding sequence of tidal and beach deposits. Coastal progradation is evidenced in Pozm Bay, where we observe a rapid buildup of the beach ridge succession (3.5 m/years lateral propagation over the last 1950 years). Dating of Beris Beach revealed high rates of uplift, comparable to the rates obtained from the nearby Late Pleistocene marine terraces. A 3150-year-old flooding surface within the sedimentary succession of Chabahar Bay was possibly caused by rapid subsidence during an earthquake. If true, this might indicate that the Western Makran does produce large earthquakes, similar to those that have occurred further east in the Pakistani Makran.

First Observations of Gigantic Jets From Geostationary Orbit

AbstractHere we report the first observations of gigantic jets (GJs) by the Geostationary Lightning Mapper (GLM) on board the Geostationary Operational Environmental Satellite‐R series. Fourteen GJs produced by Tropical Storm Harvey on 19 August 2017 were observed by both GLM and a ground‐based low‐light‐level camera system. The majority of the GJs produced distinguishable signatures in the GLM data, which include long continuous emissions, large peak flash optical energies, and small lateral propagation distances in comparison with other flashes observed by GLM. For two GJs with the best ground‐based images, each have a single pixel that contains the largest optical energy throughout the duration of the GJ and also coincides with the azimuth of the GJ from the video images. The optical energy of the pixel increases as the GJ propagates upward, reaches its peak when the GJ connects to the ionosphere, and then fades away.

Numerical Study on Medial and Lateral Wear Propagation in Total Knee Replacements Under Squat Movement

Numerical Study on Medial and Lateral Wear Propagation in Total Knee Replacements Under Squat Movement

Ultrashort pulse action onto thin film on substrate: Qualitative model of shock propagation in substrate explaining phenomenon of fast growth of a hole with increase of absorbed energy

Thin films on substrate are important class of targets for surface nanomodification for plasmonic or sensoric applications. There are many papers devoted to this problem. But all of them are concentrated on dynamics of a film, paying small attention to substrate. In these papers the substrate is just an object absorbing the first shock. Here we present another point of view directed onto dynamics of a substrate. We consider (i) generation of a shock wave (SW) in a support by impact of a contact; (ii) transition from one-dimensional to two-dimensional (2D) propagation of SW; (iii) we analyze lateral propagation of the SW along a film-support contact; and (iv) we calculate pressure in the compressed layer behind the decaying SW. This positive pressure acting from substrate to the film accelerates the film in direction to vacuum. Above some threshold, velocity of accelerated film is enough to separate the film from support. In these cases the circle of separation is significantly wider than the circle of the focal laser spot on film surface. Absorbed laser heat exponentially decays around an irradiated spot , where RL is radius of a Gaussian beam, F and Fc are local and central fluences, r is a radius from the axis. While the law of decay for the 2D SW in substrate is the power law. Therefore in our case of powerful laser action the edge of a separation circle is defined by propagation of the SW in the support.

A comprehensive layout of two-dimensional thermal network model for TIM with pulsed heat source

Transient thermal impedance (Zth) for repeated pulse is a measure of how the device behaves when any transient power is applied on it. Fluctuation in the junction temperature is caused because of these sources which need a better stabilization mechanism to overcome undesired failure. In general, ‘Zth’ is simulated by means of Cauer or Foster one-dimensional RC network analogy however this lacks generality in addressing the lateral heat propagation in stacked layers. Therefore, the present approach characterizes the importance of two-dimensional RC network modelling which can substantiate its use to capture thermal resistances and associated delays in both dimensions. The 2D transient thermal resistance (Rth) and capacitance (Cth) matrix is obtained numerically at each grid point inside present algorithm and has been explained thoroughly inside the text with plots and contours. Resultant Zth is calculated from these discrete Rth and Cth values in s-domain and finally converted to t-domain with the help of inverse Laplace transformation.

Conjugate relay zones: geometry of displacement transfer between opposed-dipping normal faults

Overlapping opposed-dipping normal faults can have complementary displacement distributions, indicating transfer of displacement between them in the same way as at relay zones between faults with the same dip direction. We constrain the mechanism by which displacement is transferred between opposed-dipping faults by examining the geometries of faulted horizons and fault throw distributions at these conjugate relay zones.Structure contour maps of horizons offset by overlapping opposed-dipping faults from different extensional settings display a consistent pattern. Above the line of intersection between the conjugate faults the deformed horizon is flat between converging faults and displacement transfer is reflected in changes in footwall elevation. Below the line of fault intersection the mutual footwall is flat and elevation changes occur in the hanging walls of the divergent faults. These elevation changes can be explained as a simple superposition of the deformation fields of two faults that have retarded lateral propagation due to the presence of the other synchronous fault, irrespective of whether the two faults actually intersect. The observed patterns of horizon elevation strongly resemble those seen at boundaries between adjacent basin-scale half-graben of opposed polarity.

Action of a femtosecond laser pulse on thin metal film supported by glass substrate

Numerous papers are devoted to the problem of irradiating thin films on the substrate for surface nano-modification. But all of them concern the dynamics of the dynamics, paying almost no attention to substrate just as object of the first shockwave absorption. A different point of view with an emphasis on the dynamics of a substrate is presented. Under powerful laser action upon a thin metal film a hole arises. Its radius depends on the absorbed laser energy. Experimental results, quantitative theoretical model and numerical research are presented and show that the hole formation is influenced by propagation of the shock wave in the substrate, but not in the film itself. Four stages are considered. (i) Shockwave generation in a support because of an impact of a contact. (ii) Transition from one-dimensional to two-dimensional propagation of the shockwave. (iii) Lateral propagation of the shockwave along a film-support contact. And (iv) calculating pressure in the compressed layer behind the decaying shockwave. This positive pressure acting from substrate on the film accelerates the film in direction to vacuum. Above some threshold, velocity of accelerated film is enough to separate the film from support. In these cases the circle of separation is significantly wider than the focal laser spot on film surface.

Transient boiling flow in 5 × 5 rod bundle under non-uniform rapid heating

Abstract Rapid thermal elevation in boiling water reactor (BWR) is an important factor for nuclear safety and there is a need to develop an analysis code for the transient phenomenon and its validation process. To evaluate the thermal property of transient boiling and its uncertainty, corroborative experimental information is crucial. In particular, the lateral propagation behavior of a vapor bubble (void) in the cross-sectional direction of fuel assembly has yet to be determined. This study evaluates the void propagation behavior in a 5 × 5 rod bundle with cross-sectional heat distribution that causes only the 3 × 3 rod bundle to generate heat; assuming rapid heating under atmospheric pressure. In this paper, using the maximum heat output applied to the nine heated rods as a parameter, from the visualization of the void behavior and the measurement of the local void fraction, the heat output conditions under circumstances where lateral propagation of voids occurs and where voids are only localized in the heated region are summarized. We quantified the time difference initially detected and the time-averaged void fraction according to the lateral propagation level.

Lateral magma propagation during the emplacement of La Gloria Pluton, central Chile

Lateral magma propagation during the emplacement of La Gloria Pluton, central Chile

Quantifying propagation characteristics of unconfined turbidity currents interacting with an obstacle within the slumping regime

ABSTRACTExperimental studies of confined turbidity currents interacting with obstacles have become popular over the last three decades; however, little work has sought to quantify the characteristics of unconfined turbidity currents interacting with obstacles. In the present study, unconfined turbidity currents colliding with a rectangular basal obstruction are investigated. With a focus on the initial theoretical slumping regime, flow characteristics are quantified and characterized. The currents varied with initial density and substrate roughness. Unobstructed currents propagated at a constant velocity, confirming previous theory that the current is within the slumping regime; however, a typical reverse ambient bore was not present. Froude and Reynolds numbers were shown to decrease over the obstacle by 43–54% and 17%, respectively. Deflected lateral propagation along the obstacle face was found to entrap ambient fluid and encourage mixing, providing a starting point for understanding the implications of lateral propagation along submerged pipelines and reservoir barriers.