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We use densely spaced campaign GPS observations and laboratory friction experiments on fault rocks from one of the world's most rapidly slipping low‐angle normal faults, the Mai'iu fault in Papua New Guinea, to investigate the nature of interseismic deformation on active low‐angle normal faults. GPS velocities reveal 8.3 ± 1.2 mm/year of horizontal extension across the Mai'iu fault, and are fit well by dislocation models with shallow fault locking (above 2 km depth), or by deeper locking (from ~5–16 km depth) together with shallower creep. Laboratory friction experiments show that gouges from the shallowest portion of the fault zone are predominantly weak and velocity‐strengthening, while fault rocks deformed at greater depths are stronger and velocity‐weakening. Evaluating the geodetic and friction results together with geophysical and microstructural evidence for mixed‐mode seismic and aseismic slip at depth, we find that the Mai'iu fault is most likely strongly locked at depths of ~5–16 km and creeping updip and downdip of this region. Our results suggest that the Mai'iu fault and other active low‐angle normal faults can slip in large (Mw > 7) earthquakes despite near‐surface interseismic creep on frictionally stable clay‐rich gouges. Plain Language Summary: In regions of extension, where tectonic plates pull apart, the Earth's crust breaks along fractures, or "normal faults", that allow parts of the crust to slip past each other. Many of these faults intersect the Earth's surface at a steep angle, but some anomalously low‐angle normal faults are oriented at a shallower angle to the surface. Faults can slip during infrequent fast earthquakes or through slower gradual fault creep. Because active low‐angle normal faults are rare and typically have low long‐term slip‐rates, it is not clear whether they cause large earthquakes or creep gradually. Using two approaches, this study addresses whether earthquakes occur on one of the fastest‐slipping of these types of faults, the Mai'iu fault in Papua New Guinea. One approach uses GPS measurements to track patterns of displacement of the Earth's surface near the Mai'iu fault over 3 years. Surface displacements confirm that the Mai'iu fault slips actively and are used to constrain models of fault slip at depth. The second approach uses laboratory experiments on rocks from the Mai'iu fault zone to test whether these rocks tend to slip unstably in earthquakes, or creep stably under conditions similar to those in the fault zone. Laboratory results show that rocks from the shallowest parts of the fault tend to creep stably, while deeper fault rocks tend to slip unstably. Combining laboratory, geological, and GPS results to map slip behaviors to different fault zone depths, we find that the Mai'iu fault most likely creeps near the Earth's surface but can generate larger earthquakes at greater depths. Key Points: GPS velocities reveal horizontal extension of 8.3 ± 1.2 mm/year (~8–11 mm/year dip‐slip) on a low‐angle normal fault dipping ≤24° at the surfaceShallowest gouges of this fault are frictionally weak and velocity‐strengthening; deeper fault rocks are stronger and velocity‐weakeningFault locking at ~5–16 km depth with shallower and deeper interseismic creep inferred from geologic, experimental, and geodetic results [ABSTRACT FROM AUTHOR]

This paper presents an investigation on the characteristics of shear stress on normal fault plane by employing the mechanical model and the characteristics of water inrush from floor strata during mining activities by employing numerical model. The shear stress formula on fault plane is obtained by using the solution of a homogeneous half-plane affected by normally distributed forces in the theory of elasticity. The mechanical model shows the variation of shear stress on fault plane with different dip angle and fault reactivation is analyzed according to the shear stress. Based on these, the fracture distribution and seepage distribution on floor strata are numerically simulated by using the RFPA2D-Flow software, and the effect of dip angle on water inrush from floor strata is discussed. These results indicate that the smaller value of dip angle is easier to be reactivated and to produce connecting fractures between floor strata and normal fault comparing with the larger value of dip angle, which provide significant insights into remaining coal pillar with similar geological conditions. [ABSTRACT FROM AUTHOR]

In the northwest of the Himalayan-Tibetan Orogen, the ∼250 km-long Kongur Shan extensional system in the eastern Pamir was formed during the convergence between the Indian and Asian plates. Tectonic activity of the Kongur Shan normal fault and the Tashkurgan normal fault can help to reveal the origin of east-west extension along the Kongur Shan extensional system. The Kongur Shan fault has been extensively studied, while the Tashkurgan fault calls for systemic research. In this study, low-temperature thermochronology including apatite fission track analysis and apatite and zircon (U-Th)/He analyses is applied to constrain the timing of activity of the Tashkurgan fault. Results indicate that the Tashkurgan fault initiated at 10−5 Ma, and most likely at 6−5 Ma. The footwall of the Tashkurgan fault has been exhumed at an average exhumation rate of 0.6−0.9 mm/a since the initiation of the Tashkurgan fault. Combined with previous research on the Kongur Shan fault, we believe that the origin of east-west extension along the Kongur Shan extensional system was driven by gravitational collapse of over-thickened Pamir crust. [ABSTRACT FROM AUTHOR]

Urban tunnels crossing faults are always at the risk of severe damages. In this paper, the effects of a reverse and a normal fault movement on a transversely crossing shallow shotcreted tunnel are investigated by 3D finite difference analysis. After verifying the accuracy of the numerical simulation predictions with the centrifuge physical model results, a parametric study is then conducted. That is, the effects of various parameters such as the sprayed concrete thickness, the geo-mechanical properties of soil, the tunnel depth, and the fault plane dip angle are studied on the displacements of the ground surface and the tunnel structure, and on the plastic strains of the soil mass around tunnel. The results of each case of reverse and normal faulting are independently discussed and then compared with each other. It is obtained that deeper tunnels show greater displacements for both types of faulting. [ABSTRACT FROM AUTHOR]

This paper presents a series of model tests on geosynthetic-reinforced soil (GRS) foundations across a normal fault. The aim was to evaluate the performance of reinforced foundations as a mitigation measure for surface faulting hazards. Experimental tests modeled a 3-m thick foundation in prototype subjected to a fault displacement up to 90 cm. Test variables included the number of reinforcement layers, reinforcement stiffness and location, and foundation height. Digital image analysis techniques were applied to determine the ground settlement profile, angular distortion, shear rupture propagation, and mobilized reinforcement tensile strain at various magnitudes of fault offset. Test results revealed that compared with the unreinforced foundation, reinforcement inclusion could effectively prevent the shear rupture propagating from the bedrock fault to the ground surface. It also spread the differential settlement to a wider influential zone, resulting in an average reduction of 60% in the fault-induced angular distortion at the ground surface. The maximum angular distortion decreased as the foundation height, number of reinforcement layers, and reinforcement stiffness increased. Relationships between the maximum angular distortion and maximum mobilized reinforcement tensile strain with fault displacement were therefore established. Based on the findings from this study, design suggestions and implications are discussed. [ABSTRACT FROM AUTHOR]

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Preexisting crustal heterogeneities are shown to influence rift process at a variety of scales. However, our understanding of how crustal inheritance influences rift‐scale spatiotemporal kinematics of faulting in magma‐poor rift environments is still very limited. Studies of active continental rifts can provide high‐fidelity assessments of extensional processes and structures that are not possible through examination of ancient rifts that have undergone subsequent deformation events or are buried deeply beneath passive margins. We examine the influence of crustal inheritance on active rifting through balancing and restoring a series of regional cross sections across the Lake Tanganyika Rift in the Western Branch of the East African Rift System. The cross sections are produced using legacy seismic reflection data, reprocessed through prestack depth migration. This type example of a young, magma‐poor continental rift transects several different basement terranes, including an Archean/Paleoproterozoic craton, and Proterozoic mobile belts. The Lake Tanganyika Rift exhibits two classic bell‐shaped profiles of extension along strike, reaching a maximum of 7.15 km. A spatiotemporal integration of the extension data, and comparison with the various basement terranes the rift transects, reveals that extension in cratonic blocks is more widely distributed compared to mobile belt terranes, where strain rapidly localizes onto border faults by later rift stages. These results reveal how crustal inheritance exerts a fundamental control on the evolution of extension localization, ultimately impacting the geometry and structural architecture of rift basins. Key Points: The first detailed study using balanced cross sections to identify how crustal inheritance influences extension in the Lake Tanganyika RiftExtension is observed to be segmented along‐strike reaching a maximum of 7.15 kmExtension shows greater distribution across the intrarift faults in cratonic areas but is focused on border faults in mobile belts [ABSTRACT FROM AUTHOR]

The thickness of the mechanical layer that hosts a group of faults can be estimated from the spacing of saturated faults (i.e. the constant spacing between faults when the fault system is fully developed and has attained its final fault density). We measured fault spacing for a group of saturated active normal faults on Miyako‐jima Island (southern Ryukyu Arc, Japan) and estimated the thickness of the faulted mechanical layer. The measured fault spacing is 1.30 ±0.14 km, and the thickness of the mechanical layer is < 3 km, which is the upper limit of the seismogenic zone. This faulted mechanical layer corresponds to a sedimentary layer in which earthquakes cannot occur. Results indicate that the shallow (< 3 km depth) normal faults on Miyako‐jima Island do not have the potential to cause medium‐size earthquakes as individual faults. The origin of the shallow normal faults might be related to the presence of a larger‐scale, deeper fault. The results indicate that fault spacing provides important information on the potential magnitude of earthquakes associated with active faults. [ABSTRACT FROM AUTHOR]

The reactivation of pre-existing fractures is an important issue in the study of nucleation, union, growth, and evolution of fault systems. Pre-existing zones of weakness, such as cooling fractures, can determine the configuration of important fault systems. In particular, it is important to study the role of cooling fractures in the reactivation of faults for three reasons: first, there are many cooling fractures in volcanic rocks; second, the vertical fractures have a low tendency to slip; and third, there are many strikes and striae in several directions, making it difficult to interpret their mecha nical origin. This paper presents an example of a fault system that overprinted on a volcanic field in Santa María del Río, San Luis Potosí, Mexico. We studied the age, geometry, activity, and kinematics of the SLTFS (San Luis-Tepehuanes Fault System) located in Santa Maria del Rio, in central Mexico, as well as the fault mechanisms and interaction with pre-existing structures, like orthogonal and polygonal cooling joints. Three sites were chosen for the measurement of structural data. The results indicate that the major faults have a NW-SE preferential trend and the minor faults show strikes in all azimuths. This faulting caused the tilt of strata. The older units have higher dips (20° to 25°) than the younger ones (~15°). Curved, superimposed slickenlines and striae parallel to the intersection of two fault planes are probably the result of the interaction with pre-existing fractures during reactivation. Based on these results as well as calculations using the ReActiva 2.4 software (Alaniz-Álvarez et al., 2000; Tolson et al., 2001), we propose that faulting began at depth, and propagated through the cooling joints while advancing to the surface in the current SLTFS configuration. [ABSTRACT FROM AUTHOR]

The Büyük Menderes Graben (BMG) is one of the best-known and the largest geological structure of the West Anatolian Extensional Province. It includes two nature conservation parks and twelve cultural heritage sites within and in its vicinity. Four geologically distinct features/locations within and in the vicinity of the BMG have been previously enlisted as geosite candidates in the provisional Geological Heritage Inventory of Turkey compiled in 2002 by the Turkish Association for the Conservation of the Geological Heritage (JEMİRKO): (1) the horst-graben structure of the Büyük Menderes region itself, (2) the tafoni from the augen-gneiss from the east of Bafa Lake, (3) the zultanite crystals from the northeast of İlbir Mountain, and (4) the tourmaline (dravite) crystals from the Camızağılı, Çine. In the current study, we are introducing additional three new geosite candidates at the western termination of the BMG with three different main geological subjects. The first one is the Yavansu Fault. Located 2 km south of the Kuşadası village, it has a clearly exposed unique fault surface which is one of the best examples of structural indicators for the WAEP with respect to the normal faulting events. The second one is located in the Hisartepe Volcanics exposed between Kuşadası and Söke, and consists of basaltic lava flows with remarkable prismatic cooling joints and a gorgeous feeder dome reaching up to 150 m height. Final suggestion is the Karina marine fan-delta complex located at the south-eastern border of the Dilek Peninsula National Park. This fan-delta complex is the largest one in the Western Anatolian scale and has remarkable paragon outcrops up to 20 m high between Doğanbey and Karina Lagoon. [ABSTRACT FROM AUTHOR]

The Campo Felice basin, in the central Apennines seismic belt (Italy), developed in the hangingwall of a 30 km-long system of NW-trending normal faults with Holocene paleoseismic activity and potential sources of M 6–7 earthquakes. We provide the first subsurface images of a key portion of the basin bounded by the Mt. Cefalone fault along two intersecting profiles trending NNE-SSW (CF-Dip, 1195 m-long) and WNW-ESE (CF-Strike, 1315-m long). We combined high-resolution depth-migrated reflection sections with P-wave velocity and electrical resistivity tomography models. CF-Dip profile displays a wedge-like syn-tectonic sedimentary sequence of alluvial and glacial deposits with Vp ∼ 2500–3000 m/s and resistivity > 500 Ωm in the hangingwall of Mt. Cefalone fault, overlying a high-Vp (>4000 m/s) limestone bedrock ∼ 300 m deep. The whole sequence displays reflectors truncated by the Mt. Cefalone fault zone and subsidiary antithetic faults. CF-Strike profile, tied to three 80–110 m-deep boreholes, shows a thick fluvio-lacustrine sequence with low-Vp (<2000 m/s) and low resistivity (<100 Ωm), and a bedrock that deepens to the southeast (>450 m). Single-station ambient noise measurements display Horizontal to Vertical Spectral Ratios with peaks at ∼1 Hz, decreasing to ∼0.8 Hz to the southeast in agreement with the bedrock deepening indicated by seismic profiling. According to our results, the Campo Felice basin is a deep asymmetric half-graben controlled by faulting whose activity likely started before the Middle Pleistocene. Our minimum displacement estimate accrued in the past 0.5 Ma by the Mt. Cefalone fault is in the range of ∼100–250 m. • Seismic and electrical images of the Campo Felice tectonic basin structure • Reflection sections show a > 450 m-deep half-graben with a SW-dipping master fault. • Buried synthetic and antithetic splays offset the alluvial and lacustrine infill. • The master fault accrued at least ∼100–250 m displacement in the past ∼0.5 Ma. [ABSTRACT FROM AUTHOR]

This document is a corrigendum for an article titled "Displacement/length scaling relationships for normal faults; a review, critique, and revised compilation." The corrigendum addresses an error in the abstract and conclusions of the article, where it incorrectly stated that active faults are over-displaced. The correction clarifies that active faults are actually under-displaced compared to inactive faults. The authors apologize for the errors and emphasize that these corrections do not change the scientific conclusions of the article. [Extracted from the article]

Relay zones on normal faults accommodate transfer of displacement between adjacent fault segments. We study vertical and horizontal displacement transfer mechanisms across a relay zone adjacent to the Moab Fault at Courthouse Rock (Utah, USA). The relay zone has a reservoir scale (map overlap length ca. 750 m, separation ca. 150 m), and is bounded by two normal fault segments with maximum throw of ca. 12 m. The relay zone is exposed on multiple, sub-parallel cliff faces and intervening rock pavements. We use photogrammetry of these exposures to build a 3D virtual outcrop model of the relay-bounding faults, subordinate faults deforming the relay zone and seven faulted stratigraphic horizons. The relay-bounding faults are right-stepping in map view and contractional in cross-section, defining a relay zone oblique to bedding in 3D. Displacement is transferred both horizontally and vertically across the relay zone. Horizontal transfer of displacement is achieved by a shallow dipping (<1°) relay ramp, whereas vertical transfer is achieved by antithetic faults within the relay ramp. Our analysis demonstrates that multiple mechanisms can work in conjunction to facilitate transfer of displacement across individual relay zones. [Display omitted] • Faults right step in map view but form a contractional step in cross-section, bounding an oblique relay zone in 3D • Displacement is transferred horizontally via a relay ramp and vertically through antithetic faults within the ramp • Multiple mechanisms can work together to facilitate displacement transfer across individual relay zones. [ABSTRACT FROM AUTHOR]

The spatio-temporal evolution for the frontal part of the Kirthar fold and thrust belt in Pakistan is constrained for the first-time using apatite (U–Th-Sm)/He (AHe) and apatite fission track (AFT) dating of samples from the Oligocene Nari Formation in combination with a published balanced cross-section. The AHe ages appear to be fully reset, allowing us to date the timing of exhumation above ramps. Comparison of partially reset AFT ages (∼22–24 Ma) with previously published zircon fission track (ZFT) ages of the Nari Formation from nearby areas suggest that rocks in the frontal zone were not buried deeper than ∼4 km after deposition. The close range of AFT ages have implications for the timing of hinterland exhumation and Oligocene age of the Nari Formation. The AHe ages suggest that deformation along the major basement ramp was active since ∼7 Ma, forming a major topographic step (∼1.5 km) in the frontal part of the Kirthar fold and thrust belt. Combined analysis of the structural cross-section and thermal modeling of the samples suggest that major cooling occurred between ∼7 Ma and ∼5 Ma. This cooling was due to the erosion of Oligocene to Miocene strata from above the samples when Precambrian to Miocene strata was thrust above the pre-existing normal fault that acted as a basement ramp. The temporal structural evolution suggests that deformation in the frontal part of the Kirthar fold and thrust belt was characterized by faster rates (∼2.5 km/Ma) of orogenic growth and exhumation between ∼7 and 5 Ma, followed by slower shortening rates (<1 km/Ma) since ∼5 Ma. • Major cooling and exhumation occurred on pre-existing basement normal fault in the frontal part of the Kirthar FTB • Deformation and related exhumation of the frontal folds of the Kirthar FTB was active since ∼7 Ma. • Faster shortening rates of ∼2.5 km/Ma between ∼7 and ∼5 Ma are estimated for frontal thrust propagation on basement ramp. • Since ∼5 Ma the long-term shortening rates for frontal structures were reduced to <1 km/Ma. [ABSTRACT FROM AUTHOR]

The formation and evolution of (normal) fault affect the formation and preservation of some reservoirs, such as fault-block reservoirs and faulted reservoirs. Strain energy is one of the parameters describing the strength of tectonic activity. Thus, the formation and evolution of normal fault can be studied by analyzing the variation of strain energy in strata. In this work, we used physical simulation to study the formation and evolution of normal fault from a strain energy perspective. Based on the similarity principle, we designed and conducted three repeated physical simulation experiments according to the normal fault in the Yanchang Formation of Jinhe oilfield, Ordos Basin, China, and obtained dip angle, fault displacement, and strain energy via the velocity profile recorded by high-resolution Particle Image Velocimetry (PIV). As a result, the strain energy is mainly released in the normal fault line zone, and can thus serve as channels for oil/gas migration and escape routes connecting to the earth’s surface, destroying the already formed oil/gas reservoirs. One might need to avoid drilling near the fault line. Besides, a significant amount of strain energy remaining in the hanging wall is the reason why the normal fault continues to evolve after the normal fault formation until the antithetic fault forms. Our findings provide important insights into the formation and evolution of normal fault from a strain energy perspective, which plays an important role in the oil/gas exploration, prediction of the shallow-source earthquake, and post-disaster reconstruction site selection.

Abstract The dips of boundaries in faults and caldera walls play an important role in understanding their formation mechanisms. The fault dip is a particularly important parameter in numerical simulations for hazard map creation as the fault dip affects estimations of the area of disaster occurrence. In this study, I introduce a technique for estimating the fault dip using the eigenvector of the observed or calculated gravity gradient tensor on a profile and investigating its properties through numerical simulations. From numerical simulations, it was found that the maximum eigenvector of the tensor points to the high-density causative body, and the dip of the maximum eigenvector closely follows the dip of the normal fault. It was also found that the minimum eigenvector of the tensor points to the low-density causative body and that the dip of the minimum eigenvector closely follows the dip of the reverse fault. It was shown that the eigenvector of the gravity gradient tensor for estimating fault dips is determined by fault type. As an application of this technique, I estimated the dip of the Kurehayama Fault located in Toyama, Japan, and obtained a result that corresponded to conventional fault dip estimations by geology and geomorphology. Because the gravity gradient tensor is required for this analysis, I present a technique that estimates the gravity gradient tensor from the gravity anomaly on a profile.

The main goal of this study is introducing a novel fault current limiter based on parallel resonance structure (PRFCL) for high voltage application. During normal mode, the PRFCL reactor is short-circuited via a rectifier bridge DC output voltage and LC resonance tank shows negligible impedance in the line. During a fault, the rectifier bridge switches are turned off, so that the parallel resonance LC tank connects to the line with high impedance. This impedance of the resonance structure can limit the fault current, successfully. It is shown that the suggested PRFCL can act as a breaker and opens the line during the fault period. In order to show the suggested PRFCL abilities, MATLAB software is used to simulate the normal and fault cases. In addition, a scale-down prototype is implemented to confirm the simulation results. The comparative study shows that PRFCL has acceptable performance in normal and current limiting operation modes.

We study the surface deformation following a moderate size M5+ earthquake sequence that occurred close to Tyrnavos village (Thessaly, Greece) in March 2021. We adopt the interferometric synthetic aperture radar (InSAR) technique to exploit several pairs of Sentinel-1 acquisitions and successfully retrieve the ground movement caused by the three major events (M5+) of the sequence. The mainshocks occurred at depths varying from ~7 to ~10 km, and are related to the activation of at least three normal faults characterizing the area previously unknown. Thanks to the 6-day repeat time of the Sentinel-1 mission, InSAR analysis allowed us to detect both the surface displacement due to the individual analyzed earthquakes and the cumulative displacement caused by the entire seismic sequence. Especially in the case of a seismic sequence that occurs over a very short time span, it is quite uncommon to be able to separate the surface effects ascribable to the mainshock and the major aftershocks because the time frequency of radar satellite acquisitions often hamper the temporal separation of such events. In this work, we present the results obtained through the InSAR data analysis, and are able to isolate single seismic events that were part of the sequence.

The Asal Rift hosts a lake located in a depression at 150 m below sea level, where recharge is influenced by regional groundwater flow interacting with the Ghoubbet Sea along the coast of Djibouti. This regional groundwater flow is believed to influence hydrothermal fluid circulation, which we aim to better understand in this study, having the objective of developing concepts for geothermal exploration in the area. To this end, magnetotelluric data acquired in the Asal Rift were processed and analyzed. 1D inversion models of electrical conductivity were interpolated for interpretation. These data were then used to build a 2D hydrogeological model, allowing multiphase flow and heat transfer simulations to be performed, considering the regional groundwater flow near the surface and the site topography, in order to confirm the preferred path of fluid flow. Geophysical data analysis indicates the presence of normal faults, notably the H fault, which may act as a conduit for the circulation of hydrothermal fluids and where the hanging wall can be a hydrogeological barrier within the hydrothermal system of the Asal Rift. The results from the 2D numerical flow and heat transfer modelling show the importance of groundwater flow responsible for thermal springs located at the periphery of Asal Lake. Reservoir temperature inferred by means of geothermometry ranging from 200 to 270 °C was shown to correspond to simulated temperature at potential reservoir depth. Moreover, simulated temperature between 600 and 1700 m depth is close to the temperature profile measured in the geothermal well Asal 6 of the area, with less than 20 °C difference. Simulations indicate that hydrothermal fluid circulation is likely influenced by the regional groundwater flow controlled by the topography and the major water bodies, the Ghoubbet Sea and Asal Lake, feeding buoyant fluids interacting with a deep magmatic source and where tectonic activity created normal faults offering a preferred path for fluid circulation.

In major earthquakes, permanent ground deformations due to the fault movements cause serious damage to the foundations and structures. Although many of structural seismic design codes have recommended avoiding the construction of structures in the adjacent to active faults, it is not always a viable option. For example, the lifeline facilities such as gas tunnels, water supply tunnels and transportation tunnels, due to their extensive length, cannot often avoid crossing active faults. Therefore, it is necessary to evaluate the interaction mechanism between structures and fault rupture for effective design to reduce the hazards associated with surface faulting. This study investigates the interactions of underground tunnel and existing shallow foundation affected by normal fault using the finite element method. The results show that the existence of a tunnel changes the fault rupture path and in some cases can increase the foundation rotation. It causes the occurrence of severe level of damage to the structure and increases fear about its instability. [ABSTRACT FROM AUTHOR]

In the Central Anatolia, the style of neotectonic regime governing the region has been a controversial issue. A tectonic study was carried out in order to contribute to this issue and better understand the neotectonic stress distribution and style of deformation in the west-southwest of the Konya region. From Middle Miocene to Recent time, Konya region was part of the Central Anatolia extensional province. The present-day topography in the west-southwestern part of Konya is characterized by alternating elongate grabens and horsts trending E-W and NW-SE. The grabens were developed upon low-grade metamorphic rocks of Palaeozoic and Mesozoic ages and ophiolite slabs of possibly Late Cretaceous age. The evolutionary history of grabens is episodic as evidenced by two graben infills; older and younger graben infills separated by an angular unconformity. The older infill consists of fluviolacustrine sequence intercalated with calc-alkaline lavas and pyroclastic rocks. This infill is folded; thrust faulted and Middle Miocene-Early Pliocene in age. The younger and undeformed basin fill comprises mainly of Plio-Quaternary conglomerates, sandstone-mudstone alternations of alluvial fan and recent basin floor deposits. Three major tectonic phases were differentiated based on the detailed mapping, morphological features and kinematic analysis. Approximately N-S trending extension began in the Middle Miocene-Early Pliocene in the region with the formation of E-W and NW-SE-trending grabens. Following NE-SW-directed compression which deformed the older basin fill deposits by folding and thrusting, a second period of ENE-WSW-trending extension began in the late Pliocene and continued to the present. The west-southwestern margin of the Konya depression is bounded by the Konya Fault Zone. It is an oblique-slip normal fault with a minor dextral strike-slip component and exhibits well-preserved fault slickensides and slickenlines. Recent seismicity and fault-related morphological features reveal that the Konya Fault Zone is an active neotectonic structure. [ABSTRACT FROM AUTHOR]

Normal faults grow via synchronous increase in displacement and length ('propagating fault model', also known as the 'isolated fault model'), or by rapid length establishment and subsequent displacement accrual (constant-length fault model). We here use time-series displacement (D) and length (L) data from natural and experimental faults to elucidate growth styles and D-L trajectories throughout fault life, and to assess the applicability of the two fault models. We show that the growth of most faults is characterized by two stages, with the first defined by fault lengthening (20–30% of fault lifespan) and the second by displacement accrual (70–80% of fault lifespan). Although broadly adhering to the constant-length model, fault growth throughout the lengthening stage, during which significant displacement (10–60% of the total end-of-life fault displacement) may also accumulate, is achieved through rapid tip propagation, relay breaching, and segment linkage, characteristics perhaps most intuitively thought to reflect growth in accordance with the propagating model. The subsequent growth stage is dominated by displacement accrual with limited lateral tip propagation, a phenomenon best described by the constant-length model. We also show that, despite being used primarily in support of the propagating model, global displacement-length (D-L) datasets are equally compatible with the constant-length model. Image 1 • We investigate fault growth using time series displacement (D) and length (L) data. • The data show that normal faults exhibit a wide spread of D-L growth trajectories. • Global D-L data compatible with both propagating and constant-length growth models. • Propagating growth typifies initial lengthening; significant slip may accumulate. • Subsequent D accrual best described by constant-length model. [ABSTRACT FROM AUTHOR]

The purpose of the present paper is to investigate the effects of a normal fault rupture propagation towards a highway embankment founded on a single-layered soil. To achieve this, quasi-static parametric numerical analyses are performed with the 2D finite difference code, FLAC. The work addresses the influence of the embankment's presence on the fault rupture path, as well as, the deformation of the embankment and the alteration of its initial compaction degree due to the rupture propagation. Results of numerical analyses indicate that the presence of embankment significantly affects the deformations of ground surface. In addition, it is observed that spread of normal fault rupture through the examined embankment causes substantial deformations of embankment's external surface and significant drop of relative compaction. This work achieves to map and quantify the damage of the embankment and therefore provides substantial information on its functionality and safety. • Normal fault rupture diffusion through an embankment based on a single-layered soil. • Effect of embankment's presence on rupture path and soil's free surface distortion. • Important deformation of embankment's external surface due to rupture propagation. • Quantification and mapping of damage pattern of the embankment. • Reduction of embankment's initial compaction degree due to rupture propagation. [ABSTRACT FROM AUTHOR]

Highlights • The Zeribar Lake basin is a pull-apart basin along the MRF in the Zagros Mountains. • This pull-apart basin is related to a dextral major strike-slip fault, MRF, in the region. • Numerous normal faults and grabens are evidence of extensional deformation. • The strike-slip faults form some characteristic landforms. Abstract The Zaribar Lake is situated along the Main Recent Fault, a dextral major strike-slip active fault system in the Zagros collision zone. The formation of the Zaribar Lake in Late Pleistocene is associated with the activities of the Main Zagros Reverse Fault, initiated in Late Oligocene, and with the Main Recent Fault, whose inception occurred about 5 Ma ago. Metamorphic, intrusive and ophiolitic rocks in the Zagros suture zone are affected by a normal fault system in the Zaribar area. Geometry and kinematics of these normal faults indicate that the Zaribar Lake is generated in a releasing zone. The strike of the Main Recent Fault varies from 300° to 330° along the Marivan fault segment. The releasing bend of the Marivan Fault around the Zaribar Lake has resulted in the extensional deformation by which the lake has been downdropped between two strike-slip faults. Besides the extensional mechanism of the main right-lateral strike-slip faults that has resulted in the formation of the Zaribar as a large-scale pull-apart basin, minor strike-slip faults have also produced specific landforms around the lake. Small-scale normal faults and large scale grabens developed around the lake are geological indicators of extensional areas. Geomorphological evidence also support the pull-apart origin for the Zaribar Lake. Beheaded rivers, numerous offsets in drainage system, half-broom shaped drainage pattern, sag ponds with different scales, linear and strike-parallel valleys and alluvial fan with high sweep angle and width/length ratio confirm the movements along right-lateral, strike slip faults around the Zaribar. [ABSTRACT FROM AUTHOR]

Inherited structural, compositional, thermal, and mechanical properties from previous tectonic phases can affect the deformation style of lithosphere entering a new stage of the Wilson cycle. When continental crust jams a subduction zone, the transition from subduction to extension can occur rapidly, as is the case following slab breakoff of the leading subducted oceanic slab. This study explores the extent to which geometric and physical properties of the subduction phase affect the subsequent deformation style and surface morphology of post subduction extensional systems. We focus on regions that transition rapidly from subduction to extension, retaining lithospheric heterogeneities and cold thermal structure inherited from subduction. We present numerical models suggesting that following failed subduction of continental crust (with or without slab breakoff), the extensional deformation style depends on the strength and dip of the preexisting subduction thrust. Our models predict three distinct extensional modes based on these inherited properties: (1) reactivation of the subduction thrust and development of a rolling‐hinge detachment that exhumes deep crustal material in a domal structure prior to onset of an asymmetric rift; (2) partial reactivation of a low‐angle subduction thrust, which is eventually abandoned as high‐angle, "domino"‐style normal faults cut and extend the crust above the inherited thrust; and (3) no reactivation of the subduction fault but instead localized rifting above the previous subduction margin as new rift‐bounding, high‐angle normal faults form. We propose that the first mode is well exemplified by the young, rapidly exhumed Dayman‐Suckling metamorphic core complex that is exhuming today in Papua New Guinea. Key Points: Strength and dip of inherited subduction thrust controls extensional style following rapid transition from subduction to extensionTectonically inherited lithospheric structure can promote metamorphic core complex formation in cold, strong lithosphereInherited subduction‐related lithosphere conditions can explain the formation and exhumation of the Dayman‐Suckling core complex [ABSTRACT FROM AUTHOR]

The Rukwa and North Malawi Rift Segments (RNMRS) both define a major rift‐oblique segment of the East African Rift System and are often regarded as discrete rifts due to the presence of the uplifted Mbozi block between them. Here we investigate the influence of basement fabrics on the coupling and linkage of border faults across an interrift transfer zone between discrete juvenile rift segments. We utilized satellite digital elevation model to investigate the morphological architecture of the rift domains and aeromagnetic data to assess the relationships (plan view) between the rift structures and the prerift basement fabrics. Our results show that the present‐day morphology of the RNMRS is characterized by along‐rift alternation of rift shoulder polarity, characteristic of coupled rift segments. Interpretation of filtered aeromagnetic maps along the boundaries of the RNMRS reveals striking alignment of the rift‐bounding faults with colinear NW‐SE trending preexisting basement fabrics. We find that rift coupling along the NE boundary of the Mbozi transfer zone is accommodated by fault‐assisted magma plumbing, whereas coupling along the SW boundary is accommodated by strike‐slip and oblique‐normal faulting that reactivated the Proterozoic Mughese shear zone, within the collisional boundary between the Tanzania craton and the Bangweulu cratonic block. Further, we show how the configuration of the basement fabrics may influence the formation of rift bifurcation across inter‐rift transfer zones. We suggest that the structural connectivity of the boundary faults along the RNMRS and their alignment with colinear basement fabrics demonstrate the influence of structural inheritance on the amalgamation of approaching rift segments. Plain Language Summary: A few studies, mostly utilizing numerical and analog modeling, have shown that rift basins may nucleate as discrete rift segments that propagate toward one another and merge to form a continuous rift segment. However, there remains a limited understanding of the factors that control how the initial discrete rifts actually link‐up to merge. Rift linkage is expressed by the border fault structure of the interacting rifts, how the border faults link up with one another, and the accompanying deformational structures and processes within the interrift transfer zone. In this study, we investigate the controls of prerift basement fabrics on the border fault structures and linkage of the Rukwa and North Malawi segments of the East African Rift. Our results reveal that the basement fabrics modulate the formation of border fault segments and the merging of these structures across the transfer zone between the Rukwa and North Malawi Rift basins. Key Points: The Rukwa and North Malawi Rift segments exhibit coupled‐rift geomorphologyFault‐guided magmatism and strike/oblique‐slip faulting that reactivated basement fabrics accommodate linkage at interrift transfer zoneBasement fabrics modulate the geometries of the rift border faults and transfer structures, and facilitate linkage between them [ABSTRACT FROM AUTHOR]

Abstract The Teruel Basin is a NNE-SSW trending intracontinental extensional basin located in central-eastern Iberia. It is asymmetrically bounded to the east by a major fault zone, but intrabasinal faults with diverse orientation (NNE-SSW to NE-SW, E-W, or NW-SE) also appear. Offsets of the successive sedimentary units and of two planation surfaces reveal that tectonic activity initiated at the border faults, while intrabasinal ones mainly developed in a later stage. Fractures on a map scale show a prevailing N-S strike in Neogene synrift rocks, while a dense network made of four main fracture sets (NE-SW, E-W to ESE-WNW, N-S and NNW-SSE), likely inherited from Mesozoic rifting stages, is observed in pre-rift units. The results of palaeostress analyses indicate an overall predominance of σ 3 directions around E-W, although two stress episodes have been distinguished during the Late Miocene-Pleistocene: (i) triaxial extension with σ 3 E-W; (ii) almost 'radial' extension (σ 1 vertical, σ 2 ≈ σ 3) with a somehow prevailing σ 3 ENE-WSW. A scenario in which the evolving extensional stress field was able to gradually activate major basement structures with different orientation, inherited from previous tectonic events, is proposed as responsible for the evolution and overall pattern of both the eastern active margin and central parts of the central-northern sector of the Teruel Basin. Highlights • Diverse orientation, border and intrabasinal faults in the Neogene Teruel basin. • Use of stratigraphical–geomorphological markers for analysing fault activity. • Characterization of Neogene deformation and structural inheritance from fracturing. • Structural inheritance and evolving stress systems as controls on basin evolution. [ABSTRACT FROM AUTHOR]

Abstract Cenozoic fault patterns associated with rift development in the Wichianburi Sub-Basin show a wide range of controls at different scales including influence by the margin of a Permian basin, and NW-SE to NE-SW trending Triassic folds and faults. During the Late Oligocene-Early Miocene phase 1 normal faults (NNW-SSE to NNE-SSW trends) developed in response to ∼ E-W extension. Faults predominantly trend NNW-SSE to N-S during this phase. During the Middle Miocene-Pliocene the extension direction rotated to a more NW-SE orientation. The old fault orientations were reactivated, and new faults also developed with predominantly NNE-SSW to NE-SW orientations. Many new faults nucleated within the syn-rift section and were not directly influenced by pre-existing fabrics in the pre-rift section. Four types of phase 2 fault can be identified: Type 1 = newly formed faults that strike sub-orthogonal to the phase 2 extension direction, Type 2 = newly formed faults that strike between the phase 1 fault orientations and Type 1 faults. Type 3 = newly formed faults that strike at angles greater than 90° with respect to the phase 2 extension direction. Type 4 = reactivated phase 1 faults. Local stress rotations, and fault linkage rotations explain many of the Type 2 and 3 fault orientations. The stress rotation in the Middle Miocene is observed in other basins in Central Thailand, notably the Suphan Buri and Phitsanulok Basins, where a range of fault patterns are produced by the effects of inherited fabrics plus multi-phase rifting. Highlights • Curved fault splays related to multi-phase oblique extension. • Linkage along first phase fault trends by second phase faults. • Regional change from E-W to NW-SE extension in Middle Miocene. • Variety of orientations to second phase faults similar to results from analogue models. [ABSTRACT FROM AUTHOR]

Abstract Utilizing seismic attributes, we image fault 3D geometry for 21 normal faults of different sizes in the Norwegian Barents Sea. We revisit the published models of fault shape and growth using the new dataset. Based on the maximum accumulated length (L m a x) of faults, we have classified them into two classes: medium size (1 ≤ L m a x ≤ 1000 m) and long faults ( L m a x > 1000 m). The common characteristics of these faults are: i) the medium size faults show mainly irregular shapes while long faults show a variety of shapes including irregular, rectangular, and elliptical. ii) in medium size faults maximum displacement is located close to the fault upper tip-line. iii) no lateral segmentation was observed for most of the medium size faults while long faults contain several internal segments at each depth. iv) linkage with other faults is less common in medium size faults in comparison to the long ones. v) long faults with an elliptical shape have several displacement maxima located near the fault centre or close to the upper tip-line. vi) long faults with irregular to rectangular shapes show the displacement maxima close to either upper or lower fault tip-line. Our results show that for many of the analyzed faults, the maximum displacement is located on the faults longest segment; however, this is not the case for some of the faults. We found that power-law fits well with the displacement-length and displacement-height relations of the faults. Furthermore, the aspect ratio, the ratio between fault maximum accumulated length and height is high for the studied faults and ranges between ∼1.5 and ∼16. The results can shed light on the understanding of fault geometry and growth for a variety of applications including geological and mechanical models incorporating faults. Highlights • Fault shape and growth models are revisited using fault seismic attributes. • Medium size faults have irregular shape and less linkage with other faults. • Long faults can have irregular, rectangular, and elliptical shapes. • The maximum displacement is not always located in the centre of isolated faults. • The ratio between fault length and height ranges between 1.5 and 16 in this study. [ABSTRACT FROM AUTHOR]

Abstract Although structural inheritance is a fundamental factor in the tectonic evolution of the crust, few studies have been aimed at understanding in detail the interaction between pre-existing normal faults in a rift zone and successive dominant strike-slip (transtensional) movements. Firstly, we present the complex pattern of faults and tension fractures of the western, pre-Holocene part of the N-S Theistareykir Fissure Swarm (ThFS - Northern Iceland Rift), crossed by the NW-SE striking, right-lateral, Husavik-Flatey Fault (HFF), and we integrate previous observations with new field data that reveal Holocene motions along the N-S faults near the HFF. Secondly, we propose a set of analogue experiments that reproduce the N-S rifting followed by superimposed transtensional faulting along the HFF. In a first set of experiments, we tested the effect of an initial extension at the shallow crustal level by forming a rift zone. During this rifting phase, we modelled the presence of a sub-orthogonal discontinuity that represents the structural inheritance of the HFF (that is older than the ThFS), but without any imposed "regional" transtensional movement along it. After that, we superimposed a dominant right-lateral movement along the HFF on the modelled rift faults in order to assess the effect of the inheritance of the rift plus the HFF. Our results show that during rifting, a series of elongated and depressed areas develop along the initial HFF discontinuity (that is locally reactivated by the rift opening), in agreement with field data. During the second experimental set of exclusively shear deformation along the HFF, the models show the development of Riedel shears at the HFF, contemporaneous to the local reactivation of normal faults and tension fractures in the previous rift zone. This reactivation occurs by block rotation, incremental dip-slip motions on pre-existing fault scarps, widening of tension fractures and development of new structures. We conclude that transversal basins can develop from the early stages of rift development, and that the structures of a pre-existing rift may reactivate under a local stress state induced by incremental transtensional motions. Highlights • Field surveys have been conducted along the Husavik-Flatey transform fault. • Field data show interaction between the transform fault and Theistareykir rift. • We studied rift development and rift-transform fault interaction by analogue modelling. • Analogue modelling have been run using GPS- and field-based extensional directions. • An innovative approach and apparatus has been used for studying this topic. [ABSTRACT FROM AUTHOR]

The plate flexure and normal faulting characteristics along the Tonga, Japan, Izu-Bonin and Mariana Trenches are investigated by combining observations and modeling of elastoplastic deformation of the subducting plate. The observed average trench relief is found to be the smallest at the Japan Trench (3 km) and the largest at the Mariana Trench (4.9 km), and the average fault throw is the smallest at the Japan Trench (113 m) and the largest at the Tonga Trench (284 m). A subducting plate is modeled to bend and generate normal faults subjected to three types of tectonic loading at the trench axis: vertical loading, bending moment, and horizontal tensional force. It is inverted for the solutions of tectonic loading that best fit the observed plate flexure and normal faulting characteristics of the four trenches. The results reveal that a horizontal tensional force (HTF) for the Japan Trench is 33%, 50% and 60% smaller than those of the Mariana, Tonga and Izu-Bonin Trenches, respectively. The normal faults are modeled to penetrate to a maximum depth of 29, 23, 32 and 32 km below the sea floor for the Tonga, Japan, Izu-Bonin and Mariana Trenches, respectively, which is consistent with the depths of relocated normal faulting earthquakes in the Japan and Izu-Bonin Trenches. Moreover, it is argued that the calculated horizontal tensional force is generally positively correlated with the observed mean fault throw, while the integrated area of the reduction in the effective elastic thickness is correlated with the trench relief. These results imply that the HTF plays a key role in controlling the normal faulting pattern and that plate weakening can lead to significant increase in the trench relief. [ABSTRACT FROM AUTHOR]

The one of the critical elements in infrastructure of today's modern cities that cover large geographic distances is Network of buried pipelines. That is why they face a variety of natural hazards due to permanent ground replacements or wave emissions. Reports suggest that the main cause of damage to these lines is not seismic vibrations but large and permanent ground deformations are major causes of infrastructures' demolition. Most recent studies are related to lines crossing the strike-slip faults, and only a few researchers have tried to study the behavior of structures against the normal fault. This article discusses the behavior and response of structures and infrastructures against the movements of normal faults using the finite elements method. In this study, the interaction between soil-soil and soil-pipe has been considered in modeling terms.