Pop-up Structure Research Articles

Engineering Lipid-Based Pop-up Conductive Interfaces with PEDOT:PSS and Light-Responsive Azopolymer Films.

Significant challenges have emerged in the development of biomimetic electronic interfaces capable of dynamic interaction with living organisms and biological systems, including neurons, muscles, and sensory organs. Yet, there remains a need for interfaces that can function on demand, facilitating communication and biorecognition with living cells in bioelectronic systems. In this study, the design and engineering of a responsive and conductive material with cell-instructive properties, allowing for the modification of its topography through light irradiation, resulting in the formation of "pop-up structures", is presented. A deformable substrate, composed of a bilayer comprising a light-responsive, azobenzene-containing polymer, pDR1m, and a conductive polymer, PEDOT:PSS, is fabricated and characterized. Moreover, the successful formation of supported lipid bilayers (SLBs) and the maintenance of integrity while deforming the pDR1m/PEDOT:PSS films represent promising advancements for future applications in responsive bioelectronics and neuroelectronic interfaces.

Structural and stratigraphic history of the southern domain of the Indian Mountain Deformed Zone, southeastern New Brunswick, Canada: Tournaisian (Lower Carboniferous) tectonic ‘pop-up’ and collapse

The southern domain of the Indian Mountain Deformed Zone (IMDZ) in southeastern New Brunswick marks a major right-lateral strike-slip fault belt active during late Tournaisian (Lower Carboniferous) sedimentation. The rocks of the Sussex Group, representing a depositional cycle from subsidence to basin inversion, occupy this zone and lie unconformable on crystalline basement, the latter representing a partially exhumed portion of the adjacent (to the south) buried Westmorland uplift. Deformation is related to early reverse faults/thrusts, later strike-slip faults. and latest normal faults. The Gorge Fault zone in the southern domain of the IMDZ demonstrates many essential features of the entire zone. The offset of The Gorge Fault zone increases to the east. In the west it forms a blind thrust and asymmetric anticline whereas in the east it expands into a reverse fault/thrust complex. A progressive evolution from reverse faults/thrusts to strike-slip fault movement resulted in a tectonic pop-up, culminating in gravitational collapse along normal faults with listric profiles that flatten out within 100–200 metres of the present erosion surface. Megabreccias formed during deposition of the Sussex Group are contemporary with reverse fault/thrusts. The geometry of the various faults is best explained by progressive deformation within an overall right-lateral strike-slip regime under general shear, with early formed features rotating both congruently and incongruently to the main IMDZ boundaries. Further complexity is a consequence of many reverse faults/thrusts and normal faults occurring close to a free surface and the latter a response to gravitational instability of the pop-up structure controlled by topography. A revised stratigraphy for the Sussex Group in the Indian Mountain Deformed Zone and its interpretation is integral to constructing the structural history. Two units, Stilesville Formation and Briggs Cross Formation, are formally defined here.

Structural inheritance through 3D reservoir modeling and ant-tracking attribute implications for structural configuration of Upper Cretaceous Pab Sandstone, Kirthar Fold Belt, Pakistan

This research presents a comprehensive investigation to enhance understanding of subsurface structural complexities within the Upper Cretaceous Pab Sandstone reservoir level in a gas-producing field within the Kirthar Fold Belt of the Southern Indus Basin, Pakistan. The seismic interpretation for accurate structural delineation and characterization of intricate fault systems is often challenging in Fold and Thrust Belt settings. The 3D structural maps of Upper Cretaceous Pab Sandstone at the reservoir level and the application of the ant-tracking attribute for fault extraction improve the structural understanding of the gas-producing field in the Kirthar Fold Belt in the Southern Indus Basin, Pakistan. Attribute-assisted 3D seismic interpretation has revealed several subsurface structure elements, including a large thrusted anticline extended towards the north-south, the pattern of north-south oblique ramp thrusts on the southeastern flank, and a combination of easterly vergent thrusts with a counter-back thrust creating a local pop-up structure in the area. A 3D structural model at the reservoir level was generated using horizon and fault framework volume-based modeling approach, serving as a structural model for Pab sandstone. The structural smoothing, variance and ant-tracking attribute were applied iteratively to get the best results and correlated with manual interpretation. 3D seismic interpretation and application of ant-tracking for fault extraction identifies discrete structural styles and revealed that all thrusting occurred due to compressional tectonics of the Plio-Pleistocene period. The apparent different styles result from the reactivation of earlier extensional fault systems and probably during phased periods of compression. The resulting 3D reservoir model can be used as an input to populate petrophysical properties and results can be extended for future field development plans. Integration of well and 3D seismic data interpretation and the application of automatic fault extraction techniques are highly recommended in structurally complex areas and have an equal implication for worldwide basins with similar conditions for reliable structural interpretation in Fold and Thrust Belts with structural complexity.

Control of décollement strength and dip on fault vergence in fold-thrust belts and accretionary prisms

Fault vergence in fold-and-thrust belts and accretionary prisms is characterized by mainly forward verging thrusts and pop-up structures, and only few examples exist where backthrusting dominates. However, backthrusting and triangle zones are known from most if not all fold-thrust belts in the world. The circumstances under which backthrusts instead of forethrusts form are still incompletely understood. Previous studies suggest that the strength and dip of the basal décollement of Coulomb wedges plays a key role. However, a systematic study of these parameters is still missing. In this study we model numerically the formation of brittle-ductile wedges, systematically, varying dip and strength of the basal décollement. To characterize wedges, we use cumulative vorticity as a measure of dominant fault vergence within the entire wedge. We find that backthrust-dominated wedges form in setups of very low basal dip (≤ 0.5°) and a weak décollement. Increasing décollement strength or basal dip results in the formation of pop-up-dominated wedges, before forethrust dominated wedges form. While our models corroborate the idea that thrust vergence and basal dip may control thrust vergence, comparison with natural examples indicates this cannot be the only explanation for the formation of backthrusts. Consequently, additional factors such as syntectonic sedimentation or changes of décollement rheology across strike may be required to explain backthrusting in fold-thrust belts.

Liquid Crystal Elastomer-Liquid Metal Composite: Ultrafast, Untethered, and Programmable Actuation by Induction Heating.

Liquid crystal elastomers (LCEs) are a class of stimuli-responsive materials that have been intensively studied for applications including artificial muscles, shape morphing structures, and soft robotics due to their capability of large, programmable, and fully reversible actuation strains. To fully take advantage of LCEs, rapid, untethered, and programmable actuation methods are highly desirable. Here, a liquid crystal elastomer-liquid metal (LCE-LM) composite is reported, which enables ultrafast and programmable actuations by eddy current induction heating. The composite consists of LM sandwiched between two LCE layers printed via direct ink writing (DIW). When subjected to a high-frequency alternating magnetic field, the composite is actuated in milliseconds. By moving the magnetic field, the eddy current is spatially controlled for selective actuation. Additionally, sequential actuation is achievable by programming the LM thickness distribution in a sample. With these capabilities, the LCE-LM composite is further exploited for multimodal deformation of a pop-up structure, on-ground omnidirectional robotic motion, and in-water targeted object manipulation and crawling.

Preliminary appraisal of deformation structures from Great Nicobar Island, Andaman-Sumatra arc system

The Andaman and Nicobar Group of Islands represent a topographic high of forearc sediments in an actively rising accretionary prism on the Andaman subduction margin. Preliminary observations of deformation structures recorded in tuff are reported from Great Nicobar Island. Active compression led to the formation of meso-scale deformation structures such as a schuppen zone with horse units; sole and roof thrusts; fault breccia zone; high angle reverse faults and pop-up structures. Offset of tuff beds up to a few centimetres are observed across these faults.

Image-Based OA-Style Paper Pop-Up Design via Mixed-Integer Programming.

Origami architecture (OA) is a fascinating papercraft that involves only a piece of paper with cuts and folds. Interesting geometric structures 'pop up' when the paper is opened. However, manually designing such a physically valid 2D paper pop-up plan is challenging since fold lines must jointly satisfy hard spatial constraints. Existing works on automatic OA-style paper pop-up design all focused on how to generate a pop-up structure that approximates a given target 3D model. This article presents the first OA-style paper pop-up design framework that takes 2D images instead of 3D models as input. Our work is inspired by the fact that artists often use 2D profiles to guide the design process, thus benefited from the high availability of 2D image resources. Due to the lack of 3D geometry information, we perform novel theoretic analysis to ensure the foldability and stability of the resultant design. Based on a novel graph representation of the paper pop-up plan, we further propose a practical optimization algorithm via mixed-integer programming that jointly optimizes the topology and geometry of the 2D plan. We also allow the user to interactively explore the design space by specifying constraints on fold lines. Finally, we evaluate our framework on various images with interesting 2D shapes. Experiments and comparisons exhibit both the efficacy and efficiency of our framework.

The influence of basal detachment strength on formation of the southwestern Sichuan fold-thrust belt: insights from discrete-element numerical simulations

Introduction: The southwestern Sichuan fold-thrust belt (SWSB) is a duplex detachment system and features the basal Precambrian detachment at a depth of approximately 15–17 km and the upper Mid-Triassic detachment. Moreover, the SWSB undergoes forward-breaking propagation during the Cenozoic. To date, the mechanism and kinematic evolution governing the SWSB in this thrusting deformation as well as the way the two detachments control the structural deformation pattern of the SWSB remains unknown.Methods: In this work, three discrete-element numerical models with the same strong upper detachment but basal detachments with different mechanical strengths and thicknesses were designed to study the deformation of the SWSB.Results: The results indicate that for the Model I with a strong frictional basal detachment with thickness of 500 m, most deformation and thrust faults concentrate near the mobile backwall. Model I exhibits characteristics such as linearly increasing wedge height and stepwise increasing wedge width and slope angle. For the Model II with a modest frictional basal detachment with thickness of 500 m, the strain and deformation propagate into the foreland quickly and multiple back-thrust and thrust faults form on the upper detachment in the second thrusting period. The first thrusting period in Model II, exhibits similarities with Model I. However, in the second period, the wedge reaches a stable state, and its geometry remains constant. In this stage, the deformation propagates along the shallow detachment into the right side of the model. The geometry and activity of thrust faults in the foreland differ significantly in the model III with a modest frictional basal detachment but a greater thickness. Two additional pop-up structures are generated in the second period in this model. The first half of the first thrusting period is similar to the first two models. In the second half of the first period and the second period, the wedge is in a stable state. In the first stage of the shortening, all models undergo a transition from a subcritical state to entering a supercritical state, which indicates that the deformation is progressing rapidly along the basal detachment towards the right side of the model.Discussion: The results of Model III are consistent with the deformation pattern of the SWSB. The study of the kinematics and interaction between two detachments could help hydrocarbon exploration beneath the upper detachment.

A new superimposed model of the Tongnanba anticline in northeastern Sichuan and its exploration implications

Understanding the structural style, kinematic process, and timing of superimposed structures worldwide is often difficult due to complex structure deformation process. Fortunately, the newly acquired high-quality seismic reflection data and geological observations covering the Tongnanba anticline provide an excellent chance to characterize such structures. Here, we used geological and seismic data from the Tongnanba region to evaluate the structural style and deformation sequence of Tongnanba anticline. In this regard, we propose a new model of the northeastern Sichuan Basin, which are different from the model that deep structures formed earlier than shallow structures demonstrated by previous studies, and we also discussed the implications of this new model for the deep oil and gas exploration. Compressed by Micangshan and Dabashan thrust belts and controlled by three detachment layers, the Tongnanba anticline shows a complex multi-stage, multi-directional, and multi-level superimposed structure. There were three deformation layers vertically, leading to the multi-level detachment thrust structure style. Specifically, the upper and middle deformation layers were mainly controlled by South Dabashan thrust belt in the early stage, forming long-distance detachment thrust structure extended in the NW-SE direction. A series of pop-up structures propagated toward the upper and middle detachment layers. On the other hand, the lower deformation layer was primarily controlled by the Micangshan thrust belt in the late stage, forming complex basement faults extended in the NE-SW direction, which was consistent with Trishear fault-propagation fold. Along the basement detachment developed multiple branch slopes spread from northeast to southwest. The middle and upper deformation layers was transformed by the basement faults, thus forming the complex superimposed structure of north-south zonation and east-west segmentation at present. It was such complex superimposed structure that control the process of hydrocarbon accumulation and adjustment in each deformation layer, and the deep-ultra-deep ancient oil and gas reservoirs may be worth of exploring.

Effects of friction properties and rheological structures on the deformation patterns and evolution of fold-and-thrust belts—New insights from analogue modelling

Studying fold-and-thrust belts is crucial in geoscience; fold-and-thrust belts are rich in petroleum and natural gas. However, the effects of friction properties and rheological structures on the deformation patterns and evolution of fold-and-thrust belts with two detachment layers are less frequently discussed. Therefore, using models with a basal silicone layer, a middle silicone layer and overlying quartz sand layers, this study conducted an analogue modelling analysis of the effects of friction conditions, rheological structures and compressional velocity on the deformation and evolution of fold-and-thrust belts. The results show the following. 1) The weak layer or low friction strength of the basement forms complex deformations of the structural style, forming forward thrust, backward thrust, symmetrical pop-up structure and frontward–backward oscillating structural characteristics. 2) The friction strength ratio between the lateral and basement layers does not determine the structural style of a fold-and-thrust belt; moreover, it is closely related to the construction of strata or rheological structures. 3) The deformation of double detachment layers complicates the structural style of fold-and-thrust belts. 4) The analogue modelling results are similar to the structural style of the simple fold belt of the Zagros fold-and-thrust belt (ZFTB), indicating that deep and middle detachment layers control the current deformation of the ZFTB.

Integration of seismic and well data for a 3D model of the Balkassar anticline (Potwar sub-basin, Pakistan)

The Potwar sub-basin is an important hydrocarbon producing zone of the Upper Indus basin and has significant oil and gas potential. The Balkassar area is the main oil field of the Potwar sub-basin and oil is mainly produced from Eocene carbonates. The Chorgali Formation is of Eocene age and is the main reservoir rock in this area. Structurally, the Potwar sub-basin is complicated, and surface features often do not reflect subsurface structures. This is due to the presence of detachments at different levels. In such cases, it is necessary to integrate seismic data with geological information for an accurate delineation of subsurface structures. Eleven seismic profiles were interpreted to understand subsurface structural style. To correlate well data with seismic data, a synthetic seismogram has been generated. Time, velocity and depth contour maps have been prepared. A 3D model for the Chorgali Formation has been prepared which confirms that this is a four-way anticlinal structure bounded by faults. It makes this structure more favorable for hydrocarbon accumulation. Moreover, a cross section has been prepared for five wells to show that the Chorgali Formation is spreading. Based on it, to show the relationship between compressional tectonics and basement slope, a 3D structural model has been prepared. In this case study, the Balkassar anticline was interpreted as a four-way closure pop-up structure which provides a structural trap for the accumulation of hydrocarbons. This study will help us understand the accumulation of hydrocarbons in the same type of structural traps in the Potwar sub-basin and in similar kinds of basins. It is also relevant to oil exploration within Pakistan.

Seismotectonic modeling of the 2017 Hojedk (Kerman) earthquake sequence from joint inversion of InSAR and offset tracking techniques

We investigate the geometric/kinematic characteristics of faulting a triplet of Mw ∼ 6 earthquakes (E1, E2, and E3) in Kerman province, Central Iran, over twelve days in December 2017. A geodetic framework is implemented and combined with seismic and geological methods to provide an integrated model of faulting within the sequence. To retrieve coseismic displacements in the complex and high-gradient near-field area, an adaptive method is proposed based on image-alignment techniques applied to both SAR (Sentinel-1) and optical data (PlanetScope). A continuous deformation map is created by combining interferometric and pixel offset tracking results through principal component analysis. We jointly invert the geodetic data, including along- and across-track displacement maps, through a constraint-based Bayesian inversion process to optimize the source parameters of the causative faults. The results reveal that the NE-dipping nodal planes, with variable slip peaks of 63 and 17.5 cm at depths of 5.5 and 9.1 km, best fit the data for the E1 and E2 events, respectively, whereas the E3 event was on a SW-dipping fault plane including ∼E- and NW-striking segments. The E3 plane was shallow with maximum slip of 1.2 m at a depth of 2.2 km. We relocate 93 events and use the InSAR slip distributions as constraints to indirectly calibrate the epicenter of the earthquake cluster, and obtain the local stress state from the inversion of the focal mechanism solutions of the ten largest events of the Hojedk cluster. The resultant compressional stress explains the dextral and sinistral components found on the western and eastern segments of the E3 rupture, respectively. All together suggest a NW-striking pop-up structure in a restraining stepover between the ∼N-striking dextral Lakarkuh and Golbaf-Sirch-Gowk fault systems. This structural model highlights the interaction between thick-skinned and thin-skinned seismic deformation within Iran.

Analysis of a travertine system controlled by the transpressional activity of the Alhama de Murcia fault: The Carraclaca site, eastern Betic Cordillera, Spain

Continental carbonates, such as travertines and tufas, formed from CO2-rich groundwater degassing as it emerges at the Earth’s surface, are often associated with major crustal-scale faults. The Carraclaca site, in the Lorca-Totana section of the Alhama de Murcia Fault, Spain, presents a complex geomorphological landscape controlled by active tectonics. The geology here records the interaction between Quaternary alluvial fans, travertines, and a pop-up structure developed in a transpressional section of the fault. The Alhama de Murcia Fault is an 80 km long left-lateral strike-slip fault that is one of the main seismogenic structures in the Iberian Peninsula. In this work, we examined the relation between travertine precipitation in the Carraclaca site and the tectonic activity of this fault zone through morphological and geochemical studies. The δ13C and δ18O isotopic signals indicate that the carbonate deposits are hydrothermal. In addition, the 87Sr/86Sr ratios in the samples suggest subsurface fluid interaction with the Miocene sediments and the Alpujárride basement, located below the alluvial deposits. Tectonic activity in the Alhama de Murcia Fault might generate the opening of deep water circulation in the crust every time a seismic event occurs, giving rise to hydrothermally derived carbonates precipitation. Deep waters rise and reach the surface interacting with meteoric waters, resulting in travertine formation. Therefore, the Carraclaca carbonate deposits study can inform us about the seismogenic cycle of the fault in the Lorca-Totana section.

Seismic Activity in the Celje Basin (Slovenia) in Roman Times—Archaeoseismological Evidence from Celeia

Searching for unknown earthquakes in Slovenia in the first millennium, we performed archaeoseismological analysis of Roman settlements. The Mesto pod mestom museum in Celje exhibits a paved Roman road, which suffered severe deformation. Built on fine gravel and sand from the Savinja River, the road displays a bulge and trench, pop-up structures, and pavement slabs tilted up to 40°. The city wall was built over the deformed road in Late Roman times, supported by a foundation containing recycled material (spolia) from public buildings, including an emperor’s statue. We hypothesize that a severe earthquake hit the town before 350 AD, causing widespread destruction. Seismic-induced liquefaction caused differential subsidence, deforming the road. One of the nearby faults from the strike-slip Periadriatic fault system was the seismic source of this event.

Seismic swarms in the Pollino seismic gap: Positive fault inversion within a popup structure

Seismic swarms frequently occur along continental fault systems and their relation with large earthquakes is often contradictory. Such a case is documented in the Pollino mountain range of southern Italy, a decoupling zone where the belt-normal stretching drastically rotates accommodating the differential SE-retreat of the Ionian slab. The paucity of historical large earthquakes has led to hypothesize the presence of a seismic gap. A long-lasting seismic swarm that climaxed with a ML = 5.2 earthquake in October 2012 was therefore thought as a possible signal of an impending large earthquake filling the gap. Seismicity data collected during a 4-years long monitoring are a powerful microscope to look through the seismic swarm. In this study, we present accurate relocations for 2385 earthquakes and high-resolution Vp and Vp/Vs models of the fault system. Seismicity occurred on two separate normal faults that were formerly part of a thrusts and back-thrusts system, originally formed as a pop-up at restraining bends of the Pollino fault, a wrench fault system that inverted the original left lateral sense of slip accommodating a differential motion induced by the southward retreat of the Ionian slab.

Several types of triangle zones from the Subandean ranges of Peru: Fish-tails, tectonic wedges and passive-roof duplexes

Surface geology, well data and 2D seismic interpretations reveal the presence of triangle zone structures at the contact of the Subandean Ranges and the Amazonian foreland in Peru. From north to south the Santiago, Marañon, Ucayali and Madre de Dios basins have been studied. Interpretations presented in this study show a great variety of structural styles at this contact area. Simple triangle zones with one back thrust, composite ones with several back thrusts, more complex double vergent ones with pop-up structures, best described as fish-tails, tectonic wedges and passive-roof duplexes are present in the study area. The role of pre-Andean tectonics and paleogeography is key to understanding the Andean evolution, due to the control on the location and geometry of the main detachment levels. The Santiago Basin is characterized by the presence of fish-tail structures with a Permian-Triassic evaporitic basal detachment located at the base of the Pucara Gr. At the Ucayali Basin, several detachment levels interact, the basal ones located within the Ordovician, Devonian, and Carboniferous defining triangle zones or tectonic wedges. At the Madre de Dios Basin, two detachment levels define the base of the triangle zone, Permian shales in the northwest at the Inambari Imbricates area, and Lower Devonian (Cabanillas Gr.) in the southeast at the Candamo area. A roof thrust is located within the Paleogene section at both the Madre de Dios and Ucayali basins, defining passive-roof duplex structures.Several detachment levels are rooted into the Lower Paleozoic; others within the Permian-Triassic section, being locally evaporitic, and finally others are located at the base of the Cretaceous. Paleozoic shales represent the main basal detachment level of the southern Subandean ranges. The role of these detachments and the role of the sedimentation rate are discussed as factors that control the development and geometry of the triangle zones described in the study area.Except for the San Martin-Sagari area of the Ucayali Basin, the triangle zones of the Santiago and Madre de Dios basins remain unexplored even though active petroleum systems are present. Sub-thrust structures at the Azulmayo area of the Madre de Dios Basin remain promising undrilled structures.

Dynamic off-fault failure and tsunamigenesis at strike-slip restraining bends: Fully-coupled models of dynamic rupture, ocean acoustic waves, and tsunami in a shallow bay

Inelastic off-fault deformation can lead to large tsunamigenesis in different tectonic settings. Here a mechanism for tsunami generation by strike-slip earthquakes that involves dynamic off-fault failure at restraining bends is presented. Dynamic rupture on a vertical strike-slip fault is modeled with undrained inelastic off-fault response incorporated by the Drucker-Prager yield criterion. I show that in a local transpressive stress regime dynamic off-fault failure at restraining bends produces significantly larger and more localized surface uplift than is produced by purely elastic dislocation models, resulting in a positive flower and coseismic pop-up structure. The larger uplift is due to frictional sliding with a thrust component on conjugate microfractures, modeled by inelastic deformation. The short-wavelength inelastic uplift, largely controlled by bend size, is shown to generate localized tsunami efficiently in a shallow bay by fully coupling dynamic rupture, ocean acoustic waves, and tsunami. Fully-coupled models also indicate that supershear rupture on a vertical planar strike-slip fault does not generate large tsunami as the large kinetic energy of supershear rupture is carried away by ocean acoustic waves. Dynamic off-fault failure at fault complexities, such as restraining bends and compressional stepovers, may need be urgently incorporated in the current tsunami hazard assessments in strike-slip environments.

Deformational in curved fold-and-thrust belts: As a function of backstop shape and basal friction: Insights from analogue modeling and application to the Pamir salient, Hindu Kush region

Curved fold-and-thrust belt (CFTB) is a common structural phenomenon in orogenic belts and accretionary wedges, which has attracted the attention of several geologists. However, the formation mechanism of CFTB, particularly the cause of Pamir salient, has been greatly controversial. Therefore, based on previous studies, CFTB was studied by 12 groups of analogue modeling using the different shapes of the backstop and variable basal friction properties, and different compression velocities. The results show that the formation of CFTB is closely associated with the initial geometric characteristics of CFTB, the strength of the basal ductile layer, and the influence of lateral friction. Although the variation in backstop geometries is dominated by the pure Coulomb wedge, CFTB with completely different structural styles can form because of different boundary shapes. The CFTB formed by lower basement friction strength has a larger deformation range, and the CFTB formed by high strength of basal friction, which is narrow, has a high uplift amplitude, forming a tensile structure around its uplift. A high compressional rate forms the higher arc curvature, and a lower compressional rate forms the smaller arc curvature. Models of a brittle basement with triangular backstop and models with ductile basement and boundary parallel to the compression direction may provide a more reliable explanation for the formation of the forward thrust, backward thrust, and symmetrical pop-up structures of the Pamir salient and its structural vergence from south to north. This study further reveals that initial boundary geometry, stratigraphic structure, and rheology with a difference in brittle and ductile layers will yield more complex structural styles and different kinematic characteristics.

Active Deformation Patterns in the Northern Birjand Mountains of the Sistan Suture Zone, Iran

In this paper, faults, one of the most important causes of geohazards, were investigated from a kinematic and geometric viewpoint in the northern part of the Sistan suture zone (SSZ), which serves as the boundary between the Afghan and Lut blocks. Furthermore, field evidence was analyzed in order to assess the structural type and deformation mechanism of the research area. In the northern Birjand mountain range, several ~E–W striking faults cut through geological units; geometric and kinematic analyses of these faults indicate that almost all faults have main reverse components, which reveals the existing compressional stress in the study area. The northern Birjand mountain range is characterized by four main reverse faults with ~E–W striking: F1–F4. The F1 and F2 reverse faults have southward dips, while the F3 and F4 reverse faults have northward dips. Moreover, the lengths of the F1, F2, F3, and F4 faults are 31, 17, 8, and 38 km, respectively. These faults, with reverse components that have interactive relationships with each other, form high relief structures. The study area’s main reverse faults, including F1 to F4, are extensions of the Nehbandan fault system, while their kinematics and geometry in the northern Birjand mountain range point to an N–S pop-up structure.

3D Modelling of Archaeoseismic Damage in the Roman Site of Baelo Claudia (Gibraltar Arc, South Spain)

This study deals with the morphometric characterization and quantification of earthquake damage in the ancient Roman city of Baelo Claudia in South Spain (Gibraltar Arc) by means of the use of 3D modelling from drone imagery. Baelo Claudia is a world-renowned archaeological site recording recurrent earthquake destruction during the first and third centuries AD. The first earthquake destroyed the lower littoral zone of the city, allowing its reconstruction from the year c. 60–70 CE, but the second earthquake in 365–390 CE led to the complete destruction of the renewed city and its eventual abandonment. This second earthquake imprinted important deformations in the main monumental zone of the city, including the basilica temples, macellum, city walls, aqueducts and funerary monuments, as well as in the main paved zones of the city. This is the case for the Forum, Decumanus and Cardos, which show a variety of folds, pop-up structures, conjugate fractures and impact marks susceptible to be measured in a 3D format. The current study presents detailed (up to 3 mm/pixel) surface models of iconic monuments within the city. The 3D models were obtained by means of serial orthophotos taken with a UAV Mavic Pro 2 (DJI) Drone device equipped with a 20 mpx camera and a 1” CMOS sensor. Each individual image was captured in a geo-referenced jpg format and processed with the Agisoft Metashape Professional software®. Depending on the measured monument, the final images consisted of 250 to 700 photographs clustered by 50,000 to 150,000 tie points. In all studied items (Decumanus, city walls and bath dish), we follow the same workflow of analysis: (1) alignment of photos with support points; (2) building a dense cloud of points; (3) creation of the surface texture; (4) creation of the Digital Elevation Model (DEM); (5) creation of the orthomosaic; and finally, (6) the building of the high-quality 3D tiled surface models. The obtained models allow the geometric quantification of earthquake deformations (displacements, amplitudes, orientation, etc.) in a GIS-based 3D environment suitable to quantify oriented damage of seismic origin. In a complementary way, these 3D models deserve to be considered for their potential role as digital seismoscopes of ancient archaeological sites and/or heritage buildings.