Complex Tectonics Research Articles

Splitting intensity tomography to image depth-dependent seismic anisotropy patterns beneath the Italian Peninsula and surrounding regions

The region between central Europe and the centre of the Mediterranean is characterised by complex tectonics and kinematics. Here, the interaction between thickened crust, subducting lithosphere and surrounding asthenosphere produces strong and pervasive anisotropy in the upper mantle. Shear wave splitting measurements, the most adopted method to image seismic anisotropy so far, when interpreted in a ray-based framework result in little or no depth resolution, hampering a correct image of the anisotropy distribution with depth. In this study, we aim to better constrain the depth-dependent seismic anisotropy beneath Italy and surrounding regions, by isolating for the first time the source region of anisotropy at different depths. To do that, we perform an anisotropy tomography, adopting the splitting intensity inversion method. It is entirely based on the finite-frequency effect in the splitting of SKS waves. We first computed the splitting intensity using SKS waves recorded at all available permanent and temporary stations over the region, obtaining a huge dataset of measurements used as an input for the tomographic inversion. The large-scale 3D model of seismic anisotropy obtained with the inversion shows a clear change of anisotropy properties in terms of fast polarisation direction and intensity for different depths, thus improving the characterization of the main sources of anisotropy in the mantle as a function of depth. Shallower layers (70–100 km depth) are characterised by a complex and variable oriented pattern of anisotropy fast direction and intensity, which becomes progressively more organised with depth (100–300 km). This pattern suggests a strong control exerted by the geometry and motion of the different slab segments and the large-scale asthenospheric flow generated by subduction and roll-back processes. The strength of anisotropy increases with depth, with high values affecting the bulge of the Alps and Apennines chains and the southern Tyrrhenian subduction system. On the contrary, weaker anisotropy characterises the transition zone from the Apennines to Alpine domains beneath the Po plain, and both the Adriatic and European domains.

Electrical conductivity of mantle minerals beneath East Asia revealed by geomagnetic observatory data

The electrical conductivity of the earth’s mantle can provide important information about geodynamic phenomena. East Asia is associated with complex tectonics and geodynamic processes. Hence, it is necessary to better understand the deep structure beneath East Asia. In this study, geomagnetic data obtained from East Asian observatories are employed to image the conductivity structure of the mantle at depths ranging from 410 to 900 km. First, the data are processed using the modified bounded influence remote reference processing (BIRRP) method and the ratio method is used to correct for the ocean effect. Thereafter, the stable C-response curves at the 27 observatories are estimated, and 1D electrical conductivity models for these observatories are established using the L-BFGS method. The conductivity-depth profiles reveal a heterogeneous distribution of the electrical conductivity beneath East Asia. The mantle transition zone (MTZ) beneath East China and Japan is found to be more conductive, whereas the MTZ beneath central and southern regions of China is more resistive. In East China, the dehydration of the stagnant Pacific slab may lead to an increase in the conductivity of the mantle minerals. There is also the possibility of upwelling of the thermal material from the lower mantle beneath the Japanese Island arc. In Northwest China, there exists a large high-conductive body beneath the Tarim area, which could indicate an upwelling of the Tarim mantle plume. Our results provide insights into the deep structure of the earth at the mantle scale.

Soil surface erosion susceptibility analysis using the USLE model. Case study: Bran - Dragoslavele Corridor, Romania

The present study falls within the scope of the analysis of the morphodynamic potential of the Bran - Dragoslavele Corridor (Romania), a low mountain area, favorable to erosion processes due to the high energy of the relief, diversified lithology, tectonic complexity, and due to the variation in the energy of atmospheric risk phenomena. For the expansion of pastoral agricultural areas and those intended for human settlements, the deforestation of the last 3-4 centuries deprived the slopes and the soil of the protective forest cover on an area of 55.44%, favoring the amplification of the action of natural morphodynamic agents. In this context, the quantitative and spatial assessment of sheet erosion, expressed as the average annual rate of surface soil erosion (measured in tons hectare–1) was approached by applying the calculation model implemented in the GIS environment by using the universal soil loss equation (USLE). Implementation of the model was realized through the spatial delimitation of the potential erosion and the rendering by susceptibility classes of the quantitative results which reveal the fact that the largest surface of the studied mountain unit (91.68%) presents tolerable values, of 0-1.5 t ha–1 year–1. The highest values, over 4 t ha–1 year–1 (1.24%), are characteristic of the calcareous areas belonging to the many sectors of the gorges with discontinuous vegetation, as well as the limestone exploitation area from Mateiaș mountain. The quantitative knowledge and spatial distribution of surface erosion becomes important for communities and local authorities, interested in the planning and management of the implementation of some agrotechnical measures to improve the quality and productivity of soils or to prevent and restrict erosion processes with a tendency to expand areally and in depth.

STRUCTURAL FEATURES OF THE PSHEKHA-ADLER FAULT ZONE OF THE GREATER CAUCASUS ACCORDING TO STRUCTURAL STUDIES

The study of minor faults carried out in the valley of the Belaya River made it possible to establish the tectodynamic conditions for the formation of the Pshekha-Adler fault zone of the Greater Caucasus. In this zone, the presence of strike-slip displacements of different scales and the predominance of the situation of horizontal displacement are shown. Using the method of cataclastic analysis, differences in the parameters of the stress-and-strain state in different tectonic complexes and structures of the region have been established. The revealed structural pattern of meridional and northeastern compression determine the regional dextral strike-slip fault and extensional fault nature of the meridional Pshekha-Adler fault zone with the development of sinistral strike-slip faults and extensional faults of the northeastern strike inside the deformation zone.

Stress regimes in the Himalaya–Karakoram–Tibet, the western part of India–Eurasia collision: stress field implications based on focal mechanism solution data

SUMMARY The stress regime patterns of high-seismically active regions within the western part of the India–Eurasia collision, spanning from 67° E to 83° E and 27° N to 39° N, are elucidated through analysis of 684 Focal Mechanism Solutions from 1962 to 2021. Eighteen seismically active zones used for the stress tensor inversion, are defined based on the spatial extent of the seismicity, the depth distribution of seismic events, focal mechanism studies, and seismotectonics of the region. The defined regimes are: (1) Sulaiman Ranges and Lobe Region, (2) Hindukush, (3) Pamir, (4) Nanga Parbat Syntaxis, (5) Hazara Syntaxis, (6) Kashmir–Zanskar region, (7) Kangra–Chamba, (8) Kinnaur and Kaurik–Chango fault zone (KCFZ), (9) Garhwal, (10) Kumaon, (11) Karakoram fault zone, and (12) Gozha–Ashikule fault zone. Seismicity is reported only in the crust or up to mid-crust in most of the regions, except for the Pamir and Hindukush, where the seismicity can be observed down to 160 and 280 km, respectively. We report a clockwise rotation of the maximum horizontal stress (SHmax) of about 42° and 21° in the Hindukush and Pamir regions, respectively. with increasing focal depths from north west to north. The region where major and strong earthquakes occur indicates pure compressive regimes. Most of the zones support transpressive and transtensional tectonics with a few zones by normal and strike-slip fault regimes. Regions like Nanga Parbat syntaxis, Kinnaur, KCFZ, and Zanskar are exceptions, where extensional and transformational tectonic features dominate. Plate convergence force has less effect on defining the stress regime in the Karakoram fault zone and Gozha–Ashikule regions, which display transtensional and pure extensional regimes, respectively. Underthrusting of the Indian plate through complex tectonics is indicated by dominant compression stresses with evidences of normal, strike-slip, and oblique fault mechanisms.

Attenuation of Coda and Body Waves for Tbilisi and Surrounding Area, Georgia

The attenuation of high-frequency seismic waves was investigated in the crust beneath Tbilisi and the surrounding territory by analysing 225 local earthquakes that occurred from 2008 to 2020 and were recorded by eight seismic stations. The quality factors of coda waves QC and direct P and S waves, QP and QS, were estimated using the single backscattering model and the extended coda normalization method, respectively. The separation of intrinsic quality factors Qi from scattering quality factor QSC was fulfilled by Wennerberg’s method. Observed results show that all evaluated attenuation parameters are frequency-dependent in the frequency range of 1-32 Hz and increase with increasing frequency. Coda QC values increase also with increasing lapse time window from 20 s to 50 s and vary from 91±5 at 1.5 Hz to 1779±108 at 24 Hz, respectively. P waves attenuate slightly faster than S waves, and the ratio of QS/QP is more than unity and varies in a range of 1.5-1.8. The intrinsic and scattering quality factors are expressed by the following power laws: Qi=77±4f0.930±0.046 and QSC=219±6f0.924±0.050. The results show that Qi is close to QC, but QSC is larger than Qi, which means that intrinsic attenuation has a dominant role compared with the scattering effect. Our results were compared with those obtained in two other seismically active regions of Georgia, as well as with regions of the world. In general, the observed quality factors and their frequency-dependent relationships follow a similar trend, characterizing seismically active regions with complex tectonics. The calculated attenuation parameters characterize the entire earth’s crust under Tbilisi and the surrounding area. The results obtained will be useful in future seismological studies since the Q parameters are estimated for the first time for the given region.

Spatial variation of body wave attenuation in Garhwal-Kumaun Himalaya region, India

We have investigated the spatial variation of body wave attenuation in Garhwal-Kumaun Himalaya region from the datasets of 465 well located earthquakes, recorded at 52 broadband stations between 2017 and 2020. The body wave attenuation parameters QP and QS were estimated at each station by applying the extended coda normalization method for five different central frequencies ranging from 1.5 to 18 Hz. Strong frequency-dependent body wave attenuation was observed at each station over the whole region. Also, we found a significant variation of QP and QS from north to south which is consistent with geotectonic diversity beneath the study region. We have also made separate estimations of frequency-dependent relations for Garhwal and Kumaun Himalaya region in order to investigate the lateral variation in attenuation characteristics, and obtained the frequency-dependent relations as follows: QP=30±3f1.05±0.05, QS=143±20f0.88±0.07 for the Garhwal Himalaya region and QP=31±1f1.09±0.02, QS=121±11f1.00±0.04 for the Kuamun Himalaya region. Obtained Q values indicate strong body wave attenuation for both the region with no significant lateral variation. It may suggest the presence of crustal level folding, faulting, aqueous fluids, and metamorphic fluids below both the regions. Also, the ratios of QS/QP are high (>1) for the entire analyzed frequency range, suggesting a significant level of heterogeneity and tectonic complexities in the crust of the study region.

Characteristic Analysis of the MS6.8 Luding Earthquake Sequence in Sichuan, China, on Sept. 5, 2022

The MS6.8 earthquake occurred in Luding County, Ganzi Prefecture, Sichuan Province, China at 12:52 p.m. on Sept. 5, 2022, is preliminarily analyzed in terms of regional tectonics, historical earthquakes, sequence characteristics and focal mechanism solutions. The results show that: 1) The magnitude difference ΔM between the main shock and the maximum aftershock, the energy ratio ER of the main shock to the aftershocks, the p-value and the estimated Mmax-value indicate that the MS6.8 Luding earthquake sequence can be divided into the main shock-aftershock type (MAT). 2) The spatial distribution of the aftershocks, their corresponding b-value and expected maximum magnitude are obviously segmented, which reflect the complexity of the seismogenic tectonics. 3) According to the focal mechanisms obtained from the HASH program, the geometry distribution of the sequence, and the relationship between the sequence and the nearby faults, it can be inferred that the Moxi fault segment of the Xianshuihe fault zone is the seismogenic tectonics of the MS6.8 Luding earthquake sequence.

Effects of differential tectonic activities on overpressure evolution in the deep-water area of the Qiongdongnan Basin: implications for gas hydrate accumulation

The lack of data on the complex tectonics of the Qiongdongnan Basin has thus far restricted our understanding of the overpressure, deep hydrocarbon and shallow gas hydrate distribution. We therefore combined integrated seismic, well and borehole test data with basin models to clarify the relationship between tectonic activity and overpressure evolution, as well as the potential effects of the subsurface pressure on gas hydrate accumulation. The results show differences in tectonic activity and pressure characteristics between the eastern and western basins. Large numbers of faults and magmatic intrusions have developed in the post-rift layer of the eastern basin (the Baodao to Changchang sub-basins) since the Late Miocene ( c. 10.5 Ma), although they seldom formed in the western basin (the Lengdong to Lingshui sub-basins). Correspondingly, the eastern basin was characterized by lower overpressures (up to 40 MPa) and the western basin displayed higher overpressures (up to 110 MPa). The results indicate that tectonic activity since c. 10.5 Ma caused the relief of overpressure in the eastern basin. In stark contrast, the overpressure in the western basin increased significantly due to the lack of structural conduits and rapid sedimentation of the thick Pliocene and Quaternary deposits. Numerical models reveal that the faults and gas chimneys associated with the intrusions constituted shallow plumbing systems through which deep natural gas was able to migrate upwards. The formation of gas hydrates relied on the migration of deep gas to the hydrate stability zone below the seafloor. The relatively lower overpressured zones due to pressure relief in the eastern basin are therefore considered the next areas potentially favourable for the formation of gas hydrates. Thematic collection: This article is part of the Emerging knowledge on the tectonics of the South China Sea collection available at: https://www.lyellcollection.org/topic/collections/south-china-sea

Multi-model seismic susceptibility assessment of the 1950 great Assam earthquake in the Eastern Himalayan front

The seismic susceptibility and mitigation management is paramount concern in tectonically active area like Northeastern India. This area has been devastated innumerably during the 1950 Assam great earthquake. The present study area falls in the foreland basin (Brahmaputra Valley) of Eastern Himalaya. This region is seismically vulnerable due to the tectonic complexity caused by the convergence of the Eurasian, Indian, and Burmese plates. In such, an area optimal disaster management and preparedness is necessary to define the non-linear character of seismic susceptibility, where population and unscientific urbanization have increased manifold. Therefore, for the present study, various multi-criteria decision making (MCDM) methods such as analytical hierarchy process (AHP), fuzzy-AHP (FAHP), and maximum entropy technique (MaxEnt) have been used for determining the seismic susceptibility, by assigning weightage to nine controlling factors such as: predominant frequency (f0), geology (G), vulnerability index (K), peak amplification (A0), liquefaction potential (LP), groundwater condition (WT), shear wave velocity (Vs30), peak ground acceleration (PGA), and land use/land cover (LU). The MaxEnt model exhibits the highest accuracy (87.5%) when the performance of the models was compared using the receiver operating characteristic curve (ROC) and area under the curve (AUC) value. Further, overlay analysis of best seismic susceptibility model using MaxEnt and PGV-based Japan Meteorological Agency (JMA) intensity shows that 40% the study area is in the very high and high seismic risk zone. In tectonically active areas, this kind of integration work is essential to improves the mitigation strategy and aids urban planners in designing earthquake-resistant buildings.

Cenozoic History of the Indonesian Gateway

The tectonically complex Indonesian Gateway is part of the global thermohaline circulation and exerts a major control on climate. Waters from the Pacific flow through the Indonesian Archipelago into the Indian Ocean via the Indonesian Throughflow. Much progress has been made toward understanding the near-modern history of the Indonesian Gateway. However, the longer-term climate and ocean consequences of Australia's progressive collision with the Eurasian Plate that created it are less known. The gateway initiated ∼23 Ma, when Australia collided with Southeast Asia. By ∼10 Ma the gateway was sufficiently restricted to create a proto–warm pool. During the Pliocene it alternated between more or less restricted conditions, until modern oceanic conditions were established by 2.7 Ma. Despite its tectonic complexity, climate modeling and Indian and Pacific scientific ocean drilling research continue to yield insights into the gateway's deep history. ▪The Indonesian Gateway is a key branch of global thermohaline oceanic circulation, exerting a major control on Earth's climate over the last 25 Myr.▪We find that a complex interplay of tectonics and sea level has controlled Indonesian Gateway restriction since 12 Myr, resulting in La Niña– and El Niño–like states in the equatorial Pacific.▪Long term Indonesian Gateway history is best determined from ocean drilling cores on the Indian and Pacific sides of the Indonesian Gateway, as records from within it are typically disrupted by tectonics.▪Model simulations show the global impact of the Indonesian Gateway. Further modeling with ocean drilling/tectonic research will enhance our understanding of Cenozoic Indonesian Gateway history.

The Attenuation and Scattering Signature of Fluid Reservoirs and Tectonic Interactions in the Central‐Southern Apennines (Italy)

AbstractDespite the high detection level of the Italian seismic network and the risk associated with its fault networks, Central‐Southern Italy has no unique geophysical model of the crust able to illuminate its complex tectonics. Here, we obtain seismic attenuation and scattering tomography models of this area; both reveal high attenuation and scattering anomalies characterizing the entire Apenninic Chain and related to its East‐ and West‐dipping extensional Quaternary tectonic alignments. Fault‐associated fractured zones become preferential ways for circulating and degassing high‐attenuation CO2‐bearing fluids. A previously undetected fluid source area is a high‐attenuation volume below the Matese complex, while a similar smaller anomaly supports a fluid source near L'Aquila. The most prominent low attenuation and scattering volumes reveal a locked aseismic zone corresponding to the Fucino‐Morrone‐Porrara fault systems, representing a zone of significant seismic hazard.

The role of continental lithospheric thermal structure in the evolution of orogenic systems: application to the Himalayan–Tibetan collision zone

Abstract. Continental collision is a crucial process in plate tectonics. However, in terms of the evolution and the controlling parameters of its lateral heterogeneity, our understanding of the tectonic complexities at such a convergent plate boundary remains largely unclear. In this study, we conducted a series of two-dimensional numerical experiments to investigate how continental lithospheric thermal structure influences the development of lateral heterogeneity along the continental collision zone. The following two end-members were achieved. First, continuous subduction mode, which prevails when the model has a cold procontinental Moho temperature (≤450 ∘C). In this case, a narrow collision orogen develops, and the subducting angle steepens with the increasing retrocontinental Moho temperature. Second, continental subduction with a slab break-off, which generates a relative wide collision orogen and dominates when the model has a relatively hot procontinental Moho temperature (≥500 ∘C), especially when the Moho temperature ≥ 550 ∘C. Radioactive heat production is the second-order controlling parameter in varying the continental collision mode, while it prefers to enhance strain localization in the upper part of the continental lithosphere and promote the growth of shear zones there. By comparing the model results with geological observations, we suggest that the discrepant evolutionary paths from the continuous subduction underlying the Hindu Kush to the continental subduction after slab break-off beneath eastern Tibet may originate from the inherited lateral inhomogeneity of the Indian lithospheric thermal structure. Besides, the high content of crustal radioactive elements may be one of the most important factors that controls the formation of large thrust fault zones in the Himalayas.

In-situ calcite U-Pb ages and absolute timing of oil charge events: A case study of ultra-deep carbonate reservoirs in the Shunbei oilfield, Tarim basin, Northwest China

To accurately determine the timing of hydrocarbon charging events in petroleum systems is important but often challenging. Traditional methods for establishing the timing of these events in tectonic complex basins frequently suffer from unreliability due to uncertain burial and/or thermal histories, as well as the poor identification of inclusion assemblage. Recently developed calcite U-Pb dating has been proven to be a valuable tool for precisely determining the timing of these events, thus enhancing our understanding of the charging histories. We integrated oil-inclusion fluorescence analysis with in-situ calcite U-Pb dating, focusing on calcite fabrics hosting primary oil inclusions, to quantitatively constrain the oil charging timing of the SHB no.1 and no.5 fault zones in the Shunbei oilfield. The fluorescence spectra of oil inclusions suggested the presence of up to three discrete charging events in these fault zones. Calcite U-Pb ages provide constraints on the timing of the first charging episode in the two fault zones, at approximately 478–469.2 Ma and ca. 447.4–424 Ma, respectively. Comparing the fluorescence spectra of reservoir oils and oil inclusions reveals that the primary charging episodes in the SHB no.1 and no.5 fault zones correspond to the latest and the earliest charging episodes, respectively. Furthermore, through a comparison of the equivalent reflectance of reservoir oils with the thermal maturation history of the Cambrian source rock, the former age can be estimated at ca. 120–0 Ma. Regions characterized by weaker late-stage fault activity exhibit a higher potential for hydrocarbon preservation in deeper reservoirs.

Perspectives of the offshore CCS development in the polish EEZ on a Baltic Sea: insights from ongoing preliminary research for pilot CO2 injection

The key to effectively combatting progressive climate change lies in promptly reducing greenhouse gas (GHG) emissions, particularly carbon dioxide (CO2), whose concentration continues to rise due to human activities. The European Union (EU) has established legally binding targets, including achieving climate neutrality by 2050, with an intermediate goal of reducing GHG emissions by 55 % by 2030 compared to 1990 levels. Poland, one of the major CO2 emitters in Europe, also possesses significant storage potential in terms of projected CO2 capacity within its sedimentary basins. Considering this, the implementation of Carbon Capture and Storage (CCS) technology could play a crucial role in Poland's efforts to decarbonize its economy. For several years, the Oil and Gas Institute – National Research Institute (INiG – PIB) has been at the forefront of domestic research activities concerning underground CO2 injection. The involvement dates back to 1996 by pioneering the development of a concept, design, and implementation of one of Europe's earliest industrial installations for reinjecting acid gas, consisting of approximately 80 % CO2 and 20 % H2S, into the reservoir water underlying a productive natural gas field. This facility in Borzęcin operated by PGNiG (now part of ORLEN GROUP), is a unique testing ground where the injection process has been running continuously for 27 years. The research conducted at INiG – PIB has played an important role in identifying appropriate geological structures in Poland with a total storage capacity of 10-15 Gt CO2. Around 90-93 % of the CO2 storage capacity is found in saline aquifers, with a significant portion of approximately 7-10 % identified within mature hydrocarbon fields.Despite recent progress in managing industrial CO2 emissions, the peace of CCS development falls short of meeting the objectives set by the Paris Agreement. The main hindrance lies in the absence of a suitable regulatory framework for CO2 transport and storage infrastructure. Recognizing this challenge, the national offshore operator, Lotos Petrobaltic (LPB), presented in 2021 a Green Paper on CCS development in Poland. This document outlines a set of recommendations for legislative alternations to facilitate the initiation of large-scale, commercial CCS projects within the country. Given the current national regulations and assumptions regarding low social barriers, the most expeditious approach to implementing a First-of-a-Kind (FOAK) large-scale CCS project in Poland seems to involve deploying depleted hydrocarbon reservoirs located at the Polish Exclusive Economic Zone (EEZ) within the Baltic Sea. The LPB, with research and scientific support from INiG – PIB, has launched a program aimed at conducting a preliminary assessment of CO2 injection in Middle Cambrian sandstones. The project is scheduled to begin with a pilot injection into the well-identified, depleted structure of the B3 oil reservoir. Subsequently, it may be expanded to include adjacent hydrocarbon reservoirs and could ultimately encompass the entire Cambrian aquifer.The Cambrian aquifer is characterized by complex tectonics, comprising several blocks separated by fault zones. These fault zones may act as barriers to the propagation of reservoir fluids, as demonstrated by the presence of hydrocarbon traps in the vicinity of some fault zones.The B3 oil field, covering an area of 36,2 km2, is an elongated SW-NE, asymmetric anticline, cut on the west side by an inverted fault zone. The reservoir interval, with an average depth of 1450 meters below sea level comprises of sandstones of the Paradoxides Paradoxissimus (Middle Cambrian Zone) horizon showing a monoclinal dip towards the south-east. The reservoir formation exhibits heterogeneity in both within the vertical profile and the horizontal direction, characterized by a wide range of petrophysical parameters values. According to preliminary assessments, the CO2 storage capacity of the B3 site is estimated to be around 7 Mt CO2. The expansion of CO2 storage to the remaining hydrocarbon fields and the overarching Cambrian aquifer megastructure could potentially increase the total storage capacity to more than 150 Mt. The envisioned CO2 sources include emitters from the chemical industry, where CO2 is a by-product of the fertilizer production process. During the project’s pilot phase, the predicted CO2 injection rate is expected to be between 25-50 kt CO2 per year. As the project transitions to the upscaled phase, the injection rate is projected to increase significantly, reaching approximately 2 Mt CO2 per year. The transportation of CO2 for full-scale injection is planned through multimodal means, considering potential synergies with the multimodal CO2 Terminal in Gdansk, which is being planned under the ECO2CEE project (formerly EU CCS Interconnector). A pipeline connection between the offshore storage area and the CO2 Terminal is under consideration.The main research problems addressed within the INiG – PIB and LPB joint initiative include determining the sequestration potential of the Cm2pp aquifer, assessing the feasibility of the CO2-EOR process, recognizing the effects of injected CO2/reservoir rock/caprock interactions on injectivity, geomechanical parameters, and sealing integrity, as well as investigating CO2-induced corrosion of steel components in the transport and injection plant.

INŽENJERSKOGEOLOŠKA ISTRAŽIVANJA I SANACIJA KAVERNI NA LOKACIJAMA VJETROELEKRANE PODVELEŽJE 1

Wind Farm Podveležje is located on the plateau Podveležje, about 10 km east of the city of Mostar, in the center of the Herzegovina-Neretva Canton. The Wind Farm consists of 15 wind turbines, each with a power of 3.2 MW, making a total capacity of 48 MW. The geological structure of the surrounding area on the Podveležje plateau is very complex due to its intricate tectonic complex, ranging from layered to thinly layered Upper Cretaceous limestone with Turonian-aged radiolites as the bedrock. Cracks are often highly prominent, filled with rock weathering products, terra rosa and clay material. During geological and geotechnical investigations at foundation locations, caverns were identified in certain places. The program of additional works (destructive boreholes and TV logging) was carried out to delineate the cavern locations on WT-3, WT-4, WT-8, WT-12, WT-15, and WT-16 plateaus. The aim of the paper is to describe the cavern rehabilitation at locations of wind turbine foundation including substrate preparation, filling procedures, mixture composition, and performing destructive boreholes to verify rock mass compactness.

The tectonic complex regulates membrane protein composition in the photoreceptor cilium

The primary cilium is a signaling organelle with a unique membrane composition maintained by a diffusional barrier residing at the transition zone. Many transition zone proteins, such as the tectonic complex, are linked to preserving ciliary composition but the mechanism remains unknown. To understand tectonic’s role, we generate a photoreceptor-specific Tctn1 knockout mouse. Loss of Tctn1 results in the absence of the entire tectonic complex and associated MKS proteins yet has minimal effects on the transition zone structure of rod photoreceptors. We find that the protein composition of the photoreceptor cilium is disrupted as non-resident membrane proteins accumulate in the cilium over time, ultimately resulting in photoreceptor degeneration. We further show that fluorescent rhodopsin moves faster through the transition zone in photoreceptors lacking tectonic, which suggests that the tectonic complex acts as a physical barrier to slow down membrane protein diffusion in the photoreceptor transition zone to ensure proper removal of non-resident membrane proteins.

Applying two methodologies of an integrated coastal vulnerability index (ICVI) to future sea-level rise

Climate change is an issue of concern and is expected to cause various adverse impacts on human societies in the near and long-term future. Sea-level rise, which is caused by global warming and melting continental ice sheets, in combination with the rising global population and evolution of human activities in coastal areas, tends to make coastal societies more prone to coastal hazards. The Gulf of Corinth in Greece with its diverse coastal landforms and tectonic complexity makes the region unique when considering an assessment of coastal vulnerability. In this study we apply an Integrated Coastal Vulnerability Index (ICVI) to a potential sea-level rise for the southern coastline of the Gulf of Corinth (Greece) consisting of physical and socio-economic parameters. Among multiple different methodologies that have been developed over the recent years, we decided to apply two of the mathematical approaches we believe are best suited for the protection of human activities in our study area. The first one, ICVI_1, is based on the Coastal Vulnerability Index (CVI) by Thieler and Hammar-Klose (1999) with variables of equal relative importance, whereas the second one, ICVI_2, uses the Analytic Hierarchic Process (AHP) with the assignment of relative weight values to each parameter. The parameters were identified and ranked into a vulnerability index with a scale from 1 to 5. The results reveal that both approaches depict more or less the same coastal sections of high or very high vulnerability, but differ in the distribution of extreme values. ICVI_1 shows that 18.3% of the total coastline features very high vulnerability (score 5), while ICVI_2 shows 9.1%. The coastal sections with the highest scores of vulnerability are mostly represented in the eastern part of the studied coastline with low-lying regions of gentle slope and concentrated human activity.

New insights into the conodont biostratigraphy and paleobiogeography of the Katkoyeh Formation (Lower–Upper Ordovician) at the Katkoyeh Section, East-Central Iran

The Katkoyeh Formation comprises most of the Ordovician strata in the Kerman Province of East-Central Iran. However, determining its depositional timing remains challenging due to conflicting biostratigraphic ages, regional stratigraphic gaps, and tectonic complexities in the area. To enhance the understanding of the Katkoyeh Formation, a new conodont sampling was conducted at the Katkoyeh type section, which revealed 1,937 conodont elements belonging to 31 species of 26 genera. They allow the recognition of the Juanognathus variabilis Range Zone (middle–upper Floian) and the Icriodella superba Range Zone (Katian–?Hirnantian) in the Katkoyeh Formation, leading to better biostratigraphic and intercontinental correlations of the Ordovician strata in East-Central Iran with the Precordillera, the Famatina System, and the Central Andean Basin of northwestern Argentina, as well as with North American Midcontinent and North Atlantic basins, and South China. Moreover, the oral structure of Juanognathus variabilis Serpagli is reassessed based on the new Iranian records, recognizing 7 morphotypes in its apparatus structure, referred to the M, Pa, Pb, Sa, Sba, Sbb and Sc positions.

Coupling the Relationship between Land Subsidence and Groundwater Level, Ground Fissures in Xi’an City Using Multi-Orbit and Multi-Temporal InSAR

The Xi’an region of China has been suffering from groundwater depletion, ground fissure hazards, and surface subsidence for a long time. Due to the complex tectonics and frequent human and natural activities, land deformation in the region is aggravated, posing a threat to infrastructure and human life. This study adopted the multi-orbit and multi-temporal InSAR technology to measure multi-dimensional displacements and time-series displacements in Xi’an City. Through the multi-dimensional deformation verification, it was found that the control of groundwater flow direction by ground fissures is the cause of horizontal deformation. On the contrary, the flow direction of groundwater from west to east was inferred using multi-dimensional deformation. Further analysis was performed by calculating the deformation gradient of the cumulative deformation to obtain differential land subsidence and angular distortions, and it was quantitatively determined that the threshold for the generation of ground fissures caused by differential subsidence is 1/500. Then, through the mutual verification of the time series data and the groundwater level, a positive correlation was obtained. However, due to the inconsistent geological conditions and soil layers at the monitoring positions of Well 2 and Well 3, the lag time was 64 days and 4 days, respectively. Finally, the relationship between the surface deformation and the groundwater in the sustained uplift areas was explored. The Well 1 groundwater-level data with a monitoring period of 22 years and the corresponding monitoring points’ time series data were modeled; it was concluded that, in the future, the groundwater level will continue to rise and surface deformation will mainly increase, without a slowing trend. Therefore, research on the impact of surface uplift on infrastructure should be strengthened. By quantifying the relationship between land subsidence, ground fissures, and the groundwater level in Xi’an, the results of this study provide a reference for groundwater monitoring and management.