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Significant infrastructure is required to establish a long-term presence of humans on the lunar surface. In-situ resource utilization (ISRU) is a fundamental approach to ensure the viability of such construction. Here, we investigate the feasibility of constructing blast shields as one example of lunar infrastructure using unprocessed lunar boulders and an autonomous robotic excavator. First, we estimate the volume of unprocessed material required for the construction of blast shield segments. Secondly, we quantify the amount of available boulders in two exploration zones (located at the Shackleton-Henson Connecting Ridge and the Aristarchus Plateau pyroclastic deposit) using LRO NAC images and boulder size-frequency distribution laws. In addition, we showcase an alternative approach that relies on Diviner rock abundance data. Thirdly, we use a path planning algorithm to derive the distance, energy, and time required to collect local material and construct blast shield elements. Our results show that our construction method requires two orders of magnitudes less energy than alternative ISRU construction methods, while maintaining realistic mission time and payload capacity margins. [ABSTRACT FROM AUTHOR]

Complex permeability distribution is frequently encountered in weathered rocks with inherited heterogeneities, such as networks of discontinuities that impact fluid flow and water‐rock interactions. Reactive transport modeling is a powerful tool for analyzing fractured media's chemical weathering dynamics. In this study, two different ways to model the fracture‐matrix interaction were explored. A 1D dual‐porosity simulation of reactive transport is designed to study the global impact of fractures on the weathering progression front, compared with a Single Porosity (S.P.) (unfractured) reference model. Then a 2D discrete model using a Discrete Fracture Matrix (DFM) representation is built to highlight the importance of medium geometry and fracture connectivity on weathering. The relevance of such models was evaluated in the case of weathering processes affecting ultramafic units in New Caledonia. Comparing the average behavior of the dual and S.P. models reveals a similar trend in both global mineralogical evolutions. Yet differences occur when confronting the weathering rates. By extending the weathering over a greater depth, the fractures favor a smoother transition between the saprolite horizon and the oxide ore. Furthermore, a partition of the newly formed phyllosilicates occurs in fractures and matrix: Ni‐phyllosilicates preferentially precipitate in fractures, while Mg‐phyllosilicates remain trapped within the matrix due to differences in residence time and liquid‐to‐solid ratio. The DFM modeling highlights the effect of the connectivity of a complex fracture network on the dissolution‐precipitation processes. Depending on the permeability and geometry, fluid flow is modified, favoring the formation of weathering heterogeneities typically observed on the field. Key Points: Dual Porosity modeling of a fractured rock mass recreates weathering heterogeneitiesWeathering heterogeneities originate from the physico‐chemical differentiation of the fractures and the matrixDiscrete Fracture Matrix modeling reveals the impact of the geometry and permeability of fractures on weathering heterogeneities [ABSTRACT FROM AUTHOR]

In a database of lunar fractured boulders (Rüsch & Bickel, 2023, https://doi.org/10.3847/psj/acd1ef), we found boulders with reflectance features dissimilar to previously known morphologies. We performed a photo‐geologic investigation and determined that the features correspond to a dust mantling on top of boulders with a unique photometric behavior. We next performed a photometric model inversion on the dust mantling using Bayesian inference sampling. Modeling indicates that the dust photometric anomaly is most likely due to a reduced opposition effect, whereas the single scattering albedo is not significantly different from that of the nearby background regolith. This implies a different structure of the dust mantling relative to the normal regolith. We identified and discussed several potential processes to explain the development of such soil. None of these mechanisms can entirely explain the multitude of observational constraints unless evoking anomalous boulder properties. Further study of these boulders can shed light on the workings of a natural dust sorting process potentially involving dust dynamics, a magnetic field, and electrostatic dust transport. The presence of these boulders appears to be limited to the Reiner K crater near the Reiner Gamma magnetic and photometric anomaly. This close spatial relationship further highlights that poorly understood processes occur in this specific region of the Moon. Plain Language Summary: The study of rocks on the surface of the Moon is important to understand the processes forming and modifying the lunar crust as well as the processes modifying rocks after their formation. The lunar rocks resting on the surface can be studied by imaging them with an orbital camera and analyzing their shape and reflectance. Here we report on the finding of a new type of brightness feature on rocks. This finding was made possible by scrutinizing a catalog of split lunar rocks. The brightness feature is found to be unique because of its rare occurrence, localization limited to near the Rainer Gamma magnetic anomaly, and association with some but not all rocks of the crater Reiner K. The feature is a dust deposit with a potentially uncommon physical structure. Key Points: In a catalog of lunar boulder images, we find a new type of reflectance feature associated with bouldersThe feature is likely a dust mantling with unique photometric propertiesSeveral formation scenarios are discussed [ABSTRACT FROM AUTHOR]

Steel baffle installed on footing is commonly used to resist and dissipate the impact energy from boulders carried by debris flow. However, the deformation of a baffle and the resulting energy transfer to the footing during the impact process compound the challenges of predicting the impact force and size of the footing required. In this study, full-scale experiments were conducted to simulate a boulder impacting a steel baffle installed on a square footing. The experimental data were back-analyzed using a three-dimensional (3D) finite element model, which was then used to conduct a parametric study to examine the effects of a range of impact energies and footing sizes. New design charts are developed to assess the required size of a square footing, embedded up to 2 m depth, for a steel baffle subjected to boulder impact with energy in the range of 10–100 kJ. [ABSTRACT FROM AUTHOR]

Large granitic boulders resting on steep slopes represent considerable safety hazards that largely depend on the location of the contact surface characterized by the impression d, denoting the parallel distance between the contact surface and the original rock surface. On the other hand, this impression reflecting the often convex nature of the contact between boulders and resting platforms, cannot be measured precisely, so Factors of Safety (FoS) computed with this input may have significant uncertainties. Using geometric 3D analysis, here, we present the concept of computing FoS as a function of the impression d, admitting a much more reliable estimate of the actual hazards. Beyond introducing the FoS functions, we also identify all failure modes, some of which have not yet been investigated. We compute the FoS functions for the boulder Pena do Equilibrio, located in Spain. Our computations for FoS against sliding match all earlier results. However, we also compute FoS against toppling and against torsion and show that the latter may be critical. Since our methods are general, this suggests that torsion phenomena, which have been scarcely studied so far, may be relevant to analyze the stability of other natural rock boulders. Highlights: A novel method to evaluate the safety of large boulders resting on steep slopes. Instead of Factors of Safety (FoS) computed at a fixed geometry with significant uncertainties, FoS functions are introduced, depending on a single geometric parameter. Considering spatial components of possible displacements, all failure modes of the boulder are identified, some of which have never been investigated before. Using geometric 3D analysis, our method is applied to the boulder Pena do Equilibrio, located in Spain and we find that torsional instability, one of the newly identified failure modes is critical. [ABSTRACT FROM AUTHOR]

From system assessment to recovery, a water utility's staff went beyond the call of duty to respond to the most destructive structural wildfire in Colorado history. [ABSTRACT FROM AUTHOR]

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Local scour holes are erosional bed structures that are related to different scientific disciplines in Earth science and hydraulic engineering. Local scouring at naturally placed boulders is ubiquitous, but many competing factors make it difficult to isolate the effects of a given variable. This is especially true for local scouring at natural instream obstacles that are exposed to unsteady flow conditions in the course of flood hydrograph experiments. Experimental investigations in laboratory flumes offer the advantage that boundary conditions can be systematically varied. We present novel experimental data on the impact of the submergence ratio, hydrograph skewness, and flow intensity on local scouring at boulder-like obstacles during unsteady flow and evaluate the effect of discharge chronologies. In total, 48 flume experiments on subcritical clear-water conditions and channel degradation were performed. The experimental results reveal that local scouring dominantly occurred at the rising limb when flow depth was comparable to the obstacle size, so the obstacle was unsubmerged. The steeper the rising limb, the quicker the local scour hole matured. The experimental results are relevant for the hydraulic interpretation of local scour holes found at boulders in the field. They may be utilized as a proxy for the minimum duration of the beginning stage of a flood. [ABSTRACT FROM AUTHOR]

To identify the origin of the Hida belt in central Japan, geochemistry and U–Pb age of zircons were analyzed for the extra‐large granitoid boulders in the Lower Cretaceous fluvial conglomerate of the Jinzu Group. This study clarified that the boulders of granitoids have geochemistry of typical A‐type granite, as characterized by high Nb + Y and high Ta + Yb values. U–Pb ages of igneous zircons from three individual granite boulders are concentrated at ca. 220 Ma (Late Triassic). As to Late Triassic A‐type granites, there is no corresponding body previously recognized within Japan, whereas identical A‐type granites occur in the eastern Songliao block on the immediate west of the Jiamusi block in NE China. The large size of boulders and the fluvial facies of the hosting conglomerate indicate their origin in the Hida belt per se, suggesting the cryptic and/or past occurrence of A‐type granite, rather than in NE China. Together with the eastern Songliao block (China), Laoelin‐Grodekov (LG) belt (Primorye, Russia), and Yamato Ridge (Japan Sea), the Hida belt forms a unique domain on the immediate west of GSC in Far East Asia, which is characterized commonly by the co‐occurrence of Permo‐Triassic and Jurassic granitoids, and probably with Late Triassic A‐type granite. These confirm that Hida belt represents an allochthonous unit tectonically emplaced onto the rest of Japan, which is composed of the Phanerozoic subduction‐related orogenic belt (Nipponides) developed along the Pacific side of Greater South China (GSC) since the Cambrian. For emphasizing a major geotectonic boundary of the Mesozoic granitoid provinces in Far East Asia, we propose the Yamato tectonic line between the easternmost Central Asian orogenic belt and GSC/Nipponides, which is traced for up to 3000 km from the Russia/China/North Korea border to SW Japan. [ABSTRACT FROM AUTHOR]

Toe and boulder due to blasts in the open pit mines reduce the production efficiency and increase extraction costs. In this study, these phenomena were reduced to correct the blast parameters of the ore blocks in the Sirjan Golgohar-2 Mine. For this purpose, the values of seven effective parameters including, an average of depth holes, burden, sub-drilling, powder factor, spacing, rock quality designation, and blastability index were collected for 19 blasting blocks in the studied mine. In this research, the values of Geo-mechanical properties of rock mass were obtained by the photogrammetric method and discontinuity set extractor software. Subsequently, the experimental models were created to predict the volume of boulder and toe relative to the volume of blasting block by nonlinear multiple regression. The predicted ability related to each of the created models by statistical indicators was investigated, and it was determined that the polynomial model to product boulder and the exponential model for toe are more accurate with 94.43 and 98.13 coefficients of determination respectively. Then, the minimization process of these phenomena was performed to access optimal values of controllable parameters and their coefficients in each of the created two models simultaneously by the combinational algorithm of Particle Swarm Optimization-Genetic algorithm. Finally, to evaluate the predicted ability of two optimized models, four blasts based on the optimized information were performed on the mine. The results showed that the models predicted the volume of boulder and toe relative to the block volume with the Root Mean Square Error 0.47 and 0.08 respectively. [ABSTRACT FROM AUTHOR]

To arrest rockfall boulders, baffles are constructed as steel members affixed on top of a concrete footing. Existing designs aim to prevent any footing rotation and steel member bending. As such, existing baffle designs require massive reinforced concrete footings and complex bolt and weld connections. Such designs have limited constructability and result in complex failure mechanisms (i.e., tensile failure of concrete foundation at connections). In this paper, we introduce a new baffle design concept that optimizes the balance between steel member bending and footing rotation to enable a compact design. Full-scale pendulum experiments are conducted to evaluate the proposed easy-to-construct and design baffle under successive boulder impacts of 50 kJ. It is demonstrated that by considering the effects of steel member deflection and concrete foundation rotation, the maximum impact force on baffles is reduced by up to two times when compared with those on a rigid barrier and the failure modes are simplified to either overturning failure of the footing or buckling failure of the steel member. A ratio that defines the flexural capacity of the steel member to the overturning capacity of the shallow concrete foundation is proposed to control the failure mode. The optimized baffle configuration for an impact energy of 50 kJ, with minimum residual deflection, has a target capacity ratio of 2.0. • A capacity ratio (flexural capacity of steel member to overturning capacity of footing) is proposed for baffle design. • A new baffle design concept is proposed and evaluated using full-scale pendulum experiments. • A failure criterion based on baffle rotation is proposed considering the residual boulder velocity. [ABSTRACT FROM AUTHOR]

The bed stabilization effect of boulders in rivers was studied by a wind tunnel experiment. Boulders were modeled by metal spheres with diameter D = 2.0 cm and were set in a sand layer, and the boulder occupancy ratio αdefined as (πD²/4)/ℓ2 (ℓ: boulder interval) in a square array was 0.014 - 0.087. The bed erosion velocity clearly decreased in the presence of boulders, and then, changed by the parameter α and would be the minimum around α = 0.056. In conclusion, it was found that boulders in rivers significantly stabilize bed variation, and that their effect will be great in the medium occupancy ratio. [ABSTRACT FROM AUTHOR]

When constructing subway tunnels in coastal cities, boulders with high strength and large volume are often encountered. A large number of engineering practices have shown that the existence of boulders will destroy the unity and homogeneity of the stratum. If the tunnel is not properly handled during crossing construction, it will lead to the collapse of surrounding rock; in serious cases, it may induce ground collapse, damage the surrounding buildings, and endanger the safety of people’s lives and property. Firstly, with the help of similar material simulation test, this paper reproduces the phenomenon of vault collapse and surface collapse when the tunnel passes through the boulder stratum, explores the law of stratum collapse and surface settlement caused by the boulder in the process of tunnel excavation, and puts forward the “weightlessness weak surface effect” of the boulder stratum disturbed. Then, taking the Liu-Bai inter-district tunnel project of Shenzhen Metro Line 13 as an example, Midas GTS NX numerical simulation software is used to compare and analyze the influence characteristics of surrounding rock deformation and surface settlement caused by the presence or absence of boulders in the tunnel through the stratum and verify the “weightlessness weak surface effect” of the boulder stratum disturbed. Finally, the engineering treatment measures for the Liu-Bai inter-district tunnel project of Shenzhen Metro Line 13 crossing the boulder stratum are given. The research results are of great significance to guide the prediction and treatment of collapse and surface settlement when crossing the boulder stratum in the tunnel construction project.

Rocky reefs provide complex structures in the otherwise largely sand-dominated coastal North Sea. Therefore, these reefs are highly important natural habitats for the functioning of coastal ecosystems, as they provide shelter, refuge and nursery grounds for various mobile and sessile species. In the North Sea, the spatial distribution of these habitats has been intensively investigated over recent years. However, these studies generally provide static accounts of the current state of these reef systems, but limited data exist on the temporal variations in sediment dynamics at and around natural rocky reefs. In this study, we provide observations from a multiannual time series of hydroacoustic seafloor surveys conducted at an isolated rocky reef in the North Sea. We use multibeam bathymetry and side-scan sonar backscatter data in combination with video observations, sediment sampling, and sub-bottom profiler data to assess the long-term variations of the rocky reef system. The reef is located in water depths between 11 and 17 m with an areal extent of ~0.5 km2 and is surrounded by mobile sands. The topography of the rocky reef appears to create a distinct hydrodynamic system that permits mobile sands to settle or move into bathymetrical deeper parts of the reef. Our results suggest a very dynamic system surrounding the reef with large scale scouring, sediment reworking and transport, while the shallower central part of the reef remains stable over time. We demonstrate the importance of hydrodynamics and current scouring around reefs for the local variability in seafloor properties over time. These small-scale dynamics are likewise reflected in the spatial distribution of sessile species, which are less abundant in proximity to mobile sands. The hydroacoustic mapping and monitoring of seafloor dynamics at higher spatial and temporal resolutions presents an important future direction in the study of valuable coastal habitats. [ABSTRACT FROM AUTHOR]

Local scour holes are erosional bed structures that are related to different scientific disciplines in Earth science and hydraulic engineering. Local scouring at naturally placed boulders is ubiquitous, but many competing factors make it difficult to isolate the effects of a given variable. This is especially true for local scouring at natural instream obstacles that are exposed to unsteady flow conditions in the course of flood hydrograph experiments. Experimental investigations in laboratory flumes offer the advantage that boundary conditions can be systematically varied. We present novel experimental data on the impact of the submergence ratio, hydrograph skewness, and flow intensity on local scouring at boulder-like obstacles during unsteady flow and evaluate the effect of discharge chronologies. In total, 48 flume experiments on subcritical clear-water conditions and channel degradation were performed. The experimental results reveal that local scouring dominantly occurred at the rising limb when flow depth was comparable to the obstacle size, so the obstacle was unsubmerged. The steeper the rising limb, the quicker the local scour hole matured. The experimental results are relevant for the hydraulic interpretation of local scour holes found at boulders in the field. They may be utilized as a proxy for the minimum duration of the beginning stage of a flood.

Geologic conditions and topographic setting are among the most critical factors for assessing rockfall hazards. However, other subtle features of rockfall motion may also govern the runout of rockfall debris, particularly for those sourced from massive cliffs where debris can have substantial momentum during transport. Rocks may undergo collisions with trees and talus boulders, with the latter potentially generating flyrock--launched rock pieces resulting from boulder collisions that follow distinctively different paths than the majority of debris. Collectively, these intricacies of rockfall kinematics may substantially govern the hazards expected from rockfall to both persons and infrastructure located beneath steep cliffs. Here, we investigate the kinematics, including outlier boulder and flyrock trajectories, of seismically triggered rockfalls on 24 June 2020 that damaged campground facilities near Whitney Portal, CA, a heavily used outdoor recreation gateway to the Sierra Nevada mountains. Our results, obtained in part by rockfall runout model simulations, indicate that outlier boulder trajectories resulted from opportunities provided by less steep terrain beyond the talus edge. The influence of trees, initially thought to have served a protective capacity in attenuating rockfall energy, appears to have been negligible for the large boulder volumes (>50 m3) mobilized, although they did potentially de- flect the trajectory of flyrock debris. Rockfall outlier boulders from the event were comparable in volume and runout distance to prehistoric boulders located beyond the talus slope, thereby providing some level of confidence in the use of a single rockfall shadow angle for estimating future rockfall hazards at the site. [ABSTRACT FROM AUTHOR]

Boulder falls are an archives of recent surface activity on Mars, however, determining how recently they fell remains elusive. Our multitemporal HiRISE image analysis shows that new tracks are characterized by a herringbone‐like ejecta pattern at each boulder bounce that we call boulder fall ejecta (BFE). First systematic survey of BFE revealed ∼4,500 tracks whose total integrated track length is ∼900 km. Our BFE longevity analysis reveals that these tracks likely formed in the last few decades. From few examples we also observed slope streaks originating from BFE tracks, providing additional evidence favoring a dry origin theory. BFE fade in as little as ∼2 to 4 Mars years, whereas, others can persist >6 Mars years suggesting differential weathering. Nearly 30% of BFE are observed in the Cerberus Fossae region, which suggests it is one of the most seismically active regions. Thus, BFE can be used to recognize very recent surface processes on planetary surfaces. Plain Language Summary: High‐resolution images of Mars have revealed numerous boulder falls on the surface. Here, we systematically surveyed images from 2006 to 2020 to find recent boulder falls which have ejecta. The images of the same place taken at different times, revealed that all new boulder falls have ejecta which we call boulder fall ejecta (BFE). We searched all the images and found BFE present in large numbers suggesting recent falls are common and widespread. Our results revealed that on Mars it takes ∼2 to 4 Mars years (4–8 Earth years) for BFE to disappear, whereas on Earth BFE are rarely preserved. We found that the Cerberus Fossae region adjacent to NASA's InSight lander landing site hosts nearly 30% of BFE, suggesting it is a currently active regions on Mars. Key Points: Comprehensive multitemporal HiRISE image analysis revealed all new boulder falls have ejecta along the track termed as boulder fall ejecta (BFE)Approximately 4,500 tracks with total integrated length of ∼900 km formed in last few decades, 30% BFE located in Cerberus Fossae suggests active regionSome BFE fade within 2–4 Mars year and few persist >6 Mars year, evidence for slope streaks originating from BFE tracks support dry theory [ABSTRACT FROM AUTHOR]

The marine acoustic techniques are powerful tools to investigate and identify the seabed objects by applying different processing and interpretation steps. Two types of marine acoustic imaging techniques used in this study; Side Scan Sonar (SSS) that mapping seabed features and identifies the objects on it, and Sub-Bottom Profiling (SBP) that providing information about sediment thicknesses and stratigraphic structure. The integration between these two marine acoustic techniques, as well as, ground truth data obtained from an underwater camera, was used to distinguish seabed objects; coastal boulder accumulations that are documented along the western Mediterranean coast of Egypt. The study and analysis of the collected data demonstrated that: the combination between side scan sonar, chirp sub-bottom profiling systems, and ROV images can successfully distinguish different types of objects. Generally, objects observed from SSS are indicated in the SBP as weak backscatter curves. The case study results, from analysis of SBP with ROV image to the object detected by SSS utilized three objects making a shadow in SSS seabed: boulder, hard substrate, and seagrass. The integration of these techniques resulting specifies the location of the geo-hazards area. [ABSTRACT FROM AUTHOR]

The art8icle focuses on future city, Ottawa 2120, by architect Zachary Colbert to exploring what the citizens of the meta-industrial city might produce and how they might interact with government. Topics discussed include aim to explore the politics of metaindustrial city through both the mundane moments of everyday life and possibilities of urbanism; relationship between life, work, and what it means to be a socially productive participant; and potential of tyrannical power.