Data acquisition by digitizing 2-D fracture networks and topographic lineaments in geographic information systems: further development and applications

Understanding the impact of fracture networks on rock mass properties is an essential part of a wide range of applications in geosciences from understanding permeability of groundwater aquifers and hydrocarbon reservoirs to erodibility properties and slope stability of rock masses for geotechnical engineering. However, gathering high-quality, oriented-fracture datasets in the field can be difficult and time-consuming, for example, due to constraints on field work time or access (e.g. cliffs). Therefore, a method for obtaining accurate, quantitative fracture data from photographs is a significant benefit. In this paper we describe a method for generating a series of digital fracture traces in a geographic information system (GIS) environment, in which spatial analysis of a fracture network can be carried out. The method is not meant to replace the gathering of data in the field but to be used in conjunction with it, and it is well suited when field work time is limited or when the section cannot be accessed directly. The basis of the method is the generation of the vector dataset (shapefile) of a fracture network from a georeferenced photograph of an outcrop in a GIS environment. From that shapefile, key parameters such as fracture density and orientation can be calculated. Furthermore, in the GIS environment more complex spatial calculations and graphical plots can be carried out such as heat maps of fracture density. Advantages and limitations compared to other fracture network capture methods are discussed

Drag forces at the ice-sheet bed and resistance of hard-rock obstacles:The physics of glacial ripping

Glacial ripping involves glaciotectonic disintegration of rock hills and extensive removal of rock at the ice-sheet bed, triggered by hydraulic jacking caused by fluctuating water pressures. Evidence from eastern Sweden shows that glacial ripping caused significant subglacial erosion during the final deglaciation of the Fennoscandian ice sheet, distinct from abrasion and plucking (quarrying). Here we analyse the ice drag forces exerted onto rock obstacles at the base of an ice sheet, and the resisting forces of such rock obstacles: glaciotectonic disintegration requires that ice drag forces exceed the resisting forces of the rock obstacle. We consider rock obstacles of different sizes, shapes and fracture patterns, informed by natural examples from eastern Sweden. Our analysis shows that limited overpressure events, unfavourable fracture patterns, low-Transmissivity fractures, slow ice and streamlined rock hamper rock hill disintegration. Conversely, under fast ice flow and fluctuating water pressures, disintegration is possible if the rock hill contains subhorizontal, transmissive fractures. Rock steps on previously smooth, abraded surfaces, caused by hydraulic jacking, also enhance drag forces and can cause disintegration of a rock hill. Glacial ripping is a physically plausible erosion mechanism, under realistic glaciological conditions prevalent near ice margins.</p

Разработка технологии и проектирование оснастки и участка сборки-сварки основания дробилки ДР-1000Ю.64

Целю работы является разработка технологии изготовления основания дробилки ДР-1000Ю.64. и проектирование участка сборки-сварки изделия. В процессе выполнения работ проводились изучение составных деталей изделия, определение марки стали, выбор метода сварки, определение режимов сварки и сварочных материалов, нормирование операций, составление технологического процесса, расчет необходимого количество оборудования и численности рабочих. В результате выполнения работ рассчитаны режимы сварки, подобрано сварочное оборудование, пронумерованы сборочно-сварочные операции.Purpose of work. The aim of the work is to develop a crusher base manufacturing technology and design a product assembly-welding area. In the process of performing the work, the study of the component parts of the product, determination of the steel grade, selection of the welding method, determination of welding modes and welding materials, standardization of operations, preparation of the technological process, calculation of the required number of equipment and the number of workers were carried out. As a result of the work, the welding modes were calculated, the welding equipment was selected, the assembly and welding operations were normalized. The coefficient of the received costs has been calculated

Rock fracturing by subglacial hydraulic jacking in basement rocks, eastern Sweden: the role of beam failure

Dense networks of dilated fractures occur locally in the upper 5–15 m of bedrock in basement gneisses in eastern Sweden. Near Forsmark, pre-existing sub-horizontal fractures have been jacked open and filled with water-lain sediment, likely during the latest Weichselian glaciation. Despite extensive previous research, it is uncertain whether subglacial hydraulic jacking led to the generation of new fractures, in addition to reactivation of pre-existing ones. Re-analysis of historic photos from excavations near the Forsmark power plant indicates formation of two types of new fracture. Firstly, rock fragments were broken off the main fracture surfaces as existing fractures were jacked open. Secondly, fracture analysis shows that whilst few subvertical fractures occur above tight sub-horizontal fractures, a higher density of vertical fractures occurs above dilated sub-horizontal fractures, suggesting new formation. We apply a model of beam failure theory, borrowed from structural engineering, to constrain potential new fracture generation, using assumptions based on measured water pressure fluctuations from beneath the Greenland Ice Sheet. This modelling shows that beam failure is a plausible mechanism for the generation of new vertical fractures during a subglacial water fluctuation cycle under a range of realistic glaciological conditions. This implies that hydraulic jacking can result in further in situ disruption and brecciation of the shallow rock mass, decreasing the rock mass strength and increasing its hydraulic conductivity. Altogether, hydraulic jacking of existing fractures and the formation of new vertical fractures results in effective subglacial mechanical weathering of the shallow rock mass

Drag forces at the ice-sheet bed and resistance of hard-rock obstacles: the physics of glacial ripping

Glacial ripping involves glaciotectonic disintegration of rock hills and extensive removal of rock at the ice-sheet bed, triggered by hydraulic jacking caused by fluctuating water pressures. Evidence from eastern Sweden shows that glacial ripping caused significant subglacial erosion during the final deglaciation of the Fennoscandian ice sheet, distinct from abrasion and plucking (quarrying). Here we analyse the ice drag forces exerted onto rock obstacles at the base of an ice sheet, and the resisting forces of such rock obstacles: glaciotectonic disintegration requires that ice drag forces exceed the resisting forces of the rock obstacle. We consider rock obstacles of different sizes, shapes and fracture patterns, informed by natural examples from eastern Sweden. Our analysis shows that limited overpressure events, unfavourable fracture patterns, low-transmissivity fractures, slow ice and streamlined rock hamper rock hill disintegration. Conversely, under fast ice flow and fluctuating water pressures, disintegration is possible if the rock hill contains subhorizontal, transmissive fractures. Rock steps on previously smooth, abraded surfaces, caused by hydraulic jacking, also enhance drag forces and can cause disintegration of a rock hill. Glacial ripping is a physically plausible erosion mechanism, under realistic glaciological conditions prevalent near ice margins

Mapping landslides from space: a review

Landslide hazards have significant social, economic, and environmental impact. This work provides a critical review of the main existing literature using satellite data for mapping landslides. We created and examined an extensive bibliographic database from Web of Science (WoS) consisting in 291 outputs from > 1,000 authors who studied almost 700,000 landslides across all continents, for a total of 52 countries represented with China and Italy on top of the list with more authors. The outputs are equivalent to ~ 5% of the whole landslide-related production for the period 1996–2022, with a 600% increase in the number of papers after 2014 driven by the availability of Sentinel-1 and Sentinel-2 data. Analysis of the geographical location across the 66 different countries analysed shows that, within the total number of contributions, the satellite imagery was used to detect and map two main types of landslides: flows and slides. When specified in the manuscripts, the events have been triggered by rainfall (104 cases), earthquakes (32 cases), or both (17 cases). Slope instabilities in these areas were predominantly identified through manual detection (40%); but since 2020, the advent of artificial intelligence is suppressing all other techniques. Despite the undisputed progress of EO-based landslide mapping over the last 26 years, which makes it a consolidated tool for many landslide-related applications, challenges still remain for an effective and operational use of EO images for landslide detection and mapping, and we provide a perspective for future applications considering the existing and the planned SAR satellite missions

Understanding geological hazards to support disaster risk assessment in Indonesia : a report on a collaborative workshop between Resilience Development Initiative and the British Geological Survey

Indonesia encompasses one of the most active tectonic regions on Earth. Geological hazards in the country are a potent threat to a large and vulnerable population. It is therefore important that decisions made by disaster managers are informed by the best available earth science. However, large areas remain unstudied, with limited knowledge of past behaviour impacting understanding of future hazards and risks. To understand the challenges and research opportunities related to natural hazards in Indonesia, the Resilience Development Initiative (RDI) and British Geological Survey (BGS) organised a collaborative workshop over two days in January 2022. The workshop provided an opportunity to bring together key stakeholders in disaster risk science and management in Indonesia. The workshop aimed to discuss and offer a forum to explore research needs in terms of understanding, measuring, mitigating, and modelling geological hazards in Indonesia, with a specific focus on earthquakes, landslides, volcanoes and tsunamis. The main findings from this exercise are summarised below. Fundamental hazard assessment. A common theme across the four geological hazards discussed was the need to improve fundamental hazard assessments. For earthquakes, this involves improving the understanding of crustal faults at the local level and feeding this into national hazard assessment exercises. For landslides, a significant challenge raised was the resolution of susceptibility maps. There is a need to produce local hazard assessments considering local geological and environmental conditions. For volcanoes, the challenges were around understanding how past activity can be used to inform understanding of future hazards. However, participants agreed that it is difficult to understand the potential range of activity at infrequently active volcanoes, making hazard assessment more challenging. The main challenge for tsunamis was understanding the relative importance of various tsunami mechanisms. Earthquake-triggered tsunamis are relatively well understood compared to tsunamis triggered by volcanic eruptions and sediment movement. Baseline geological data. High-quality, up-todate, and complete data are the foundation of the best quality science. It is therefore imperative to collect and manage baseline data. For hazard assessments, there is a clear need for geological data to provide knowledge of past events and understand the possible future activity. Key points were raised around data availability and accessibility, where datasets are stored and who is responsible for storing, maintaining, and sharing data. An important first step to improving knowledge of hazards is to first determine how much data exists and where there are data gaps that can be filled through collaborative research. Collaboration and interdisciplinary working. Disaster Risk Reduction (DRR) challenges require a holistic approach to hazard research and management. Common across all hazards is the need to work across different groups, from researchers to stakeholders and local communities, and across disciplines of science and education, in cluding geology, engineering, sociology, and psychology, among others. Collaboration in every aspect of geological hazard monitoring in Indonesia is crucial among stakeholders. Integration between researchers, government, community and media is needed to close the gap between geological hazards research and community risk perception. Community and culture. Indonesia is a vast country with different communities and cultures. In some communities, there may be a tendency for people to trust local beliefs over official sources such as local scientists or the government. Researchers need to understand and respect the different structures that exist in different communities and find appropriate ways of communicating that are sensitive to these dynamics. Involving communities in the scientific process is a critical way of embedding a safety culture into communities. Transient populations such as displaced peoples, tourists and migrants were identified as particularly vulnerable to geological hazards. Understanding how to reduce the risk to these populations is an important research gap. Communication and engagement. Communication could be improved by involving communities in the scientific process, co-developing outreach and education programs for schools and communities, and through the use of citizen science tools. Additionally, exploring the use of storytelling through traditional art, poems, songs, stories, and films can be a way of raising awareness of hazards and remembering and learning from past events. Institutional responsibilities. The DRR lifecycle from hazard monitoring to crisis response requires precise coordination, collaboration, and division of responsibilities. Making progress on hazard science requires an understanding of institutional roles and responsibilities, and clarity on mandates and relationships between different government organisations and research institutions