Suchergebnisse

Abstract. The town of Machu Picchu, Peru, serves the >700 000 tourists visiting Machu Picchu annually. It has grown threefold in population in the past two decades. Due to the limited low-lying ground, construction is occurring on the unstable valley slopes. Slopes range from <10° on the valley floor to >70° in the surrounding mountains. The town has grown on a delta formed at the confluence of the Alcamayo, Aguas Calientes and Vilcanota Rivers. Geohazards in and around the town of particular concern are 1) large rocks falling onto the town and/or the rail line, 2) flash flooding by any one of its three rivers, and 3) mudflows and landslides. A prototype early warning system that could monitor weather, river flow and slope stability was installed along the Aguas Calientes River in 2009. This has a distributed modular construction allowing components to be installed, maintained, salvaged, and repaired by local technicians. A diverse set of candidate power, communication and sensor technologies was evaluated. Most of the technologies had never been deployed in similar terrain, altitude or weather. The successful deployment of the prototype proved that it is technically feasible to develop early warning capacity in the town.

1. Natural and man-made hazards: their increasing importance in the end-20th century world -- One Volcanic Hazards -- 2. Volcano risk mitigation through training -- 3. Volunteer Observers Program: a tool for monitoring volcanic and seismic events in the Philippines -- 4. Monitoring and warning of volcanic eruptions by remote sensing -- 5. Volcanic hazards in Colombia and Indonesia: lahars and related phenomena -- 6. The 1985 Nevado del Ruiz eruption: scientific, social and governmental response and interaction before the event -- 7. Lahars of Cotopaxi Volcano, Ecuador: hazard and risk evaluation -- 8. Seismic monitoring of Lake Nyos, Cameroon, following the gas release disaster of August, 1986 -- Two Earthquake Hazards -- 9. Long-term seismic hazard in the Eastern Mediterranean region -- 10. The ROA Earthquake Hazard Atlas project: recent work from the Middle East -- 11. Some implications of the 1985 Mexican earthquake for hazard assessment -- Three Landslide Hazards -- 12. Lanslide hazard assessment in the context of development -- 13. The identification and mitigation of glacier-related hazards: examples from the Cordillera Blanca, Peru -- Four The 'Quiet' Hazards -- 14. Sea-level changes in China — past and future: their impact and countermeasures -- 15. Rising groundwater: a problem of development in some urban areas of the Middle East -- 16. Factors affecting losses of soil and agricultural land in tropical countries -- 17. Reduction of biodiversity — the ultimate disaster? -- Five What Can Be Done? -- 18. Policy in response to geohazards: lessons from the developed world? -- 19. Some perspectives on geological hazards -- 20. The International Decade for Natural Disaster Reduction and the Geohazards Unit at Polytechnic South West, Plymouth, UK -- Place name index.

Landslides along a 10 km reach of Thompson River south of Ashcroft, British Columbia, have repeatedly damaged vital railway infrastructure, while also placing public safety, the environment, natural resources, and cultural heritage features at risk. Government agencies, universities, and the railway industry are focusing research efforts on a representative test site — the very-slow-moving Ripley Landslide — to manage better the geohazard risk in this corridor. We characterize the landslide's form and function through hydrogeological and geophysical mapping. Field mapping and exploratory drilling distinguish 10 hydrogeological units in surficial deposits and fractured bedrock. Electrical resistivity tomography, frequency domain electromagnetic conductivity measurements, ground-penetrating radar, seismic pressure wave refraction, and multispectral analysis of shear waves; in conjunction with downhole measurement of natural gamma radiation, induction conductivity, and magnetic susceptibility provide a detailed, static picture of soil moisture and groundwater conditions within the hydrogeological units. Differences in electrical resistivity of the units reflect a combination of hydrogeological characteristics and climatic factors, namely temperature and precipitation. Resistive earth materials include dry glaciofluvial outwash and nonfractured bedrock; whereas glaciolacustrine clay and silt, water-bearing fractured bedrock, and periodically saturated subglacial till and outwash are conductive. Dynamic, continuous real-time monitoring of electrical resistivity, now underway, will help characterize water-flow paths, and possible relationships to independently monitor pore pressures and slope creep. These new hydrogeological and geophysical data sets enhance understanding of the composition and internal structure of this landslide and provide important context to interpret multiyear slope stability monitoring ongoing in the valley. ; University College Dublin

Earth Observations (EO) encompasses different types of sensors (e.g., Synthetic Aperture Radar, Laser Imaging Detection and Ranging, Optical and multispectral) and platforms (e.g., satellites, aircraft, and Unmanned Aerial Vehicles) and enables us to monitor and model geohazards over regions at different scales in which ground observations may not be possible due to physical and/or political constraints. EO can provide high spatial, temporal and spectral resolution, stereo-mapping and all-weather-imaging capabilities, but not by a single satellite at a time. Improved satellite and sensor technologies, increased frequency of satellite measurements, and easier access and interpretation of EO data have all contributed to the increased demand for satellite EO data. EO, combined with complementary terrestrial observations and with physical models, have been widely used to monitor geohazards, revolutionizing our understanding of how the Earth system works. This Special Issue presents a collection of scientific contributions focusing on innovative EO methods and applications for monitoring and modeling geohazards, consisting of four Sections: (1) earthquake hazards; (2) landslide hazards; (3) land subsidence hazards; and (4) new EO techniques and services. ; Part of this work was supported by the UK Natural Environmental Research Council (NERC) through the Centre for the Observation and Modelling of Earthquakes, Volcanoes and Tectonics (COMET, ref.: come30001) and the LICS and CEDRRIC projects (refs. NE/K010794/1 and NE/N012151/1, respectively), European Space Agency through the ESA-MOST DRAGON-4 projects (ref. 32244) and the Spanish Ministry of Economy and Competitiveness and EU FEDER funds under projects TIN2014-55413- C2-2-P and ESP2013-47780-C2-2-R.

Geomatics is the discipline of electronically gathering, storing, processing, and delivering spatially related digital information; it continues to be one of the fastest expanding global markets, driven by technology. The British Geological Survey (BGS) geomatics capabilities have been utilized in a variety of scientific studies such as the monitoring of actively growing volcanic lava domes and rapidly retreating glaciers; coastal erosion and platform evolution; inland and coastal landslide modelling; mapping of geological structures and fault boundaries; rock stability and subsidence feature analysis, and geo-conservation. In 2000, the BGS became the first organization outside the mining industry to use Terrestrial LiDAR Scanning (TLS) as a tool for measuring change; paired with a Global Navigation Satellite System (GNSS), BGS were able to measure, monitor, and model geomorphological features of landslides in the United Kingdom (UK) digitally. Many technologies are used by the BGS to monitor the earth, employed on satellites, airplanes, drones, and ground-based equipment, in both research and commercial settings to carry out mapping, monitoring, and modelling of earth surfaces and processes. Outside BGS, these technologies are used for close-range, high-accuracy applications such as bridge and dam monitoring, crime and accident scene analysis, forest canopy and biomass measurements and military applications.

Abstract. In this publication we address the lack of technical expertise in the geoscience community in the design and construction of photogrammetric systems for monitoring natural hazards at high spatio-temporal resolution. Accordingly, we provide in-depth information on the components, assembly instructions, and programming codes required to build them, making them accessible to researchers from different disciplines who are interested in 3D change detection monitoring. Each system comprises five photographic modules and a wireless transmission system for real-time image transfer. As an alternative to lidar (light detection and ranging), high-end digital cameras offer a simpler and more cost-effective solution for the generation of 3D models, especially in fixed time-lapse monitoring systems. The acquired images, in combination with algorithms that allow the creation of improved 3D models, offer change detection performance comparable to lidar. We showcase the usefulness of our approach by presenting real-world applications in the field of geohazard monitoring. Our findings highlight the potential of our method to detect pre-failure deformation and identify rockfalls with a theoretical change detection threshold of only 3–4 cm, thereby demonstrating the potential to achieve similar accuracies to lidar but at a much lower cost. Furthermore, thanks to the higher data acquisition frequency, the results show how the overlap of events that leads to an erroneous interpretation of the behaviour of the active area is minimized, allowing, for example, more accurate correlations between weather conditions and rockfall activity.

Salt deposits characterize the subsurface of Tuzla (BiH) and made it famous since the ancient times. Archeological discoveries demonstrate the presence of a Neolithic pile-dwelling settlement related to the existence of saltwater springs that contributed to make the most of the area a swampy ground. Since the Roman times, the town is reported as "the City of Salt deposits and Springs"; "tuz" is the Turkish word for salt, as the Ottomans renamed the settlement in the 15th century following their conquest of the medieval Bosnia (Donia and Fine, 1994). Natural brine springs were located everywhere and salt has been evaporated by means of hot charcoals since pre-Roman times. The ancient use of salt was just a small exploitation compared to the massive salt production carried out during the 20th century by means of classical mine methodologies and especially wild brine pumping. In the past salt extraction was practised tapping natural brine springs, while the modern technique consists in about 100 boreholes with pumps tapped to the natural underground brine runs, at an average depth of 400-500 m. The mining operation changed the hydrogeological conditions enabling the downward flow of fresh water causing additional salt dissolution. This process induced severe ground subsidence during the last 60 years reaching up to 10 meters of sinking in the most affected area. Stress and strain of the overlying rocks induced the formation of numerous fractures over a conspicuous area (3 Km2). Consequently serious damages occurred to buildings and infrastructures such as water supply system, sewage networks and power lines. Downtown urban life was compromised by the destruction of more than 2000 buildings that collapsed or needed to be demolished causing the resettlement of about 15000 inhabitants (Tatić, 1979). Recently salt extraction activities have been strongly reduced, but the underground water system is returning to his natural conditions, threatening the flooding of the most collapsed area. During the last 60 years local government developed a monitoring system of the phenomenon, collecting several data about geodetic measurements, amount of brine pumped, piezometry, lithostratigraphy, extension of the salt body and geotechnical parameters. A database was created within a scientific cooperation between the municipality of Tuzla and the city of Rotterdam (D.O.O. Mining Institute Tuzla, 2000). The scientific investigation presented in this dissertation has been financially supported by a cooperation project between the Municipality of Tuzla, The University of Bologna (CIRSA) and the Province of Ravenna. The University of Tuzla (RGGF) gave an important scientific support in particular about the geological and hydrogeological features. Subsidence damage resulting from evaporite dissolution generates substantial losses throughout the world, but the causes are only well understood in a few areas (Gutierrez et al., 2008). The subject of this study is the collapsing phenomenon occurring in Tuzla area with the aim to identify and quantify the several factors involved in the system and their correlations. Tuzla subsidence phenomenon can be defined as geohazard, which represents the consequence of an adverse combination of geological processes and ground conditions precipitated by human activity with the potential to cause harm (Rosenbaum and Culshaw, 2003). Where an hazard induces a risk to a vulnerable element, a risk management process is required. The single factors involved in the subsidence of Tuzla can be considered as hazards. The final objective of this dissertation represents a preliminary risk assessment procedure and guidelines, developed in order to quantify the buildings vulnerability in relation to the overall geohazard that affect the town. The historical available database, never fully processed, have been analyzed by means of geographic information systems and mathematical interpolators (PART I). Modern geomatic applications have been implemented to deeply investigate the most relevant hazards (PART II). In order to monitor and quantify the actual subsidence rates, geodetic GPS technologies have been implemented and 4 survey campaigns have been carried out once a year. Subsidence related fractures system has been identified by means of field surveys and mathematical interpretations of the sinking surface, called curvature analysis. The comparison of mapped and predicted fractures leaded to a better comprehension of the problem. Results confirmed the reliability of fractures identification using curvature analysis applied to sinking data instead of topographic or seismic data. Urban changes evolution has been reconstructed analyzing topographic maps and satellite imageries, identifying the most damaged areas. This part of the investigation was very important for the quantification of buildings vulnerability.

In this paper, we review both practical and theoretical assessments for evaluating radon geohazards from permafrost landforms in northern environments (>60º N). Here, we show that polar amplification (i.e. climate change) leads to the development of thawing permafrost, ground subsidence, and thawed conduits (i.e. Taliks), which allow radon migration from the subsurface to near surface environment. Based on these survey results, we conjecture that abruptly thawing permafrost soils will allow radon migration to the near surface, and likely impacting human settlements located here. We analyze potential geohazards associated with elevated ground concentrations of natural radionuclides. From these results, we apply the main existing legislation governing the control of radon parameters in the design, construction and use of buildings, as well as existing technologies for assessing the radon hazard. We found that at present, these laws do not consider our findings, namely, that increasing supply of radon to the surface during thawing of permafrost will enhance radon exposure, thereby, changing prior assumptions from which the initial legislation was determined. Hence, the legislation will likely need to respond and reconsider risk assessments of public health in relation to radon exposure. We discuss the prospects for developing radon geohazard monitoring, methodical approaches, and share recommendations based on the current state of research in permafrost effected environments.

Abstract. Coal mines in the western areas of China experience low mining rates and induce many geohazards when using the room and pillar mining method. In this research, we proposed a roadway backfill method during longwall mining to target these problems. We tested the mechanical properties of the backfill materials to determine a reasonable ratio of backfill materials for the driving roadway during longwall mining. We also introduced the roadway layout and the backfill mining technique required for this method. Based on the effects of the abutment stress from a single roadway driving task, we designed the distance between roadways and a driving and filling sequence for multiple-roadway driving. By doing so, we found the movement characteristics of the strata with quadratic stabilization for backfill mining during roadway driving. Based on this research, the driving and filling sequence of the 3101 working face in Changxing coal mine was optimized to avoid the superimposed influence of mining-induced stress. According to the analysis of the surface monitoring data, the accumulated maximum subsidence is 15 mm and the maximum horizontal deformation is 0.8 mm m−1, which indicated that the ground basically had no obvious deformation after the implementation of the roadway backfill method at 3101 working face.

This work assesses the feasibility of national ground deformation monitoring of Great Britain using synthetic aperture radar (SAR) imagery acquired by Copernicus' Sentinel-1 constellation and interferometric SAR (InSAR) analyses. As of December 2016, the assessment reveals that, since May 2015, more than 250 interferometric wide (IW) swath products have been acquired on average every month by the constellation at regular revisit cycles for the entirety of Great Britain. A simulation of radar distortions (layover, foreshortening, and shadow) confirms that topographic constraints have a limited effect on SAR visibility of the landmass and, despite the predominance of rural land cover types, there is potential for over 22,000,000 intermittent small baseline subset (ISBAS) monitoring targets for each acquisition geometry (ascending and descending) using a set of IW image frames covering the entire landmass. Finally, InSAR results derived through ISBAS processing of the Doncaster area with an increasing amount of Sentinel-1 IW scenes reveal a consistent decrease of standard deviation of InSAR velocities from 6 mm/year to ≤2 mm/year. Such results can be integrated with geological and geohazard susceptibility data and provide key information to inform the government, other institutions and the public on the stability of the landmass.

Volume 2: Handbook of Spatio-Temporal Monitoring of Water Resources and Climate is aimed to describe the current state of knowledge and developments of geospatial technologies (Remote Sensing and Geographic Information Systems) for assessing and managing water resources under climate change. It is a collective achievement of renowned researchers and academicians working in the Hindu Kush Himalayan (HKH) mountain range. The HKH region is a part of the Third Pole outside the polar regions due to its largest permanent snow cover. Importantly, the Himalayan belt is geologically fragile and vulnerable to geohazards (e.g. landslides, land subsidence, rockfalls, debris flow, avalanches, and earthquakes). Therefore, critical assessment and geospatial solutions are indispensable to safeguard the natural resources and human beings in the Himalayas using space-borne satellite datasets. This book also showcases various remote sensing techniques and algorithms in the field of urban sprawling, urban microclimate and air pollution. The potential impacts of climate change on the cryosphere and water resources are also highlighted. This comprehensive Handbook is highly interdisciplinary and explains the role of geospatial technologies in studying the water resources of the Himalayas considering climate change. Key Features This book is unique as it focuses on the utility of satellite data for monitoring snow cover variability, snowmelt runoff, glacier lakes, avalanche susceptibility and flood modeling. Explain how Remote Sensing techniques are useful for mapping and managing the morphology and ecology of the Himalayan River. Addresses how geospatial technologies are valuable for understanding climate change impact on hydrological extremes, the potential impact of land use/land cover change (LULC) on hydrology and water resources management. It highlights the impact of LULC changes on land surface temperature, groundwater, and air pollution in urban areas. Includes contributions from global professionals working in the HKH region. Readership The Handbook serves as a valuable reference for students, researchers, scientists, Hydrologists, hydro-ecologists, meteorologists, geologists, decision makers and all others who wish to advance their knowledge on monitoring and managing water resources and urban ecosystem using remote sensing in the HKH region considering climate change.

Destructive shaking movements triggered by earthquakes can cause significant losses such as human sacrifice, house damage and property loss. Sichuan earthquake of 2008, happened in southwestern China, caused over 69,000 death and 374,176 injured[1]. It is not just the earthquake itself that is deadly, the subsequent debris flows and plagues deprived more lives. For instance, outbreaks of the Plague of Justinian occur months or even up to a year after high-magnitude earthquakes. Large earthquakes initiate chains of surface and underground processes that last much longer than the brief moments of strong shaking [2]. Earthquake induced geohazards, including landslides in mountainous regions, floods from temporary lakes, plague after major rainfalls, remain a significant threat[2]. Even extreme geohazard like volcanic eruption can be triggered by earthquakes. An apparent question is raised: 'what if we can predict shaking with previous seconds of warning once an earthquake rupture begins?'. Earthquake early warning (EEW) system shows us the answer, using seismic knowledge and the technology of monitoring systems to alert devices when shaking waves generated by an earthquake appeared (USGS, 2012). Accurate prediction of earthquake can give people more time to prepare for shaking and the geohazard events it triggers. Governments should provide more resources to EEW to reduce earthquake damage to people and property, especially in poor countries where the education about disaster prevention is immature.

In the European Union (EU) project Terrafirma, which is supported by the European Space Agency to stimulate the Global Monitoring Environment System, we are using the latest technology to measure terrain motion on the basis of satellite radar data. The technique we employ is known as persistent scatterer interferometry (PSI); in Denmark, it was previously used to map areas of subsidence susceptible to flooding in the Danish part of the Wadden Sea (Vadehavet) area (Pedersen et al. 2011). That study was part of the flooding risk theme under the TerraFirma Extension project. Another coastal protection monitoring activity in the EU seventh framework project SubCoast followed, in which the low-lying south coast of Lolland, prone to flooding, was studied. The Geological Survey of Denmark and Greenland (GEUS) is also involved in the three-year EU collaborative project PanGeo in which GEUS is one of 27 EU national geological surveys. The objective of PanGeo is to provide free and open access to geohazard information in support of the Global Monitoring Environment System. This will be achieved by providing a free, online geohazard information service for the two largest cities in each EU country, i.e. 52 towns throughout Europe with c. 13% of EU's population.

Abstract. Rockfall is a complex natural process that can present risks to
the effective operation of infrastructure in mountainous terrain. Remote
sensing tools and techniques are rapidly becoming the state of the practice in
the characterization, monitoring and management of these geohazards. The aim
of this study is to address the methods and implications of how the
dimensions of three-dimensional rockfall objects, derived from sequential
terrestrial laser scans (TLSs), are measured. Previous approaches are
reviewed, and two new methods are introduced in an attempt to standardize
the process. The approaches are applied to a set of synthetic rockfall
objects generated in the open-source software package Blender. Fifty
rockfall events derived from sequential TLS monitoring in the White Canyon,
British Columbia, Canada, are used to demonstrate the application of the
proposed algorithms. This study illustrates that the method used to
calculate the rockfall dimensions has a significant impact on how the shape
of a rockfall object is classified. This has implications for rockfall
modelling as the block shape is known to influence rockfall runout.

Abstract. Gully-type debris flow induced by high-intensity and short-duration rainfall
frequently causes great loss of properties and causalities in mountainous
regions of southwest China. In order to reduce the risk by geohazards, early
warning systems have been provided. A triggering index can be detected in an
early stage by the monitoring of rainfall and the changes in physical
properties of the deposited materials along debris flow channels. Based on the
method of critical pore pressure for slope stability analysis, this study
presents critical pore pressure threshold in combination with rainfall
factors for gully-type debris flow early warning. The Wenjia gully, which
contains an enormous amount of loose material, was selected as a case study
to reveal the relationship between the rainfall and pore pressure by field
monitoring data. A three-level early warning system (zero, attention, and
warning) is adopted and the corresponding judgement conditions are defined in
real time. Based on this threshold, there are several rainfall events in
recent years have been validated in Wenjia gully, which prove that such a
combined threshold may be a reliable approach for the early warning of
gully-type debris flow to safeguard the population in the mountainous areas.