In this case study we present preliminary results from a joint analysis of magnetometry data, remote sensing data, and excavation results generated in the course of research on the Early Bronze Age fortified hilltop settlement of Ratzers-dorf/Am Dachsgraben in Lower Austria. In an effort to evaluate the interpretive potential of each data set we conclude that a combined analysis of all available data is essential for a comprehensive understanding of anthropogenic and natural features and formation processes. At the Ratzersdorf site specifically, the visibility of both anthropogenic and geological structures in the magnetometry data demonstrates the importance of the combination of complementary data for the verification or falsification of preliminary interpretive ideas.

Interdisciplinary cooperation between geoelectrics and archaeology made it possible to identify a swamp as an integral part of a defense concept for the first time in Austria at the Early Bronze Age hilltop settlement of Ratzersdorf, Lower Austria. The marsh and a spring were included as natural topographic structures in the defense conception of the fortification.

The reuse of vintage datasets which were acquired in the 20th century can pose challenges for modern geophysical modeling due to missing detailed preprocessing information, significant uncertainties, or lack of precise tracking, etc. Nevertheless, they are often the only available datasets in a target region. We explore here the potential of such vintage airborne geophysical datasets (magnetics, AEM, radiometrics) to detect the location and dip direction of geological faults, using a non-modeling interpretation approach based on multiple GIS tools. We apply our approach in a geologically well-known region where four different types of faults are mapped. The applicability of the tools used in this study depend on the geological setting of each fault and is evaluated based on the comparison with geological and—where available—with modeling data. In general, the GIS tools, especially used on a combination of datasets, show reliable results concerning the location and strike of faults, and even seem to be able to predict the dip direction of a fault.

We describe here the results of the characterization of subsurface structures in an area of the south-eastern edge of the Bohemian Massif, in Austria by high-resolution geophysical survey techniques and advanced analysis methods of potential fields. The employed methods included potential field multiscale techniques for source-edge location and characterization of sources at depth. Our results confirmed the presence of already known structures: the location of the Diendorf Fault and the Moldanubian Shearzone are clearly recognized in the data at the same location as on the geological maps, even where the Diendorf fault is covered with sediments of the Molasse Basin. In addition, we detected several geological contacts between different rock types in the Bohemian Massif west of the Diendorf Fault. From our results, we were also able to quickly identify and image, without a priori information, previously unknown structures, such as faults with-depth-to-the top of about 500 m and magmatic intrusions about 400 m deep.

Continuous INSAR-monitoring of slow mass movements in the surrounding of fast (m/year) or acute processes can deliver important data complementing geomorphologic information in order to understand the broader dynamic context in which a landslide is situated. In course of the Landslide-EVO project (NERC/SHEAR funded), focusing on flood and landside risk assessment and mitigation in the Karnali river basin region in Far Western Nepal by inclusion of local community, this has been evaluated within a test of integrated monitoring methods (comprising eg. ERT, UAV-photogrammetry, D-GPS/geodesy, microseismics, soil water saturation, rainfall, and other) on regional as well as local scale at two selected sites at Bajura and Sunkoda. It was possible to derive extended information about movements in a ROI covering 120 km by 120 km. The PSI/SBAS based velocity analysis exhibits density variations due to specific slope/sensor system geometry, vegetation, data gaps, atmospheric conditions, and high velocities in the most active sites, which causes decorrelation. However, in the less active surrounding of active landslides the velocity information shows generally higher density. INSAR techniques could well complement optical image analysis in the low velocity range of centimetres to several decimetres per year, generally too slow for optical satellite image analysis in this time scale. InSAR-data has the potential to be used for estimating a slow moving masses acceleration or a deep-seated gravitational slope deformations cumulative displacement leading to a partial or total reactivation before other indication appears. It has been shown that large and difficult accessible areas can be monitored with InSAR techniques, while specific sites are equipped with corner reflectors for better signal. The study represents the first of this kind in the region and proves the ability of INSAR techniques for retrieving critical information about mass movements affecting local communities in the Karnali river basin as an example of a developing region.

PreviousNext No AccessProceedings of the 13th SEGJ International Symposium, Tokyo, Japan, 12–14 November 2018Building up a national center for Geo-Monitoring in the fields of natural hazards in Austria - a new task for a geological survey.Authors: Robert SupperMarc OstermannBirgit JochumDavid OttowitzRobert SupperGeological Survey of AustriaSearch for more papers by this author, Marc OstermannGeological Survey of AustriaSearch for more papers by this author, Birgit JochumGeological Survey of AustriaSearch for more papers by this author, and David OttowitzGeological Survey of AustriaSearch for more papers by this authorhttps://doi.org/10.1190/SEGJ2018-076.1 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract Austria’s national territory is characterized by high mountains as well by lowlands and any kind of landforms in-between. Its position within and on the brink of the Alps causes that many inhabited areas are affected by natural hazards. Dealing with different types of mass movements is one of the most challenging tasks for the Austrian administration. To provide reliable information about triggering processes and threshold values for early warning, the availability of long term, high quality monitoring data is a necessity. Therefore the Geological Survey of Austria (GBA) initiated a close collaboration with the Torrent and Avalanche Control and several universities to set up Austria’s Centre for Geo-Monitoring. Keywords: landslides, monitoring, geophysics, geoelectricPermalink: https://doi.org/10.1190/SEGJ2018-076.1FiguresReferencesRelatedDetails Proceedings of the 13th SEGJ International Symposium, Tokyo, Japan, 12–14 November 2018ISSN (online):2159-6832Copyright: 2019 Pages: 588 publication data© 2018 Published in electronic format with permission by the Society of Exploration Geophysicists of JapanPublisher:Society of Exploration GeophysicistsSociety of Exploration Geophysicists of Japan HistoryPublished Online: 29 Apr 2019 CITATION INFORMATION Robert Supper, Marc Ostermann, Birgit Jochum, and David Ottowitz, (2019), "Building up a national center for Geo-Monitoring in the fields of natural hazards in Austria - a new task for a geological survey.," SEG Global Meeting Abstracts : 292-295. https://doi.org/10.1190/SEGJ2018-076.1 Plain-Language Summary KeywordslandslidesmonitoringgeophysicsgeoelectricPDF DownloadLoading ...

PreviousNext No AccessProceedings of the 13th SEGJ International Symposium, Tokyo, Japan, 12–14 November 2018Lessons from interpretations of aeromagnetic anomalies of active volcanoesAuthors: Shigeo OkumaTadashi NakatsukaRobert SupperCarol FinnShigeo OkumaGeological Survey of Japan, AISTSearch for more papers by this author, Tadashi NakatsukaGeological Survey of Japan, AISTSearch for more papers by this author, Robert SupperGeological Survey of AustriaSearch for more papers by this author, and Carol FinnU.S. Geological SurveySearch for more papers by this authorhttps://doi.org/10.1190/SEGJ2018-143.1 SectionsAboutPDF/ePub ToolsAdd to favoritesDownload CitationsTrack CitationsPermissions ShareFacebookTwitterLinked InRedditEmail Abstract We have interpreted aeromagnetic anomalies of many active volcanoes not only in Japan but also in Italy and the USA. We review the results of these interpretations and indicate that aeromagnetic survey is a useful tool for better understanding the subsurface structures of active volcanoes. At the initial stage, forward modeling with thin structures was adapted to interpret aeromagnetic anomalies of the Yurihara area and was successful for delineating the distributions of the Kisakata Debris Avalanche Deposits in the Yurihara Plateau. Then, 2D magnetic inversion called apparent magnetization mapping was developed and was applied to the magnetic anomalies of Izu-Oshima volcano with a success in mapping of the distributions of old volcanoes on the east coast as well as lavas from the center cone, Mt. Mihara. The method was also applied to magnetic anomalies of Yellowstone National Park, USA and the resultant apparent magnetization map showed a good agreement between magnetization lows and hydrothermally altered areas. Recently 2D apparent magnetization mapping was expanded to 3D magnetic imaging and the new method was used to estimate the subsurface structures of many volcanoes. For instance, it was applied to magnetic anomalies of Stromboli volcano, Italy, indicating that the summit eruption areas correspond to magnetization lows probably because of demagnetization by heat and/or hydrothermal alteration. In 2000, Usu volcano erupted after 22-year dormancy from the 1977-1978 eruption and a high-resolution aeromagnetic survey was conducted to monitor the volcanic activity. Although the survey was successful for mapping normally magnetized Quaternary soma lavas and reversely magnetized Pleistocene volcanic rocks, features related to the ongoing volcanic activity then were not obvious by the survey. In 2010, a repeat aeromagnetic survey was conducted over the volcano and had succeeded in suggesting the existence of cooling intruded magmas of the 2010 eruption as well as 1977-1978 eruption. Keywords: Aeromagnetic survey, magnetic anomaly, magnetic interpretation, 3D magnetic imaging, repeat aeromagnetic survey, active volcanoPermalink: https://doi.org/10.1190/SEGJ2018-143.1FiguresReferencesRelatedDetails Proceedings of the 13th SEGJ International Symposium, Tokyo, Japan, 12–14 November 2018ISSN (online):2159-6832Copyright: 2019 Pages: 588 publication data© 2018 Published in electronic format with permission by the Society of Exploration Geophysicists of JapanPublisher:Society of Exploration GeophysicistsSociety of Exploration Geophysicists of Japan HistoryPublished Online: 29 Apr 2019 CITATION INFORMATION Shigeo Okuma, Tadashi Nakatsuka, Robert Supper, and Carol Finn, (2019), "Lessons from interpretations of aeromagnetic anomalies of active volcanoes," SEG Global Meeting Abstracts : 554-557. https://doi.org/10.1190/SEGJ2018-143.1 Plain-Language Summary KeywordsAeromagnetic surveymagnetic anomalymagnetic interpretation3D magnetic imagingrepeat aeromagnetic surveyactive volcanoPDF DownloadLoading ...

In disaster risk management (DRM), an emerging shift has been noted from broad‐scale, top‐down assessments toward more participatory, community‐based, bottom‐up approaches. Arguably, nonscientist local stakeholders have always played an important role in knowledge risk management and resilience building within a hydrological context, such as flood response and drought alleviation. However, rapidly developing information and communication technologies such as the Internet, smartphones, and social media have already demonstrated their sizeable potential to make knowledge creation more multidirectional, decentralized, diverse, and inclusive. Combined with technologies for robust and low‐cost sensor networks, a ‘citizen science’ approach has recently emerged as a promising direction in the provision of extensive, real‐time information for risk management. Such projects work best when there is community buy‐in, when their purpose(s) are clearly defined at the outset, and when the motivations and skillsets of all participants and stakeholders are well understood. They have great potential to enhance knowledge creation, not only for data collection, but also for analysis or interpretation. In addition, they can serve as a means of educating and empowering communities and stakeholders that are bypassed by more traditional knowledge generation processes. Here, we review the state‐of‐the‐art of citizen science within the context of hydrological risk reduction and resilience building. Particularly when embedded within a polycentric approach toward risk governance, we argue that citizen science could complement more traditional knowledge generation practices, and also enhance innovation, adaptation, multidirectional information provision, risk management, and local resilience building. WIREs Water 2018, 5:e1262. doi: 10.1002/wat2.1262 This article is categorized under: Engineering Water > Planning Water Science of Water > Water Extremes

Introduction. The Island of Socorro (Fig. 1) is located 700 km off the western coastline of Mexico at the northern Mathematicians Ridge, an abandoned mid-ocean ridge spreading centre. Together with several other islands (e.g., San Benedicto and Clarion) and numerous seamounts, the so called Revillagigedo archipelago represents post-abandonment alkaline magmatism [e.g., Taran et al. (2002) and references therein]. The last volcanic event in the area of Socorro took place in 1993 (e.g., Siebe et al., 1995), when a submarine basaltic eruption threatened the small settlement on the island. Until today, due to the remote location of the island, little knowledge is available concerning the subsurface structure of the volcanic edifice. In support of plans of the Mexican government to enlarge the settlement on the island, a combined geophysical survey was conducted in February 2009 to open up new resources for local groundwater supply. Investigations were focused on determining the resistivity structure of the shallow subsurface of the volcanic edifice, as this parameter is directly related to the water content of subsurface structures. However other parameters such as clay content, fluid conductivity and temperature control the subsurface resistivity and these parameters normally show significant variations in volcanic areas. Thus, we conducted other investigations/analyses over the island, such as airborne magnetic, electromagnetic and gamma-ray measurements in order to have an overall view of the main structural/lithological features of the island. The aim of this work is to retrieve information about the surface and subsurface geology of the island based on the analysis and interpretation of magnetic and gamma-ray airborne data, integrated with available geo-volcanological information.

Summary The generation of a map of lateral conductivity variations is a task within the framework “GEOMAGICA”, a project coordinated by ZAMG (Zentralanstalt für Meteorologie und Geodynamik). Project goal is the development of a near real-time model of geomagnetically induced currents in mid-latitude Central Europe ( Bailey R., 2017 ). It is carried out, due to the fact, that large currents also pose a threat to Austria, not only in high- latitude countries, where geomagnetic storms are more powerful and have potentially more dangerous consequences. In order to understand the interaction between geomagnetically induced currents, ground conductivity and electrical infrastructure, a map of lateral conductivity variations was built, which is outlined in this work. The herein presented project shows a new application and the value of aeroelectromagnetic data gathered recently and also over a long period in the past for an important infrastructural problem.

In the context of landslide monitoring, permanent measurements of electrical resistivity have been performed using the GEOMON4D system at several landslide sites, in combination with complementary monitoring techniques. In this study, we present the results of the resistivity data from two landslide areas, Laakirchen (Upper Austria) and Rosano (Northwest Italy). These sites are part of the geoelectrical monitoring network set up by the Geological Survey of Austria (GSA), which has been initiated in the frame of the European FP7 SafeLand project and the TEMPEL project (Austrian Science Fund, TRP 175 - N21) (R. Supper et al., 2014). The geoelectrical methods are currently employed as a routine for the investigation of the landslide body in terms of the geological/hydrogeological characterization with high spatial resolution tomographic imaging. However, temporal variations of the electrical resistivity can be informative of the modifications of slope saturation conditions occurring in the subsurface. Since one of the main precursors for landslide activation (or reactivation) is intense and prolonged precipitation, as well as the influence of underground water on slope stability, electrical resistivity monitoring supports the interpretation of near-surface infiltration processes. Variations of resistivity due to rainfall can have very small magnitude, therefore an accurate data processing method is fundamental to map these changes in the investigated subsurface. Focusing on the most intense precipitation events, the apparent resistivity data have been processed with an innovative 4D inversion algorithm (J.-H. Kim et al., 2009), developed within the cooperation between GSA and KIGAM. The result of the 4D inversion is a time-space model of electrical resistivity, achieved by inverting simultaneously consecutive acquisitions during a specific monitoring period of interest. High-resolution tomographic images obtained with this method help to identify areas in the subsurface that are most affected by saturation processes due to water infiltration.

Summary In an effort to introduce and evaluate the GREATEM system in Korean geologic condition, test airborne geophysical surveys were conducted over a known uranium deposit. The results were compared with previously available loop-loop AEM data by Hummingbird system. The main geologic feature of the test site is the phyllite formation with uranium mineralization in a graphitic zone and graphitic conductors were successfully delineated. Considering the field condition with tough topographic variation, GREATEM system seems to have better performance in terms of data acquisition and depth of investigation. Sign reversal in the GREATEM data was also observed, which can be modeled and interpreted with 3-D inversion algorithm. By this comparative study, we could convince that AEM technology is a very effective tool to the exploration of mineralized zone in Korean geologic environment.

Electrical Resistivity Tomography (ERT) has become a standard application for evaluation of structural and hydraulic properties of landslides. The technical improvement during the last few years made the method of ERT also attractive for long-term monitoring in term of regularly repeated measurements as newly developed 4-D inversion routines can assure the comparability of different ERT measurements. The interpretation of the achieved data is typically carried out qualitatively on a visual basis. In the framework of the LAMOND project (Long-Term Landslide Monitoring for Understanding of Underlying Dynamic Processes as Basis for an End-User Focused Early Warning) the abilities of numerical optimization and finite element modeling are conducted to close the gap between ERT observations and a dynamic, hydrological process model. So far, only one site could be examined and a workflow for numerical optimization of Archies law has been developed. These results will be the basis for a finite element process model which will deliver basic insights and help in decision-making for early warning systems.

Information from the application of geophysical and geotechnical methods are essential for decision makers to initiate appropriate emergency or remediation measures in case of a catastrophic landslide event. This paper summarizes all the applied measuring and monitoring methods that accompanied the catastrophic landslide event of Pechgraben (Upper Austria) in 2013 as well as the three years after the completion of major parts of the remediation work. Beside scientific aspects, the focus of the geophysical/geotechnical investigations was put on the support of decision makers. To improve the efficiency of the support for future similar landslide events, it is necessary to evaluate the applied methods in terms of their information content concerning the emergency and remediation strategy. We ended up with the conclusion that there are a few key methods providing essential information for decision makers during different time phases of the landslide event. However, for a detailed understanding of the landslide behavior and the ongoing subsurface processes, a combination of different methods is required.

In Disaster Risk Management, an emerging shift has been noted from broad-scale, top-down assessments towards more participatory, community-based, bottom-up approaches. Combined with technologies for robust and low-cost sensor networks, a citizen science approach has recently emerged as a promising direction in the provision of extensive, real-time information for flood early warning systems. Here we present the framework and initial results of a major new international project, Landslide EVO, aimed at increasing local resilience against hydrologically induced disasters in western Nepal by exploiting participatory approaches to knowledge generation and risk governance. We identify three major technological developments that strongly support our approach to flood early warning and resilience building in Nepal. First, distributed sensor networks, participatory monitoring, and citizen science hold great …