The global increase in damaging landslide events is raising the attention of governments, practitioners and scientists to develop functional, reliable and (when possible) low cost monitoring strategies. Several case studies have demonstrated how a well-planned monitoring system of landslides is of fundamental importance for long and short-term risk reduction.
Today, the temporal evolution of a landslide is addressed in several ways, encompassing classical and more complex in situ measurements or remotely sensed data acquired from satellite and aerial platforms. All these techniques are adopted for the same final scope: measure landslide motion over time, trying to forecast its future evolution or at least to reconstruct its recent past. Real time, near-real time and deferred time strategies can be profitably used for landslide monitoring, depending on the type of phenomenon, the selected monitoring tool and the acceptable level of risk.
The session follows the general objectives of the International Consortium on Landslides, namely: (i) promote landslide research for the benefit of society, (ii) integrate geosciences and technology within the cultural and social contexts to evaluate landslide risk, and (iii) combine and coordinate international expertise.
Considering these key conceptual drivers, we aim to present successful monitoring experiences worldwide based on both in situ and/or remotely sensed data. The integration and synergic use of different techniques is welcome, as well as newly developed tools or data analysis approaches (focusing on big data management). We expect case studies in which multi-temporal and multi-platform monitoring data are exploited for risk management and Civil Protection aims with positive effects in social and economic terms.

Convener: Lorenzo SolariECSECS | Co-conveners: Corey Froese, Peter Bobrowsky, Davide Bertolo, Mateja Jemec Auflič, Federico Raspini, Veronica Tofani
| Attendance Thu, 07 May, 10:45–12:30 (CEST)

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Chat time: Thursday, 7 May 2020, 10:45–12:30

Chairperson: Lorenzo Solari
D1852 |
Nicușor Necula, Kami Mohammadi, Mostafa Khoshmanesh, and Domniki Asimaki

As urbanized areas increasingly expand into mountainous terrains and climate change accentuates extreme weather conditions (rainfall or drought), slow-moving landslides increasingly threaten the resilience of infrastructure systems. Referred to as creeping landslides, these features may appear benign but can abruptly turn into catastrophic failures and debris flows during heavy rainfall or an earthquake. Because of the spatial extent and time evolution of ground deformation risk, conventional observation techniques such as site surveying, that rely on human resource availability and involve safety considerations, cannot be used to identify precursors of impending failures. Instead, remote sensing techniques for landslide monitoring such as differential SAR Interferometry (DInSAR) allow the spatiotemporal retrieval of surface changes with millimeter accuracy. We here test the reliability of repeat-pass interferometry techniques coupled with numerical models of creep to quantify the time-dependent deformations of a landslide in the Bel Air district of Los Angeles, USA. We validate our measurements and predictions by comparison with in-situ deformation profiles, and provide detailed representations of ground surface and subsurface displacements, along with the relationship between environmental factors and material properties. The wealth of in-situ measurements and site characterization data at the site improves our understanding of deformation precursors that can be used to minimize the risk posed to communities by slow-moving landslides.

How to cite: Necula, N., Mohammadi, K., Khoshmanesh, M., and Asimaki, D.: Time-dependent investigation of a slow-moving landslide in Los Angeles, CA, through SAR observations and numerical simulations, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-12196, https://doi.org/10.5194/egusphere-egu2020-12196, 2020.

D1853 |
Tiggi Choanji, Michel Jaboyedoff, Marc-Henri Derron, Li Fei, and Chunwei Sun

As a growing city, Batam Islands has an immense potential to become one of the strategic positions in Southeast Asia. However, as the city developed, it also followed with the deformation and potential areas which has prone to shallow landslides. Using 32 Sentinel-1A Satellite Images Data and 17 years of Optical images data, analysis of time series is conducted using Persistent Scattered Interferometry method and mapped for landslide events in the Islands. As a result, several regions impacted 4 – 10 mm/year of velocity deformation in the center part of the island and several locations simulated to be prone to shallow landslide. So, by coupling method of SAR data and optical images, has giving prominent possibility for detecting and predicting hazard potential in this island.

How to cite: Choanji, T., Jaboyedoff, M., Derron, M.-H., Fei, L., and Sun, C.: Images Time Series Analysis for Land Deformation and Mapping Shallow Landslides based on SENTINEL - 1 and Optical Satellite Images Data: Case Study on Batam Island, Indonesia, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5018, https://doi.org/10.5194/egusphere-egu2020-5018, 2020.

D1854 |
Pierluigi Confuorto, Silvia Bianchini, Davide Festa, Federico Raspini, and Nicola Casagli

Continuous monitoring of the Earth surface is fundamental for the development and the evolution of the society, to reduce the risks posed by major geo-hazards like landslides, subsidence and sinkholes, which have a large impact on urban areas and can cause direct and indirect socio-economic losses. The start of spaceborne Synthetic Aperture Radar systems represented a milestone for the control of the territory, since SAR-based monitoring enables accurate measurement of the surface deformation over large areas, with a frequency dependent on the revisit time of the satellites. In this sense, the launch of the European Space Agency Sentinel-1 mission, characterized by a 6-days repeat pass, portrayed a great innovation and a step towards near-real-time monitoring. In this work, we present the first results of the continuous monitoring of the Veneto region (Northeastern Italy) performed by means of Sentinel-1 data, in the framework of an operational monitoring service. The procedure applied is based on a systematic processing chain made of four steps: i) Continuous generation of Sentinel-1 ground deformation maps, providing Measurement Points (MP) characterized by annual average velocity (mm/yr) and displacement Time Series (TS); ii) TS screening and classification, applied after each new satellite acquisition, to identify any change in the deformation pattern, according to a selected threshold; iii) constant update of the “anomalies” and their classification, according to the type of deformation; iv) warning to local authorities, in case of persistent and significant anomalous trends which require further investigations and field surveys. Its first application on the Veneto region shows promising outcomes, evidencing those areas characterized by movements that can be detected by SAR satellites. A few examples of this operational procedure are here shown, such as the cases of Lamosano, where a translational slide involves the local village, or of Recoaro Terme, where the Mt. Rotolon landslide is constantly studied. Moreover, subsidence is also a major threat in Veneto region, testified by the long-term phenomena of the NE plain (Verona and Vicenza provinces) and by the city of Venice, where the interaction of tides and subsidence causes the periodical flooding (“acqua alta”) of the renowned UNESCO site. The presented results want to demonstrate that the constant and continuous monitoring of the territory through Sentinel-1 data represents a best practice for the detection of ground deformation events, aiming at the natural risk mitigation for the development of the human environment.

How to cite: Confuorto, P., Bianchini, S., Festa, D., Raspini, F., and Casagli, N.: Continuous monitoring of ground deformational scenario of Veneto region (Italy) through Sentinel-1 data, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-3648, https://doi.org/10.5194/egusphere-egu2020-3648, 2020.

D1855 |
Nathan Magnall, Adam Thomas, and Rachel Holley

Recent mining disasters, such as the collapse of the Brumadinho tailings dam in Brazil, have placed intense pressure on mining companies to effectively monitor their active and historical assets. Particular focus has been placed on none-profit generating aspects of mines, specifically tailings storage facilities (TSFs). These may be poorly monitored, not routinely maintained, and of unknown construction. Remote sensing techniques present an attractive option for monitoring such facilities, reducing the need for the deployment of expensive ground monitoring systems and personnel.

Here we demonstrate how satellite InSAR can be used as an effective remote monitoring solution for both active and inactive TSFs. InSAR is a powerful tool for mining companies, allowing for both frequent ongoing monitoring and, somewhat uniquely, the ability to look at historical deformation and perform post-event analysis. Furthermore, the increasing availability of satellite data, both commercial and open-access, means that regular monitoring programs are increasingly feasible and economically viable.

The application of InSAR across a mine is by no means without challenges. Active sites typically suffer from poor coherence due to mine activities, while closed sites can be heavily vegetated which further impacts coherence. Despite these challenges, InSAR can be a highly effective component of a mine monitoring program, particularly when integrated with ground based systems.

How to cite: Magnall, N., Thomas, A., and Holley, R.: InSAR as an operational tool for remote mine monitoring, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-2394, https://doi.org/10.5194/egusphere-egu2020-2394, 2020.

D1856 |
Susanne Wahlen, Lorenz Meier, and Gian Darms

We present an operational innovative early warning system for real-time rockfall detection with automatic road closure and simultaneous slope monitoring for a rockfall prone section of Axenstrasse in Central Switzerland. The comprehensive monitoring system combines various technologies, including interferometric radar, Doppler radar, seismic sensors, high-resolution deformation cameras, combi-motion sensors and various webcams, to achieve maximum detection reliability at minimal closing time for waiting traffic.

The Axenstrasse is a scenic road section along Lake Lucerne with an average traffic volume of 16,000 vehicles a day. On 18 July 2019, heavy rainfall triggered a small debris flow in the steep Gumpisch valley and released a large boulder. The 12-ton boulder crossed the road fortunately without causing any significant damage. The road operator closed the route immediately for safety reasons; large debris accumulations of a previous rockfall remained in the upper Gumpisch valley and further similar events are very likely. In an effort to reopen the important traffic axis as soon as possible, we developed, installed and commissioned an alarm system with automatic traffic control within only a few weeks.

The system combines two different types of technologies: First, sensors for real-time detection of fast movements and second, techniques for long-term monitoring of surface deformation. For reliable rockfall detection, we use a combination of long-range Doppler radar technology and high-sensitivity seismic sensors to minimize false alarm rates while maintaining high probability of detection. The rockfall radar remotely detects moving debris or large boulders whereas the seismic sensors recognise rockfall based on ground motion. Both technologies work in real time and independent of visibility conditions (day/night, fog, snowfall). At a suitable rock spur, we installed two rockfall radars, one facing up and one down the valley, and three seismic sensors in an array.

Given the short warning time of around 20-30 seconds, it is vital to close the road immediately once an event is detected. However, many events remain small and never reach the road. In order to avoid unnecessary road closures for minor events, we equipped the protection nets above the road with combi-motion sensors that automatically detect an impact by a boulder or a debris flow passage. The system automatically reopens the road after 2 minutes, if an event was detected in the upper part, but no impact was recorded in the nets. In this way, we can guarantee road safety and avoid long closure times. 

For long-term slope monitoring, we installed an interferometric radar with autonomous power supply for permanent, sub-mm monitoring of the rock face where rockfall initially occurred. Further, two deformation cameras observe the gully and provide daily surface deformation analyses through automatic comparison of high-resolution imagery. This type of data allows to identify unstable zones and detect a potential acceleration early.

All sensor data and camera imagery are continuously transmitted to an online data portal for user access at any time via PC, tablet or smartphone.

How to cite: Wahlen, S., Meier, L., and Darms, G.: Rockfall Alarm System with Automatic Road Closure/Reopening and long-term Slope Monitoring for major European North-South Route (Axenstrasse), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5138, https://doi.org/10.5194/egusphere-egu2020-5138, 2020.

D1857 |
Andy Take, Nancy Berg, and Toshikazu Hori

Point cloud data capturing ground surface elevation at two instants in time are commonly used to identify the occurrence of landslides, identify their spatial extent, and to provide an estimate of the volume of depletion/accretion. In this study, it is hypothesized that this same point cloud data has the potential to yield much more valuable quantitative information regarding landslide behaviour, including the direction, magnitude, and rate of surface displacement.  Given point cloud data contains roughness information, shaded projections (hillshade images) of the slope at two or more instants in time can be processed using digital image correlation (DIC) to track displacement in the plane of the projection. If multiple view angles are used to generate the hill shade images, 3D surface displacements of the landslide surface should theoretically be resolved. Furthermore, if point clouds are generated with sufficiently high temporal resolution, it should be possible to estimate the time to failure. We explore this hypothesis in field experiment conducted in Tsukuba, Japan in which we bring a 3.5 m high earth dam to shear failure under high reservoir levels and extreme rainfall. Point clouds of the downstream dam surface generated at high temporal resolution were successfully used to calculate the 3D displacement of the dam surface, and to calculate the time of failure using the inverse-velocity method to within four minutes of the observed slope failure.

How to cite: Take, A., Berg, N., and Hori, T.: Can point cloud data be used to calculate time to failure of a landslide?, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-20356, https://doi.org/10.5194/egusphere-egu2020-20356, 2020.

D1858 |
Alexandra Royer, Mathieu Le Breton, Antoine Guillemot, Noélie Bontemps, Eric Larose, Laurent Baillet, Denis Jongmans, Fabrice Guyoton, Michel Jaboyedoff, and Raphael Mayoraz

Monitoring landslides is essential to understand their dynamics and to reduce the risk of human losses by detecting precursors before failures. In general, surface observations need to be complemented by observation at depth, in the bulk of the material. A decade ago, the ambient seismic noise interferometry method was proposed to monitor changes in the seismic surface wave velocity. As seismic wave velocities are directly related to the rigidity of the material, any reduction of seismic velocity can be associated to a loss of rigidity with high probability (a route toward soil liquefaction or to high fracturation). This technique led to detect a velocity decrease several days before the failure of a clayey landslide [1], paving the way to a novel precursor signal that could serve for alert or early warning systems. Here we report at least five different landslides that have been monitored, over several years [2]. In this paper, we detail the standard experimental configuration, the basic signal processing procedure, the sensitivity and resolution of the method, together with its advantages and possible limitations. Environmental effects on the relative seismic velocity change are discussed.

In order to make the technology operational for decision makers, we built an online application with web portal displaying daily evolution of seismic velocity variation. This portal also integrates other available observations like environmental parameters (weather, precipitations) or surface observation (photogrammetry, gps, extensometers…).

[1] G. Mainsant, E. Larose, C. Brönnimann, D. Jongmans, C. Michoud, M. Jaboyedoff, Ambient seismic noise monitoring of a clay landslide : toward failure prediction, J. Geophys. Res. 117, F01030 (2012).

[2] M. Le Breton, N. Bontemps, A. Guillemot, L. Baillet, E. Larose, Landslide Monitoring Using Seismic Ambient Noise In-terferometry: Challenges and Applications, Earth Science Review (under review) (2020)

How to cite: Royer, A., Le Breton, M., Guillemot, A., Bontemps, N., Larose, E., Baillet, L., Jongmans, D., Guyoton, F., Jaboyedoff, M., and Mayoraz, R.: Ambient seismic noise monitoring: an online application for decision makers – example of various applications for different slopes configurations., EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6565, https://doi.org/10.5194/egusphere-egu2020-6565, 2020.

D1859 |
Matteo Del Soldato, Lorenzo Solari, Federico Raspini, Silvia Bianchini, Andrea Ciampalini, Roberto Montalti, and Nicola Casagli

Thanks to the launch of the ESA’s Sentinel-1 constellation the scientific community re-evaluated the way to use these data, shifting from a static view of the territory to a continuous streaming of ground motion measurements from space. The Tuscany region (central Italy) has been the first worldwide region to adopt a satellite continuous monitoring service for ground deformation. Taking advantage from the wide area coverage, short revisiting time, cost efficiency and non-invasiveness of the satellite interferometric techniques, in addition to the increased processing capabilities, it was possible to set up a 12 days updated system. The processing chain combines the SqueeSAR algorithm and a time-series data mining algorithm aimed to highlight benchmarks, named “anomalous points”, with significant trend variations. The anomalous points are radar-interpreted in order to classify all of them according to possible causes (e.g. landslide, subsidence, uplift, mining activity). The results of each update of the service are delivered to the regional authorities in the form of a bulletin. It contains a map of the tuscan municipalities differently coloured according to the number of anomalous points, their persistence and relevance. In case of anomalous points representing a potential threat, a field campaign for field-verifying the situation and the potential active phenomena is conducted.

A sheet survey has been realized for the field campaign in order to collect several useful information with the final aim of qualitatively estimating the risk and suggesting short-term actions to be taken by local entities. It is useful to have a complete vision on several elements following a sort of checklist (i.e. general information for describing the phenomena, intensity of the event noting down the damage, exposure of elements) drastically reducing the subjectivity of the surveyors. The whole procedure, from the download and processing of the satellite raw images to the field surveys, requires less than 10 days. The monitoring service provides extremely useful information for prevention, monitoring and risk management activities related to hydrogeological phenomena. Another important consequence is the raised awareness of local and regional authorities in terms of geohazards affecting their territories.

How to cite: Del Soldato, M., Solari, L., Raspini, F., Bianchini, S., Ciampalini, A., Montalti, R., and Casagli, N.: How to manage a monitoring service based on satellite interferometry: a practical approach from the Tuscany region (central Italy), EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1952, https://doi.org/10.5194/egusphere-egu2020-1952, 2020.

D1860 |
André Burnol, Michael Foumelis, Sébastien Gourdier, and Daniel Raucoules

In France, the risk due to clay shrinking and swelling is the second most important cause of financial compensation from insurance companies behind flood risk. In 2010, BRGM published a first global hazard map, based on the 1:50 000 geological map, geotechnical data and spatial distribution of building damages. The traditional way to improve this map consists of monitoring instrumented experimental sites. Since September 2016, a new site has been implemented at Chaingy (Centre-Val de Loire) by choosing a clayey soil in an urban context exposed to a semi-oceanic climate. Two in situ extensometers (E1, E2) have been installed to monitor vertical displacements due to a continuous clay layer at a depth between about 80 cm and 160 cm and capacitive sensors have been deployed inside boreholes at about 120 cm depth to track soil moisture variations in clayey soils.

During a three-year period (September 2016 – September 2019), the extensometers show that the swelling peak level is attained during the spring (with a maximum of 10 millimeters in only 4 months) and the peak of ground settlement during the fall. Another result is a strong spatial and temporal variability comparing the two extensometers, spaced only about 12 m apart: the expansion is up to three times higher at E2 than at E1 during this period.

Another innovative way to improve the swelling-risk map is to use Synthetic Aperture Radar Interferometry (InSAR) technique. During the same 3-year period, the Copernicus Sentinel-1 acquisitions were processed using the P-SBAS (Parallel Small BAseline Subset) service of CNR-IREA to monitor the temporal evolution of ground deformation. Using both ascending and descending tracks, the motion in the vicinity of E1 and E2 reflects roughly the seasonal variation of the clay swelling and settlement. Moreover, the estimated displacement rates are consistent to both extensometers linear trends, taking into account averaging effects due to the spatial resolution of the InSAR measurements.

During the same 3-year period, the 10-day SMOS surface soil moisture (SSM) products for descending acquisition geometry are also used to calculate the average of the median, minimum and maximum SSM values. These surface moistures are in phase advance with respect to the soil moistures measurements at 1.2 m depth. The cross wavelet transform (XWT) between SSM and the vertical displacement at extensometer E2 reveals in the time/frequency space two different periods: 1) the seasonal period (one year), 2) another period (between 4 and 5 months). SSM shows an advance of phase with respect to vertical E2 displacement for both periods. This result is consistent with a water infiltration in the unsaturated zone followed by the swelling of the clay layer.

To a lesser extent, a similar correlation with a phase delay is observed using XWT between SSM and LOS displacement time series. As a perspective, the same method coupling both satellite acquisitions (Sentinel-1 and SMOS) may be generalized to improve the global French shrink/swell risk evaluation at a finer resolution.

How to cite: Burnol, A., Foumelis, M., Gourdier, S., and Raucoules, D.: Characterization of clay shrinking and swelling at the Chaingy site (Centre-Val de Loire) combining in situ extensometers, SMOS surface soil moistures and Sentinel-1 interferometric spaceborne measurements, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-11592, https://doi.org/10.5194/egusphere-egu2020-11592, 2020.

D1861 |
Vladislav Ivanov, Laura Longoni, Maddalena Ferrario, Marco Brunero, and Monica Papini

Landslide monitoring must keep pace with the development of technology. The costs of elaborate monitoring tools could however be quite elevated, especially when considering that monitoring instruments in direct contact with the measurand could undergo irreversible damage and thus be obliterated. A variety of landslide monitoring tools based on the optical fibre technology have emerged in the past few decades. While authors tend to focus on the reduced costs of the sensing cables, the economic and practical aspects related to the interrogating systems are often disregarded. In fact, commercially available units are hardly exploitable outside the laboratory. In this regard, we propose a newly developed interferometric optical fibre-based monitoring system which offers high sensitivity strain monitoring at a significantly reduced cost of the instrumentation involved. Moreover, the devised setup could easily be exported for field use. The setup has been tested in controlled conditions as a monitoring tool in a downscaled landslide model. Two major modes of operation have been experimented: a) direct strain sensor where the optical fibre cable undergoes deformation, and b) a high frequency elastic wave detection mode where the sensor is able to distinguish the energetic footprint generated by ground movement. The two experimental schemes indicate that the newly developed sensing system could eventually be put into effective use for a variety of landslide phenomena where the most appropriate mode of application would depend of the circumstances of the problem under investigation. The design of a field application of the monitoring tool are currently underway.

How to cite: Ivanov, V., Longoni, L., Ferrario, M., Brunero, M., and Papini, M.: Low-cost interferometric optical fibre-based sensor for landslide monitoring: laboratory tests under different applications , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-1043, https://doi.org/10.5194/egusphere-egu2020-1043, 2020.

D1862 |
Ela Šegina, Mateja Jemec Auflič, Tina Peternel, Matija Zupan, Jernej Jež, Eugenio Realini, Ismael Colomina, Michele Crosetto, Angelo Consoli, Sara Luca, and Joaquín Reyes González⁷

Geodetic Integrated Monitoring System (GIMS) has been developed as a low-cost solution for detecting and measuring ground movements (https://www.gims-project.eu/). The prototype has been tested on the landslide on Potoška planina in the north of Slovenia that has been monitored by the seven GIMS units. These units, consisting of GNSS receiver and inclinometer, provide live monitoring data with millimetric precision. In this paper, the project consortium presents the first results of the prototype measuring system and estimate its applicability in modern landslides monitoring. The GIMS measurements have been validated by the wire crackmeter located at the site. The data were correlated to the groundwater level in a piezometer and to the amount of precipitation detected at the rain gauge. Results of GIMS units show good comparability to the wire crackmeter measurements and increased precision in detecting variations in landslide movements. The latter enables us to precisely define the rainfall threshold value for the particular landslide as crucial information needed for a reliable early warning system.


How to cite: Šegina, E., Jemec Auflič, M., Peternel, T., Zupan, M., Jež, J., Realini, E., Colomina, I., Crosetto, M., Consoli, A., Luca, S., and Reyes González⁷, J.: Validation and interpretation of data obtained by the newly developed low-cost Geodetic Integrated Monitoring System (GIMS) , EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-5170, https://doi.org/10.5194/egusphere-egu2020-5170, 2020.

D1863 |
Juan Ma, Mingzhi Zhang, Gan Qi, Gloria Xing, and Zack Huang

Hilly and mountainous areas account for 65% of the total land area in China. There were 286,708 potential geological hazard sites registered at the end of 2018, among which 276,600 were small-and medium-sized. Small and medium geological hazards are a priority in geological disaster prevention. However, due to their large number and the high prices of professional monitoring equipment, it is difficult to find a cost-effective and accurate monitoring technology, method, or means for their long-term disaster monitoring. To this end, this paper aims to explore a reliable, cost-effective, precise, easily installable, low-power solution for small and medium geological hazard monitoring and early warning, centring on characteristic quantities such as deformation before collapse, landslides, and other disasters, and some key impact factors such as rainfall, moisture content, stress, and displacement velocity. Using universal  equipment based on microelectromechanical sensing technology and narrowband IoT technology, laboratory simulations and field tests were performed to research the equipment in terms of adaptation scenarios, effective monitoring ranges, installation methods and locations, and normalization of data reporting content, thus setting up a scientific method for small and medium geological hazard monitoring and early warning.

How to cite: Ma, J., Zhang, M., Qi, G., Xing, G., and Huang, Z.: Research and Development of Universal Equipment for Geological Hazard Monitoring and Early Warning, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-8494, https://doi.org/10.5194/egusphere-egu2020-8494, 2020.

D1864 |
Lavinia Tunini, David Zuliani, Paolo Fabris, and Marco Severin

The Global Navigation Satellite Systems (GNSS) provide a globally extended dataset of primordial importance for a wide range of applications, such as crustal deformation, topographic measurements, or near surface processes studies. However, the high costs of GNSS receivers and the supporting software can represent a strong limitation for the applicability to landslide monitoring. Low-cost tools and techniques are strongly required to face the plausible risk of losing the equipment during a landslide event.

Centro di Ricerche Sismologiche (CRS) of Istituto Nazionale di Oceanografia e di Geofisica Sperimentale OGS in collaboration with SoluTOP, in the last years, has developed a cost-effective GNSS device, called LZER0, both for post-processing and real-time applications. The aim is to satisfy the needs of both scientific and professional communities which require low-cost equipment to increase and improve the measurements on structures at risk, such as landslides or buildings, without losing precision.

The landslide monitoring system implements single-frequency GNSS devices and open source software packages for GNSS positioning, dialoguing through Linux shell scripts. Furthermore a front-end web page has been developed to show real-time tracks. The system allows measuring real-time surface displacements with a centimetre precision and with a cost ten times minor than a standard RTK GPS operational system.

This monitoring system has been tested and now applied to two landslides in NE- Italy: one near Tolmezzo municipality and one near Brugnera village. Part of the device development has been included inside the project CLARA 'CLoud plAtform and smart underground imaging for natural Risk Assessment' funded by the Italian Ministry of Education, University and Research (MIUR).

How to cite: Tunini, L., Zuliani, D., Fabris, P., and Severin, M.: LZER0: GNSS cost-effective real-time positioning applied to landslide monitoring, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-9506, https://doi.org/10.5194/egusphere-egu2020-9506, 2020.

D1865 |
Wooseok Kim, Kiyoung Koo, Oil Kwon, and Jinhwan Kim

In Korea, basic safety management and maintenance are performed with budget support and done systematically in the case of common general national road, highway and railroad slopes. However, in the case of local governments with a low fiscal self-reliance ratio, even the current state of slopes is not assessed. With this in mind, research development for the maintenance of various slopes to enable analysis within a budget and management automation is required.
This research aims to build an digital mapping production platform to be used as a part of the slope investigation and maintenance on slopes affecting national highways. Digital mapping produced through this platform are used as input data for the automatic identification of slope weak points. For this, an analysis was performed for the adaptability of the drawing products using Open-source photogrammetry S/W which is known to have excellent performance. The performance of this S/W was verified using LIDAR data for small size bedrock, and its adaptability was verified using measured data for actual slopes.
The utilization of the results of this research are adjudged and made available for actual slope image data. The results also are available for the foundation of utilizing operation guidelines for supporting using multiple resolutions (Project Number: 20SCIP-C151408-02).

How to cite: Kim, W., Koo, K., Kwon, O., and Kim, J.: Establishment of Digital mapping for Slope Maintenance, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4834, https://doi.org/10.5194/egusphere-egu2020-4834, 2020.

D1866 |
Byungsuk Park, Oil Kwon, Seunghyn Kim, Jonghyun Lee, and Yonghoon Woo

Recently, various drawbacks have been pointed out on the aspects of design, construction, and maintenance of anchor-reinforced slopes, and in some research the causes of increases and decreases of the tension force of the anchor are analyzed. However, research on the development of technology to cope with increases and decreases of the tension force in terms of maintenance is rare. In case that slipping occurs on an anchor-reinforced slope, shear and bending stress will occur in the shear section along the slip surface, and the anchor force may increase when slipping persists due to the deformation of the anchor body. Additionally, if shear deformation occurs in the anchor, cracks will occur in the grout at a relatively low deformation rate, and when deformation continues, the tension force may be further reduced due to the destruction of the grout. We tried to define investigation methodologies and safety plans through the analysis of case studies on functional loss sections, such as fractures of strands due to the excessive load placed on the anchors. From the results of the anchor lift-off test of 466 holes, the number of anchors that could not be retensioned was 177 holes, and the number of anchors with an increased tension force was 49 holes. From the results of ground exploration, it was found that soiled weathering zones or weathering zones with fractured bedrock were distributed at depths of 30m or more. It is analyzed that most anchor settlement with insufficient anchor forces were located in the slip surface and lacked anchor length. It is found that the safety of the slope can be secured if additional reinforcing anchors are installed around anchors with poor strand strength or anchors that cannot be retensioned.(Project Number: 20SCIP-C151408-02).

How to cite: Park, B., Kwon, O., Kim, S., Lee, J., and Woo, Y.: A Research on Technology Development in response to Slope Reinforcing Facility (Anchor) Aging, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-4875, https://doi.org/10.5194/egusphere-egu2020-4875, 2020.

D1867 |
Margherita J. Stumvoll, Robert Fahrngruber, and Thomas Glade

Quantitative data of the sub-surface properties and dynamics of recently active landslides spanning a temporal scale of more than a few years are still fairly rare. This is due to the fact that long-term landslide-monitoring setups are expensive regarding both financial and human resources as well as to install and maintain. Yet, a comprehensive understanding of potential landslide triggering thresholds is mandatory.
Apart from external triggers the internal hydrological, soil mechanical and geophysical properties of a hillslope determine its potential for displacement. The spatial distribution of groundwater levels and soil water contents as well as of the regolith material, resistance and depth define potential areas of activity. The internal structure of a landslide needs to be assessed in order to be able to evaluate magnitude and frequency as well as potential triggers of activity.

In this study, we present a long-term monitoring setup for the detection of sub-surface properties, structure and dynamics of the complex Hofermühle-landslide near Konradsheim in Lower Austria. A combination of direct (invasive) and indirect (non-invasive) methods is used. Direct methods include 1) dynamic probing to investigate sub-surface resistance and 2) the analysis of cores generated via drilling. Data analysis hereby focus on geotechnical parameters such as soil properties, regolith depth and resistance. To investigate hydrological properties data regarding 3) groundwater level using piezometers as well as 4) soil moisture using time domain reflectometry (TDR) probes are used. Data analysis focus on the spatio-temporal behaviour of soil moisture and groundwater level changes in order to assess sub-surface water pathways, water residence time and the connection to changes – regarding both input (precipitation) and output (evapotranspiration). Sub-surface movement rates and their position along vertical soil profiles are planned to be analysed using 5) inclinometer data. Direct methods are combined with non-invasive geophysical methods. As this monitoring setup will be maintained for a longer time period (>10a), the setup itself is assessed critically; challenges and issues of the installation, data transfer and analysis are discussed.

First results regarding the analysis of hydrological parameters indicate a heterogenic distribution of groundwater static level, soil water retention time after infiltration and flow paths. A first interpretation of the sediment core, dynamic probing as well as geophysical results support this heterogeneity. Sub-surface areas of potential activity could be presumed to be correlated with the spatial distribution of surface displacements as these also show a heterogenic distribution.

How to cite: Stumvoll, M. J., Fahrngruber, R., and Glade, T.: Complex landslide dynamics: establishing a monitoring setup to investigate sub-surface properties and displacements of a slow moving landslide system, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-16405, https://doi.org/10.5194/egusphere-egu2020-16405, 2020.

D1868 |
Anna Buczyńska

Mining activity on the area of ​​the former open-pit and underground brown coal mine called Friendship of Nations - Shaft Babina, which is at this moment part of the UNESCO Geopark - the Muskau Arch, was finished in 1973 and reclamation works were started with a special dedication to the forestation. As a part of the reclamation works, a number of technical and biological operations were performed, the subjects were: adjustment of water conditions, relevant land forming, development of ​​the former mine area by plantings and improvement of soil condition. The last of mentioned factor is extremely significant element whose condition determines the proper growth of vegetation. Considering the mining-industrial history and current development of this area, it seems necessary to constantly monitor the components of the natural environment, in particular soils. Adequate and timely used remedies can limit the negative effects and degradation of flora. The purpose of this research was an analysis of the soils condition in 2009-2019 on the area of Babina mine on the basis of geological indices determined using multispectral images of Sentinel-2 and Landsat 5/8 satellite missions. The subjects of analysis were the following soil properties: humidity, overall condition, salinity, texture and chemical composition. It should be emphasized that the research was the first on this area in which remote sensing data was used. Obtained results allowed determining of the current condition of soils, describing their changes in the last 10 years and indicating spatial and temporal trends of changes in the future. In addition, the results of the analysis made it possible to identify areas that may still be under the influence of former mining activities that adversely affect the condition of soils.

How to cite: Buczyńska, A.: Studies on soils condition on the area of the closed Babina mine in 2009-2019 using multispectral satellite images, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-6985, https://doi.org/10.5194/egusphere-egu2020-6985, 2020.

D1869 |
Marta Roca, Eleanor Ainscoe, Gregor Petkovsek, Mark Wetton, Ye Liu, Mark Davison, and Alberto Riera

Tailings dams and storage facilities store toxic mine waste and effluent. Failure of a tailings storage facility can cause dramatic local ecosystem damage, water contamination and, if a tailings dam fails, loss of life due to inundation of the downstream area. The failure rate of tailings dams is known to be significantly greater than that of conventional water retention dams, but monitoring all tailings dams and storage facilities through frequent site visits could be an expensive and resource-demanding task.

Monitoring tools based on remote sensing and internet of things (IoT) sensors have the potential to reduce the risk from tailings storage failures by enabling the organisations responsible to conduct some monitoring remotely, and hence direct their resources for detailed monitoring more efficiently.

We present an overview of DAMSAT (Dam Monitoring from SATellites), an operational tool for monitoring tailings dams, tailings deposit areas and water dams. The tool consists of several different modules. Radar and optical satellite remote sensing data, and in situ internet of things (IoT) sensors are used to monitor surface movement and indicators of pollution at tailings storage sites. Meteorological forecasts are coupled to hydrological models in order to forecast changes in water level at the dams. DAMSAT presents the monitoring information together with risk information from hazard, consequence and evacuation models of possible dam failures in one integrated platform. The project is a partnership between UK and Peruvian organisations. This approach, alongside proactive user engagement activities and user requirements analysis, is designed to ensure that the system is developed with the needs of the user community in mind.

How to cite: Roca, M., Ainscoe, E., Petkovsek, G., Wetton, M., Liu, Y., Davison, M., and Riera, A.: DAMSAT: An operational system for tailings dam monitoring by bringing together remote sensing, meteorological and on-site observations with site metadata, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-18772, https://doi.org/10.5194/egusphere-egu2020-18772, 2020.

D1870 |
Amanda Markert, Kel Markert, Timothy Mayer, Farrukh Chisthie, Biplov Bhandari Bhandari, Thannarot Kunlamai, Arjen Haag, Martijn Kwant, Willem van Verseveld, Kittiphong Phongsapan, David Saah, and Claire Nauman

Floods and water-related disasters impact local populations across many regions in Southeast Asia during the annual monsoon season.  Satellite remote sensing serves as a critical resource for generating flood maps used in disaster efforts to evaluate flood extent and monitor recovery in remote and isolated regions where information is limited.  However, these data are retrieved by multiple sensors, have varying latencies, spatial, temporal, and radiometric resolutions, are distributed in different formats, and require different processing methods making it difficult for end-users to use the data.  SERVIR-Mekong has developed a near real-time flood service, HYDRAFloods, in partnership with Myanmar’s Department of Disaster Management that leverages Google Earth Engine and cloud computing to generate automated multi-sensor flood maps using the most recent imagery available of affected areas. The HYDRAFloods application increases the spatiotemporal monitoring of hydrologic events across large areas by leveraging optical, SAR, and microwave remote sensing data to generate flood water extent maps.  Beta testing of HYDRFloods conducted during the 2019 Southeast Asia monsoon season emphasized the importance of multi-sensor observations as frequent cloud cover limited useable imagery for flood event monitoring. Given HYDRAFloods’ multi-sensor approach, cloud-based resources offer a means to consolidate and streamline the process of accessing, processing, and visualizing flood maps in a more cost effective and computationally efficient way. The HYDRAFlood’s cloud-based approach enables a consistent, automated methodology for generating flood extent maps that are made available through a single, tailored, mapviewer that has been customized based on end-user feedback, allowing users to switch their focus to using data for disaster response.

How to cite: Markert, A., Markert, K., Mayer, T., Chisthie, F., Bhandari, B. B., Kunlamai, T., Haag, A., Kwant, M., van Verseveld, W., Phongsapan, K., Saah, D., and Nauman, C.: Automated Multi-Sensor Near-Real Time Flood Monitoring in the Lower Mekong, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21149, https://doi.org/10.5194/egusphere-egu2020-21149, 2020.