Long-term geophysical-geotechnical monitoring of landslide processes

2020 ◽  
Author(s):  
Jon Chambers ◽  
Keyword(s):  
Slope Stability ◽  
Slope Failure ◽  
Time Lapse ◽  
Early Warning Systems ◽  
Substantial Contribution ◽  
Data Sets ◽  
Geophysical Monitoring ◽  
Geotechnical Monitoring ◽  
Time Estimates ◽  
Landslide Processes

<p>We assess the use of novel geophysical monitoring approaches to spatially characterise geotechnical properties and processes driving slope failure, and consider the contribution of geophysical technologies to the development of slope-scale early warning systems (EWS). In particular, we focus on geoelectrical monitoring approaches to image moisture driven processes, supported by the use of shallow seismic surveys to illuminate elastic property distributions and changes. We describe an approach for using spatial and volumetric geophysical models of slope structures and processes to better inform geotechnical models of slope stability and estimates of factor of safety.</p><p>Key components of the approach have included: automated schemes and instrumentation for measuring and processing field-scale time-lapse geophysical and geotechnical data sets; laboratory based assessments of geophysical-geotechnical property relationships (e.g. between resistivity, moisture content and pore suctions) to aid the interpretation of slope-scale geophysical models; and linked geophysical-geomechanical modelling to provide near-real-time estimates of slope stability to aid forecasting of landslide events. Our approach is illustrated with results from a range of field sites located on natural and engineered slopes. We conclude that the spatially rich subsurface information provided by geophysical monitoring can make a substantial contribution to landslide EWS and can provide an improved understanding of the condition of unstable slopes.</p>

scholarly journals Brief communication: The role of geophysical imaging in local landslide early warning systems

2021 ◽  
Author(s):  
Jim Scott Whiteley ◽  
Arnaud Watlet ◽  
Jonathan Michael Kendall ◽  
Jonathan Edward Chambers
Keyword(s):  
Remote Sensing ◽  
Early Warning ◽  
Slope Failure ◽  
Time Lapse ◽  
Early Warning Systems ◽  
Warning Systems ◽  
Geophysical Monitoring ◽  
Landslide Early Warning ◽  
Geophysical Imaging

Abstract. We summarise the contribution of geophysical imaging to local landslide early warning systems (LoLEWS), highlighting how LoLEWS design and monitoring components benefit from the enhanced spatial and temporal resolutions of time-lapse geophysical imaging. In addition, we discuss how with appropriate laboratory-based petrophysical transforms, these geophysical data can be crucial for future slope failure forecasting and modelling, linking other methods of remote sensing and intrusive monitoring across different scales. We conclude that in light of ever increasing spatiotemporal resolutions of data acquisition, geophysical monitoring should be a more widely considered technology in the toolbox of methods available to stakeholders operating LoLEWS.

scholarly journals Brief communication: The role of geophysical imaging in local landslide early warning systems

2021 ◽  
Vol 21 (12) ◽  
pp. 3863-3871
Author(s):  
Jim S. Whiteley ◽  
Arnaud Watlet ◽  
J. Michael Kendall ◽  
Jonathan E. Chambers
Keyword(s):  
Remote Sensing ◽  
Early Warning ◽  
Slope Failure ◽  
Time Lapse ◽  
Early Warning Systems ◽  
Warning Systems ◽  
Geophysical Monitoring ◽  
Landslide Early Warning ◽  
Geophysical Imaging

Abstract. We summarise the contribution of geophysical imaging to local landslide early warning systems (LoLEWS), highlighting how the design and monitoring components of LoLEWS benefit from the enhanced spatial and temporal resolutions of time-lapse geophysical imaging. In addition, we discuss how with appropriate laboratory-based petrophysical transforms, geophysical data can be crucial for future slope failure forecasting and modelling, linking other methods of remote sensing and intrusive monitoring across different scales. We conclude that in light of ever-increasing spatiotemporal resolutions of data acquisition, geophysical monitoring should be a more widely considered technology in the toolbox of methods available to stakeholders operating LoLEWS.

scholarly journals Internet-of-Things-Based Geotechnical Monitoring Boosted by Satellite InSAR Data

2021 ◽  
Vol 13 (14) ◽  
pp. 2757
Author(s):  
Denis Guilhot ◽  
Toni Martinez del Hoyo ◽  
Andrea Bartoli ◽  
Pooja Ramakrishnan ◽  
Gijs Leemans ◽  
...  
Keyword(s):  
Urban Areas ◽  
Slope Failure ◽  
Significant Risk ◽  
Surface Displacement ◽  
Cost Effective ◽  
Technical Note ◽  
Data Sets ◽  
Geotechnical Monitoring ◽  
Cost Effective Method ◽  
In Situ Sensors

Landslides, often a side effect of mining activities, pose a significant risk to humans and infrastructures such as urban areas, power lines, and dams. Operational ground motion monitoring can help detect the spatial pattern of surface changes and their evolution over time. In this technical note, a commercial, cost-effective method combining a network of geotechnical surface sensors with the InSAR data was reported for the first time to accurately monitor surface displacement. The correlation of both data sets is demonstrated in the Gediminas Castle testbed, where slope failure events were detected. Two specific events were analyzed, and possible causes proposed. The combination of techniques allows one to detect the precursors of the events and characterize the consequences of the failures in different areas in proximity to the castle walls, since the solution allows for the confirmation of long-term drifts and sudden movements in real time. The data from the in situ sensors were also used to refine the satellite data analysis. The results demonstrate that not all events pose a direct threat to the safety of the structure monitored.

scholarly journals The Hydromechanical Interplay in the Simplified Three-Dimensional Limit Equilibrium Analyses of Unsaturated Slope Stability

Geosciences ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 73
Author(s):  
Panagiotis Sitarenios ◽  
Francesca Casini
Keyword(s):  
Analytical Solution ◽  
Slope Stability ◽  
Slope Failure ◽  
Failure Modes ◽  
Pore Water Pressure ◽  
Limit Equilibrium ◽  
Water Pressure ◽  
Three Dimensional ◽  
Stability Limit ◽  
Smooth Transition

This paper presents a three-dimensional slope stability limit equilibrium solution for translational planar failure modes. The proposed solution uses Bishop’s average skeleton stress combined with the Mohr–Coulomb failure criterion to describe soil strength evolution under unsaturated conditions while its formulation ensures a natural and smooth transition from the unsaturated to the saturated regime and vice versa. The proposed analytical solution is evaluated by comparing its predictions with the results of the Ruedlingen slope failure experiment. The comparison suggests that, despite its relative simplicity, the analytical solution can capture the experimentally observed behaviour well and highlights the importance of considering lateral resistance together with a realistic interplay between mechanical parameters (cohesion) and hydraulic (pore water pressure) conditions.

scholarly journals Advantages of IoT-Based Geotechnical Monitoring Systems Integrating Automatic Procedures for Data Acquisition and Elaboration

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 2249
Author(s):  
Andrea Carri ◽  
Alessandro Valletta ◽  
Edoardo Cavalca ◽  
Roberto Savi ◽  
Andrea Segalini
Keyword(s):  
Early Warning Systems ◽  
Web Based ◽  
Efficient System ◽  
Geotechnical Monitoring ◽  
Site Investigations ◽  
Field Data Collection ◽  
Monitoring Technologies ◽  
Technological Improvements ◽  
Monitoring Devices ◽  
The Internet Of Things

Monitoring instrumentation plays a major role in the study of natural phenomena and analysis for risk prevention purposes, especially when facing the management of critical events. Within the geotechnical field, data collection has traditionally been performed with a manual approach characterized by time-expensive on-site investigations and monitoring devices activated by an operator. Due to these reasons, innovative instruments have been developed in recent years in order to provide a complete and more efficient system thanks to technological improvements. This paper aims to illustrate the advantages deriving from the application of a monitoring approach, named Internet of natural hazards, relying on the Internet of things principles applied to monitoring technologies. One of the main features of the system is the ability of automatic tools to acquire and elaborate data independently, which has led to the development of dedicated software and web-based visualization platforms for faster, more efficient and accessible data management. Additionally, automatic procedures play a key role in the implementation of early warning systems with a near-real-time approach, providing a valuable tool to the decision-makers and authorities responsible for emergency management. Moreover, the possibility of recording a large number of different parameters and physical quantities with high sampling frequency allows to perform meaningful statistical analyses and identify cause–effect relationships. A series of examples deriving from different case studies are reported in this paper in order to present the practical implications of the IoNH approach application to geotechnical monitoring.

scholarly journals Dynamics of the Askja caldera July 2014 landslide, Iceland, from seismic signal analysis: precursor, motion and aftermath

2017 ◽  
Author(s):  
Anne Schöpa ◽  
Wei-An Chao ◽  
Bradley Lipovsky ◽  
Niels Hovius ◽  
Robert S. White ◽  
...  
Keyword(s):  
Seismic Data ◽  
Signal Analysis ◽  
Slope Failure ◽  
Stable State ◽  
Seismic Signal ◽  
Early Warning Systems ◽  
High Energy ◽  
Stick Slip ◽  
Short Period ◽  
Large Landslide

Abstract. Using data from a network of 58 seismic stations, we characterise a large landslide that occurred at the southeastern corner of the Askja caldera, Iceland, on 21 July 2014, including its precursory tremor and mass wasting aftermath. Our study is motivated by the need for deeper generic understanding of the processes operating not only at the time of catastrophic slope failure, but also in the preparatory phase and during the transient into the subsequent stable state. In addition, it is prompted by the high hazard potential of the steep caldera lake walls at Askja as tsunami waves created by the landslide reached famous tourist spots 60 m above the lake level. Since direct observations of the event are lacking, the seismic data give valuable details on the dynamics of this landslide episode. The excellent seismic data quality and coverage of the stations of the Askja network made it possible to jointly analyse the long- and short-period signals of the landslide to obtain information about the triggering, initiation, timing, and propagation of the slide. The seismic signal analysis and a landslide force history inversion of the long-period seismic signals showed that the Askja landslide was a single, large event starting at the SE corner of the caldera lake at 23:24:05 UTC and propagating to the NW in the following 2 min. The bulk sliding mass was 7–16 × 1010 kg, equivalent to a collapsed volume of 35–80 × 106 m3, and the centre of mass was displaced horizontally downslope by 1260 ± 250 m during landsliding. The seismic records of stations up to 30 km away from the landslide source area show a tremor signal that started 30 min before the main landslide failure. It is harmonic, with a fundamental frequency of 2.5 Hz and shows time-dependent changes of its frequency content. We attribute the complex tremor signal to accelerating and decelerating stick-slip motion on failure planes at the base and the sides of the landslide body. The accelerating motion culminated in aseismic slip of the landslide visible as a drop in the seismic amplitudes down to the background noise level 2 min before the landslide high-energy signal begins. We propose that the seismic signal of the precursory tremor may be developed as an indicator for landslide early-warning systems. The 8 hours after the main landslide failure are characterised by smaller slope failures originating from the destabilised caldera wall decaying in frequency and magnitude. We introduce the term afterslides for this subsequent, declining slope activity after a large landslide.

scholarly journals Long-term time-lapse microgravity and geotechnical monitoring of relict salt mines, Marston, Cheshire, U. K.

Geophysics ◽  
2012 ◽  
Vol 77 (6) ◽  
pp. B287-B294 ◽  
Author(s):  
Jamie K. Pringle ◽  
Peter Styles ◽  
Claire P. Howell ◽  
Michael W. Branston ◽  
Rebecca Furner ◽  
...  
Keyword(s):  
Time Lapse ◽  
Ground Subsidence ◽  
Near Surface ◽  
Geotechnical Monitoring ◽  
Salt Mines ◽  
History Of ◽  
Mine Workings ◽  
The Village ◽  
The Town

The area around the town of Northwich in Cheshire, U. K., has a long history of catastrophic ground subsidence caused by a combination of natural dissolution and collapsing abandoned mine workings within the underlying Triassic halite bedrock geology. In the village of Marston, the Trent and Mersey Canal crosses several abandoned salt mine workings and previously subsiding areas, the canal being breached by a catastrophic subsidence event in 1953. This canal section is the focus of a long-term monitoring study by conventional geotechnical topographic and microgravity surveys. Results of 20 years of topographic time-lapse surveys indicate specific areas of local subsidence that could not be predicted by available site and mine abandonment plan and shaft data. Subsidence has subsequently necessitated four phases of temporary canal bank remediation. Ten years of microgravity time-lapse data have recorded major deepening negative anomalies in specific sections that correlate with topographic data. Gravity 2D modeling using available site data found upwardly propagating voids, and associated collapse material produced a good match with observed microgravity data. Intrusive investigations have confirmed a void at the major anomaly. The advantages of undertaking such long-term studies for near-surface geophysicists, geotechnical engineers, and researchers working in other application areas are discussed.

Common-focus point-based target-oriented imaging approach for continuous seismic reservoir monitoring

Geophysics ◽  
2018 ◽  
Vol 83 (4) ◽  
pp. M41-M48 ◽  
Author(s):  
Hongwei Liu ◽  
Mustafa Naser Al-Ali
Keyword(s):  
Seismic Data ◽  
Rock Physics ◽  
Time Lapse ◽  
Velocity Estimation ◽  
Estimation Methods ◽  
Data Sets ◽  
Data Set ◽  
Velocity Models ◽  
Reservoir Monitoring ◽  
Focus Point

The ideal approach for continuous reservoir monitoring allows generation of fast and accurate images to cope with the massive data sets acquired for such a task. Conventionally, rigorous depth-oriented velocity-estimation methods are performed to produce sufficiently accurate velocity models. Unlike the traditional way, the target-oriented imaging technology based on the common-focus point (CFP) theory can be an alternative for continuous reservoir monitoring. The solution is based on a robust data-driven iterative operator updating strategy without deriving a detailed velocity model. The same focusing operator is applied on successive 3D seismic data sets for the first time to generate efficient and accurate 4D target-oriented seismic stacked images from time-lapse field seismic data sets acquired in a [Formula: see text] injection project in Saudi Arabia. Using the focusing operator, target-oriented prestack angle domain common-image gathers (ADCIGs) could be derived to perform amplitude-versus-angle analysis. To preserve the amplitude information in the ADCIGs, an amplitude-balancing factor is applied by embedding a synthetic data set using the real acquisition geometry to remove the geometry imprint artifact. Applying the CFP-based target-oriented imaging to time-lapse data sets revealed changes at the reservoir level in the poststack and prestack time-lapse signals, which is consistent with the [Formula: see text] injection history and rock physics.

scholarly journals Characteristics of ground motion and threshold values for colluvium slope displacement induced by heavy rainfall: a case study in northern Taiwan

2016 ◽  
Vol 16 (6) ◽  
pp. 1309-1321 ◽  
Author(s):  
Ching-Jiang Jeng ◽  
Dar-Zen Sue
Keyword(s):  
Slope Stability ◽  
Heavy Rainfall ◽  
Slope Failure ◽  
Drainage System ◽  
Threshold Value ◽  
Slope Instability ◽  
Disaster Prevention ◽  
Strain Gages ◽  
Slope Displacement ◽  
Northern Taiwan

Abstract. The Huafan University campus is located in the Ta-lun Shan area in northern Taiwan, which is characterized by a dip slope covered by colluvium soil of various depths. For slope disaster prevention, a monitoring system was constructed that consisted of inclinometers, tiltmeters, crack gages, groundwater level observation wells, settlement and displacement observation marks, rebar strain gages, concrete strain gages, and rain gages. The monitoring data derived from hundreds of settlement and displacement observation marks were analyzed and compared with the displacement recorded by inclinometers. The analysis results revealed that the maximum settlement and displacement were concentrated on the areas around the Hui-Tsui, Zhi-An, and Wu-Ming buildings and coincided with periods of heavy rainfall. The computer program STABL was applied for slope stability analysis and modeling of slope failure. For prevention of slope instability, a drainage system and tieback anchors with additional stability measures were proposed to discharge excess groundwater following rainfall. Finally, threshold value curves of rainfall based on slope displacement were proposed. The curves can be applied for predicting slope stability when typhoons are expected to bring heavy rainfall and should be significant in slope disaster prevention.

Sign in / Sign up

Export Citation Format

Share Document