scholarly journals Unraveling Spatial and Temporal Heterogeneities of Very Slow Rock-Slope Deformations with Targeted DInSAR Analyses

2020 ◽  
Vol 12 (8) ◽  
pp. 1329 ◽  
Author(s):  
Chiara Crippa ◽  
Federico Franzosi ◽  
Mattia Zonca ◽  
Andrea Manconi ◽  
Giovanni B. Crosta ◽  
...  
Keyword(s):  
Rock Slope ◽  
Signal To Noise Ratio ◽  
Structural Heterogeneity ◽  
Linear Displacement ◽  
Slope Instability ◽  
Gps Data ◽  
Displacement Signal ◽  
Spatially Distributed ◽  
Multi Temporal ◽  
Displacement Patterns

Spaceborne radar interferometry is a powerful tool to characterize landslides at local and regional scales. However, its application to very slow rock slope deformations in alpine environments (displacement rates < 5 cm/year) remains challenging, mainly due to low signal to noise ratio, atmospheric disturbances, snow cover effects, and complexities resulting from heterogeneous displacement in space and time. Here we combine SqueeSARTM data, targeted multi-temporal baseline DInSAR, GPS data, and detailed field morpho-structural mapping, to unravel the kinematics, internal segmentation, and style of activity of the Mt. Mater deep-seated gravitational slope deformation (DSGSD) in Valle Spluga (Italy). We retrieve slope kinematics by performing 2D decomposition (2D InSAR) of SqueeSARTM products derived from Sentinel-1 data acquired in ascending and descending orbits. To achieve a spatially-distributed characterization of DSGSD displacement patterns and activity, we process Sentinel-1 A/B images (2016-2019) with increasing temporal baselines (ranging from 24-days to 1-year) and generate several multi-temporal interferograms. Unwrapped displacement maps are validated using ground-based GPS data. Interferograms derived with different temporal baselines reveal a strong kinematic and morpho-structural heterogeneity and outline nested rockslides and active sectors, that arise from the background displacement signal of the main DSGSD. Seasonal interferograms, supported by GPS displacement measurements, reveal non-linear displacement trends suggesting a complex response of different slope sectors to rainfall and snowmelt. Our analyses clearly outline a composite slope instability with different nested sectors possibly undergoing different evolutionary trends towards failure. The results herein outline the potential of a targeted use of DInSAR for the detailed investigation of very slow rock slope deformations in different geological and geomorphological settings.

scholarly journals Unraveling spatial and temporal heterogeneities of very slow rock-slope deformations with targeted DInSAR analyses

2021 ◽  
Author(s):  
Federico Franzosi ◽  
Chiara Crippa ◽  
Mattia Zonca ◽  
Andrea Manconi ◽  
Giovanni B. Crosta ◽  
...  
Keyword(s):  
Rock Slope ◽  
Regional Scale ◽  
Temporal Trends ◽  
Structural Data ◽  
Local Scale ◽  
Slope Deformation ◽  
Slope Instability ◽  
Gps Data ◽  
Multi Temporal

&lt;p&gt;Spaceborne radar interferometry is a powerful tool to characterize landslide activity. However, its application to very slow rock slope deformations (displacement rates &lt; 5 cm/yr) in alpine environments remains challenging due to low signal-to-noise ratio, severe atmospheric and snow cover effects, and heterogeneous deformation patterns related to complex landslide mechanisms in space and time.&lt;/p&gt;&lt;p&gt;In this study we combine available SqueeSAR&lt;sup&gt;TM&lt;/sup&gt; data (Sentinel 1A/B ascending and descending, 2015-2017), ad hoc multi-temporal baseline DInSAR processing (2016-2019), GPS data (2015 to 2019) and detailed field mapping to unravel the kinematics, internal segmentation and style of activity of the Mt. Mater deep-seated gravitational slope deformation (DSGSD) in Valle Spluga (Italy). The high relief slope (1500-3000 m.a.s.l.) is made of dominant micaschist and paragneiss of the Stella-Timun complex (Suretta nappe) and ranges in inclination between 33&amp;#176; (&lt; 2500 m a.s.l.) and 25&amp;#176; (&gt; 2500 m a.s.l.). At 2900 m a.s.l. the slope is cut by a sharp triangular headscarp with a vertical downthrow of about 40 m, moving downslope, shallower arcuate scarps mark the transition to two nested large landslides, affecting the slope between 2400 m a.s.l. and 1550 m a.s.l; with highly deformed toes.&lt;/p&gt;&lt;p&gt;Through 2DInSAR decomposition, we highlight the global translational kinematics of the DSGSD. However, regional scale processed PSI data result unsuitable to capture the spatial complexity of the phenomenon at the local scale. To obtain a spatially-distributed characterization of the DSGSD displacement patterns, we process several multi-temporal interferograms and retrieve unwrapped phase and displacement maps according to a process-oriented, targeted approach based on variable temporal baselines (from 24-days to 1-year). In this context: a) 1-year interferograms provide a picture of long-term background DSGSD displacement signals; b) seasonal interferograms highlight displacement trends suggesting a complex response of different slope sectors to hydrological input; c) 24 days interferograms outline a triangular shaped active sector extending between 2500 m a.s.l. and the main DSGSD headscarp, corresponding to the movement of extensive debris cover and overlying periglacial features.&lt;/p&gt;&lt;p&gt;Our analyses clearly outline a composite slope instability and a strong spatial heterogeneity with different nested sectors possibly undergoing different evolutionary trends towards failure. The combined analysis of seasonal interferograms and GPS data further confirm a sensitivity of the different slope sectors to hydrological forcing modulated by snowmelt and rainfalls. The herein results outline the potential of a targeted use of DInSAR, carefully constrained by field geological and morpho-structural data, for the detailed investigation of a complex very slow rock slope deformation successfully unravelling its mechanisms, temporal trends of activity and forcing factors. Ground-truthing by means of GPS data further prove that, in the context of very slow rock deformations, PSI data are useful for a first-order characterization of slope activity and kinematics, but often fail to capture local scale spatial segmentation, temporal trends and associated mechanisms.&lt;/p&gt;&lt;p&gt;Our approach prove to be effective in providing key information for the definition of possible evolutive scenarios for risk analysis and mitigation of a widespread, yet challenging class of slope instabilities.&lt;/p&gt;

scholarly journals Identification of active release planes using ground-based differential InSAR at the Randa rock slope instability, Switzerland

2009 ◽  
Vol 9 (6) ◽  
pp. 2027-2038 ◽  
Author(s):  
V. Gischig ◽  
S. Loew ◽  
A. Kos ◽  
J. R. Moore ◽  
H. Raetzo ◽  
...  
Keyword(s):  
Rock Slope ◽  
Hazard Analysis ◽  
Failure Surface ◽  
Accurate Estimate ◽  
Slope Instability ◽  
Lateral Release ◽  
Rupture Plane ◽  
Local Movement ◽  
Active Release ◽  
Displacement Patterns

Abstract. Five ground-based differential interferometric synthetic aperture radar (GB-DInSAR) surveys were conducted between 2005 and 2007 at the rock slope instability at Randa, Switzerland. Resultant displacement maps revealed, for the first time, the presence of an active basal rupture zone and a lateral release surface daylighting on the exposed 1991 failure scarp. Structures correlated with the boundaries of interferometric displacement domains were confirmed using a helicopter-based LiDAR DTM and oblique aerial photography. Former investigations at the site failed to conclusively detect these active release surfaces essential for kinematic and hazard analysis of the instability, although their existence had been hypothesized. The determination of the basal and lateral release planes also allowed a more accurate estimate of the currently unstable volume of 5.7±1.5 million m3. The displacement patterns reveal that two different kinematic behaviors dominate the instability, i.e. toppling above 2200 m and translational failure below. In the toppling part of the instability the areas with the highest GB-DInSAR displacements correspond to areas of enhanced micro-seismic activity. The observation of only few strongly active discontinuities daylighting on the 1991 failure surface points to a rather uniform movement in the lower portion of the instability, while most of the slip occurs along the basal rupture plane. Comparison of GB-DInSAR displacements with mapped discontinuities revealed correlations between displacement patterns and active structures, although spatial offsets occur as a result of the effective resolution of GB-DInSAR. Similarly, comparisons with measurements from total station surveys generally showed good agreement. Discrepancies arose in several cases due to local movement of blocks, the size of which could not be resolved using GB-DInSAR.

scholarly journals Estimating velocity from noisy GPS data for investigating the temporal variability of slope movements

2014 ◽  
Vol 2 (2) ◽  
pp. 1153-1192
Author(s):  
V. Wirz ◽  
S. Gruber ◽  
S. Gubler ◽  
R. S. Purves
Keyword(s):  
Temporal Variability ◽  
Time Window ◽  
Signal To Noise Ratio ◽  
Slope Instability ◽  
Gps Data ◽  
Factors Affecting ◽  
Slope Movements ◽  
Abstract Knowledge ◽  
Sensitivity Tests ◽  
Synthetic Time Series

Abstract. Knowledge of processes and factors affecting slope instability is essential for detecting and monitoring potentially hazardous slopes. Knowing the timing of acceleration or deceleration of slope movements can help to identify important controls and hence to increase our process understanding. For this methods to derive reliable velocity estimations are important. The aim of this study was to develop and test a method to derive velocities based on noisy GPS data of various movement patterns and variable signal-to-noise-ratio (SNR). Derived velocities represent reliable average velocities representative for a given period. The applied smoothing windows directly depends on the SNR of the data, which is modeled using Monte Carlo simulation. Hence, all obtained velocities have a SNR above a predefined threshold and for each velocity period the SNR is known, which helps to interpret the temporal variability. In sensitivity tests with synthetic time-series the method was compared to established methods to derive velocities based on GPS positions, including spline and Kernel regression smoothing. Those sensitivity tests clearly demonstrated that methods are required that adopt the time window to the underlying error of the position data. The presented method performs well, even for a high noise levels and variable SNR. Different methods were further applied to investigate the inter-annual variability of permafrost slope movements based on daily GPS- and inclinometer data. In the framework of the new method, we further analyzed the error caused by a rotation of the GPS mast (hmast = 1.5 m). If the tilting is higher than its uncertainty, the rotational movement can be separated and the direction of movement became more uniform. At one GPS station, more than 12% of the measured displacement at the antenna was caused by the rotation of the station.

Rock slope instability assessment using spatially distributed structural orientation data in Darjeeling Himalaya (India)

2010 ◽  
Vol 35 (15) ◽  
pp. 1773-1792 ◽  
Author(s):  
Saibal Ghosh ◽  
Andreas Günther ◽  
Emmanuel John M. Carranza ◽  
Cees J. van Westen ◽  
Victor G. Jetten
Keyword(s):  
Rock Slope ◽  
Slope Instability ◽  
Orientation Data ◽  
Structural Orientation ◽  
Darjeeling Himalaya ◽  
Spatially Distributed

scholarly journals Changes in ground deformation prior to and following a large urban landslide in La Paz, Bolivia revealed by advanced InSAR

2018 ◽  
Author(s):  
Nicholas J. Roberts ◽  
Bernhard T. Rabus ◽  
John J. Clague ◽  
Reginald L. Hermanns ◽  
Marco-Antonio Guzmán ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Ground Surface ◽  
Slope Instability ◽  
Small Scale ◽  
Spatial And Temporal Patterns ◽  
La Paz ◽  
Fine Grained ◽  
Measured Displacement ◽  
Optical Satellite Images ◽  
Displacement Patterns

Abstract. We characterize and compare creep preceding and following the 2011 Pampahasi landslide (∼ 40 Mm3 ± 50 %) in the city of La Paz, Bolivia, using spaceborne RADAR interferometry (InSAR) that combines displacement records from both distributed and point scatterers. The failure remobilised deposits of an ancient landslide in weakly cemented, predominantly fine-grained sediments and affected ∼ 1.5 km2 of suburban development. During the 30 months preceding failure, about half of the toe area was creeping at 3–8 cm/a and localized parts of the scarp area showed displacements of up to 14 cm/a. Changes in deformation in the 10 months following the landslide are contrary to the common assumption that stress released during a discrete failure increases stability. During that period, most of the landslide toe and areas near the headscarp accelerated, respectively, to 4–14 and 14 cm/a. The extent of deformation increased to cover most, or probably all, of the 2011 landslide as well as adjacent parts of the slope and plateau above. The InSAR-measured displacement patterns – supplemented by field observations and by optical satellite images – indicate that kinematically complex, steady-state creep along pre-existing sliding surfaces temporarily accelerated in response to heavy rainfall, after which the slope quickly achieved a slightly faster and expanded steadily creeping state. This case study demonstrates that high-quality ground-surface motion fields derived using spaceborne InSAR can help to characterize creep mechanisms, quantify spatial and temporal patterns of slope activity, and identify isolated small-scale instabilities. Characterizing slope instability before, during, and after the 2011 Pampahasi landslide is particularly important for understanding landslide hazard in La Paz, half of which is underlain by similar, large paleolandslides.

scholarly journals Integration of Satellite InSAR with a Wireless Network of Geotechnical Sensors for Slope Monitoring in Urban Areas: The Pariana Landslide Case (Massa, Italy)

2021 ◽  
Vol 13 (13) ◽  
pp. 2534
Author(s):  
Andrea Ciampalini ◽  
Paolo Farina ◽  
Luca Lombardi ◽  
Massimiliano Nocentini ◽  
Veronica Taurino ◽  
...  
Keyword(s):  
Urban Areas ◽  
Temporal Evolution ◽  
Monitoring Program ◽  
Slope Instability ◽  
Time Data ◽  
Public Authorities ◽  
Slope Movements ◽  
Multi Temporal ◽  
Slow Moving ◽  
Slope Monitoring

Slow to extremely slow landslides in urban areas may cause severe damage to buildings and infrastructure that can lead to the evacuation of local populations in case of slope accelerations. Monitoring the spatial and temporal evolution of this type of natural hazard represents a major concern for the public authorities in charge of risk management. Pariana, a village with 400 residents located in the Apuan Alps (Massa, Tuscany, Italy), is an example of urban settlement where the population has long been forced to live with considerable slope instability. In the last 30 years, due to the slope movements associated with a slow-moving landslide that has affected a significant portion of the built-up area, several buildings have been damaged, including a school and the provincial road crossing the unstable area, leading to the need for an installation of a slope monitoring system with early warning capabilities, in parallel with the implementation of mitigation works. In this paper, we show how satellite multi-temporal interferometric synthetic aperture radar (MT-InSAR) data can be effectively used when coupled with a wireless sensor network made of several bar extensometers and a borehole inclinometer. In fact, thanks to their wide area coverage and opportunistic nature, satellite InSAR data allow one to clearly identify the spatial distribution of surface movements and their long-term temporal evolution. On the other hand, geotechnical sensors installed on specific elements at risk (e.g., private buildings, retaining walls, etc.), and collected through Wi-Fi dataloggers, provide near real-time data that can be used to identify sudden accelerations in slope movements, subsequently triggering alarms. The integration of those two-monitoring systems has been tested and assessed in Pariana. Results show how a hybrid slope monitoring program based on the two different technologies can be used to effectively monitor slow-moving landslides and to identify sudden accelerations and activate a response plan.

scholarly journals Assessment of Slope Instability and Risk Analysis of Road Cut Slopes in Lashotor Pass, Iran

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Mohammad Hossein Taherynia ◽  
Mojtaba Mohammadi ◽  
Rasoul Ajalloeian
Keyword(s):  
Rock Mass ◽  
Risk Analysis ◽  
Rock Slope ◽  
Classification Systems ◽  
Slope Instability ◽  
Rock Slope Stability ◽  
Rock Slopes ◽  
The Stability ◽  
Cut Slopes ◽  
Road Cut Slopes

Assessment of the stability of natural and artificial rock slopes is an important topic in the rock mechanics sciences. One of the most widely used methods for this purpose is the classification of the slope rock mass. In the recent decades, several rock slope classification systems are presented by many researchers. Each one of these rock mass classification systems uses different parameters and rating systems. These differences are due to the diversity of affecting parameters and the degree of influence on the rock slope stability. Another important point in rock slope stability is appraisal hazard and risk analysis. In the risk analysis, the degree of danger of rock slope instability is determined. The Lashotor pass is located in the Shiraz-Isfahan highway in Iran. Field surveys indicate that there are high potentialities of instability in the road cut slopes of the Lashotor pass. In the current paper, the stability of the rock slopes in the Lashotor pass is studied comprehensively with different classification methods. For risk analyses, we estimated dangerous area by use of the RocFall software. Furthermore, the dangers of falling rocks for the vehicles passing the Lashotor pass are estimated according to rockfall hazard rating system.

scholarly journals Separating the scattered wavefield from teleseismic P using curvelets on the long beach array data set

2019 ◽  
Vol 220 (2) ◽  
pp. 1112-1127
Author(s):  
Jia Zhang ◽  
Charles A Langston
Keyword(s):  
Wave Propagation ◽  
Signal To Noise Ratio ◽  
Spherical Wave ◽  
Curvelet Transform ◽  
Structural Heterogeneity ◽  
Seismic Array ◽  
P Wave ◽  
Long Beach ◽  
Data Set ◽  
Array Data

SUMMARY A dense seismic array, composed of over 5000 stations with an average spacing close to 120 m was deployed in Long Beach, CA, by NodalSeismic and Signal Hill Petroleum as part of a survey associated with the Long Beach oilfield. Among many interesting wave propagation effects that have been reported by others, we observe that the coda of teleseismic P waves display waves caused by obvious local scattering from the Signal Hill popup structure between strands of the Newport-Inglewood fault. The density of the seismic array allows space-based methods, such as the Curvelet transform, to be investigated to separate the teleseismic and local scattered wavefields. We decompose a synthetic wavefield composed of a teleseismic plane wave and local scattered spherical wave in the curvelet domain to test the plausibility of our curvelet analysis and then apply the technique to the Long Beach array data set. Background noise is removed by a soft thresholding method and a declustering technique is applied to separate the teleseismic and local scattered wavefield in the curvelet domain. Decomposed results illustrate that the signal-to-noise ratio of the teleseismic P wave can be significantly improved by curvelet analysis. The scattered wavefield is composed of locally propagating Rayleigh waves from the pop-up structure and from the Newport Inglewood fault itself. Observing the wavefield both in space and time clearly improves understanding of wave propagation complexities due to structural heterogeneity.

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