Time-dependent investigation of a slow-moving landslide in Los Angeles, CA, through SAR observations and numerical simulations

2020 ◽  
Author(s):  
Nicușor Necula ◽  
Kami Mohammadi ◽  
Mostafa Khoshmanesh ◽  
Domniki Asimaki
Keyword(s):  
Los Angeles ◽  
Ground Deformation ◽  
Numerical Models ◽  
Ground Surface ◽  
Weather Conditions ◽  
Sar Interferometry ◽  
Time Dependent ◽  
Landslide Monitoring ◽  
Slow Moving

<p>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.</p>

scholarly journals Numerical models for ground deformation and gravity changes during volcanic unrest: simulating the hydrothermal system dynamics of a restless caldera

Solid Earth ◽  
2016 ◽  
Vol 7 (2) ◽  
pp. 557-577 ◽  
Author(s):  
A. Coco ◽  
J. Gottsmann ◽  
F. Whitaker ◽  
A. Rust ◽  
G. Currenti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pore Pressure ◽  
Hydrothermal System ◽  
Ground Deformation ◽  
Numerical Models ◽  
Gravity Data ◽  
Ground Surface ◽  
Campi Flegrei ◽  
Hazard Evaluation ◽  
Gravity Changes

Abstract. Ground deformation and gravity changes in restless calderas during periods of unrest can signal an impending eruption and thus must be correctly interpreted for hazard evaluation. It is critical to differentiate variation of geophysical observables related to volume and pressure changes induced by magma migration from shallow hydrothermal activity associated with hot fluids of magmatic origin rising from depth. In this paper we present a numerical model to evaluate the thermo-poroelastic response of the hydrothermal system in a caldera setting by simulating pore pressure and thermal expansion associated with deep injection of hot fluids (water and carbon dioxide). Hydrothermal fluid circulation is simulated using TOUGH2, a multicomponent multiphase simulator of fluid flows in porous media. Changes in pore pressure and temperature are then evaluated and fed into a thermo-poroelastic model (one-way coupling), which is based on a finite-difference numerical method designed for axi-symmetric problems in unbounded domains.Informed by constraints available for the Campi Flegrei caldera (Italy), a series of simulations assess the influence of fluid injection rates and mechanical properties on the hydrothermal system, uplift and gravity. Heterogeneities in hydrological and mechanical properties associated with the presence of ring faults are a key determinant of the fluid flow pattern and consequently the geophysical observables. Peaks (in absolute value) of uplift and gravity change profiles computed at the ground surface are located close to injection points (namely at the centre of the model and fault areas). Temporal evolution of the ground deformation indicates that the contribution of thermal effects to the total uplift is almost negligible with respect to the pore pressure contribution during the first years of the unrest, but increases in time and becomes dominant after a long period of the simulation. After a transient increase over the first years of unrest, gravity changes become negative and decrease monotonically towards a steady-state value.Since the physics of the investigated hydrothermal system is similar to any fluid-filled reservoir, such as oil fields or CO2 reservoirs produced by sequestration, the generic formulation of the model will allow it to be employed in monitoring and interpretation of deformation and gravity data associated with other geophysical hazards that pose a risk to human activity.

Mapping ground surface deformation using temporarily coherent point SAR interferometry: Application to Los Angeles Basin

2012 ◽  
Vol 117 ◽  
pp. 429-439 ◽  
Author(s):  
Lei Zhang ◽  
Zhong Lu ◽  
Xiaoli Ding ◽  
Hyung-sup Jung ◽  
Guangcai Feng ◽  
...  
Keyword(s):  
Los Angeles ◽  
Surface Deformation ◽  
Ground Surface ◽  
Sar Interferometry ◽  
Los Angeles Basin

scholarly journals Coseismic Ground Deformation Reproduced through Numerical Modeling: A Parameter Sensitivity Analysis

Geosciences ◽  
2019 ◽  
Vol 9 (9) ◽  
pp. 370 ◽  
Author(s):  
Panara ◽  
Toscani ◽  
Cooke ◽  
Seno ◽  
Perotti
Keyword(s):  
Stress Drop ◽  
Surface Deformation ◽  
Slip Surface ◽  
Ground Deformation ◽  
Numerical Models ◽  
Three Dimensional ◽  
Ground Surface ◽  
Line Of Sight ◽  
Coseismic Slip ◽  
2009 L’Aquila Earthquake

Coseismic ground displacements detected through remote sensing surveys are often used to invert the coseismic slip distribution on geologically reliable fault planes. We analyze a well-known case study (2009 L’Aquila earthquake) to investigate how three-dimensional (3D) slip configuration affects coseismic ground surface deformation. Different coseismic slip surface configurations reconstructed using aftershocks distribution and coseismic cracks, were tested using 3D boundary element method numerical models. The models include two with slip patches that reach the surface and three models of blind normal-slip surfaces with different configurations of slip along shallowly-dipping secondary faults. We test the sensitivity of surface deformation to variations in stress drop and rock stiffness. We compare numerical models’ results with line of sight (LOS) surface deformation detected from differential SAR (Synthetic Aperture Radar) interferometry (DInSAR). The variations in fault configuration, rock stiffness and stress drop associated with the earthquake considerably impact the pattern of surface subsidence. In particular, the models with a coseismic slip patch that does not reach the surface have a better match to the line of sight coseismic surface deformation, as well as better match to the aftershock pattern, than models with rupture that reaches the surface. The coseismic slip along shallowly dipping secondary faults seems to provide a minor contribution toward surface deformation.

scholarly journals Numerical models for ground deformation and gravity changes during volcanic unrest: simulating the hydrothermal system dynamics of an active caldera

2015 ◽  
Vol 7 (3) ◽  
pp. 2055-2107 ◽  
Author(s):  
A. Coco ◽  
J. Gottsmann ◽  
F. Whitaker ◽  
A. Rust ◽  
G. Currenti ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Pore Pressure ◽  
Hydrothermal System ◽  
Ground Deformation ◽  
Numerical Models ◽  
Gravity Data ◽  
Ground Surface ◽  
Campi Flegrei ◽  
Hazard Evaluation ◽  
Gravity Changes

Abstract. Ground deformation and gravity changes in active calderas during periods of unrest can signal an impending eruption and thus must be correctly interpreted for hazard evaluation. It is critical to differentiate variation of geophysical observables related to volume and pressure changes induced by magma migration from shallow hydrothermal activity associated with hot fluids of magmatic origin rising from depth. In this paper we present a numerical model to evaluate the thermo-poroelastic response of the hydrothermal system in a caldera setting by simulating pore pressure and thermal expansion associated with deep injection of hot fluids (water and carbon dioxide). Hydrothermal fluid circulation is simulated using TOUGH2, a multicomponent multiphase simulator of fluid flows in porous media. Changes in pore pressure and temperature are then evaluated and fed into a thermo-poroelastic model (one-way coupling), which is based on a finite-difference numerical method designed for axi-symmetric problems in unbounded domains. Based on data for the Campi Flegrei caldera (Italy), a series of simulations assess the influence of fluid injection rates and mechanical properties on the hydrothermal system, uplift and gravity. Heterogeneities in hydrological and mechanical properties associated with the presence of ring faults are a key determinant of the fluid flow pattern and consequently the geophysical observables. Peaks (in absolute value) of uplift and gravity change profiles computed at the ground surface are located close to injection points (namely at the centre of the model and fault areas). Temporal evolution of the ground deformation indicates that the contribution of thermal effects to the total uplift is almost negligible with respect to the pore pressure contribution during the first years of the unrest, but increases in time and becomes dominant after a long period of the simulation. After a transient increase over the first years of unrest, gravity changes become negative and decrease monotonically towards a steady state value. Since the physics of the investigated hydrothermal system is similar to any fluid-filled reservoir, such as oil fields or CO2 reservoirs produced by sequestration, the generic formulation of the model will allow it to be employed in monitoring and interpretation of deformation and gravity data associated with other geophysical hazards that pose a risk to human activity.

scholarly journals The Multiple Aperture SAR Interferometry (MAI) Technique for the Detection of Large Ground Displacement Dynamics: An Overview

2020 ◽  
Vol 12 (7) ◽  
pp. 1189 ◽  
Author(s):  
Pietro Mastro ◽  
Carmine Serio ◽  
Guido Masiello ◽  
Antonio Pepe
Keyword(s):  
Time Series ◽  
Synthetic Aperture Radar ◽  
Surface Deformation ◽  
Ground Deformation ◽  
Ground Surface ◽  
Surface Displacement ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Signal Spectrum ◽  
Aperture Radar

This work presents an overview of the multiple aperture synthetic aperture radar interferometric (MAI) technique, which is primarily used to measure the along-track components of the Earth’s surface deformation, by investigating its capabilities and potential applications. Such a method is widely used to monitor the time evolution of ground surface changes in areas with large deformations (e.g., due to glaciers movements or seismic episodes), permitting one to discriminate the three-dimensional (up–down, east–west, north–south) components of the Earth’s surface displacements. The MAI technique relies on the spectral diversity (SD) method, which consists of splitting the azimuth (range) Synthetic Aperture RADAR (SAR) signal spectrum into separate sub-bands to get an estimate of the surface displacement along the azimuth (sensor line-of-sight (LOS)) direction. Moreover, the SD techniques are also used to correct the atmospheric phase screen (APS) artefacts (e.g., the ionospheric and water vapor phase distortion effects) that corrupt surface displacement time-series obtained by currently available multi-temporal InSAR (MT-InSAR) tools. More recently, the SD methods have also been exploited for the fine co-registration of SAR data acquired with the Terrain Observation with Progressive Scans (TOPS) mode. This work is primarily devoted to illustrating the underlying rationale and effectiveness of the MAI and SD techniques as well as their applications. In addition, we present an innovative method to combine complementary information of the ground deformation collected from multi-orbit/multi-track satellite observations. In particular, the presented technique complements the recently developed Minimum Acceleration combination (MinA) method with MAI-driven azimuthal ground deformation measurements to obtain the time-series of the 3-D components of the deformation in areas affected by large deformation episodes. Experimental results encompass several case studies. The validity and relevance of the presented approaches are clearly demonstrated in the context of geospatial analyses.

In Situ Tests on Creep Behavior of Rock Mass with Joint or Shearing Zone in Foundation of Large-Scale Hydroelectric Projects

2004 ◽  
Vol 261-263 ◽  
pp. 1097-1102 ◽  
Author(s):  
Jian Liu ◽  
Xia Ting Feng ◽  
Xiu Li Ding ◽  
Huo Ming Zhou
Keyword(s):  
Rock Mass ◽  
Creep Behavior ◽  
Large Scale ◽  
Time Dependent ◽  
Three Gorges Project ◽  
Three Gorges ◽  
The Three Gorges ◽  
The Three Gorges Project

The time-dependent behavior of rock mass, which is generally governed by joints and shearing zones, is of great significance for engineering design and prediction of long-term deformation and stability. In situ creep test is a more effective method than laboratory test in characterizing the creep behavior of rock mass with joint or shearing zone due to the complexity of field conditions. A series of in situ creep tests on granite with joint at the shiplock area of the Three-Gorges Project and basalt with shearing zone at the right abutment of the Xiluodu Project were performed in this study. Based on the test results, the stress-displacement-time responses of the joints and basalt are analyzed, and their time-dependent constitutive model and model coefficients are given, which is crucial for the design to prevent the creep deformations of rock masses from causing the failure of the operation of the shiplock gate at the Three-Gorges Project and long-term stability of the Xiluodu arc dam.

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 Sub-Level Stoping in an Underground Limestone Quarry: An Analysis of the State of Stress in an Evolutionary Scenario

2016 ◽  
Vol 61 (1) ◽  
pp. 199-216 ◽  
Author(s):  
Marilena Cardu ◽  
Sergio Dipietromaria ◽  
Pierpaolo Oreste
Keyword(s):  
Numerical Models ◽  
The State ◽  
In Situ Tests ◽  
Future Scenario ◽  
Limestone Quarry ◽  
Geomechanical Properties ◽  
State Of Stress ◽  
Upper Level ◽  
Pillar Structure

Abstract The aim of this study was to evaluate the state of stress of a „voids-pillar“ structure excavated by means of the sub-level stoping method in an underground limestone quarry near Bergamo (Italy). Both the current structure of the quarry (i.e. the rooms exploited till now) and a possible future scenario were analysed using the (FDM) FLAC 2D code. The quarry has been in operation since 1927; at present, exploitation is carried out underground via the sub-level stoping method. Exploitation involves two levels, with 5 rooms on the upper level and 9 rooms on the lower level. After analysing data obtained from laboratory and in situ tests carried out on rock samples and natural discontinuities, the geomechanical properties of the medium, knowledge of which is essential in order to establish the parameters that must be included in the numerical model, were evaluated. The implementation of three numerical models made it possible to study both the present conditions of quarry exploitation and the evolution of the exploited rooms, as well as a possible expansion involving a third level of rooms. Using the results obtained regarding the stress-strain present in the pillars, a potential change in room geometry was proposed aimed at reducing the stress state inside the pillars, decreasing plasticity and increasing overall quarry safety.

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