Ground Deformation Monitoring Research Articles

IESID: Automatic system for monitoring ground deformation on the Deception Island volcano (Antarctica)

When establishing the relative distance between two GNSS–GPS stations with sub-centimeter accuracy, it is necessary to have auxiliary data, some of which can only be collected some time after the moment of measurement.However, for monitoring highly-active geodynamic areas, such as volcanoes and landslides, data precision is not as essential as rapid availability, processing of data in real-time, and fast interpretation of the results.This paper describes the development of an integrated automatic system for monitoring volcanic deformation in quasi real-time, applied to the Deception volcano (Antarctica). This experimental system integrates two independent modules that enable researchers to monitor and control the status of the GNSS–GPS stations, and to determine a surface deformation parameter. It comprises three permanent stations, one of which serves as the reference for assessing the relative distance in relation to the other two. The availability of GNSS–GPS data in quasi real-time is achieved by means of a WiFi infrastructure and automated data processing. This system provides, in quasi real-time, a time series of varying distances that tells us the extent to which any ground deformation is taking place.

GPS monitoring and analysis of ground movement and deformation induced by transition from open-pit to underground mining

Abstract: To trace the potential hazards of open-pit slope in Longshou mine, global positioning system (GPS) is applied to monitoring ground movement and deformation induced by transition from open-pit to underground mining. Through long-term monitoring from 2003 to 2008, huge amounts of data were acquired. Monitoring results show that large-scale ground movement and deformation have occurred in mining area, and the movement area is ellipse-shaped. The displacement boundary of settlement trough is 2.0 km long along the exploratory line, and 1.5 km long along the strike of ore body. GPS monitoring results basically agree with the practical deformation state of open-pit slope. It is indicated that the long-term GPS monitoring is an effective way to understand the mechanism of ground movement and deformation in mine area.

Ground Deformation Monitoring in the Greater Cairo Metropolitan Region (Egypt) by SAR Interferometry

Ground Deformation Monitoring in the Greater Cairo Metropolitan Region (Egypt) by SAR Interferometry

Time Series Synthetic Aperture Radar Interferometry for Ground Deformation Monitoring over a Small Scale Tectonically Active Deltaic Environment (Mornos, Central Greece)

ABSTRACT Parcharidis, I.; Kourkouli, P.; Karymbalis, E.; Foumelis, M., and Karathanassi, V., 2013, Time series synthetic aperture radar interferometry for ground deformation monitoring over a small scale tectonically active deltaic environment (Mornos, Central Greece). This study deals with the estimation of subtle ground deformation at millimetric accuracy over the broader area of the Mornos River delta in Central Greece and its spatio-temporal distribution for the period between 1992 and 2009 through Persistent Scatterers Interferometry (PSI). The results showed that the majority of the scatterers, which show subsidence, are located within the delta plain with mean subsidence rates throughout the delta varying between −7.2 and +0.7 mm/y. An attempt is made to highlight the geographic distribution, the amplitude, and the causes of the observed delta plain subsidence. The positive correlation between the thickness of the fine-grained Holocene deltaic deposits and the subsidence rates reveals that the main...

Monitoring ground deformation in Beijing, China with persistent scatterer SAR interferometry

This paper investigated the long term ground deformation in Beijing, China, using persistent/permanent scatterer interferometry (PSI) techniques. GEOS-PSI (Geodesy and Earth Observing Systems-PSI), an in-house software developed at UNSW for PSI, has been applied to 41 ENVISAT ASAR images acquired over the metropolitan area of Beijing City between June 2003 and March 2009 and 24 ALOS PALSAR images (two Paths: 10 acquisitions from January 2007 to October 2008 and 14 acquisitions from February 2007 to September 2009). The results generated using these datasets from the two satellites were cross-validated. Correlations between the results of ENVISAT ASAR and ALOS PALSAR agreed very well. The horizontal and vertical displacement rate maps over Beijing City were obtained from the results generated with data acquired by both satellites over the period from 1st February 2007 to 1st November 2008. The results indicate that the displacements in Beijing City were mainly in the vertical direction. The majority of the easting displacement rates were in the range of −10 mm/year to 10 mm/year, while the vertical rates were in the range of −115 mm/year to 6 mm/year. The possible cause for the ground deformation is groundwater extraction based on our research as well as earlier published studies.

Integration of InSAR and GPS for Ground Deformation Monitoring

The technique of InSAR have great potential in detecting displacements caused by ground subsidence which sometimes can't be achieved by other methods.But the application and accuracy of InSAR will be influenced because of its some inherent factors and variations of ground plant,humidity and atmosphere at different time.Meanwhile,application of GPS to measures land deformation has become an efficiently and accurately measuring technology.GPS-InSAR integration can enhance the ability of measuring land deformation in both temporal and spatial resolution;it is becoming an emphasis of land subsidence investigation.This paper introduces firstly the complement of the InSAR and GPS.Then,the approach to derive atmospheric corrections to the InSAR images from CGPS datas and the method to remove or mitigate SAR satellite orbit errors using GPS results as constraints are analyzed.Finally,the Double Interpolation and Double Prediction(DIDP) approach for integrating InSAR and GPS results is given.

Advances in space-borne SAR interferometry and its application to ground deformation monitoring

The development of Differential Synthetic Aperture Radar Interferometry (D-InSAR), in terms of its evolution from classic to advanced forms, such as Least-Squares approach, Permanent Scatterer Interferometry, Small Baseline Subset, and Coherent Pixel Technique, is reviewed, describing concisely the main principles of each method and highlighting the difference and relationship between them. Applications of InSAR technology in China were then introduced, together with the obstacles to overcome and feasible strategies, such as integrating MERIS/MODIS data to compensate for the atmospheric effect and GPS, and multi-platform SAR data to make InSAR technique practical and operational under various conditions. The latest developments were then analyzed along with high-quality SAR data, available thanks to the newly launched high-tech satellites, TerraSAR-X, and Cosmo Sky-med, and conclusions were drawn about the main limitations of the technique.

Some challenges of monitoring a potentially active volcanic field in a large urban area: Auckland volcanic field, New Zealand

The city of Auckland (population 1.3 million) is built on and around a potentially active basaltic intraplate volcanic system, the Auckland volcanic field. This monogenetic field of around 50 small volcanoes covers an area of 360 km2 and may have been active for ca. 250 ka. Volcano monitoring can be difficult in small distributed volcanic fields such as the AVF as the next vent location is not known, and traditional techniques such as geochemical and ground deformation monitoring may therefore not be feasible as there is no obvious target for measurements. In such cases, seismic monitoring may be the only technique suitable. High levels of background (cultural) seismic noise and extremely low levels of historical seismicity make volcano monitoring particularly challenging in the AVF. Here, we report on recent attempts to improve monitoring capability in the AVF, which include the installation of downhole seismometers and a seismic refraction study to refine the velocity model used to locate earthquakes. We conclude that downhole instrumentation in a volcano-monitoring network allows better detection of local earthquakes, but note that several downhole sensors would be required for a network to realise the full benefits of downhole instrumentation. Our refinement of the general velocity model for Auckland has some effect on calculated earthquake locations and depths, and we suggest that further work on refining the velocity model and then its incorporation into the GeoNet earthquake location system could help us be better prepared for a future AVF eruption.

Detection of ground deformation over Sharm El-Sheikh–Ras Nasrani coastal zone, South Sinai (Egypt), by using time series SAR interferometry

The investigation area is located in the most southern part of Sinai Peninsula boarded from the west by the Gulf of Suez and from the east by the Gulf of Aqaba. The present study concerns the application of stacking and persistent scattering of SAR interferometry in order to monitor ground deformation in the southern part of Sharm El-Shiekh area. The specific techniques were applied in order to reduce the influence of atmospheric effects on the ground deformation estimates. For this purpose a total number of 26 ENVISAT ASAR scenes covering the period between 2003 and 2009 were processed and analyzed. Interferometric processing results show both patterns of uplift and downlift in the study area. Specifically an area along the coastline with a N–S direction, corresponding to the build up zone of Sharm El-Sheikh, shows annual average subsidence rates between 5 and 7 mm/yr along the line of sight (LOS). On the contrary, Sharm El-Maya, an inner zone, parallel to the above subsided area; shows maximum slant range uplift of 5 mm/yr. The obtained results of both stacking and persistent scattering indicate that the ground deformation in Sharm El-Sheikh–Ras Nasrani coastal zone is attributed to several effecting factors compromising water pumping, lithology, seismicity, and possible active fracture. The contribution of all these factors is discussed in the context.

Ground deformation monitoring using small baseline DInSAR technique: A case study in Taiyuan City from 2003 to 2009

DInSAR technique based on time series of SAR images has been very popular to monitor ground slow deformation in recent years,such as permanent scatterers (PS)method, small baseline subsets (SBAS)method,and coherent targets (CT)method.By taking advantage of PS method and CT method,in this paper,small baseline DInSAR technique is used to investigate the ground deformation of Taiyuan City,Shanxi Province,from 2003 to 2009 by using 23 ENVISAT ASAR images.The experiment results demonstrate that;(1)during this period, four significant subsidence centers have been developed in Taiyuan,namely Xiayuan,Wujiabu, Xiaodian,Sunjiazhai.The largest subsidence center is Sunjiazhai with an average subsidence rate of —77.28 mm/a;(2)The subsidence of the old center,Wanbolin,has slowed down.And the subsidence in the northern region has stopped and some areas even rebounded.(3)The change of subsidence centers indicates that the control measures of closing wells and reducing exploitation taken by the Taiyuan government has achieved initial effects.(4)The experiment results have been validated with leveling data and the accuracy is 2.90 mm,which shows that the small baseline DInSAR technique can be used to monitor urban ground deformation.

Landslide monitoring by corner reflectors differential interferometry SAR

Although the differential interferometric synthetic aperture radar (DInSAR) technique has the potential for monitoring ground deformation with millimetric accuracy, it still suffers from temporal and geometric decorrelation. In this paper, the corner reflectors differential interferometry synthetic aperture radar (CRDInSAR) technique was used to overcome the limitations of conventional DInSAR. We studied the basic principles of CRDInSAR, discussed the calculation of the flat earth and topographic phases based on the geometry of satellite and corner reflectors, presented the phase unwrapping approach for the sparse grid of corner reflectors, then investigated the construction of, and solution to, the unwrapped phase system equation. Subsequently, we applied CRDInSAR to monitor the displacement of the Shuping landslide in Hubei Province, China. In this study, we processed five SAR images on a descending pass acquired by the Environmental Satellite (ENVISAT) Advanced Synthetic Aperture Radar (ASAR) sensor from September 2005 to March 2006, and compared the achieved results of CRDInSAR with Global Positioning System (GPS) measurements at the same time of the SAR data acquisition assumed as reference. The result indicates a good agreement between the measurements provided by the two different techniques, which shows that CRDInSAR allows monitoring of slow landslide deformation in low coherence areas and provides accurate results.

Ground deformation monitoring at Taiwan Light Source due to the construction of Taiwan Photon Source

Taiwan Photon Source is now under construction at NSRRC Taiwan. In order to maintain the Taiwan Light Source (TLS) for normal operation, a hydrostatic levelling system and precision inclination sensor (Leica Nivel 220) were installed both in the storage ring and beamlines to monitor ground deformation arising. This paper presents the monitoring system setup and the circumstances of ground deformation including vertical settlement and floor inclination during the ground breaking period to provide a criterion for TLS operation.

Numerical Study of the Long-Term Performance of an Underground Powerhouse Subjected to Varying Initial Stress States, Cyclic Water Heads, and Temperature Variations

Many large underground structures may be subjected to varying initial stress states, cyclic water heads, and long-term temperature variations. When the maintenance and extension of the service life of such structures are accounted for, their long-term performance under varying initial stress states, cyclic water heads, and temperature variations becomes very important. The authors were involved with the evaluation of the long-term performance of an underground powerhouse in central Japan constructed for a pumped-storage scheme. The evaluations involved both numerical studies on the long-term effects of varying initial stress states, cyclic water heads, and temperature variations on the performance of the powerhouse considering the degradation of support systems and creep phenomenon and the monitoring of ground deformations, temperatures, and vibrations induced by turbines. The outcome of these studies are presented in this article.

PSInSAR as a new tool to monitor pre‐eruptive volcano ground deformation: Validation using GPS measurements on Piton de la Fournaise

The Permanent Scatterers Synthetic Aperture Radar Interferometry (PSInSAR™) is a technique, which aims at ground deformation mapping with millimetric precision. In the framework of the Globvolcano ESA project, we evaluated a PSInSAR derived approach to monitor ground deformation in highly active volcanic areas, based on the example of Piton de La Fournaise. The Permanent Scatterer (PS) velocities show two main areas of deformation: (1) the eastern flank displaying old lava flow subsidence (0.05–0.13 m.y−1); and (2) the summit cone highly disturbed by eruptions. The PS time series for the summit area agree with the cGPS trends with small long‐term (weeks/months) ground displacements preceding eruptions (0.05–0.35 m.y−1) and large rapid ground displacements linked to eruptions. Despite some limitations, such as the loss of coherence during the most rapid ground displacements and lava flow emplacement, PSInSAR and its derived approach provide a reliable inference of the volcano ground deformation over large areas.

Evolution of fluid geochemistry at the Turrialba volcano (Costa Rica) from 1998 to 2008

Turrialba (10°02′N, 83°45′W) is a 3,349-m high stratovolcano belonging to the Holocene “Cordillera Central” volcanic belt of Costa Rica. The summit consists of three EW-oriented craters (East, Central, and West). Since its last eruptive phase (1864–1866), the Central and West craters have displayed modest fumarolic activity, with outlet temperatures clustering around 90°C. In 2001, seismic swarms, ground deformation, and increasing fumarolic activity occurred. From 2005 to 2008, new fumarolic vents opened between and within the Central and West craters, and along the western and southwestern outer flanks of the volcanic edifice. These physical changes were accompanied by a drastic modification in the gas chemistry that can be divided in three stages: (1) hydrothermal (from 1998 to autumn 2001), characterized by the presence of H2O, CO2, H2S, and, to a very minor extent, HCl and HF; (2) hydrothermal/magmatic (autumn 2001–2007), with the appearance of SO2 and a significant increase of HCl and HF; and (3) magmatic-dominated (2007–2008), characterized by increased SO2 content, SO2/H2S > 100, and temperatures up to 282°C. Accordingly, gas equilibrium in the CO2-CH4-H2 system suggests a progressive evolution of the deep fluid reservoir toward higher temperatures and more oxidizing conditions. The chemical–physical modifications of Turrialba in the last decade can be interpreted as part of a cyclic mechanism controlling the balance between the hydrothermal and the magmatic systems. Nevertheless, the risk of rejuvenation of the volcanic activity cannot be excluded, and an appropriate seismic, ground deformation, and geochemical monitoring program is highly recommended. Turrialba lies at a distance of 35 and 15 km from San Jose and Cartago, respectively, the two largest cities in Costa Rica.

Atmospheric anomalies over Mt.Etna using GPS signal delays and tomography of radio wave velocities

Due to the prominent topography of Mt. Etna, the use of satellite geodetic techniques may significantly suffer from atmospheric heterogeneities. This problem mainly affects the DInSAR technique. To overcome these drawbacks the present study attempts to make headway in measuring and interpreting atmospheric anomalies. We used the GAMIT software to obtain the ZTD (Zenith Total Delay) values for the GPS sessions performed on 1996-97, during ERS-2 passes at Mt. Etna. GAMIT software also allows to characterize the statistical behaviour of the tropospheric effects, by using residuals for each station-satellite pair, and to locate the atmospheric anomalies, present mostly at low altitudes. The attempt at using these results to produce a tomography of radio waves velocity of the troposphere suggests that the number of GPS stations used to investigate atmosphere is a critical point in such a study. The three stations are too few to invert anomalies eventually existing in the lower atmosphere. This result is a good starting point for better direct future study to verify the applicability of this tomographic technique to a geodetic network with a higher number of stations, with the aim of characterizing the lower atmosphere of Mt. Etna for a more accurate monitoring of ground deformations.

Ground tilt monitoring at Phlegraean Fields (Italy): a methodological approach

Among geodetic methods used for monitoring ground deformation in volcanic areas, tiltmetry represents the most rapid technique and therefore it is used by almost all the volcanological observatories in the world. The deformation of volcanic building is not only the result of endogenous causes (i.e. dykes injection or magma rising), but also non-tectonic environmental factors. Such troubles cannot be removed completely but they can be reduce. This article outlines the main source of errors affecting the signals recorded by Phlegraean tilt, network, such as the dependence of the tilt response on temperature and to the thermoelastic effect on ground deformation. The analytical procedure used to evaluate about such errors and their reduction is explained. An application to data acquired from the tilt network during two distinct phases of ground uplift and subsidence of the Phlegraean Fields is reported.

Acoustic emission (AE) as a diagnostic tool in geophysics

Acoustic Emissions (AE) are effective for monitoring ground deformation and temporal variation of its porosity. AE are complementary to seismic information, related to the same area, though AE and earthquakes focus on observational evidence concerned with substantially different space- and time-scales. AE information is pertinent (i) either for geodynamically stable areas, where it probes the diurnal thermal and/or tidal deformation, (ii) or for seismic areas where it provides some as yet unexploited precursors, (iii) or for volcanic areas, where it appears capable of recognising precursors originated by some hot fluid that penetrates by diffusion into rock pores, from those associated with eventual plutonic magma intrusions, (iv) and also for monitoring periods of time during which a volcano is «inflated» by underground hot fluids compared to others during which it «deflates». Upon direct comparison between 6 data sets concerned with different physical settings, it seems to be possible (fig. 3 and table II) to distinguish a few significantly different behaviours associated either (i) with a mere compression (such as occurs for Stromboli, Vesuvius, and a sample compressed in the laboratory), or (ii) with a slip strain, such as it typically occurs in association with faulting or with diurnal thermal rock deformation.

Detection and Monitoring of Active Faults in Urban Environments: Time Series Interferometry on the Cities of Patras and Pyrgos (Peloponnese, Greece)

Monitoring of active faults in urban areas is of great importance, providing useful information to assess seismic hazards and risks. The present study concerns the monitoring of the potential ground deformation caused by the active tectonism in the cities of Patras and Pyrgos in Western Greece. A PS interferometric analysis technique was applied using a rich data–set of ERS–1 & 2 SLC images. The results of the interferometric analysis were compared with the tectonic maps of the two cities. Patras show clearer uplift–subsidence results due to the more distinct fault pattern and intense deformation compared to the Pyrgos area, where more diffused deformation is observed, with no significant displacements on the surface.

Estimating Spatiotemporal Ground Deformation With Improved Persistent-Scatterer Radar Interferometry$^\ast$

Synthetic aperture radar interferometry has been applied widely in recent years to ground deformation monitoring although difficulties are often encountered when applying the technology, among which the spatial and temporal decorrelation and atmospheric artifacts are the most prominent. The persistent-scatterer interferometric synthetic aperture radar (PS-InSAR) technique has overcome some of the difficulties by focusing only on the temporally coherent radar targets in a time series of synthetic aperture radar (SAR) images. This paper presents an improved PS-InSAR technique by introducing PS-neighborhood networking and empirical mode decomposition (EMD) approaches in the PS-InSAR solution. Linear deformation rates and topographic errors are estimated based on a least squares method, while the nonlinear deformation and atmospheric signals are computed by singular value decomposition and the EMD method. An area in Phoenix, AZ, is used as a test site to determine its historical subsidence with 39 C-band SAR images acquired by European Remote Sensing 1 and 2 satellites from 1992 to 2000.