Differential Interferometric Synthetic Aperture Radar Research Articles

Sentinel-1 A-DInSAR Approaches to Map and Monitor Ground Displacements

Persistent scatterer interferometry (PSI) is a group of advanced interferometric synthetic aperture radar (SAR) techniques used to measure and monitor terrain deformation. Sentinel-1 has improved the data acquisition throughout and, compared to previous sensors, increased considerably the differential interferometric SAR (DInSAR) and PSI deformation monitoring potential. The low density of persistent scatterer (PS) in non-urban areas is a critical issue in DInSAR and has inspired the development of alternative approaches and refinement of the PS chains. This paper proposes two different and complementary data-driven procedures to obtain terrain deformation maps. These approaches aim to exploit Sentinel-1 highly coherent interferograms and their short revisit time. The first approach, called direct integration (DI), aims at providing a very fast and straightforward approach to screen-wide areas and easily detects active areas. This approach fully exploits the coherent interferograms from consecutive images provided by Sentinel-1, resulting in a very high sampling density. However, it lacks robustness and its usability lays on the operator experience. The second method, called persistent scatterer interferometry geomatics (PSIG) short temporal baseline, provides a constrained application of the PSIG chain, the CTTC approach to the PSI. It uses short temporal baseline interferograms and does not assume any deformation model for point selection. It is also quite a straightforward approach, which improves the performances of the standard PSIG approach, increasing the PS density and providing robust measurements. The effectiveness of the approaches is illustrated through analyses performed on different test sites.

Three-dimensional strain descriptors at the Earth’s surface through 3D retrieved co-event displacement fields of differential interferometric synthetic aperture radar

In deformation analysis, invariant strain descriptors that are independent of the coordinate system are significant. An approach is proposed to determine the strain tensor and invariant strain quantities through the 3D retrieved co-event displacement of differential interferometric synthetic aperture radar (DInSAR). An optimal cell count is selected based on the proposed rule-of-thumb formula. This set of coherent cells with prescribed acceptable minimum value coherence is distributed on the domain through a quasi-random number generator. The recursive moving least squares method is applied to estimate the components of strain and differential rotation tensors. In practice, this method is not limited to the homogeneous strain field hypothesis. The objective here is to propose an approach to determine the local and regional strain patterns in SAR’s image resolution details. This approach is tested on both synthetic and real data. The real data consist of 3D displacements of 19 global navigation satellite system stations and SAR images of Kilauea Volcano eruption in July 2007. Results indicate that the areas with maximum shear strain and maximum dilatation are located exactly near the east rift zone of the volcano.

An Application of Persistent Scatterer Interferometry (PSI) Technique for Infrastructure Monitoring

In the absence of systematic structural monitoring to support adequate maintenance standards, many existing infrastructures may reach unacceptable quality levels during their life cycle, resulting in significant damage and even potential failure. The metropolitan area of the Gulf of Salerno (Italy), served by a complex multimodal transport network connecting the port area to the roads and railways surrounding the urban area, represents an important industrial and commercial hub at the local and international scale. This particular scenario, developed in a complex morphological and geological context, has led to the interference and overlapping of the transport network (highway, railway, main and secondary roads) that run through the piedmont area north of the port. Given the relevance of the area, our research aims to highlight the capabilities of the persistent scatterer interferometry (PSI) technique, belonging to the group of differential interferometric synthetic aperture radar (SAR), to extract space–temporal series of displacements on ground points or artifacts with millimeter accuracy useful to understand ongoing deformation processes. By using archived data from the European Space Agency missions, i.e., ERS1/2 (European remote-sensing satellite) and ENVISAT (environmental satellite), and the most recent data from COSMO-SkyMed constellations, it was possible to collect a 28-year dataset that was used to spatially analyze displacement patterns at a site-specific scale to check the stability of viaducts and embankments, and on a larger scale to understand the activity of the surrounding slopes. Despite the different resolution and subsequently the ground density, the analysis of the different datasets showed a spatiotemporal consistency in the displacement patterns that concerned two subareas showing significant annual velocity trends, one northeast of the city and the second in the port area. The analysis presented in this paper highlights how a complex geologic area, combining slope movements and various fault systems, could be a major concern for the stability of the overlying infrastructure and also the role that a PSI analysis can play in remotely monitoring their behavior over long periods of time.

Estimation of regional surface deformation post the 2001 Bhuj earthquake in the Kachchh region, Western India using RADAR interferometry

The key objective of the present study is to estimate the surface displacement and to understand/monitor the active deformation pattern in the Kachchh region post the 2001 Bhuj Earthquake by implementing the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) and Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques. We employed the ENVISAT ASAR (15 images), ALOS PALSAR (6 pairs) and SENTINEL-1A (117 images) data sets acquired during the periods 2003–2005, 2007–2009, and 2016–2020 respectively. The PSI results of the Envisat dataset reveals that the Kachchh mainland region has undergone an average surface deformation of ± 22 mm/yr during 2003–2005. The maximum displacement observed from the ALOS PALSAR data sets (Window-1 to 6) during the period 2007–2009 is ∼ ± 1.2 cm. Further, the ground displacement observed from the Sentinel-1A dataset during the period 2016–2020 is ±16 mm/yr for the west-central region and 6 mm/yr uplift and 8 mm/yr subsidence in the eastern Kachchh mainland region. Surprisingly, high rate of deformation is detected towards the Pachham Island, Banni, Rann and the eastern region of the Kachchh after the 2001 Bhuj event. Correlating the results of different data sets, it is concluded that the deformation is high near the vicinity of the fault zones indicating the tectonically active nature of the faults. From the obtained results, we infer that, post the 2001 Bhuj earthquake, the surface displacement in the Kachchh mainland region is escalated till 2009 which is due to continuous aftershock activity and then started declining because of the ongoing seismic settlement. The acquired deformation rates are correlating well with the GPS derived displacement rates. Further, our results will assist in accurately demarcating the extent of the fault zones and also helps in precisely marking the areas undergoing active deformation, which will aid in micro zonation studies, mitigation planning and also for the preparation of an active tectonic map for the region.

D-InSAR monitoring of ground deformation related to the dewatering of construction sites. A case study of Glòries Square, Barcelona

The aim of this paper is to demonstrate how the integration of differential interferometric synthetic aperture radar (D-InSAR) and levelling improves the monitoring of ground deformation phenomena, thereby enabling their complete understanding. The complementarity between D-InSAR and levelling is illustrated through a case study of the construction of a road tunnel beneath Glòries Square, Barcelona; D-InSAR is employed to continuously monitor the works, notably the dewatering of the site. This study focuses primarily on D-InSAR data obtained from the processing of Sentinel-1A data following a persistent scatterer interferometry procedure. The spatial distribution of the deformation and its temporal evolution are analysed with detailed hydrogeological and piezometric data. The magnitude of deformation is discussed using levelling data and an analytical estimation based on the hydromechanical parameters of the ground obtained from a pre-existing hydrogeological numerical model and pumping tests. The D-InSAR results are shown to be essential for identifying the origin of ground deformation and the constraints on its spread. Such observations at the construction site and district (~2 km radius) scales with sub-centimetric deformation are precious contributions of D-InSAR data, whereas levelling offers a more accurate quantification of the deformation, although this remains an open issue to be further investigated. • Differential interferometric SAR as monitoring technique in civil works. • Ground deformation related to the dewatering of construction works. • Hydrogeological interpretation of D-InSAR results. • Complementarity of differential interferometric SAR and levelling.

Land subsidence estimation using DinSAR method ALOS PALSAR image in Padang City West Sumatra, Indonesia

Land subsidence is a phenomenon that occurs in big cities around the world and in Indonesia. Padang as one of the largest cities in West Sumatera also facing land subsidence due to natural phenomena and human induced. Padang City is located at the west coast of Sumatera Island which is the junction point of three active plates that cause frequent earthquakes. Main goals of this research are to know the distribution of area affected by land subsidence, to know the estimated value of land subsidence and to know the value of the velocity of land subsidence in Padang area using DInSAR method. The data used in this study is ALOS PALSAR Image Level 1.1 of Padang city during 2007 to 2010 was obtained through JMRSL CERES Chiba University, Japan and collected through Alaska Satellite Facility website. Differential Interferometric Synthetic Aperture Radar (DInSAR) is a technique considered to be one of the most efficient technique for detecting land subsidence. The DInSAR method is used in mapping altitude changes developed into a land-subsidence map each year. The mapping results show the distribution of the areas affected by the maximum land subsidence in Padang area of West Sumatera are Padang Utara, Nanggalo, and Padang Barat Subdistricts. The land subsidence insignificant occurred is Padang Selatan and Lubuk Begalung Subdistricts. The estimated value of the land subsidence distribution in Padang area using DInSAR method has decreased significantly after the earthquake of September 30, 2009 in Padang Utara, Nanggalo and West Padang Subdistricts is around 0 - 32.70 cm, and the value of land subsidence velocity is around 0.13 - 12 cm/year. One of the expected effects of land subsidence can be increased in the area susceptible for flooding in Padang city.

Assessment of groundwater depletion–induced land subsidence and characterisation of damaging cracks on houses: a case study in Mohali-Chandigarh area, India

The present study identified groundwater depletion–induced land subsidence by spaceborne differential interferometric SAR (DInSAR) technique and assessed the damaging impacts of land subsidence by characterising the cracks on houses in Mohali-Chandigarh area of India. First, we identified groundwater depletion hot spots using pre-monsoon and post-monsoon groundwater-level (GWL) data of Central Ground Water Board (CGWB), India, for the period of 2005–2018. Both conventional and advanced DInSAR techniques were used to identify temporally consistent subsiding areas and measure precise rates of subsidence in and around groundwater depletion hot spots. We studied the damaging impacts of land surface deformation by characterising the damaging cracks on houses in affected areas. Groundwater depletion and resulting aquifer-system compaction increase effective stress on confining clay layer which leads to stress build-up at the soil-structure interface and causes damaging cracks on houses. A variety of damaging cracks on houses were observed at the affected areas such as Sohana, Landran, Kharar and Kurali localities. We attempted to characterise the damaging cracks on the basis of shape, size, orientation, surface morphology and texture of the cracks; sense of ground movement; and nature of stress build-up at the interface. We identified tensional cracks, compressional cracks and shear cracks with diverse orientations and separation widths. Finally, a comparative assessment of groundwater depletion, land subsidence and damaging impacts on houses has been made. Using DInSAR technique, we identified land subsidence in and around the groundwater depletion areas in Sohana and Landran (both in Mohali City area), Kharar and Kurali (in Mohali district outside Mohali City area) and Sectors 27–28 in Chandigarh with radar line-of-sight subsidence rates of ~6–7.5 cm/year, ~5.5–6.5 cm/year, and ~ 4 cm/year respectively. We observed that the houses in and around Landran appears to be worst affected followed by Kharar, Sohana and Kurali. From this study, it appears that the type of construction of the houses, e.g. prevalence of masonry and reinforced masonry structures, is primarily responsible for the worst damaging impacts of the houses in Landran and Kurali areas besides the magnitude of land subsidence.

Detection of active landslides by DInSAR in Andean Precordillera of San Juan, Argentina

Landslides are downslope mass movements, which implies the combination of natural complex processes and sometimes affect anthropic resources. Many researchers inventoried landslides in the Argentinian Andean Precordillera by using aerial photography, satellite images, geomorphological analyses and GPS measures. Those located in latitudes between 31°S and 34°S have been mainly linked to seismic activity. However, due to the inaccessibility of sites, permanent monitoring has proved difficult. In this contribution, we detect three active landslides occurring in the Andean Precordillera of San Juan province using Differential Interferometric Synthetic Aperture Radar (DInSAR) based time series techniques and preliminary characterize its geomorphology. We use data provided by ESA's Sentinel 1 (C-Band SAR), Sentinel 2 (Optical) acquired between October 2014 and December 2018. The observed landslides are located at unstable hillsides oriented to the West and their deposits could potentially end in the San Juan River. As a result of the time series analysis, we interpreted that the three landslides seem to be reactivated by Illapel Mw 8.3 Earthquake (September 16th, 2015). In addition, one of them, has an acceleration at the beginning of 2016, linked to rapid snow melt.

SBAS-InSAR deformation reconstruction based on low-rank matrix completion in southern Zibo, China

As an advanced form of differential interferometric synthetic aperture radar (DInSAR), small baseline subset (SBAS)-interferometric synthetic aperture radar (InSAR) boasts large space coverage and high precision and provides an effective monitoring technique for ground deformations. Maintaining high coherence through the monitoring process is a common method for SBAS-InSAR to select ground stable points. Usually, such points are obtained with small temporal and spatial baselines. However, it is unlikely to maintain high coherence in non-urban and non-rock landscapes, due to the change of surface cover or vegetation growth. This change is common in long-term surface deformation. Even with a high average coherence, an interferogram still contains many low coherence areas, where it is difficult to implement phase unwrapping or collect sufficient deformation information. This often results in an incomplete spatial image of the deformation pattern, which hinders the interpretation and research of surface deformation. What is worse, surface deformation might not be detected at all in incoherence areas. To solve these problems, this paper proposes a low-rank matrix completion method to complete the low coherence areas, making the interferograms complete. Then, the general SBAS method was followed to extract the deformed time series. The proposed strategy was applied to the time series monitoring of surface deformation of a 250-km2 area in southern Zibo, China, from January 2, 2016, to March 22, 2018. Compared with the traditional SBAS method, the proposed method can obtain more information of surface deformation. The complete deformation information of the area is obtained.

Optimization of three-dimensional multi-level surface deformation in mining areas through integration of deformation fusion model and Lagrange multiplier method based on single high resolution OTD-InSAR pair

Underground longwall mining activities usually induce three-dimensional (3-D) multi-level surface deformation, which could lead to serious natural hazards. Offset-tracking (OT) and differential interferometric synthetic aperture radar (DInSAR) technology (referred to as OTD-InSAR) can be used to observe the large-level and small-level mining deformations based on single InSAR pair, but the measured deformation is only along the radar line-of-sight (LOS) or the azimuth directions rather than in the 3-D directions. The conventional InSAR-based methods to resolve 3-D mining deformation have the strict restrictions and low south-north accuracy. In this paper, a novel methodology is proposed to utilize a multi-level deformation fusion model and the Lagrange multiplier method based on single OTD-InSAR pair (hereafter called MAOTD-InSAR) to estimate and optimize the 3-D multi-level surface deformation. The Daliuta coal mining area of China was selected to verify the feasibility and precision of the proposed method using high resolution TerraSAR-X (TSX) SAR images with six pairs. Results show that the root mean square errors (RMSEs) of MAOTD-InSAR against in-situ measured data are less than 0.2214 m, 0.1612 m and 0.1880 m in the east, north and vertical directions, respectively. The minimum RMSE in the horizontal direction could reach 0.0361 m with an improvement of about 82.6%, which particularly improve the accuracy in the south-north direction for the TSX satellite since its direction of azimuth deformation is approximately north direction, and this is also adequate for the other satellites in the near-polar orbit. In addition, an empirical model was generated with respect to the gradients of ground fissures on horizontal deformation, and this model enabled us to remove large errors caused by ground fissures. The verification results show that the proposed method provides higher precision and reliability for the resolved 3-D multi-level surface deformation, which presents 3-D mining deformation with more details from the edge to the center of the subsidence basin and will show some possibilities for new findings and interpretations in the process of coal mining.

Estimation of Coseismic Deformation With Multitemporal Radar Interferometry

Differential interferometric synthetic aperture radar (DInSAR) has been widely used as one of the most important technologies for determining coseismic deformation. However, DInSAR processing is often perturbed by errors including atmospheric effects and those in topographic models, SAR satellite orbits, and phase unwrapping operation. These nuisance components can degrade the accuracy of the measurements and, therefore, distort the inversion of fault slips especially for moderate earthquakes. We propose in this letter a multitemporal InSAR (MTInSAR) method aiming to accurately determine coseismic deformation. By jointly analyzing a set of preseismic SAR images and one postseismic image, the method allows effective separation of coseismic deformation from topographic and satellite orbital errors deformation based on the distinct spatio-temporal characteristics of the signals. Since the solution is achieved directly from wrapped differential phases, the retrieved deformation is also immune to phase unwrapping errors. The October 6, 2008 Mw 6.3 Dangxiong, China earthquake is studied with the proposed method as an example. The slip inverted, respectively, from the MTInSAR and DInSAR coseismic deformation measurements shows up to 34-cm differences, indicating that the topographic error and inaccurate removal of orbital errors can bias the fault slip inversion.

The application of DInSAR and Bayesian statistics for the assessment of landslide susceptibility

The use of an inventory map of past landslide events in the derivation of susceptibility models is considered common practice. However, evidence of landslide activity may be lost due to various degrees of modification by subsequent landslides, erosional processes, vegetation growth and anthropic influences. The timely detection of active landslides can form an effective supplement to landslide records for improving the accuracy of landslide susceptibility maps. In this paper, we present a landslide susceptibility assessment carried out in a southwestern region of Cyprus using a synergy of differential interferometry and evidential statistics. A measurement of the vertical and horizontal displacements for the period 2016–2018 was done using the Small BAseline Subset multi-pass Differential Interferometric Synthetic Aperture Radar technique. Based on the results, a total of 8859 raster cells/pixels were classified as active landslides. The weight-of-evidence technique was applied to determine the weights of seven geomorphological and hydrological factors to landslide occurrence and compile a susceptibility model. The success and prediction rates of the derived model were calculated as 79.6% and 78.9%, respectively. The validation of the results against the existing landslide inventory indicates an 84% agreement with respect to the moderate and high landslide susceptibility zones. The proposed methodology can complement existing conventional landslide inventories as a means of providing updated landslide activity at frequent intervals and can provide valuable information regarding the distribution of landslides to support a detailed landslide assessment.

November 08, 2019 Turkmanchay earthquake (Mw: 5.9) in NW Iran: an assessment of the earthquake using DInSAR time-series and field evidence

The arc-shaped Bozgush Mountains is a remarkable morphological feature bounded by active faults in northwest Iran. The southern and northern parts of the mountain belt are limited by the South and North Bozgush Fault Zones, which produced numerous destructive earthquakes in historical and instrumental periods. We employed the Sentinel-1A Differential Interferometric Synthetic Aperture Radar (DInSAR) method to map the deformation details of the November 08, 2019, Turkmanchay earthquake (Mw: 5.9) along the South Bozgush Fault Zone to understand the earthquake-triggered surface deformations and seismogenic faulting characteristics. The results of the DInSAR time-series analysis show that subsidence and uplift range from − 5 cm to + 6 cm, respectively. The total line of sight (LOS) displacement was approximately 11 cm. Interferogram fringes and deformation patterns indicate that the direction of the potential seismogenic fault is WNW-ESE. These patterns are consistent with the orientation of the South Bozgush Fault Zone, including primarily right-lateral strike-slip characteristics with reverse components. Continuous patterns of the obtained interferogram fringes indicate that surface rupture did not occur during the earthquake. Our Coulomb failure function results in preferred faults derived from geological structures, indicating that the stress rate was positive and high in several segments of the South and North Bozgush Faults, revealing that the main earthquake event might trigger those faults. The large aftershocks that occurred on the same faults supported our results, and the distribution of aftershocks in the Bozgush Mountains suggests that the WNW-ESE orientation is consistent with the orientation of segments constituting the South Bozgush Fault Zone.

Mining Subsidence Prediction Parameter Inversion by Combining GNSS and DInSAR Deformation Measurements

Line of Sight (LOS) deformation based on Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques cannot be used in traditional probability integration method (PIM) parameter inversion. To improve the accuracy of parameter inversion, a model based on 3D deformation was proposed. The model simulates 3D deformation using PIM directly. The inverse of the Sum of the Squared Errors (SSE) of the PIM results and the measured deformation results was used as a fitting function within the GA. Reliable PIM parameters can be obtained based on this GA model. To identify the surface movement law of the Jinfeng coal mine, 6 Global Navigation Satellite System (GNSS) monitor points were established over the 011207 and 011809 working panels. Due to the limited number of points and the large distance between the points, it is not sufficient to obtain reliable PIM parameters using GNSS only. As a complement, 83 Sentinel-1A images were analyzed with small baseline subset (SBAS) DInSAR, and the LOS direction deformation was obtained. The reliable PIM parameters were calculated with the 3D inversion model based on the combination of LOS direction deformation and GNSS-monitored deformation. Then, those parameters were used to predict the coal mine deformation of panels 011207 and 011809, which demonstrated that the prediction results coincide with the measured results. The model can be used to study the laws of mining subsidence combined with DInSAR and GNSS, which can reduce the requirements of the number of GNSS points and the impact of radar decoherence. This provides a new technical approach for studying the law of surface movement in mining subsidence research.

Time Series Deformation Monitoring over Large Infrastructures around Dongting Lake Using X‐Band PSI with a Combined Thermal Expansion and Seasonal Model

The long‐term spatial‐temporal deformation monitoring of densely distributed infrastructures near the lake area is of great significance to understand the urban health status and prevent the potential traffic safety problems. In this paper, the permanent scatterer interferometry (PSI) technology with TerraSAR‐X imagery over the area around Dongting Lake was utilized to generate the long‐term spatial‐temporal deformation. Since the X‐band SAR interferometric phases are highly influenced by the thermal dilation of the observed objects, and the deformation of large infrastructures are highly related to external temperature, a combined deformation model considering the thermal expansion and the seasonal environmental factors was proposed to model the temporal variations of the deformation. The time series deformation and the thermal dilation parameter over the area were obtained, and a comparative study with the traditional linear model was conducted. The Dongting Lake Bridge and the typical feature points distributed around the lake were analyzed in details. In order to compensate for the unavailability of external in situ measurements over the area, phase residuals and the subsidence generated through Differential Interferometric Synthetic Aperture Radar (D‐InSAR) were utilized to verify the accuracy of the obtained deformation time series. Experiment results suggested that the proposed model is suitable and suggested for the selected study site. The root mean square error (RMSE) of the residual phase was estimated as 0.32 rad, and the RMSE compared with D‐InSAR derived deformation was ±1.1 mm.

Pyrenees deformation monitoring using Sentinel-1 data and the Persistent Scatterer Interferometry technique

Abstract This study focuses on deformation mapping and monitoring using Sentinel-1 radar data and the DInSAR (Differential Interferometric Synthetic Aperture Radar) technique. In particular, a Persistent Scatterer Interferometry technique was used over 15000 km2 of the Pyrenees, located in Spain, Andorra and France. The main goal is to monitor deformations over a vegetated and mountainous region by exploiting the wide-area coverage, the high coherence and temporal sampling provided by the Sentinel-1 satellites. All possible interferograms were generated using 150 images covering five years. The velocity map of the entire region is presented considering the characteristics of the study area, including vegetation and severe steep mountains. Two areas of deformation are shown, which are characterized by velocity values ranging between -20 to -40 mm/year.

Identifying Land Subsidence Using Global Digital Elevation Models

Recent developments in space-based surveying methods of the Earth's topography, including the differential interferometric synthetic aperture radar (DInSAR), have increased the availability of options for monitoring land subsidence. However, DInSAR methods require expert knowledge and specialized software, and they are time-consuming. Here, we demonstrate that a land subsidence signal can be identified in the differences in the freely available global digital elevation models (e.g., SRTM and TanDEM-X) using a simple statistical method. This finding opens up a venue to develop a computer application to identify land subsidence or uplift of a few decimeters per at least a decade order. Such an application enables monitoring the effects of underground mining, seismic/tectonic movements, landslides, volcanic activities, and similar effects on the Earth's topography. It can also provide a valuable and cost-effective tool for studying land deformation.

Geomorphologic Domination on Urban Sprawl of Southern Riyadh, Saudi Arabia Using Differential Interferometric Synthetic Aperture Radar (DInSAR)

This study tests the southern part of the Riyadh City growth domination by the Early Quaternary-Holocene trans-tensional Central Arabian graben system reactivation and the subsequent dissolution-induced collapses and karstification. This study utilizes Synthetic Aperture Radar (SAR) and Differential Interferometric Synthetic Aperture Radar (DinSAR) to examine the morphology of arid landscape, south of Riyadh. Eight Single Look Complex (SLC) amplitude images are calibrated, filtered, georeferenced and orthorectified at a resolution of 20 meters, and compared with one another by producing 17 diachronic images of the pairs at different intervals (1996, 2003-2005, 2008). The diachronic SAR intensity imageries suggest a downthrown displacement reaching 600 m and eastward tilting at the bottoms of the grabens. Also, the structurally-controlled valleys are developing an eastward-running drainage system towards the oasis of Al-Kharj and capturing an older hydrologic system. Moreover, a 12-year period (1996-2008) of the SAR data was obtained to examine the average annual rate of southern Riyadh’s urban sprawl, which is estimated at approximately 390 metres/year over the 12 years and constrained by geomorphological features towards the deformed area. DInSAR imageries show the primary results obtained from the 26 May 2004 and 31 Jan. 2005 pair of images, merged with 30 m resolution DEM-SRTM data for the arid region south of Riyadh to eliminate the influence of topography. DInSAR is applied in this study for its ability to detect small displacements at the centimetre scale (1/2 wavelength). Although the DInSAR’s coherence and phase imageries suggest a fairly stable region since the last tectonic and subsequent geomorphic events, erosional and artificial changes are observed, bounded within the valleys and depressions, primarily due to aeolian and fluvial processes and agriculture. It is highly recommended to preserve the area for sustainability and economy.

SIP-Based Inversion Model of Mining-Induced 3D Deformation

Underground mining causes many forms of surface deformation, including vertical subsidence as well as strike and dip horizontal displacement. Differential interferometric synthetic-aperture radar (D-InSAR) has become a widely applied technique for precise and detailed mapping of the Earth's surface deformation caused by underground mining. However, the technology can only detect a one-dimensional displacement in the satellite's line of sight. To address this deficiency, we propose an improved three-dimensional displacement inversion model based on symmetry characteristics (imDIMSC) of a mining subsidence basin by the stacking technology of multiple single-track InSAR pairs. In this study, both field-observed surface displacement and simulated data were applied to calibrate and validate the proposed imDIMSC model. A methodology and algorithm were then developed to determine the symmetrical center for the two special mining circumstances. Comparison of the field-observed data, the proposed methodology, and the imDIMSC model provided significantly more accurate 3D displacement estimations.

4-② 地震前後の衛星SAR画像解析とレーザ地形データ差分解析による造成地周辺の地盤変位

4-② 地震前後の衛星SAR画像解析とレーザ地形データ差分解析による造成地周辺の地盤変位