Multi-temporal InSAR Analysis Research Articles

Dynamics of the 2021 unrest at Changbaishan Tianchi volcano from ALOS-2/PALSAR-2 and seismic data

The Changbaishan Tianchi intraplate volcano is one of the most active and hazardous volcanoes of NE Asia, characterized by a summit caldera formed after the 946 CE ‘Millennium’ Plinian eruption. From December 2020 to June 2021, the frequency and magnitude of earthquakes at Tianchi were significantly higher than during background periods, with hundreds of earthquakes (46 events per month in average) and reaching a local magnitude of ML 3.1. This study reports a comprehensive deformation analysis and geophysical inversion scheme aimed to unveil the dynamics of this period. Multi-temporal InSAR analysis results of 32 ALOS-2 images from 2018 to 2022 show that the surface deformation is a combination of seasonal fluctuations (± 25 mm in average, with a maximum ± 45 mm) and a long-term positive component. The least squares linear regression of the deformation time series and temperature data, isolates the seasonal fluctuations, revealing a clear uplift-subsidence process from June 2020 to July 2021 in the caldera area. To constrain the Tianchi plumbing system dynamics, a combined inversion scheme consisting of three deformation sources is designed. The inversion results and the seismic records indicate that Tianchi volcano has experienced a low-level unrest episode from December 2020 to June 2021. The shallower plumbing system, located at about 5–9 km depth and modelled by pressurized spheroids, underwent a cumulative volume increase of 26 × 106 m3 from November 2018 to April 2021, followed by a volume decrease of 9 × 106 m3 from April to July 2021. This suggests magma uprising from the 14 km deep storage zone to the shallower plumbing system, followed by depressurization of the plumbing system due to the escape of fluids. This research provides a comprehensive understanding of the magma and fluid migration dynamics within the Tianchi multi-level plumbing system for the first time.

Along-strike variations of strain partitioning within the Apennines determined from large-scale multi-temporal InSAR analysis

In the Apennine Mountains of the Italian Peninsula, GPS data display 3–4 mm/yr of divergent motion oriented N50°E between the Adriatic and Tyrrhenian coastlines. However, the mechanisms driving this extension remain debated and along-strike variations of extension within the actively deforming belt remain poorly constrained. Here, we derived the first large-scale extensional and vertical velocity field for the Apennines by multi-temporal InSAR analysis of 7 years of Sentinel-1 data at the scale of the entire range, improving the spatial resolution and vertical accuracy of existing GPS measurements. The results reveal along-strike variations of extensional rates and gradients, with extension concentrated on single fault systems in the north, consistent with the loci of seismicity and recent moderate earthquakes, and distributed throughout the central Apennines, where the range is widening. Vertical surface displacements do not resolve any active long-wavelength uplift of the orogenic belt and, on average, show more subsidence than uplift relative to the Tyrrhenian and Adriatic coasts. This work provides the first InSAR-based geodetic map of differential extension and uplift within the Italian Peninsula. Our results are compatible with a pure shear extensional model of the crust, driven by both boundary and gravitational forces.

Multi-sensor and multi-temporal approach in monitoring of deformation zone with permanent monitoring solution and management of environmental changes: A case study of Solotvyno salt mine, Ukraine

Salt deposits were a rich source of mineral resources in the past, and some are still mined today. However, salt mines, especially abandoned ones, pose a threat to populated areas, infrastructure and the natural environment. Solotvyno (Ukraine) is one of the most significantly affected areas, with a deformation zone where significant year-on-year subsidences occur. Mining activities have caused a disturbance of the balance in the mountain massif, and as a consequence, the mountains are being reshaped, and the land cover is deformed. Deformation zone of the historical salt mine Solotvyno (Ukraine), Tyachiv district of Zakarpattia region is situated on the right bank of the Tisza river in the border area with Romania in Central Europe. This paper deals with the multi-sensor monitoring of the active deformation zone over the Solotvyno salt mine using satellite radar data (Sentinel-1), optical satellite imagery (Pleiades, SPOT) and in-situ UAV photogrammetry. Since the area represents a significant geohazard from a hydrogeological (Tisza River) and civil security standpoints (infrastructure of the inhabited regions), the design of a high-precision monitoring system to monitor and evaluate current environmental changes is proposed. Multi-temporal InSAR analysis exposed steeper subsidence tendencies of >−2 cm in the central part of the monitored area. Optical satellite and UAV images confirmed the increase in water surface in sinkhole areas up to 28,500 m2 and proved the emergence of new sinkholes in the central part of the Solotvyno mine. The aim of this study is to describe the post-collapse deformation processes by Pleiades and SPOT multi-spectral sensors and Sentinel-1 satellite SAR sensors since the 2010 collapse in order to describe the trends of deformation due to undermining and propose a high-precision permanent monitoring system based on satellite radar interferometry (InSAR).

Extending polarimetric optimization of multi-temporal InSAR techniques on dual polarized Sentinel-1 data

The rationale of combining polarimetric SAR data with multi-temporal InSAR techniques, which is based on polarimetric optimization, is to improve their performance in identifying coherent pixels and increasing the accuracy of deformation monitoring. This paper extended the polarimetric optimization of Persistent Scatterer Interferometry (PSI) and Small Baseline Subset (SBAS) techniques on dual-polarized Sentinel-1 data. For this purpose, 20 dual-polarization (VV/VH) SAR images acquired by the Sentinel-1A sensor were used. The results indicated that by applying polarimetric optimization on dual-polarized data in the SBAS technique, the number of candidate and final coherent pixels increased 2.95 and 1.42 times, respectively. Similarly, the number of candidate and final coherent pixels (CP) increased 3.12 and 1.45 times in the PSI technique, respectively. Also, the effect of the polarimetric optimization on increasing the density of coherent points in different regions was investigated. In this framework, Sentinel-2 time-series images were classified into four classes (bare soil, vegetation, build-up, and others) using Google Earth Engine by applying remote sensing indices. This demonstrated that polarimetric optimization of the SBAS technique was more effective in bare soil and vegetated regions than in urban areas. However, polarimetric optimization of the PSI technique was more successful in non-urban regions than in urban areas. An external comparative analysis was also performed between the deformation results derived by PSI and SBAS techniques and GPS observation. The evaluation demonstrated that polarimetric optimization coupled with multi-temporal InSAR analysis yielded more reliable deformation results than conventional single-polarimetric data.

A methodology to characterize 4D post-failure slope instability dynamics using remote sensing measurements: A case study of the Aniangzhai landslide in Sichuan, Southwest China

A massive landslide often causes long-lasting instability dynamics that need to be analyzed in detail for risk management and mitigation. Multiple satellite remote sensing observations, in-situ measurements, and geophysical approaches have been jointly implemented to monitor and interpret the life cycle of landslides and their failure mechanisms from various perspectives. In this work, we propose a framework where satellite optical and synthetic aperture radar (SAR) remote sensing techniques are combined with feature extractions using independent component analysis (ICA) and a mathematical relaxation model to assess the complete four-dimensional (4D) spatiotemporal patterns of post-failure slope evolution. The large, deep-seated Aniangzhai landslide in Southwest China that occurred on 17 June 2020 is comprehensively analyzed and characterized for its post-failure mechanism. Time series of Planet high-resolution optical images are first explored to derive the large horizontal motions for the first six months after the failure. Spatiotemporal dynamics of line-of-sight (LOS) displacement in the landslide body are then derived between November 2020 and February 2022 by combining 40 TerraSAR-X (TSX) High-resolution Spotlight (HS) images and 76 medium-resolution Sentinel-1 (S1) SAR datasets using Multi-temporal InSAR (MTI) method. The InSAR-derived results are subsequently analyzed with ICA to find common deformation components of points between optical and MTI results, indicating the same temporal evolution in the deformation pattern. Finally, the complete 4D deformation field for the whole post-failure period is modeled using a decaying exponential model representing stress relaxation after the failure by integrating multiple remote sensing datasets. Cross-correlation analysis of Planet imagery shows a decaying exponential pattern of post-failure displacements with an approximately 94% reduction in the deformation rate after six months with respect to the co-failure event. MTI analysis suggests a maximum LOS displacement rate of approximately 30 cm/year over the main failure body from November 2020 to February 2022; while the high-resolution TSX datasets show irreplaceable advantages in choosing the number of measurement points in MTI analysis with the number of measurement points being five times larger than those obtained by S1 datasets. The ICA analysis reveals three main types of kinematic patterns in the temporal evolution of post-failure deformation in MTI results, the dominant one being an exponential declining pattern similar to the results from Planet observations. Integrated 4D deformation modeling suggests that the most significant post-failure displacement mainly occurred toward the west, amounting to 28 m during the entire post-failure acquisitions from June 2020 until February 2022. Additionally, maximum displacements of 17 m and 19 m occurred in this period toward the north and downward, respectively.

RETROSPECTIVE STUDY OF VERTICAL GROUND DEFORMATION IN COMO, NORTHERN ITALY: INTEGRATION OF LEVELLING AND PSI MEASUREMENTS

Abstract. Subsidence-related vertical ground deformation due to natural and anthropogenic factors may lead to considerable damages to structures and infrastructures, and may increase the occurrence probability of consequential events, such as floods, especially on sea and lake shores. Como city, placed in the north of Italy, adjacent to Como Lake, is subjected to significant subsidence phenomenon, which has been monitored by geodetic levelling networks. In this work the historical geodetic levelling measurements and satellite-based Synthetic Aperture Radar (SAR) data archive are integrated to assess the accuracy of Atmospheric Delay and Deformation Rate estimations obtained through Persistent Scatter Interferometry (PSI) techniques. Tree levelling measurement datasets acquired in 1990, 1997 and 2004 are used in order to obtain the precise deformation rate at the benchmarks for two periods of 1990–1997 and 1997–2004. For multi-temporal InSAR analysis, 106 SAR images (1992–2004) and 41 SAR images (1992–2004) in Ascending Track orbit from ERS-1/2 missions are used in this study. The assessment is performed through a statistical comparison between two sets of vertical land deformation rates obtained by integrated methods. The results of the validation represented a good consistency between deformation rates derived by both techniques. Also, this study has revealed the potential of SAR images acquired in gyro-less mode by ERS-2 mission (2001–2004) in terms of the estimation of ground deformation.

Investigation of Ground Deformation around The Segments of Kendeng Fault in East Java 2017-2020 using Multi-Temporal InSAR Analysis with GACOS Correction Product

Multi-Temporal Interferometric SAR (MT-InSAR) analysis technique can provide spatially continuous measurements of the ground deformation and monitoring caused by the movement of four segments in the Kendeng Fault, East Java. Most ground deformation in these segments is indicated by the dominance of local thrust movements, folds, and the seismic density of earthquakes. In this study, ground deformation detection was carried out using the Small Baseline Subset Algorithm in the MT-InSAR process with the tropospheric correction from GACOS to determine ground deformation during 2017-2020. The percentage of change in the deformation velocity value resulting from applying the GACOS correction is up to 33.8% compared to without the tropospheric correction. The most significant troposphere effect correction is the area around the Cepu segments, which are dominated by high elevation thrust and folds. The results of the mean LOS velocity around the southern segments of Cepu, Waru, and Surabaya based on the Sentinel 1A SAR represent the occurrence of land subsidence in the south part of the area around segments with values ranging from 3.0 mm/yr to 6.0 mm/yr. Thus, the deformation effect causes land subsidence in the area around the delineation of the northern fault segment up to -3.0 mm/yr.

Monitoring Subsidence over the Planned Jakarta–Bandung (Indonesia) High-Speed Railway Using Sentinel-1 Multi-Temporal InSAR Data

Investigation of subsidence situations is important for the design of railway lines. Traditional geological investigations are expensive. Multi-temporal InSAR (MT-InSAR) analysis has shown great potential for detecting subsidence areas along large-scale manmade linear features (LMLFs). The disadvantage of applying high-resolution SAR data such as that from TerraSAR-X and COSMO-SkyMed data is the high cost. By contrast, the free and open data from Sentinel-1 A/B offer an unprecedented opportunity for InSAR applications. Despite these advantages, research investigating the potential for monitoring subsidence along LMSFs using multi-temporal Sentinel-1 InSAR data at the design stage of LMSFs is limited. This paper explores the monitoring ability of MT-InSAR analysis with Sentinel-1 A/B multi-temporal data in an experiment along the planned Jakarta-Bandung high-speed railway in Bandung, Indonesia. Subsidence patterns along the route of the planned high-speed railway were analyzed in detail. By means of validation using 12 leveling points, the root mean square error (RMSE) of the average displacement velocity that was obtained from the MT-InSAR results was found to be 10.31 mm/yr. This paper demonstrates the potential of Sentinel-1 multi-temporal INSAR data to detect potential subsidence areas along planned LMLFs (e.g., the planned high-speed railway that is the focus of this study), serving as a reference for further planning of monitoring subsidence over planned LMLFs.

A model-backfeed deformation estimation method for revealing 20-year surface dynamics of the Groningen gas field using multi-platform SAR imagery

• The model-backfeed deformation estimation method offers more reliable InSAR deformation parameter estimations. • Multiple Hypothesis Testing is employed to determine the best deformation models. • Geolocation error ellipsoids and Monte Carlo methods are used for spatial integration. • Three SAR missions are used to map 20-year Groningen gas field subsidence. The Groningen gas field, the largest natural gas field in Europe, was discovered in 1959 and started its production in 1963. The Earth surface above it experienced subsidence over the past six decades because of gas extraction activities. To accurately reveal this surface movement with satellite SAR data, our study first proposes and demonstrates a model-backfeed (MBF) InSAR deformation estimation method to improve InSAR deformation time series modeling. This method allowed us to include a priori knowledge and to iteratively optimize functional and stochastic models. Using this method and employing a spatio-temporal SAR data integration method based upon Monte Carlo and Multiple Hypothesis Testing methods, we retrieved the 20-year subsidence history of the Groningen gas field by integrating 32 ERS-1/2, 68 Envisat and 82 Radarsat-2 SAR images. The results show that the maximum cumulative surface subsidence in this gas field has been as much as 15.5 cm between 1995 and 2015. In terms of precision and accuracy, our MBF method offered a better result than the standard Multi-Temporal InSAR analysis method: the Ensemble Coherence increased by 10%–19% and Spatio-Temporal Consistency decreased by 2%–20%. In terms of accuracy, our results better concur with the external GNSS reference observations. We further show that the spatio-temporal SAR data integration method has better links with multi-platform SAR data if the uncertainties of the InSAR geolocation and temporal deformation are included. The study demonstrates that the MBF method optimized the estimation of deformation parameters and mitigated unwrapping errors.

Long term displacement observation of the Atatürk Dam, Turkey by multi-temporal InSAR analysis

Monitoring large infrastructures is vital for determining structural safety over time. Dams are structures that influence agricultural activities and have high economic contributions. The dams' structural safety was mainly addressed using conventional measurement techniques. However, these might not be time-efficient and practical, considering the large surfaces of dams. This paper presents a long-term InSAR analysis of the Atatürk Dam, Turkey's largest and one of the five biggest dams in Europe using ERS, ENVISAT, and Sentinel-1 satellites images. Since only Sentinel-1 data have acquisitions in ascending and descending orbits, we could estimate surface movements also in the vertical and east-west directions using both lines of sight (LOS) displacements. The results showed that the east-west movement is higher than vertical movement. As a result, we observe a maximum of 10 mm/yr displacement in the LOS direction at the dam's crest for period of 2003 and 2010, decreasing down the slope.

Ground Deformation of Wuhan, China, Revealed by Multi-Temporal InSAR Analysis

Wuhan, the largest city in central China, has experienced rapid urban development leading to land subsidence as well as environmental concerns in recent years. Although a few studies have analyzed the land subsidence of Wuhan based on ALOS-1, Envisat, and Sentinel-1 datasets, the research on long-term land subsidence is still lacking. In this study, we employed multi-temporal InSAR to investigate and reveal the spatiotemporal evolution of land subsidence over Wuhan with ALOS-1, Envisat, and Sentinel-1 images from 2007–2010, 2008–2010, 2015–2019, respectively. The results detected by InSAR were cross-validated by two independent SAR datasets, and leveling observations were applied to the calibration of InSAR-derived measurements. The correlation coefficient between the leveling and InSAR has reached 0.89. The study detected six main land subsidence zones during the monitoring period, with the maximum land subsidence velocity of −46 mm/a during the 2015–2019 analysis. Both the magnitude and the extent of the land subsidence have reduced since 2017. The causes of land subsidence are discussed in terms of urban construction, Yangtze river water level changes, and subsurface water level changes. Our results provide insight for understanding the causes of land subsidence in Wuhan and serve as reference for city management for reducing the land subsidence in Wuhan and mitigating the potential hazards.

Multi-Temporal InSAR Analysis for Monitoring Ground Deformation in Amorgos Island, Greece.

Radar Interferometry is a widely used method for estimating ground deformation, as it provides precision to a few millimeters to centimeters, and at the same time, a wide spatial coverage of the study area. On 9 July 1956, one of the strongest earthquakes of the 20th century in the area of the South Aegean, occurred in Amorgos, with a magnitude of Mw = 7.7. The objective of this research is to map ground deformation in Amorgos island, using InSAR techniques. We conducted a multi-temporal analysis of all available data from 2003 to 2019 by exploiting historical ENVISAT SAR imagery, as well as the dense archive of Sentinel-1 SLC imagery. Persistent Scatterer Interferometry (PS) and Small Baseline Subset (SBAS) methods were implemented. Results of both data-sets indicate a small-scale deformation on the island. A multi-track analysis was implemented on Sentinel-1 data to decompose the line of sight velocities to vertical and horizontal. The central south coast is experiencing horizontal movement, while uplift of a maximum value of 5 mm/y is observed in the southeastern coast. The combination of the good spatial coverage achievable via InSAR, with GPS measurements, is suggested an important tool for the seamless monitoring of Amorgos island towards tectonic hazard estimation.

Classification of slope processes based on multitemporal DInSAR analyses in the Himalaya of NW Bhutan

Slope deformation in mountainous terrain can be driven by different processes, the nature of which is either gravitational and irreversible or seasonal and reversible, the latter induced by permafrost variations or by hydromechanical or thermomechanical effects. The importance of identifying such deformations is not only related to the hazard they can pose, but also to the understanding of changes that permafrost or local hydrological conditions undergo. Here, we carry out a multi-temporal InSAR analysis over a mountainous area 8000 km2 large, straddling north-western Bhutan and southern Tibet. We propose a methodology to separate locally deforming areas from the effects of long-wavelength signals through the analysis of the spatio-temporal behaviour of 4-years long time series of surface displacements. We present the mapping of hundreds of small-scale features that appear to be actively deforming, as well as several examples of reversible deformation rarely detected at this scale in such a challenging and vast region. The analysis of the multi-annual trend of ground deformation shows a relatively small number of irreversible gravitational movements clearly related to rock slides which attests a low level of recent activity of large rock slope instabilities in the region. In the southernmost, lower elevation parts of the study area, we quantify reversible surface displacements with amplitudes ranging between 5 and 17 mm, and showing maximum displacements towards the satellite in summer months, thus compatible with hydro-mechanical effects related to groundwater table variations. In addition, the ground movement induced by the active layer's response to thawing and freezing over the gentler slopes and high-elevation permafrost regions of Bhutan and southern Tibet is on average around 10 mm, with maxima up to 28 mm. The localised displacements appear to be largely associated to braided stream plains, glacier outwash plains or low angle, fine sediment covered slopes.

Interseismic and Postseismic Shallow Creep of the North Qaidam Thrust Faults Detected with a Multitemporal InSAR Analysis

AbstractUnderstanding the mechanisms by which earthquake cycles produce folding and accommodate shortening is essential to quantify the seismic potential of active faults and integrate aseismic slip within our understanding of the physical mechanisms of the long‐term deformation. However, measuring such small deformation signals in mountainous areas is challenging with current space‐geodesy techniques, due to the low rates of motion relative to the amplitude of the noise. Here we successfully carry out a multitemporal Interferometric Synthetic Aperture Radar analysis over the North Qaidam fold‐thrust system in NE Tibet, where eight Mw> 5.2 earthquakes occurred between 2003 and 2009. We report various cases of aseismic slip uplifting the thickened crust at short wavelengths. We provide a rare example of a steep, shallow, 13‐km‐long and 6‐km‐wide afterslip signal that coincides spatially with an anticline and that continues into 2011 in response to a Mw 6.3 event in 2003. We suggest that a buried seismic slip during the 2003 earthquake has triggered both plastic an‐elastic folding and aseismic slip on the shallow thrusts. We produce a first‐order two‐dimensional model of the postseismic surface displacements due to the 2003 earthquake and highlight a segmented slip on three fault patches that steepen approaching the surface. This study emphasizes the fundamental role of shallow aseismic slip in the long‐term and permanent deformation of thrusts and folds and the potential of Interferometric Synthetic Aperture Radar for detecting and characterizing the spatiotemporal behavior of aseismic slip over large mountainous regions.

Feasibility of the Sentinel-1 Multi-temporal InSAR system based on the SNAP and StaMPS: Case study from the Tatra Mts., Slovakia

We present first full-resolution and large area Sentinel-1 multi-temporal InSAR analysis of the Tatra Mts. region within Slovakia as a case study on a feasibility of processing chain based on the Sentinels Application Platform (SNAP) and Stanford method for Persistent Scatterers (StaMPS). We utilize all Sentinel-1 data from three individual orbits, acquired from the beginning of the mission until the end of 2017. Study area was chosen to test the performance of our system over mountainous and sparsely urbanized land characteristic for strong atmospheric perturbations. Our results reveal several distinct areas of small-scale deformation phenomena, e.g. rockslides or land subsidence. InSAR displacement time series are validated via GNSS observations at the points of Slovakian permanent reference network. We conclude with the potential of proposed workflow for the future Slovakian nation-wide multi-temporal InSAR processing.

Monitoring structure health of urban bridges with advanced multi-temporal InSAR analysis

ABSTRACTActing as economic lifelines, bridges are essential infrastructure elements in China. The continuous monitoring of their stability therefore is of utmost significance to prevent the public death and injures resulting from bridge collapses. Typically, the deformation of bridges is detected by traditional on-structure surveying methods which are limited by the sparse measurements and large consumption of time and manpower. Thanks to the availability of numerous archived high-resolution spaceborne synthetic aperture radar (SAR) images coupled with the technology development of multi-temporal interferometry SAR, currently, millimetre level of subtle deformation monitoring and health diagnosis on bridges through the estimation of subsidence velocities using time-series SAR images has become a precise and cost-effective solution, assisting the conventional measures for bridges monitoring. Due to the fine level of detail information in X-band SAR images, the identification of even smaller bridges is possible. In this article, the special appearance of bridges over water in TerraSAR-X Stripmap images is discussed based on the backscattering mechanism analysis. Besides, an advanced high-resolution multi-temporal SAR Interferometry processing and analysis approach to enhance the capabilities for bridge health monitoring is illustrated based on the case study of Lupu Bridge in Shanghai, before discussing the existing challenges and future developments associated with bridge-specific deformation surveillance.

Monitoring of Subsidence along Jingjin Inter-City Railway with High-Resolution TerraSAR-X MT-InSAR Analysis

Synthetic Aperture Radar Interferometry (InSAR), widely applied for the monitoring of land subsidence, has the advantage of high accuracy and wide coverage. High-resolution SAR data offers a chance to reveal impressive details of large-scale man-made linear features (LMLFs) with Multi-temporal InSAR (MT-InSAR) analysis. Despite these advantages, research validating high-resolution MT-InSAR results along high-speed railways with high spatial and temporal density leveling data is limited. This paper explored the monitoring ability of high-resolution MT-InSAR in an experiment along Jingjin Inter-City Railway, located in Tianjin, China. Validation between these MT-InSAR results and a high spatial/temporal density leveling measurement was conducted. A total of 37 TSX images spanning half a year were processed for MT-InSAR analysis. The distance between two consecutive leveling points is 60 m along Jingjin Inter-City railway and the time interval of the study was about one month. The Root Mean Square Error (RMSE) index of average subsidence rate comparison between MT-InSAR results and leveling data was 3.28 mm/yr, with 34 points, and that of the displacement comparison was 2.90 mm with 464 valid observations. The experimental results along Jingjin Inter-City railway showed a high correlation between these two distinct measurements. These analyses show that millimeter accuracy can be achieved with MT-InSAR analysis when monitoring subsidence along a high-speed railway. We discuss the possible reason for the subsiding center, and the characteristics of both leveling and MT-InSAR results. We propose further planning for the monitoring of subsidence over LMLFs.

Detecting Subsidence Along a High Speed Railway by Ultrashort Baseline TCP-InSAR with High Resolution Images

Abstract. A High Speed Railway goes across Wuqing district of Tianjin, China. Historical studies showed that the land subsidence of this area was very serious, which would give rise to huge security risk to the high speed railway. For detecting the detailed subsidence related to the high speed railway, we use the multi-temporal InSAR (MT-InSAR) technique to extract regional scale subsidence of Wuqing district. Take it into consideration that Wuqing district is a suburban region with large area of low coherence farmland, we select the temporarily coherent point InSAR (TCP-InSAR) approach for MT-InSAR analysis. The TCP-InSAR is a potential approach for detecting land subsidence in low coherence areas as it can identify and analysis coherent points between just two images and can acquire a reliable solution without conventional phase unwrapping. This paper extended the TCP-InSAR with use of ultrashort spatial baseline (USB) interferograms. As thetopographic effects are negligible in the USB interferograms, an external digital elevation model (DEM) is no longer needed in interferometric processing, and the parameters needed to be estimated were simplified at the same time. With use of 17 TerraSAR-X (TSX) images acquired from 2009 to 2010 over Wuqing district, the annual subsidence rates along the high speed railway were derived by the USB-TCPInSAR approach. Two subsidence funnels were found at ShuangJie town and around Wuqing Station with subsidence rate of −17 ∼ −27 mm/year and −7 ∼ −17 mm/year, respectively. The subsidence rates derived by USB-TCPInSAR were compared with those derived by the conventional TCP-InSAR that uses an external DEM for differential interferometry. The mean and the standard deviation of the differences between two types of results at 370697 TCPs are −4.43 × 10−6 mm/year and ±1.4673 mm/year, respectively. Further comparison with the subsidence results mentioned in several other studies were made, which shows good consistencies. The results verify that even without using a DEM the USB-TCPInSAR method can detect land subsidence accurately in flat areas.