Coseismic ground deformation of the November 26, 2019 M6.4 earthquake of Durrës, Albania estimated by DInSAR

An earthquake of magnitude 6.4 occurred in Albania on November 26, 2019 at 03:54:12 (local time). The epicenterof the earthquake was about20 km from the coastal city of Durrës. The purpose of this study is toestimate the ground deformation associated with thisearthquakeby Differential Interferometric Synthetic Aperture Radar (DInSAR) technique. A differential interferogram was formed using the two Sentinel-1 Single Look Complex (SLC) images. The flattened and filtered differential interferogram was unwrapped and converted to ground displacement. The results indicatethat in the area close tothe epicentrethe ground is uplifted at a maximum of 8 cm along the radar line-of-sight (LOS). Progressively smaller ground uplift isdetected in an area of about 10-15 km around the major uplift zone. The earthquake could be related with under thrustingof Adria microplate or fault processes within the under thrustedAdria microplate itself. Further monitoring by satellite imagery is needed to investigate the post-seismic ground deformation in the area

Terrain mapping for the southwestern desert of Iraq using interferometry method from sentinel-1A images

Synthetic aperture radar Interferometry is a popular three-dimensional imaging technique for creating a Digital Elevation Model. Using traditional methods for creating DEMs and terrain mapping is one of the methods that require high cost and time-consuming, which has affected the creation and updating of terrain maps in Iraq, so this study aims to use the InSAR technology to generate DEM, which contributes to the creation of terrain maps. In this work, the synthetic aperture radar interferometry approach was used on the interference stack generated from a pair of Sentinel-1A images within the SNAP program to generate a DEM and a terrain map of the desert region in south-western Iraq. The elevations of the digital elevation model were compared with those of the RTK-GCPs points in the region of interest. The results obtained from this study are a terrain map with the contour lines generated from the digital elevation model created by the InSAR technique with an accuracy of 18 m, with the root mean square error of the DEM being 8.17. The outputs prove the effectiveness of InSAR technology in generating accurate DEM that contributes to creating terrain maps in less time and cost than traditional methods

Detection of Ground Subsidence in the City of Durrës, Albania, by Persistent Scatterer Interferometry of Sentinel-1 Radar Imagery: Detection of Ground Subsidence in the City of Durrës, Albania, by Persistent Scatterer Interferometry of Sentinel-1 Radar Imagery

Persistent Scatterer Interferometry (PSI) analysis of multi-temporal Sentinel-1 synthetic aperture radar (SAR) imagery was carried out to detect ground displacement in the city of Durrës, Albania. The analyzed interferometric stack consisted of fifty-eight Sentinel-1 images in ascending orbit covering the time period January 2017-December 2018. The results show a zone of ground subsidence with values of up to -30 mm/year that occur within and very close to the boundaries of the reclaimed lands of the Durrës marsh. Rapid urbanization, generally in the form of informal settlements, has taken place in this area in the last twenty years. In the Port of Durrës, a recently constructed breakwater shows high rates of ground settlement up to -30 mm/year, as well. The study is the first application of satellite radar imagery for the detection of ground displacement in the city of Durrës, Albania. Further monitoring is needed to better understand the ground subsidence and ground settlement processes that occur in the city of Durrës

Deformation monitoring using Persistent Scatterer Interferometry and Sentinel-1 SAR data

During the last decades, Persistent Scatterer Interferometry (PSI) has demonstrated to be a powerful tool able to measure and monitor deformations. This technique makes use of large stacks of interferometric SAR images to derive the deformation maps and deformation time series. In this paper, Sentinel-1 images are used to derive the deformation monitoring over the Catalonia region (Spain). These images brings new improvements due to its wide coverage and high revisiting time, which allows us to make a wide area processing. The first part of the paper describes the data processing implemented by the authors to analyze Sentinel-1 data and the PSI approach used in this ongoing research. The second part of the paper illustrates the results derived over an area of 6750 km2 using Sentinel-1 images

DETECTING DEFORMATION DUE TO THE 2018 MERAPI VOLCANO ERUPTION USING INTERFEROMETRIC SYNTHETIC APERTURE RADAR (INSAR) FROM SENTINEL-1 TOPS

This paper describes the application of Sentinel-1 TOPS (Terrain Observation with Progressive Scans), the latest generation of SAR satellite imagery, to detect displacement of the Merapi volcano due to the May–June 2018 eruption. Deformation was detected by measuring the vertical displacement of the surface topography around the eruption centre. The Interferometric Synthetic Aperture Radar (InSAR) technique was used to measure the vertical displacement. Furthermore, several Landsat-8 Thermal Infra Red Sensor (TIRS) imageries were used to confirm that the displacement was generated by the volcanic eruption. The increasing temperature of the crater was the main parameter derived using the Landsat-8 TIRS, in order to determine the increase in volcanic activity. To understand this phenomenon, we used Landsat-8 TIRS acquisition dates before, during and after the eruption. The results show that the eruption in the May–June 2018 period led to a small negative vertical displacement. This vertical displacement occurred in the peak of volcano range from -0.260 to -0.063 m. The crater, centre of eruption and upper slope of the volcano experienced negative vertical displacement. The results of the analysis from Landsat-8 TIRS in the form of an increase in temperature during the 2018 eruption confirmed that the displacement detected by Sentinel-1 TOPS SAR was due to the impact of volcanic activity. Based on the results of this analysis, it can be seen that the integration of SAR and thermal optical data can be very useful in understanding whether deformation is certain to have been caused by volcanic activity

Coseismic DInSAR Analysis of the 2020 Petrinja Earthquake Sequence

Interferometric SAR analysis provides an excellent opportunity to perform large-scale and rapid coseismic deformation mapping. Between December 28-30, 2020, three earthquakes with magnitudes greater than 4.3 occurred during the 2020 Petrinja Earthquake Sequence near Petrinja in Croatia, resulting in significant coseismic deformation. Considering both the available ascending and descending Sentinel-1A/B images preceding and following the Petrinja Earthquake Sequence, 2.5D differential interferometric analysis was performed to determine the resulting deformation field, which have significant importance in civil engineering related countermeasures and hazard assessment. With the applied methodology, the derived horizontal and vertical deformation fields can be characterized by a maximum of ±0.43 m local East-West, a maximum of 0.15 m local subsidence and a maximum of 0.19 m local vertical uplift near Petrinja

The 21 August 2017 Ischia (Italy) Earthquake Source Model Inferred From Seismological, GPS, and DInSAR Measurements

The causative source of the first damaging earthquake instrumentally recorded in the Island of Ischia, occurred on 21 August 2017, has been studied through a multiparametric geophysical approach. In order to investigate the source geometry and kinematics we exploit seismological, Global Positioning System, and Sentinel-1 and COSMO-SkyMed differential interferometric synthetic aperture radar coseismic measurements. Our results indicate that the retrieved solutions from the geodetic data modeling and the seismological data are plausible; in particular, the best fit solution consists of an E-W striking, south dipping normal fault, with its center located at a depth of 800 m. Moreover, the retrieved causative fault is consistent with the rheological stratification of the crust in this zone. This study allows us to improve the knowledge of the volcano-tectonic processes occurring on the Island, which is crucial for a better assessment of the seismic risk in the area.Published2193-22023T. Sorgente sismicaJCR Journa

Accuracy of Sentinel-1 Interferometry Monitoring System based on Topography-free Phase Images

Our automatized interferometric monitoring system, IT4S1, contains a database of Sentinel-1 satellite image bursts that have been preprocessed to the state of a consistent well-coregistered dataset. The coregistration solution introduces a new type of data, an SLC-C (corrected single look complex data). These are SLC images ready for interferometric analyses with maximally reduced phase signature of topography and flat-Earth phase. The further processing time for multitemporal interferometry techniques is significantly reduced for achieving velocity maps based on e.g. Persistent Scatterers or Small Baseline techniques. In this paper, authors focus on quality of estimated topographic phase, finding out that computation of perpendicular baseline between satellite positions based on precise orbit ephemerides can differ and thus the approach may suffer from a residual topographic signature or a flat-Earth phase. The paper presents conclusions taken by an investigation of one such pre-prepared dataset over a mountainous area in southern Spain. Though some orbital inparallelity occurs during Sentinel-1 acquisitions (causing inaccuracies of perpendicular baselines within first meters), the flat-Earth is removed properly using this approach. The paper further demonstrates results using SLC-C approach using available and custom processing techniques and notifies about the possibility that in terms of overall accuracy and precision of multitemporal interferometry this approach contains inaccuracies that can be either estimated as part of error phase screens or even neglected

Moving Target Azimuth Velocity Estimation for the MASA Mode Based on Sequential SAR Images

A novel azimuth velocity estimation method is proposed based on the multiple azimuth squint angles (MASA) imaging mode, acquiring sequential synthetic aperture radar images with different squint angles and time lags. The MASA mode acquisition geometry is given first, and the effect of target motion on azimuth offset and slant range offset is discussed in detail. Then, the azimuth velocity estimation accuracy is analyzed, considering the errors caused by registration, defocusing, and range velocity. Moreover, the interaction between target azimuth velocity and range velocity is studied for a better understanding of the azimuth velocity estimation error caused by the range velocity. With the proposed error compensation step, the new method can achieve a very high accuracy in azimuth velocity estimation, as verified by experimental results based on both simulated data and the TerraSAR-X data

PSINSAR COHERENCE BASED DISPLACEMENT ANALYSIS OF KRISHNA DELTA USING SENTINEL-1 INTERFEROMETRIC WIDE SWATH DATA

The problem of decorrelation leading to loss of coherence has been a major source of concern to identify the various problems of erosion and deposition in delta. In this study, Permanent Scatter Interferometric SAR (PsInSAR) technique was used to identify the Permanent Scatter Candidates (PSCs) to explore its potential in identifying displacement based on coherence of various features in delta during the dry and wet periods. PSCs are coherent over interferograms acquired during different time periods. The study was conducted using Sentinel-1 C-band Interferometric Wide (IW) swath datasets acquired from 25th October 2016 to 10th June 2017 over Krishna Delta. The datasets were deramped and stitched prior to co-registering the master and slave images. Interferograms were generated, phase unwrapped and filtered after which the PSCs were identified based on Amplitude Stability index. The problem of tropospheric phase delay causing decorrelation was removed based on the difference in the phase residual of the connected PSCs. Ps coherence map was generated showing coherence as low as 0.28 to 0.38 in mangroves due to volume decorrelation and 0.5 to 0.85 in village areas. A prominent feature, vernal pool exhibited high variation in coherence (0.28 to 0.45) depending on monsoon or summer season. An integrated cumulative displacement map was generated indicating the areas where erosion and deposition has taken place and these depositional values of certain deltaic features were in conjunction with coherence