scholarly journals Multi-temporal SAR interferometry for monitoring ground deformation in Greece

2020 ◽  
Author(s):  
Σταυρούλα-Δροσούλα Αλατζά
Keyword(s):  
Ground Deformation ◽  
Sar Interferometry ◽  
Persistent Scatterers ◽  
Multi Temporal

Η παρούσα διατριβή εστιάζει στις εφαρμογές της συμβολομετρίας SAR και συγκεκριμένα, στις τεχνικές InSAR για διαχρονική παρακολούθηση των μετατοπίσεων του εδάφους, σε ενεργές τεκτονικά περιοχές του Ελλαδικού χώρου. Τρεις περιοχές σεισμικού ενδιαφέροντος, επιλέχθηκαν για μελέτη εδαφικών παραμορφώσεων με μεθόδους διαχρονικής συμβολομετρίας. Επίσης, δύο μεγάλα σεισμικά γεγονότα στον Ελλαδικό χώρο, αποτέλεσαν τη βάση για την ανάπτυξη μίας μεθοδολογίας για την επεξεργασία δεδομένων από τον δορυφόρο ERS, με βελτιωμένη ακρίβεια στη συνοχή φάσης. Για τη μελέτη χρονοσειρών αξιοποιήθηκαν δεδομένα από το 1992 έως το 2019, από τους δορυφόρους ERS, ENVISAT και Sentinel-1. Η συνδυασμένη μέθοδος των σταθερών σκεδαστών και των υποσυνόλων μικρών βάσεων StaMPS/MTI (Stanford Method for Persistent Scatterers-Multi-Temporal InSAR) εφαρμόστηκε σε δεδομένα από τους δορυφόρους ERS και ENVISAT. Η μέθοδος σταθερώνσκεδαστών του Stanford (Stanford Method for Persistent Scatterers) εφαρμόστηκε σε δεδομένα από τον δορυφόρο Sentinel-1. Με στόχο τον προσδιορισμό των οριζόντιων και κάθετων μετατοπίσεων, οι ταχύτητες LOS αναλύθηκαν στις κάθετες και οριζόντιες συνιστώσεις της κίνησης. Η διερεύνηση των αλγορίθμων και παραμέτρων του βήματος της συμπροσαρμογής των εικόνων SAR οδήγησε σε έναν βέλτιστο συνδυασμό, με στόχο τη δημιουργία μεθοδολογίας, για να χρησιμεύσει ως μία γενική προσέγγιση για την επεξεργασία δεδομένων από ιστορικούς δορυφόρους. Προσδιορίστηκε ο πιο αποτελεσματικός συνδυασμός αλγορίθμων και παραμέτρων, που παρέχει την βέλτιστη συνοχή εικόνων και αξιολογήθηκε από στατιστική ανάλυση της συνοχής φάσης. Η μελέτη χρονοσειρών για το νησί της Αμοργού με τη χρήση μεθόδων διαχρονικής συμβολομετρίας SAR, αφενός επιβεβαίωσε τις προϋπάρχουσες τεκτονικές μελέτες που έχουν πραγματοποιηθεί στην περιοχή, αφετέρου πρόσθεσε πληροφορίες σχετικά με τη νεοτεκτονική συμπεριφορά του νησιού και το συσχετισμό της με το σεισμικό γεγονός του 1956. Συγκεκριμένα, η ανύψωση στην ΝΑ ακτή του νησιού, σχετίζεται με ανύψωση του υποκείμενου τομέα του ρήγματος που υπάρχει στην περιοχή. Επίσης, η καθίζηση που εντοπίστηκε στην Χοζοβιώτισσα, σχετίζεται με την καθίζηση του υπερκείμενου τομέα του ρήγματος στην περιοχή. Συνοψίζοντας, η ερμηνεία των εκτιμώμενων μετατοπίσεων στην Αμοργό,υποδηλώνει ότι οι κινήσεις του ανώτερου φλοιού, αντικατοπτρίζουν μετασεισμική χαλάρωση, γεγονός που προκύπτει από μεγάλους σεισμούς, ως ανακατανομή της παραμόρφωσης και της έντασης. Η μελέτη στην περιοχή των Κυθήρων, παρουσίασε, οριζόντιες μετατοπίσεις στην ΝΑ ακτή κοντά στον Ποταμό, με μέγιστη τιμή -3mm/y (ανατολικής κίνησης) και δυτικά από το Λιβάδι, μικρότερης έντασης. Κατακόρυφες μετατοπίσεις έως 5mm/y εντοπίστηκαν για τη χρονική περίοδο 2015-2019. Οι κατακόρυφες μετατοπίσεις είναι κατά μία τάξη μεγαλύτερες της μακροχρόνιας ανύψωσης στο νησί, που πιθανόν οφείλονται σε ασεισμική ολίσθηση ή καθίζηση υποπλακών. Όσον αφορά τη μελέτη στη Χαλκιδική, δεδομένης της υπερεκμετάλλευσης της λεκάνης απορροής των Μουδανιών, όπως παρατηρήθηκε από υδρολογικές μελέτες στην περιοχή, για την χρονική περίοδο πριν το 2014, τα αποτελέσματα των χρονοσειρών για το χρονικό διάστημα 2014-2018, πρόσθεσαν νέα γνώση σχετικά με τις πρόσφατες παραμορφώσεις του εδάφους, που σχετίζονται με την υπερεκμετάλλευση του υδροφόρου ορίζοντα στα Μουδανιά, υποδηλώνοντας ότι δεν έχει αποκατασταθεί η ισορροπία και ότι το φαινόμενο της υπερκμετάλλευσης του υδροφόρου ορίζοντα συνεχίζεται και μετά το 2014. Η ανάπτυξη ειδικής μεθοδολογίας για το στάδιο της συμπροσαρμογής των εικόνων, η οποία επιφέρει αισθητή βελτίωση στη συνοχή φάσης των εικόνων από τον δορυφόρο ERS, είναι εφαρμόσιμη σε κάθε τύπο εδάφους (αγροτικό ή αστικό περιβάλλον) και δεν απαιτεί ιδιαίτερη υπολογιστική ισχύ, λόγω του αποτελεσματικού συνδυασμού γρήγορων υπολογιστικά αλγορίθμων.

Remote sensing of steep-slope volcanoes: the Stromboli case study

2021 ◽  
Author(s):  
Federico Di Traglia ◽  
Claudio De Luca ◽  
Alessandro Fornaciai ◽  
Mariarosaria Manzo ◽  
Teresa Nolesini ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Volcanic Activity ◽  
Ground Deformation ◽  
Steep Slope ◽  
Sar Interferometry ◽  
Large Set ◽  
Multi Temporal ◽  
Optical Imagery ◽  
Gravitational Processes ◽  
Sciara Del Fuoco

<p>Steep-slope volcanoes are geomorphological systems receptive to both exogenous and endogenous phenomena. Volcanic activity produces debris and lava accumulation, whereas magmatic/tectonic and gravitational processes can have a destructive effect, triggering mass-wasting and erosion.</p><p>Optical and radar sensors have often been used to identify areas impacted by eruptive and post-eruptive phenomena, quantify of topographic changes, and/or map ground deformation related to magmatic-tectonic-gravitational processes.</p><p>In this work, the slope processes on high-gradient volcano flanks in response to shift in volcanic activity have been identified by means of remote sensing techniques. The Sciara del Fuoco unstable flank of Stromboli volcano (Italy) was studied, having a very large set (2010-2020) of different remote sensing data available.</p><p>Data includes LiDAR and tri-stereo PLEIADES-1 DEMs, high-spatial-resolution (HSR) optical imagery (QUICKBIRD and PLEIADES-1), and space-borne and ground-based Synthetic Aperture Radar (SAR) data. Multi-temporal DEMs and HSR optical imagery permits to map areas affected by major lithological and morphological changes, and the volumes of deposited/eroded material. The results lead to the identification of topographical variations and geomorphological processes that occurred in response to the variation in eruptive intensity. The joint exploitation of space-borne and ground-based Differential and Multi Temporal SAR Interferometry (InSAR and MT-InSAR) measurements revealed deformation phenomena affecting the volcano edifice, and in particular the Sciara del Fuoco flank.</p><p>The presented results demonstrate the effectiveness of the joint exploitation of multi-temporal DEMs, HSR optical imagery, and InSAR measurements obtained through satellite and terrestrial SAR systems, highlighting their strong complementarity to map and interpret the slope phenomena in volcanic areas.</p><p>This work was financially supported by the “Presidenza del Consiglio dei Ministri – Dipartimento della Protezione Civile” (Presidency of the Council of Ministers – Department of Civil Protection); this publication, however, does not reflect the position and official policies of the Department".</p>

SpaCeborne SAR Interferometry as a Noninvasive tool to assess the vulnerability over Cultural hEritage sites (SCIENCE)

2021 ◽  
Author(s):  
Athanasia-Maria Tompolidi ◽  
Issaak Parcharidis ◽  
Constantinos Loupasakis ◽  
Michalis Fragkiadakis ◽  
Pantelis Soupios ◽  
...  
Keyword(s):  
Remote Sensing ◽  
Cultural Heritage ◽  
Ming Dynasty ◽  
Ground Deformation ◽  
Sar Interferometry ◽  
Archaeological Sites ◽  
Science Project ◽  
Heritage Sites ◽  
Persistent Scatterers ◽  
Great Wall

<p>Cultural heritage is a key element of history as the ancient monuments and archaeological sites enrich today’s societies and help connect us to our cultural origins. The project entitled ''SpaCeborne SAR Interferometry as a Nonivasive tool to assess the vulnerability over Cultural hEritage sites (SCIENCE)'' has as ultimate objective to predict the vulnerability of the archaeological sites to ground deformation in time and space and protect them against natural/man-made damage. The SCIENCE project aims to develop, demonstrate, and validate, in terms of geotechnical local conditions and monuments’ structural health, SAR interferometric techniques to monitor potential ground deformation affecting the archaeological sites and monuments of great importance. </p><p>During the last few years, spaceborne Synthetic Aperture Radar (SAR) interferometry has proven to be a powerful remote sensing tool for detecting and measuring ground deformation and studying the deformation’s impact on man-made structures. It provides centimeter to millimeter resolution and even single buildings/monuments can be mapped from space. Considering the limitations of conventional MT-InSAR techniques, such as Persistent Scatterers Interferometry (PSI), in this project a two-step Tomography-based Persistent Scatterers (PS) Interferometry (Tomo-PSInSAR) approach is proposed for monitoring ground deformation and structural instabilities over the Ancient City Walls (Ming Dynasty) in Nanjing city, China and in the Great Wall in Zhangjiakou, China. The Tomo-PSInSAR is capable of separating overlaid PS in the same location, minimizing the unfavorable layover effects of slant-range imaging in SAR data. Moreover, the demonstrations are performed on well-known test sites in China and in Greece, such as: a) Ming Dynasty City Walls in Nanjing, b) Great Wall in Zhangjiakou, c) Acropolis complex of Athens and d) Heraklion walls (Crete Island), respectively.</p><p>In particular, in the framework of SCIENCE project are processed several radar datasets such as Sentinel 1 A & B data of Copernicus program and the high resolution TerraSAR-X data. The products of Persistent Scatterers Interferometry (PSI) are exported in various formats for the identification of the persistent scatterers using high resolution optical images, aerial photographs and fusing with high accuracy Digital Surface Models (DSM). In addition, the validation of the results is taking place through in-situ measurements (geological, geothechnical e.t.c) and data for the cultural heritage sites conditions.</p><p>SCIENCE project’s final goal is the risk assessment analysis of the cultural heritage monuments and their surrounding areas aiming to benefit institutions, organizations, stakeholders and private agencies in the cultural heritage domain through the creation of a validated pre-operation non-invasive system and service based on earth observation data supporting end-user needs by the provision knowledge about cultural heritage protection. In conclusion, SCIENCE project is composed by a bilateral consortium of the Greek delegation of Harokopio University of Athens, National Technical University of Athens, Terra Spatium S.A, Ephorate of Antiquities of Heraklion (Crete), Acropolis Restoration Service (Athens) of Ministry of Culture and Sports and by the Chinese delegation of Science Academy of China (Institute of Remote Sensing and Digital Earth) and  International Centre on Space Technologies for Natural and Cultural Heritage (HIST) under the auspices of UNESCO (HIST-UNESCO).</p>

scholarly journals Complex Surface Displacements above the Storage Cavern Field at Epe, NW-Germany, Observed by Multi-Temporal SAR-Interferometry

2020 ◽  
Vol 12 (20) ◽  
pp. 3348
Author(s):  
Markus Even ◽  
Malte Westerhaus ◽  
Verena Simon
Keyword(s):  
Ground Truth ◽  
Complex Surface ◽  
Sar Interferometry ◽  
Storage Site ◽  
Geophysical Modeling ◽  
The North ◽  
Persistent Scatterers ◽  
Surface Displacements ◽  
Multi Temporal ◽  
Pressure Changes

The storage cavern field at Epe has been brined out of a salt deposit belonging to the lower Rhine salt flat, which extends under the surface of the North German lowlands and part of the Netherlands. Cavern convergence and operational pressure changes cause surface displacements that have been studied for this work with the help of SAR interferometry (InSAR) using distributed and persistent scatterers. Vertical and East-West movements have been determined based on Sentinel-1 data from ascending and descending orbit. Simple geophysical modeling is used to support InSAR processing and helps to interpret the observations. In particular, an approach is presented that allows to relate the deposit pressures with the observed surface displacements. Seasonal movements occurring over a fen situated over the western part of the storage site further complicate the analysis. Findings are validated with ground truth from levelling and groundwater level measurements.

scholarly journals SLOPE INSTABILITY MONITORING BY SPACE-BORNE SAR INTERFEROMETRY: PRELIMINARY RESULTS FROM PANACHAICO MOUNTAIN (WESTERN GREECE)

2017 ◽  
Vol 43 (3) ◽  
pp. 1301
Author(s):  
I. Parcharidis ◽  
M. Foumelis ◽  
P. Kourkouli
Keyword(s):  
Ground Deformation ◽  
Slope Instability ◽  
Sar Interferometry ◽  
Rock Outcrops ◽  
Preliminary Results ◽  
Synthetic Aperture Radar Interferometry ◽  
Point Target ◽  
Persistent Scatterers ◽  
Differential Interferometry ◽  
The City

Space borne differential synthetic aperture radar interferometry (DInSAR) has already proven its potential for mapping ground deformation phenomena, e.g. earthquakes, volcano dynamics, etc covering in continuity large areas. The innovative Persistent Scatterers Interferometry (PSI) technique, which overcomes several limitations of conventional SAR differential interferometry especially for applications in landslide studies, is suitable for monitoring slope deformations with millimetric precision. With PSI technique we detect the deformation, for long periods, that occur in an area as average annual deformation (mm/y) and is not spatially continuous but in terms of points (point targets). The aim of this study is to present preliminary results on the monitoring of slope instability in Panachaiko Mountain and particularly of the slopes facing the city of Patras. For this purpose we processed and analysed 42 ERS 1 and ERS 2 SAR scenes acquired in the time span 1992 and 2001, by applying the Interferometric Point Target Analysis algorithm. Point target reflectors with stable radar response over time were selected. In this case most of the point targets correspond to buildings of the local settlements or to rock outcrops. Additionally, millimetric target displacements along the line of sight direction were detected allowing measurements of slow terrain motion.

scholarly journals Long-Term Remote Monitoring of Ground Deformation Using Sentinel-1 Interferometric Synthetic Aperture Radar (InSAR): Applications and Insights into Geotechnical Engineering Practices

2020 ◽  
Vol 10 (21) ◽  
pp. 7447
Author(s):  
Ryan Ramirez ◽  
Seung-Rae Lee ◽  
Tae-Hyuk Kwon
Keyword(s):  
Synthetic Aperture Radar ◽  
Ground Deformation ◽  
Geotechnical Engineering ◽  
Sar Interferometry ◽  
Synthetic Aperture ◽  
Successful Implementation ◽  
Persistent Scatterers ◽  
Sar Data ◽  
Aperture Radar

Development of synthetic aperture radar (SAR) technology and the dedicated suite of processing tools have aided the evolution of remote sensing techniques for various Earth Observation (EO) applications. Interferometric SAR (InSAR) is a relatively new geodetic technique which provides high-speed and reliable geographic, geologic, and hazards information allowing the prognosis of future environmental and urban planning. In this study, we explored the applicability of two differential interferometry techniques, conventional and advanced differential InSAR (A-DInSAR), for topographic mapping and long-term geotechnical monitoring by exploiting satellite data, particularly Sentinel-1 SAR data, which is publicly shared. We specifically used the open-source tools of SeNtinel Application Platform (SNAP) and Stanford Method for Persistent Scatterers (StaMPS) for interferometric data processing to implement A-DInSAR. This study presents various applications, which include generation of a digital elevation model (DEM), mapping of seismically induced displacement and associated damages, and detection and long-term monitoring of tunneling-induced ground deformation and rainfall-induced landslide. Geometric and temporal decorrelations posed challenges and limitations in the successful implementation of Sentinel-1 SAR interferometry specifically in vegetated areas. The presented results proved the validity and reliability of the exploited SAR data and InSAR techniques for addressing geotechnical engineering related problems.

scholarly journals Combining High- and Low-Rate Geodetic Data Analysis for Unveiling Rapid Magma Transfer Feeding a Sequence of Violent Summit Paroxysms at Etna in Late 2015

2021 ◽  
Vol 11 (10) ◽  
pp. 4630
Author(s):  
Alessandro Bonforte ◽  
Flavio Cannavò ◽  
Salvatore Gambino ◽  
Francesco Guglielmino
Keyword(s):  
Ground Deformation ◽  
High Rate ◽  
Rate Data ◽  
Scale Analysis ◽  
Feeding System ◽  
Magma Sources ◽  
Mt Etna ◽  
Multi Temporal ◽  
Gnss Measurements ◽  
Low Rate

We propose a multi-temporal-scale analysis of ground deformation data using both high-rate tilt and GNSS measurements and the DInSAR and daily GNSS solutions in order to investigate a sequence of four paroxysmal episodes of the Voragine crater occurring in December 2015 at Mt. Etna (Italy). The analysis aimed at inferring the magma sources feeding a sequence of very violent eruptions, in order to understand the dynamics and to image the shallow feeding system of the volcano that enabled such a rapid magma accumulation and discharge. The high-rate data allowed us to constrain the sources responsible for the fast and violent dynamics of each paroxysm, while the cumulated deformation measured by DInSAR and daily GNSS solutions, over a period of 12 days encompassing the entire eruptive sequence, also showed the deeper part of the source involved in the considered period, where magma was stored. We defined the dynamics and rates of the magma transfer, with a middle-depth storage of gas-rich magma that charges, more or less continuously, a shallower level where magma stops temporarily, accumulating pressure due to the gas exsolution. This machine-gun-like mechanism could represent a general conceptual model for similar events at Etna and at all volcanoes.

scholarly journals A Workflow Based on SNAP–StaMPS Open-Source Tools and GNSS Data for PSI-Based Ground Deformation Using Dual-Orbit Sentinel-1 Data: Accuracy Assessment with Error Propagation Analysis

2021 ◽  
Vol 13 (4) ◽  
pp. 753 ◽  
Author(s):  
Francesco Mancini ◽  
Francesca Grassi ◽  
Nicola Cenni
Keyword(s):  
Open Source ◽  
Error Propagation ◽  
Ground Deformation ◽  
Accuracy Assessment ◽  
Decomposition Analysis ◽  
Anthropogenic Sources ◽  
Synthetic Aperture Radar Data ◽  
Persistent Scatterers ◽  
Propagation Analysis ◽  
Error Propagation Analysis

This paper discusses a full interferometry processing chain based on dual-orbit Sentinel-1A and Sentinel-1B (S1) synthetic aperture radar data and a combination of open-source routines from the Sentinel Application Platform (SNAP), Stanford Method for Persistent Scatterers (StaMPS), and additional routines introduced by the authors. These are used to provide vertical and East-West horizontal velocity maps over a study area in the south-western sector of the Po Plain (Italy) where land subsidence is recognized. The processing of long time series of displacements from a cluster of continuous global navigation satellite system stations is used to provide a global reference frame for line-of-sight–projected velocities and to validate velocity maps after the decomposition analysis. We thus introduce the main theoretical aspects related to error propagation analysis for the proposed methodology and provide the level of uncertainty of the validation analysis at relevant points. The combined SNAP–StaMPS workflow is shown to be a reliable tool for S1 data processing. Based on the validation procedure, the workflow allows decomposed velocity maps to be obtained with an accuracy of 2 mm/yr with expected uncertainty levels lower than 2 mm/yr. Slant-oriented and decomposed velocity maps provide new insights into the ground deformation phenomena that affect the study area arising from a combination of natural and anthropogenic sources.

scholarly journals Ground deformation of Dongsheng mining area revealed by multi-temporal InSAR

2021 ◽  
Vol 675 (1) ◽  
pp. 012029
Author(s):  
Qing Yang ◽  
Zhanqiang Chang ◽  
Yanqiao Wang ◽  
Yanxin Zhang ◽  
Songbo Huang
Keyword(s):  
Ground Deformation ◽  
Mining Area ◽  
Multi Temporal
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