Land subsidence along the Ionian coast of SE Sicily (Italy), detection and analysis via Small Baseline Subset (SBAS) multitemporal differential SAR interferometry

Land subsidence is often occurred by compaction of alluvial sediments due to groundwater extraction and threatens invaluable lives and properties. Space-based interferometric Synthetic Aperture Radar (SAR) observation has been widely used to estimate surface displacement precisely. Especially, Small BAseline Subset (SBAS) technique with SAR Interferometry (InSAR) could serve to monitor a time-series of the land subsidence. In this study, the SBAS with L-band ALOS PALSAR and C-band Sentinel-1 observations have been applied to investigate the land subsidence in Noksan reclaimed land, Busan, South Korea. The average velocity showing the largest displacement is -3.40 cm/year from ALOS PALSAR and -2.17 cm/year with Sentinel-1 dataset at the line of sight (LOS) direction. An annual subsidence rate of -2.77 cm/year was estimated assuming that the surface has been deformed linearly for the data acquisition period.

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Detecting land deformation due to groundwater changes with InSAR observations - the case of the island of Gotland, Sweden

10.5194/egusphere-egu21-3402 ◽

2021 ◽

Author(s):

Mehdi Darvishi ◽

Fernando Jaramillo

Keyword(s):

Land Subsidence ◽

Groundwater Level ◽

Ground Deformation ◽

Soil Depth ◽

Ground Surface ◽

Groundwater Depletion ◽

Groundwater Levels ◽

Small Baseline Subset ◽

Small Baseline ◽

The Baltic

In the recent years, southern Sweden has experienced drought conditions during the summer with potential risks of groundwater shortages. One of the main physical effects of groundwater depletion is land subsidence, a geohazard that potentially damages urban infrastructure, natural resources and can generate casualties. We here investigate land subsidence induced by groundwater depletion and/or seasonal variations in Gotland, an agricultural island in the Baltic Sea experiencing recent hydrological droughts in the summer. Taking advantage of the multiple monitoring groundwater wells active on the island, we explore the existence of a relationship between groundwater fluctuations and ground deformation, as obtained from Interferometric Synthetic Aperture Radar (InSAR). The aim in the long-term is to develop a high-accuracy map of land subsidence with an appropriate temporal and spatial resolution to understand groundwater changes in the area are recognize hydroclimatic and anthropogenic drivers of change.We processed Sentinel-1 (S1) data, covering the time span of 2016-2019, by using the Small BAseline Subset (SBAS) to process 119 S1-A/B data (descending mode). The groundwater level of Nineteen wells distributed over the Gotland island were used to assess the relationship between groundwater depletion and the detected InSAR displacement. In addition to that, the roles of other geological key factors such as soil depth, ground capacity in bed rock, karstification, structure of bedrock and soil type in occurring land subsidence also investigated. The findings showed that the groundwater level in thirteen wells with soil depths of less than 5 meters correlated well with InSAR displacements. The closeness of bedrock to ground surface (small soil depth) was responsible for high coherence values near the wells, and enabled the detection land subsidence. The results demonstrated that InSAR could use as an effective monitoring system for groundwater management and can assist in predicting or estimating low groundwater levels during summer conditions.

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MONITORING OF LAND SUBSIDENCE IN RAVENNA MUNICIPALITY USING INTEGRATED SAR - GPS TECHNIQUES: DESCRIPTION AND FIRST RESULTS

ISPRS - International Archives of the Photogrammetry, Remote Sensing and Spatial Information Sciences ◽

10.5194/isprsarchives-xli-b7-23-2016 ◽

2016 ◽

Vol XLI-B7 ◽

pp. 23-28 ◽

Cited By ~ 4

Author(s):

G. Artese ◽

S. Fiaschi ◽

D. Di Martire ◽

S. Tessitore ◽

M. Fabris ◽

...

Keyword(s):

Land Subsidence ◽

Interferometric Synthetic Aperture Radar ◽

Persistent Scatterers ◽

Gps Measurement ◽

Measurement Results ◽

Prone Area ◽

First Results ◽

Emilia Romagna Region ◽

Small Baseline Subset ◽

Small Baseline

The Emilia Romagna Region (N-E Italy) and in particular the Adriatic Sea coastline of Ravenna, is affected by a noticeable subsidence that started in the 1950s, when the exploitation of on and off-shore methane reservoirs began, along with the pumping of groundwater for industrial uses. In such area the current subsidence rate, even if lower than in the past, reaches the -2 cm/y. Over the years, local Authorities have monitored this phenomenon with different techniques: spirit levelling, GPS surveys and, more recently, Differential Interferometric Synthetic Aperture Radar (DInSAR) techniques, confirming the critical situation of land subsidence risk. In this work, we present the comparison between the results obtained with DInSAR and GPS techniques applied to the study of the land subsidence in the Ravenna territory. With regard to the DInSAR, the Small Baseline Subset (SBAS) and the Coherent Pixel Technique (CPT) techniques have been used. Different SAR datasets have been exploited: ERS-1/2, ENVISAT, TerraSAR-X and Sentinel-1. Some GPS campaigns have been also carried out in a subsidence prone area. 3D vertices have been selected very close to existing persistent scatterers in order to link the GPS measurement results to the SAR ones. GPS data were processed into the International reference system and the comparisons between the coordinates, for the first 6 months of the monitoring, provided results with the same trend of the DInSAR data, even if inside the precision of the method.

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SBAS-InSAR Based Deformation Detection of Urban Land, Created from Mega-Scale Mountain Excavating and Valley Filling in the Loess Plateau: The Case Study of Yan’an City

Remote Sensing ◽

10.3390/rs11141673 ◽

2019 ◽

Vol 11 (14) ◽

pp. 1673 ◽

Cited By ~ 9

Author(s):

Qiong Wu ◽

Chunting Jia ◽

Shengbo Chen ◽

Hongqing Li

Keyword(s):

Loess Plateau ◽

Land Subsidence ◽

Surface Deformation ◽

Land Uplift ◽

Synthetic Aperture Radar Interferometry ◽

Urban Buildings ◽

Small Baseline Subset ◽

Land Deformation ◽

Small Baseline ◽

Sbas Insar

Yan’an new district (YND) is one of the largest civil engineering projects for land creation in Loess Plateau, of which the amount of earthwork exceeds 600 million m3, to create 78.5 km2 of flat land. Such mega-scale engineering activities and complex geological characteristics have induced wide land deformation in the region. Small baseline subset synthetic aperture radar interferometry (SBAS-InSAR) method and 55 Sentinel-1A (S-1A) images were utilized in the present work to investigate the urban surface deformation in the Yan’an urban area and Yan’an new airport (YNA) from 2015 to 2019. The results were validated by the ground leveling measurements in the YNA. It is found that significant uneven surface deformation existed in both YND and YNA areas with maximum accumulative subsidence of 300 and 217 mm, respectively. Moreover, the average subsidence rate of the YND and YNA areas ranged from −70 to 30 mm/year and −50 to 25 mm/year, respectively. The present work shows that the land deformation suffered two periods (from 2015 to 2017 and from 2017 to 2019) and expanded from urban center to surrounding resettlement area, which are highly relevant with urban earthwork process. It is found that more than 60% of land subsidence occurs at filled areas, while more than 65% of surface uplifting occurs at excavation areas. The present work shows that the subsidence originates from the earth filling and the load of urban buildings, while the release of stress is the major factor for the land uplift. Moreover, it is found that the collapsibility of loess and concentrated precipitation deteriorates the degree of local land subsidence. The deformation discovered by this paper shows that the city may suffer a long period of subsidence, and huge challenges may exist in the period of urban maintaining buildings and infrastructure facilities.

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Time-Series InSAR Analysis of the Small Baseline Subset to Estimate Surface Deformation at Mt. Bromo Indonesia

Teknik ◽

10.14710/teknik.v39i2.20052 ◽

2019 ◽

Vol 39 (2) ◽

pp. 126

Author(s):

Arliandy Pratama Arbad ◽

Wataru Takeuchi ◽

Yosuke Aoki ◽

Achmad Ardy ◽

Mutiara Jamilah

Keyword(s):

Time Series ◽

Surface Deformation ◽

Sar Interferometry ◽

Alos Palsar ◽

Small Baseline Subset ◽

Sar Data ◽

Small Baseline

Penginderaan jauh kini memainkan peranan penting dalam pengamatan perilaku gunung api. Penelitian ini bertujuan untuk mengamati deformasi permukaan Gunung Bromo, yang terletak di Jawa bagian Timur, Indonesia, yang masuk dalam rangkaian sistem volkanik di Taman Nasional Bukit Tengger Semeru (TNBTS). Penggunaan algoritma SAR Interferometry (InSAR) yang disebut sebagai pendekatan Small Baseline Subset (SBAS) memungkinkan perancangan peta kecepatan deformasi rata-rata dan and peta time series displacement di wilayah kajian. Teknik SBAS yang biasa menghasilkan rangkaian observasi tahap interferometrik. Ini tercatat sebagai kombinasi linear dari nilai fase SAR scene untuk setiap pixel secara tersendiri. Analisis yang dilakukan terutama berdasarkan 22 data SAR data yang diperoleh melalui sensor ALOS/PALSAR selama kurun waktu 2007–2011. Beberapa penelitian menunjukkan bahwa kemampuan analisis InSAR dalam menyelidiki siklus gunung api, terutama Gunung Bromo yang memiliki karakteristik erupsi stratovolcano dalam satu hingga lima tahun. Analisis hasil memperlihatkan adanya kemajuan dari kajian sebelumnya akan InSAR wilayah tersebut, yang lebih fokus kepada deformasi yang berpengaruh kepada kaldera. Hal ini menunjukkan bahwa penelitian ini bisa diimplementasikan pada manajemen risiko atau manajemen infrastruktur

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Land subsidence in Mexico City mapped by ERS differential SAR interferometry

IEEE 1999 International Geoscience and Remote Sensing Symposium. IGARSS'99 (Cat. No.99CH36293) ◽

10.1109/igarss.1999.774993 ◽

2003 ◽

Cited By ~ 10

Author(s):

T. Strozzi ◽

U. Wegmuller

Keyword(s):

Mexico City ◽

Land Subsidence ◽

Sar Interferometry ◽

Differential Sar Interferometry

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Comment on “Study of Systematic Bias in Measuring Surface Deformation With SAR Interferometry” by Ansari et al. (2021)

10.36227/techrxiv.14691333 ◽

2021 ◽

Author(s):

Claudio De Luca ◽

Francesco Casu ◽

Michele Manunta ◽

Giovanni Onorato ◽

Riccardo Lanari

Keyword(s):

Surface Deformation ◽

Sar Interferometry ◽

Systematic Bias ◽

Phase Errors ◽

Measuring Surface ◽

Systematic Biases ◽

Small Baseline ◽

Differential Sar Interferometry ◽

Long Baselines ◽

Baseline Approach

In a recent publication Ansari et al. (2021) [1] claim (see, in particular, the Discussion and Recommendation Section in their article) that the advanced differential SAR interferometry (InSAR) algorithms for surface deformation retrieval, based on the small baseline approach, are affected by systematic biases in the generated InSAR products. Therefore, to avoid such biases, they recommend a strategy primarily focused on excluding “the short temporal baseline interferograms and using long baselines to decrease the overall phase errors”. In particular, among various techniques, Ansari et al. (2021) [1] identify the solution presented by Manunta et al. (2019) [2] as a small baseline advanced InSAR processing approach where the presence of the above-mentioned biases (referred to as a fading signal) compromises the accuracy of the retrieved InSAR deformation products. We show that the claim of Ansari et al. (2021) [1] is not correct (at least) for what concerns the mentioned approach discussed by Manunta et al. (2019) [2]. In particular, by processing the Sentinel-1 dataset relevant to the same area in Sicily (southern Italy) investigated by Ansari et al. (2021) [1], we demonstrate that the generated InSAR products do not show any significant bias.

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Comment on “Pre-Collapse Space Geodetic Observations of Critical Infrastructure: The Morandi Bridge, Genoa, Italy” by Milillo et al. (2019)

Remote Sensing ◽

10.3390/rs12244011 ◽

2020 ◽

Vol 12 (24) ◽

pp. 4011 ◽

Cited By ~ 1

Author(s):

Riccardo Lanari ◽

Diego Reale ◽

Manuela Bonano ◽

Simona Verde ◽

Yasir Muhammad ◽

...

Keyword(s):

Critical Infrastructure ◽

High Spatial Resolution ◽

Sar Interferometry ◽

Large Displacements ◽

Area Of Interest ◽

Multi Temporal ◽

Small Baseline Subset ◽

Small Baseline ◽

Processing Techniques ◽

Over Time

We present in this comment a Multi-Temporal SAR Interferometry (MT-InSAR) analysis showing that the results published by Milillo et al. (2019) in the Remote Sensing Journal, presenting the evidence of space geodetic observations relevant to displacements occurring before the collapse of the Morandi Bridge, happened in Genova (Italy) on the 14 August 2018, are questionable. In particular, we focus on the InSAR results obtained by Milillo et al. (2019) by processing the 3 m × 3 m resolution COSMO-SkyMed (CSK) data collected from ascending and descending orbits on the area of interest. These results, thanks to the high spatial resolution and the short revisit time characterizing this multi-orbit SAR dataset, represent the cornerstone of their analysis. The main findings of their study allow Milillo et al. to conclude that the InSAR processing of this COSMO-SkyMed dataset reveals the increased deformation magnitude over time of points located near the strands of the deck next to the collapsed pier, between 12 March 2017 and August 2018. In this comment, we show the results obtained by the IREA-CNR SAR team after processing the same ascending and descending CSK dataset, but by using two alternative and independent processing techniques: the Small BAseline Subset (SBAS) and the Advanced Tomographic SAR (TomoSAR) approaches, respectively. Our analysis shows that, although both the SBAS and the TomoSAR analyses allow achieving denser coherent pixel maps relevant to the Morandi bridge, nothing of the pre-collapse large displacements reported in Milillo et al. (2019) appears in our results, leading us to deeply disagree with the findings of their InSAR analysis.

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Using Multisensor SAR Datasets to Monitor Land Subsidence in Los Angeles from 2003 to 2017

Journal of Sensors ◽

10.1155/2019/9389820 ◽

2019 ◽

Vol 2019 ◽

pp. 1-15 ◽

Cited By ~ 1

Author(s):

Bo Hu ◽

Xiongle Chen ◽

Xingfu Zhang

Keyword(s):

Los Angeles ◽

Land Subsidence ◽

Disaster Prevention ◽

Practical Application ◽

Gps Measurements ◽

The Past ◽

Groundwater Overexploitation ◽

Small Baseline Subset ◽

Temporal And Spatial ◽

Small Baseline

Los Angeles has undergone tremendous deformations over the past few decades, mainly due to human factors such as natural disasters and earthquakes, urban construction, overexploitation of groundwater, and oil extraction. The purpose of this study is to map the temporal and spatial variations of land subsidence in Los Angeles and to use the improved SBAS (small baseline subset) technique and multisensor SAR datasets to analyze the causes of deformations in this area from October 2003 to October 2017. At the same time, the deformation results of SBAS inversion are compared with the GPS measurements and the multisensor SAR dataset deformation, and the results are highly consistent. During the period from 2003 to 2017, there were several subsidence regions and one uplift region in Los Angeles. The cumulative subsidence was -266.8 mm at the maximum, and the average annual subsidence velocity was -19 mm/yr, which was mainly caused by groundwater overexploitation. The maximum amount of accumulated lift is +104.8 mm, and the average annual lifting velocity can reach +7.5 mm/yr. Our results have very strong practical application value and can provide a significant basis for local government services in disaster prevention and mitigation decision-making.

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Understanding Land Subsidence Along the Coastal Areas of Guangdong, China, by Analyzing Multi-Track MTInSAR Data

Remote Sensing ◽

10.3390/rs12020299 ◽

2020 ◽

Vol 12 (2) ◽

pp. 299 ◽

Cited By ~ 1

Author(s):

Yanan Du ◽

Guangcai Feng ◽

Lin Liu ◽

Haiqiang Fu ◽

Xing Peng ◽

...

Keyword(s):

Land Subsidence ◽

Coastal Areas ◽

Alos Palsar ◽

Groundwater Exploitation ◽

Average Deformation ◽

Deformation Velocity ◽

Multi Temporal ◽

Small Baseline Subset ◽

Small Baseline ◽

The Stability

Coastal areas are usually densely populated, economically developed, ecologically dense, and subject to a phenomenon that is becoming increasingly serious, land subsidence. Land subsidence can accelerate the increase in relative sea level, lead to a series of potential hazards, and threaten the stability of the ecological environment and human lives. In this paper, we adopted two commonly used multi-temporal interferometric synthetic aperture radar (MTInSAR) techniques, Small baseline subset (SBAS) and Temporarily coherent point (TCP) InSAR, to monitor the land subsidence along the entire coastline of Guangdong Province. The long-wavelength L-band ALOS/PALSAR-1 dataset collected from 2007 to 2011 is used to generate the average deformation velocity and deformation time series. Linear subsidence rates over 150 mm/yr are observed in the Chaoshan Plain. The spatiotemporal characteristics are analyzed and then compared with land use and geology to infer potential causes of the land subsidence. The results show that (1) subsidence with notable rates (>20 mm/yr) mainly occurs in areas of aquaculture, followed by urban, agricultural, and forest areas, with percentages of 40.8%, 37.1%, 21.5%, and 0.6%, respectively; (2) subsidence is mainly concentrated in the compressible Holocene deposits, and clearly associated with the thickness of the deposits; and (3) groundwater exploitation for aquaculture and agricultural use outside city areas is probably the main cause of subsidence along these coastal areas.

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