Ground deformation associated with the August 2019 eruption of Piton de la Fournaise (La Réunion Island) inferred from DInSAR measurements

2020 ◽  
Author(s):  
Vincenzo De Novellis ◽  
Francesco Casu ◽  
Claudio De Luca ◽  
Mariarosaria Manzo ◽  
Fernando Monterroso ◽  
...  
Keyword(s):  
Ground Deformation ◽  
Coseismic Deformation ◽  
Southeastern Part ◽  
Eruptive Fissure ◽  
Piton De La Fournaise ◽  
Synthetic Aperture Radar Interferometry ◽  
Small Baseline Subset ◽  
Small Baseline ◽  
Deformation Patterns ◽  
Eruptive Fissures

<p>Piton de la Fournaise volcano forms the southeastern part of La Réunion, an oceanic basaltic island in the southernmost part of Mascarene Basin (Indian Ocean). Five eruptions occurred at Piton in 2019, accompanied by seismic activity, lava flow, and lava fountaining. Here below, we focus on the fourth eruption occurred between August 11 and 15 on the southern-southeastern flank of the volcano, inside the Enclos Fouqué caldera. This eruption was characterized by the opening of two eruptive fissures. We retrieve the surface deformations induced by the eruptive activity through space-borne Differential Synthetic Aperture Radar Interferometry (DInSAR) measurements. First, we generated the coseismic deformation maps by applying the DInSAR technique to SAR data collected along ascending and descending orbits by the Sentinel-1 constellation of the European Copernicus Programme. The DInSAR technique allows us to analyze the deformation patterns caused by the 11 August 2019 eruption. We also retrieved the pre-eruptive deformation through the Small BAseline Subset (SBAS) DInSAR approach. Then, we modelled the DInSAR displacements to constrain the geometry and characteristics of the eruptive source. The modelling results suggest that the observed deformation can be attributed to the interaction between a shallow magma reservoir located at ~1.5-2 km depth below the summit, and the intrusion of a dike feeding the eruptive fissure inside the Enclos Fouqué caldera.</p><p><em>This work is supported by: the 2019-2021 IREA-CNR and Italian Civil Protection Department agreement; the EPOS-SP project (GA 871121); and the I-AMICA (PONa3_00363) project.</em></p>

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

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

<p>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.</p><p>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.</p>

scholarly journals 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

2019 ◽  
Vol 11 (14) ◽  
pp. 1673 ◽  
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.

scholarly journals Analysis of deformation patterns through advanced DINSAR techniques in Istanbul megacity

2014 ◽  
Vol XL-7 ◽  
pp. 19-21
Author(s):  
F. Balik Sanli ◽  
F. Calò ◽  
S. Abdikan ◽  
A. Pepe ◽  
T. Gorum
Keyword(s):  
Rural Areas ◽  
Ground Deformation ◽  
Mitigation Strategies ◽  
Sar Interferometry ◽  
Economic Losses ◽  
Hazard And Risk ◽  
Small Baseline ◽  
Urbanization Rate ◽  
Deformation Patterns ◽  
Urban Planning And Management

As result of the Turkey’s economic growth and heavy migration processes from rural areas, Istanbul has experienced a high urbanization rate, with severe impacts on the environment in terms of natural resources pressure, land-cover changes and uncontrolled sprawl. As a consequence, the city became extremely vulnerable to natural and man-made hazards, inducing ground deformation phenomena that threaten buildings and infrastructures and often cause significant socio-economic losses. Therefore, the detection and monitoring of such deformation patterns is of primary importance for hazard and risk assessment as well as for the design and implementation of effective mitigation strategies. Aim of this work is to analyze the spatial distribution and temporal evolution of deformations affecting the Istanbul metropolitan area, by exploiting advanced Differential SAR Interferometry (DInSAR) techniques. In particular, we apply the Small BAseline Subset (SBAS) approach to a dataset of 43 TerraSAR-X images acquired, between November 2010 and June 2012, along descending orbits with an 11-day revisit time and a 3 m × 3 m spatial resolution. The SBAS processing allowed us to remotely detect and monitor subsidence patterns over all the urban area as well as to provide detailed information at the scale of the single building. Such SBAS measurements, effectively integrated with ground-based monitoring data and thematic maps, allows to explore the relationship between the detected deformation phenomena and urbanization, contributing to improve the urban planning and management.

scholarly journals Monitoring of Ground Deformation due to Excessive Withdrawal of Natural Gas Using SBAS

2014 ◽  
Vol 2014 ◽  
pp. 1-6
Author(s):  
Bo Hu
Keyword(s):  
Natural Gas ◽  
Ground Deformation ◽  
Spatial And Temporal Variation ◽  
Chiba Prefecture ◽  
Average Deformation ◽  
Wide Range ◽  
Deformation Velocity ◽  
Uplift Rates ◽  
Small Baseline Subset ◽  
Small Baseline

The excessive withdrawal of natural gas can generate a wide range of ground deformation. The aim of this paper is to investigate ground deformation in Chiba Prefecture, Japan, using the Small Baseline Subset (SBAS) technique. In recent years, the local government has taken a series of measures such as artificial recharge and reduction of groundwater withdrawal to alleviate the ground settlement. In order to more fully investigate the spatial and temporal variation of deformation that occurred in Chiba Prefecture, we process a dataset of 34 ASAR images acquired from September 2006 to August 2010 based on SBAS technique and generate the mean deformation velocity map and time series deformation maps. The results show that (1) a relatively stable in Mao Yuan area, with an average subsidence velocity of −0.91 mm/y. (2) large uplift rates were highlighted in albino Ding and Kujukuri, which average deformation velocity were about 5.11 mm/y and 6.15 mm/y respectively.

scholarly journals Assessments of land subsidence along the Rizhao–Lankao high-speed railway at Heze, China, between 2015 and 2019 with Sentinel-1 data

2020 ◽  
Vol 20 (12) ◽  
pp. 3399-3411
Author(s):  
Chuanguang Zhu ◽  
Wenhao Wu ◽  
Mahdi Motagh ◽  
Liya Zhang ◽  
Zongli Jiang ◽  
...  
Keyword(s):  
Land Subsidence ◽  
High Speed ◽  
Underground Mining ◽  
Ground Deformation ◽  
Ground Subsidence ◽  
Monthly Precipitation ◽  
High Speed Railway ◽  
Small Baseline Subset ◽  
Small Baseline ◽  
Under Construction

Abstract. The Heze section of Rizhao–Lankao high-speed railway (RLHR-HZ) has been under construction since 2018 and will be in operation by the end of 2021. However, there is a concern that land subsidence in the Heze region may affect the regular operation of RLHR-HZ. In this study, we investigate the contemporary ground deformation in the region between 2015 and 2019 by using more than 350 C-band interferograms constructed from two tracks of Sentinel-1 data over the region. The small baseline subset (SBAS) technique is adopted to compile the time-series displacement. We find that the RLHR-HZ runs through two main subsidence areas: one is located east of the Heze region with rates ranging from −4 to −1 cm yr−1, and another one is located in the coalfield with rates ranging from −8 to −2 cm yr−1. A total length of 35 km of RLHR-HZ is affected by the two subsidence basins. Considering the previous investigation and the monthly precipitation, we infer that the subsidence bowl east of the Heze region is due to massive extraction of deep groundwater. Close inspections of the relative locations between the second subsidence area and the underground mining reveals that the subsidence there is probably caused by the groundwater outflow and fault instability due to mining, rather than being directly caused by mining. The InSAR-derived ground subsidence implies that it is necessary to continue monitoring the ground deformation along RLHR-HZ.

scholarly journals Advanced SBAS-DInSAR Technique for Controlling Large Civil Infrastructures: An Application to the Genzano di Lucania Dam

Sensors ◽  
2018 ◽  
Vol 18 (7) ◽  
pp. 2371 ◽  
Author(s):  
Marco Corsetti ◽  
Fabrizio Fossati ◽  
Michele Manunta ◽  
Maria Marsella
Keyword(s):  
Surface Deformation ◽  
Numerical Models ◽  
Earth Dam ◽  
Structural Behaviour ◽  
Safety Standards ◽  
Civil Infrastructures ◽  
Synthetic Aperture Radar Interferometry ◽  
Small Baseline Subset ◽  
Comparable Accuracy ◽  
Small Baseline

Monitoring surface deformation on dams is commonly carried out by in situ geodetic surveying, which is time consuming and characterized by some limitations in space coverage and frequency. More recently microwave satellite-based technologies, such as advanced-DInSAR (Differential Synthetic Aperture Radar Interferometry), have allowed the integration and improvement of the observation capabilities of ground-based methods thanks to their effectiveness in collecting displacement measurements on many non-destructive control points, corresponding to radar reflecting targets. The availability of such a large number of points of measurement, which are distributed along the whole structure and are characterized by millimetric accuracy on displacement rates, can be profitably adopted for the calibration of numerical models. These models are implemented to simulate the structural behaviour of a dam under conditions of stress thus improving the ability to maintain safety standards. In this work, after having analysed how advanced DInSAR can effectively enhance the results from traditional monitoring systems that provide comparable accuracy measurements on a limited number of points, an FEM model of the Genzano di Lucania earth dam is developed and calibrated. This work is concentrated on the advanced DInSAR technique referred to as Small BAseline Subset (SBAS) approach, benefiting from its capability to generate deformation time series at full spatial resolution and from multi-sensor SAR data, to measure the vertical consolidation displacement of the Genzano di Lucania earth dam.

scholarly journals Advanced analysis of satellite data reveals ground deformation precursors to the Brumadinho Tailings Dam collapse

2021 ◽  
Vol 2 (1) ◽  
Author(s):  
Stephen Grebby ◽  
Andrew Sowter ◽  
Jon Gluyas ◽  
David Toll ◽  
David Gee ◽  
...  
Keyword(s):  
Iron Ore ◽  
Ground Deformation ◽  
Synthetic Aperture ◽  
Environmental Damage ◽  
Interferometric Synthetic Aperture Radar ◽  
Tailings Dam ◽  
Consolidation Settlement ◽  
Small Baseline Subset ◽  
Advanced Analysis ◽  
Small Baseline

AbstractCatastrophic failure of a tailings dam at an iron ore mine complex in Brumadinho, Brazil, on 25th January 2019 released 11.7 million m3 of tailings downstream. Although reportedly monitored using an array of geotechnical techniques, the collapse occurred without any apparent warning. It claimed more than 200 lives and caused considerable environmental damage. Here we present the Intermittent Small Baseline Subset (ISBAS) technique on satellite-based interferometric synthetic aperture radar (InSAR) data to assess the course of events. We find that parts of the dam wall and tailings were experiencing deformation not consistent with consolidation settlement preceding the collapse. Furthermore, we show that the timing of the dam collapse would have been foreseeable based on this observed precursory deformation. We conclude that satellite-based monitoring techniques may help mitigate similar catastrophes in the future.

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