ESTIMATION OF LAND SUBSIDENCE IN THE MEKONG DELTA AND ITS SURROUNDING AREAS

2021 ◽  
Vol 66 (3) ◽  
pp. 180-194
Author(s):  
Khac Dang Vu ◽  
Trinh Phan Trong ◽  
Vinh Dinh Xuan
Keyword(s):  
Land Subsidence ◽  
Mekong Delta ◽  
Maximum Velocity ◽  
Line Of Sight ◽  
Interferometric Synthetic Aperture Radar ◽  
Ground Displacement ◽  
Persistent Scatterer ◽  
The One ◽  
Surrounding Areas ◽  
The Impact

Land subsidence becomes a trouble for the different regions of the Mekong delta, where many places will be severely affected by sea-level rise in the context of climate change. Land subsidence could amplify this situation by inducing interactive hazards such as submerged land and saline intrusion, etc. Mapping the spatial distribution of land subsidence become a crucial task, and the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSInSAR) approach was applied to 120 Sentinel-1A images within three scenes, captured from October 2016 to October 2020 with the interval of 36 days between two consecutive images. This approach allows mapping ground displacement by continuously extracting deformation signals and estimating the position of targets that persistently scatter radar beams. The average velocity map shows that eight main subsidence areas in the Mekong delta have been affected in recent years with the maximum velocity of -39.61 mm year-1 and the cumulative displacement ranging from 60 to 100 mm in the Line Of Sight (LOS) direction over four years. The validation using 40 Sentinel-1B images, captured in identical periods indicates a consistent result in comparison with the one issued from Sentinel-1A. These pieces of knowledge are essential for improving both citizen’s life and reducing the impact of land subsidence on the natural environment.

scholarly journals Extensive Investigation of the Land Subsidence Impressions on Gedebage District, Bandung, Indonesia

2021 ◽  
Vol 873 (1) ◽  
pp. 012044
Author(s):  
I Gumilar ◽  
TP. Sidiq ◽  
I Meilano ◽  
B Bramanto ◽  
G Pambudi
Keyword(s):  
Land Subsidence ◽  
Urban Areas ◽  
Average Rate ◽  
Satellite System ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Infrastructure Development ◽  
Global Navigation Satellite ◽  
Almost All ◽  
The Impact

Abstract Gedebage district is presently experiencing rapid and mass infrastructure development and becoming one of the developed districts in Bandung, Indonesia. A football stadium, several luxury housing, the grand mosque of West Java province, and a business center have been built in this district. However, it is well known that the Gedebage district has turned into one of the Bandung districts that suffers from land subsidence phenomena. Since 2000, the Gedebage district has suffered land subsidence at an average rate of 10 cm per year and becoming one of the fastest sinking districts in Bandung. This fast land subsidence phenomenon is suspected of affecting the infrastructure in this district. Therefore, this work aims to capture the current subsidence rate in the Gedebage district using the geodetic approach of the combination of the Global Navigation Satellite System (GNSS) with Interferometric Synthetic Aperture Radar (InSAR) and investigate the impact of land subsidence on infrastructures in Gedebage district. We use GNSS campaign datasets from the years 2016 and 2019. Each GNSS campaign was performed at least 10-12 hours of observations. We also utilize a similar period of 2016 to 2019 for the InSAR datasets. Utilizing both GNSS and InSAR datasets, we can capture the subsidence with the rate reaching 4 -15 cm per year between 2016 and 2019, and it occurs uniformly in this district. The impact of land subsidence occurred in almost all urban areas in the Gedebage district. These impacts include cracks in buildings, bridges and roads, and also tilted buildings.

scholarly journals Analysis of Clay-Induced Land Subsidence in Uppsala City Using Sentinel-1 SAR Data and Precise Leveling

2019 ◽  
Vol 11 (23) ◽  
pp. 2764 ◽  
Author(s):  
Jonas Fryksten ◽  
Faramarz Nilfouroushan
Keyword(s):  
Land Subsidence ◽  
Ground Deformation ◽  
Ground Surface ◽  
Urban Infrastructure ◽  
Data Sets ◽  
Interferometric Synthetic Aperture Radar ◽  
Persistent Scatterer Interferometry ◽  
New Methods ◽  
Persistent Scatterer ◽  
The City

Land subsidence and its subsequent hazardous effects on buildings and urban infrastructure are important issues in many cities around the world. The city of Uppsala in Sweden is undergoing significant subsidence in areas that are located on clay. Underlying clay units in parts of Uppsala act as mechanically weak layers, which for instance, cause sinking of the ground surface and tilting buildings. Interferometric Synthetic Aperture Radar (InSAR) has given rise to new methods of measuring movements on earth surface with a precision of a few mm. In this study, a Persistent Scatterer Interferometry (PSI) analysis was performed to map the ongoing ground deformation in Uppsala. The subsidence rate measured with PSI was validated with precise leveling data at different locations. Two ascending and descending data sets were analyzed using SARPROZ software, with Sentinel-1 data from the period March 2015 to April 2019. After the PSI analyses, comparative Permanent Scatterer (PS) points and metal pegs (measured with precise leveling) were identified creating validation pairs. According to the PSI analyses, Uppsala was undergoing significant subsidence in some areas, with an annual rate of about 6 mm/year in the line-of-sight direction. Interestingly, the areas of great deformation were exclusively found on postglacial clay.

scholarly journals Time-series evolution patterns of land subsidence in the eastern Beijing Plain, China

2019 ◽  
Vol 11 (5) ◽  
pp. 539 ◽  
Author(s):  
Junjie Zuo ◽  
Huili Gong ◽  
Beibei Chen ◽  
Kaisi Liu ◽  
Chaofan Zhou ◽  
...  
Keyword(s):  
Time Series ◽  
Land Subsidence ◽  
Groundwater Level ◽  
Permutation Entropy ◽  
Interferometric Synthetic Aperture Radar ◽  
Beijing Plain ◽  
Evolution Pattern ◽  
Persistent Scatterer ◽  
Geological Conditions ◽  
Two Stages

Land subsidence in the Eastern Beijing Plain has a long history and is always serious. In this paper, we consider the time-series evolution patterns of the eastern of Beijing Plain. First, we use the Persistent Scatterer Interferometric Synthetic Aperture Radar (PSI) technique, with Envisat and Radarsat-2 data, to monitor the deformation of Beijing Plain from 2007 to 2015. Second, we adopt the standard deviation ellipse (SDE) method, combined with hydrogeological data, to analyze the spatial evolution patterns of land subsidence. The results suggest that land subsidence developed mainly in the northwest–southeast direction until 2012 and then expanded in all directions. This process corresponds to the expansion of the groundwater cone of depression range after 2012, although subsidence is restricted by geological conditions. Then, we use the permutation entropy (PE) algorithm to reverse the temporal evolution pattern of land subsidence, and interpret the causes of the phenomenon in combination with groundwater level change data. The results show that the time-series evolution pattern of the land subsidence funnel edge can be divided into three stages. From 2009 to 2010, the land subsidence development was uneven. From 2010 to 2012, the land subsidence development was relatively even. From 2012 to 2013, the development of land subsidence became uneven. However, subsidence within the land subsidence funnel is divided into two stages. From 2009 to 2012, the land subsidence tended to be even, and from 2012 to 2015, the land subsidence was relatively more even. The main reason for the different time-series evolution patterns at these two locations is the annual groundwater level variations. The larger the variation range of groundwater is, the higher the corresponding PE value, which means the development of the land subsidence tends to be uneven.

scholarly journals A Two-Phased Guidance Law for Impact Angle Control with Seeker’s Field-of-View Limit

2018 ◽  
Vol 2018 ◽  
pp. 1-13 ◽  
Author(s):  
Haoqiang Zhang ◽  
Shengjing Tang ◽  
Jie Guo ◽  
Wan Zhang
Keyword(s):  
Impact Angle ◽  
Quadratic Equation ◽  
Field Of View ◽  
Line Of Sight ◽  
Guidance Law ◽  
Physical Limit ◽  
The Look ◽  
The One ◽  
The Impact ◽  
Impact Angle Constraint

A two-phased guidance problem with terminal impact angle constraints and seeker’s field-of-view limit is addressed in this paper for a missile against a nonmaneuvering incoming target. From the conventional PN guidance without any constraints, it is found that satisfying the impact angle constraint causes a more curved missile trajectory requiring a large look angle. To avoid the look angle exceeding the seeker’s physical limit, a two-phased look angle control guidance scheme with the terminal constraint is introduced. The PN-typed guidance law is designed for each guidance phase with a specific switching condition of line-of-sight. The proposed guidance law is comprised of two types of acceleration commands: the one in the initial phase which aims at controlling the missile’s look angle to reach the limit and the other for final phase which is produced by switching the navigation gain. The monotonicity of the line-of-sight angle and look angle is analyzed and proved to support the proposed method. To evaluate the specific navigation gains for both initial and final phases, the scaling coefficient between them is discussed by solving a quadratic equation with respect to the initial navigation gain. To avoid a great abrupt acceleration change at the switching instant, a minimum coefficient is chosen. Extensive simulations are performed to validate the efficiency of the proposed approach.

scholarly journals DATA OPTIMALIZATION IN PERMANENT SCATTERER INTERFEROMETRIC SYNTHETIC APERTURE RADAR (PS-INSAR) TECHNIQUE FOR LAND SUBSIDENCE ESTIMATION

2018 ◽  
Author(s):  
Ketut Wikantika
Keyword(s):  
Land Subsidence ◽  
Research Data ◽  
Synthetic Aperture ◽  
Interferometric Synthetic Aperture Radar ◽  
Alos Palsar ◽  
Persistent Scatterer ◽  
Land Deformation ◽  
L Band

Since the introduction of the persistent scatterer technique (PS-InSAR) in the early 1999, the applicability of radar interferometry has increased considerably.In this research, PS-InSAR technique is proposed to retrieve the volume change of long-term continuously land deformation. This technique is used to analyze subsidence in Bandung City, West Java-Indonesia by assessing 19 ALOS PALSAR images (Japanese L band spaceborne) during the periods of July 2007-February 2011. In this research, data are optimized by reducing set data images with iterative PS-InSAR processing. This PS-InSAR processing chain based on a rigid quality assessment of the estimated parameter like minimum coherence (0.9) and PS density point (200), in order to get an optimum quality of light PS-InSAR (LPS-InSAR) concept technique. Moreover, a strict quality validation of PS-InSAR with other geodetic techniques such as DInSAR and GPS methods. The result of validation has resulted such as 1,4 ± 1,4 cm/year (PS InSAR-DInSAR) and 1,6 ± 0,7 cm/year (PS-InSAR-GPS). For land subsidence velocity in Bandung City has results between 0,6 ± 0,4 cm/year and 2,1 ± 1,2 cm/year. This research shows a capability of data optimalization in PS-InSAR technique as basic concept of LPS-InSAR processing.

scholarly journals Analysis of Clay-Induced Land Subsidence in Uppsala City Using Sentinel-1 SAR Data and Precise Leveling

2020 ◽  
Author(s):  
Faramarz Nilfouroushan ◽  
Jonas Fryksten
Keyword(s):  
Land Subsidence ◽  
Ground Deformation ◽  
Ground Surface ◽  
Urban Infrastructure ◽  
Annual Rate ◽  
Line Of Sight ◽  
Data Sets ◽  
Persistent Scatterer ◽  
The World ◽  
The City

<p>Land subsidence and its subsequent hazardous effects on buildings and urban infrastructure are important issues in many cities around the world. The city of Uppsala in Sweden is undergoing significant subsidence in areas that are located on clay. Underlying clay units in parts of Uppsala act as mechanically weak layers, which for instance, cause sinking of the ground surface and tilting buildings. In this study, a Persistent Scatterer InSAR (PSI) analysis was performed to map the ongoing ground deformation in Uppsala. The subsidence rate measured with PSI was validated with precise leveling data at different locations. Two ascending and descending data sets were analyzed using SARPROZ software, with Sentinel-1 data from the period March 2015 to April 2019. After the PSI analyses, comparative permanent scatterer (PS) points and metal pegs (measured with precise leveling) were identified creating validation pairs. According to the PSI analyses, Uppsala was undergoing significant subsidence in some areas, with an annual rate of about 6 mm/year in the line-of-sight direction. Interestingly, the areas of great deformation were exclusively found on postglacial clay.</p>

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