Space-Time Evolutions of Land Subsidence in the Choushui River Alluvial Fan (Taiwan) from Multiple-Sensor Observations

Land subsidence is a significant problem around the world that can increase the risk of flooding, damage to infrastructure, and economic loss. Hence, the continual monitoring of subsidence is important for early detection, mechanism understanding, countermeasure implementation, and deformation prediction. In this study, we used multiple-sensor observations from the Continuous Global Positioning System (CGPS), the small baseline subset (SBAS) algorithm, interferometric synthetic-aperture radar (InSAR), precise leveling, multi-layer compaction monitoring wells (MLCWs), and groundwater observation wells (GWs) to show the spatial and temporal details of land subsidence in the Choushui River alluvial fan (CRAF), Taiwan, from 1993 to 2019. The results showed that significant land subsidence has occurred along the coastal areas in the CRAF, and most of the inland subsidence areas have also experienced higher subsidence rates (>30 mm/yr). The analysis of subsidence along the Taiwan High Speed Rail (THSR) revealed a newly formed subsidence center between Tuku and Yuanchang Townships in Yunlin, with high subsidence rates ranging from 30 to 70 mm/yr. We propose a map showing, for the first time, the distribution of deep compactions occurring below 300 m depth in the CRAF.

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IoT technology and big data processing for monitoring and analysing land subsidence in Central Taiwan

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-382-103-2020 ◽

2020 ◽

Vol 382 ◽

pp. 103-109

Author(s):

Wei-Chia Hung ◽

Yi-An Chen ◽

Cheinway Hwang

Keyword(s):

Land Subsidence ◽

High Speed ◽

Large Scale ◽

Alluvial Fan ◽

Monitoring Wells ◽

Multi Temporal ◽

Multiple Sensor Monitoring ◽

Large Scale Land ◽

Central Taiwan ◽

Subsidence Monitoring

Abstract. Over 1992–2018, groundwater overexploitation had caused large-scale land subsidence in the Choshui River Alluvial Fan (CRAF) in Taiwan. The Taiwan High Speed Railway (THSR) passes through an area of severe subsidence in CRAF, and the subsidence poses a serious threat to its operation. How to effectively monitor land subsidence here has become a major issue in Taiwan. In this paper, we introduce a multiple-sensor monitoring system for land subsidence, including 50 continuous operation reference stations (CORS), multi temporal InSAR (MT-InSAR), a 1000 km levelling network, 34 multi-layer compaction monitoring wells and 116 groundwater monitoring wells. This system can monitor the extent of land subsidence and provide data for studying the mechanism of land subsidence. We use the Internet of Things (IoT) technology to control and manage the sensors and develop a bigdata processing procedure to analyse the monitoring data for the system of sensors. The procedure makes the land subsidence monitoring more efficient and intelligent.

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Surface Deformation from Sentinel-1A InSAR: Relation to Seasonal Groundwater Extraction and Rainfall in Central Taiwan

Remote Sensing ◽

10.3390/rs11232817 ◽

2019 ◽

Vol 11 (23) ◽

pp. 2817 ◽

Cited By ~ 4

Author(s):

Yi-Jie Yang ◽

Cheinway Hwang ◽

Wei-Chia Hung ◽

Thomas Fuhrmann ◽

Yi-An Chen ◽

...

Keyword(s):

Land Subsidence ◽

High Speed ◽

Large Scale ◽

Surface Deformation ◽

Dry Season ◽

Severe Drought ◽

Groundwater Extraction ◽

Large Scale Land ◽

Small Baseline ◽

Central Taiwan

Extracting groundwater for agricultural, aquacultural, and industrial use in central Taiwan has caused large-scale land subsidence that poses a threat to the operation of the Taiwan High Speed Railway near Yunlin County. We detected Yunlin subsidence using the Sentinel-1A Synthetic Aperture Radar (SAR) by the Small BAseline Subset (SBAS) method from April 2016 to April 2017. We calibrated the initial InSAR-derived displacement rates using GPS measurements and reduced the velocity difference between the two sensors from 15.0 to 8.5 mm/a. In Yunlin’s severe subsidence regions, cumulative displacements from InSAR and GPS showed that the dry-season subsidence contributed 60%–74% of the annual subsidence. The InSAR-derived vertical velocities matched the velocities from leveling to better than 10 mm/a. In regions with few leveling measurements, InSAR increased the spatial resolution of the vertical velocity field and identified two previously unknown subsidence spots over an industrial zone and steel factory. Annual significant subsidence areas (subsidence rate > 30 mm/a) from leveling from 2011 to 2017 increased with the declining dry-season rainfalls, suggesting that the dry-season rainfall was the deciding factor for land subsidence. A severe drought in 2015 (an El Niño year) dramatically increased the significant subsidence area to 659 km2. Both InSAR and leveling detected similarly significant subsidence areas in 2017, showing that InSAR was an effective technique for assessing whether a subsidence mitigation measure worked. The newly opened Hushan Reservoir can supply surface water during dry seasons and droughts to counter rain shortage and can thereby potentially reduce land subsidence caused by groundwater extraction.

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Securing the subterranean volumes: Geometrics, land subsidence and the materialities of things

Environment and Planning D Society and Space ◽

10.1177/0263775820958030 ◽

2020 ◽

pp. 026377582095803

Author(s):

Chi-Mao Wang

Keyword(s):

Environmental Management ◽

Land Subsidence ◽

High Speed ◽

Management Programme ◽

Three Dimensions ◽

Chaotic State ◽

High Speed Rail ◽

New Horizons ◽

Rail Infrastructure ◽

Monitoring Technologies

In 2011, thousands of Taiwanese farmers gathered in Yunlin County to protest against a government environmental management programme which attempted to address the land subsidence that has threatened Taiwan’s High-Speed Rail infrastructure. New environmental monitoring technologies have been developed to deal with the land subsidence but these have, simultaneously, provoked contestation. The dispute indicates that the horizontalism inherent in traditional studies of geopolitics fails to account for the politics of verticality. Indeed, recent work on volumetric politics opens up new horizons for thinking about the exercise of power through three dimensions; the geopolitics of the underground have remained untheorised. Moreover, the existing literature on volume also fails to account for the chaotic state of the material world. From the perspective of assemblage thinking, I outline three characteristics which shape the ‘geopolitics of land subsidence’. From this standpoint, this paper argues for a geographical approach to subterranean politics which puts more emphasis on volume, emergence and matter. With reference to ethnographical fieldwork conducted in scientific laboratories and in Yunlin County, I demonstrate how subterranean materials continuously frustrate the state’s volumetric practices. By problematising the geopolitics of land subsidence, this paper also advances the understanding of political geology, which is seeking to ‘decolonise’ and ‘pluralise geological thought’.

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

Natural Hazards and Earth System Science ◽

10.5194/nhess-20-3399-2020 ◽

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.

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The reason of land subsidence and prevention measures of Beijing segment of Beijing-Tianjin high-speed rail

2014 Third International Workshop on Earth Observation and Remote Sensing Applications (EORSA) ◽

10.1109/eorsa.2014.6927904 ◽

2014 ◽

Author(s):

Liu Huanhuan ◽

Zhang Youquan ◽

Wang Rong

Keyword(s):

Land Subsidence ◽

High Speed ◽

Prevention Measures ◽

High Speed Rail

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Multiple sensors applied to monitorland subsidence in Central Taiwan

Proceedings of the International Association of Hydrological Sciences ◽

10.5194/piahs-372-385-2015 ◽

2015 ◽

Vol 372 ◽

pp. 385-391 ◽

Cited By ~ 1

Author(s):

W.-C. Hung ◽

C. Wang ◽

C. Hwang ◽

Y.-A. Chen ◽

H.-C. Chiu ◽

...

Keyword(s):

High Speed ◽

Large Scale ◽

Alluvial Fan ◽

Persistent Scatterer Interferometry ◽

High Speed Rail ◽

Aquifer System ◽

Multiple Sensors ◽

Persistent Scatterer ◽

Global Positioning ◽

Central Taiwan

Abstract. During 1992–2013, pumping of groundwater caused large-scale aquifer-system compaction and land subsidence in the Choshui River Alluvial Fan (CRAF) in Taiwan. The subsidence has already endangered the operation of Taiwan High Speed Rail (THSR). In this paper, we introduce the multiple sensors monitoring system to study the extent of subsidence in CRAF and its mechanism, including GPS (Global Positioning System), PSI (Persistent Scatterer Interferometry), leveling and multi-layer compaction monitoring well. These sensors complement each other in spatial and temporal resolutions.

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