Improving global land subsidence analysis

2021 ◽  
Author(s):  
Pablo Ezquerro ◽  
Gerardo Herrera-García ◽  
Roberto Tomás ◽  
Marta Béjar-Pizarro ◽  
Juan López-Vinielles ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Urban Areas ◽  
Global Climate ◽  
Groundwater Resources ◽  
Unconsolidated Sediments ◽  
Subsidence Analysis ◽  
Global Land ◽  
Arid And Semiarid Areas ◽  
Calculated Probability ◽  
Global Threat

<p>Land subsidence associated with groundwater withdrawal is often an underestimated geological hazard that may produce important damage to buildings and infrastructure, change flood risk in some areas, and cause loss of groundwater storage capacity. In the current framework of global climate change, the increasing agricultural and urban use of groundwater resources is a growing problem, especially in arid and semiarid areas. Because monitoring subsidence in these areas is important for management, but early detection is difficult due to slow displacement rates, we developed global groundwater induced land subsidence probability maps.  Global land subsidence probability was calculated by applying statistical methods to a set of susceptible geographical, environmental and geological properties based on known, documented subsidence affected areas. Highest values of subsidence probability are concentrated over flat areas composed of unconsolidated sediments, and in agricultural or urban areas subject to prolonged dry periods. Including water scarcity and groundwater use data resulted in an estimation of a proxy land subsidence hazard. Calculated probability does not imply that all the high value areas are currently incurring land subsidence, but it can alert policymakers and groundwater managers to areas that have potential exposure to subsidence hazards and warrant monitoring. The complete results of this work are published in Science Policy Forum section under the title “Mapping the global threat of land subsidence” DOI: 10.1126/science.abb8549</p>

scholarly journals REVIEW OF THE LAND SUBSIDENCE HAZARD IN PEKALONGAN DELTA, CENTRAL JAVA: INSIGHTS FROM THE SUBSURFACE

2021 ◽  
Vol 36 (4) ◽  
pp. 163-176
Author(s):  
Dwi Sarah ◽  
Eko Soebowo ◽  
Nugroho Aji Satriyo
Keyword(s):  
Land Subsidence ◽  
Groundwater Resources ◽  
Research Direction ◽  
Future Research ◽  
Land Loss ◽  
Subsurface Geology ◽  
The North ◽  
Central Java ◽  
Over Exploitation ◽  
Global Threat

Land subsidence is a global threat to coastal areas worldwide, including the North Java coastal area. Of many areas experiencing land subsidence in North Java, the rate of land subsidence in Pekalongan has matched the high subsidence rates usually found in big cities. The rate of land subsidence in Pekalongan far exceeds the sea-level rise, resulting in a looming threat of land loss. The devastating impacts of land subsidence are the manifestation of its subsurface movement. Therefore, it is essential to understand the subsurface to elucidate the mechanism of land subsidence. Previous studies on land subsidence in Pekalongan are mainly related to subsidence rate monitoring and have not elaborated on the subsurface condition. This paper reviews the Pekalongan subsurface geology based on available literature to provide insight into the land subsidence problem. The results revealed that the land subsidence occurs in the recent alluvial plain of Pekalongan, consisting of a 30-70 m thick compressible deposit. Possible mechanisms of land subsidence arise from natural compaction, over-exploitation of confined groundwater, and increased built areas. As the seismicity of the study area is low, tectonic influence on land subsidence is considered negligible. It is expected that the offshore, nearshore, and swamp deposits are still naturally compacting. As the surface water supply is minimal, over-exploitation of groundwater resources from the deltaic and Damar Formation aquifers occurs. In the end, future research direction is proposed to reduce the impacts of the subsidence hazard.

scholarly journals Hydrofacies reconstruction of glaciofluvial aquifers and groundwater flow modelling in a densely urbanized area under changing climatic conditions

2017 ◽  
Author(s):  
Mattia De Caro ◽  
Giovanni B. Crosta ◽  
Paolo Frattini ◽  
Roberta Perico ◽  
Giorgio Volpi
Keyword(s):  
Climate Change ◽  
Steady State ◽  
Groundwater Flow ◽  
Groundwater Level ◽  
Urban Areas ◽  
Global Climate ◽  
Groundwater Resources ◽  
Base Flow ◽  
Stratigraphic Model ◽  
Groundwater Flow Modelling

Abstract. Potential impacts of global climate changes on the groundwater are largely unknown, especially for densely populated areas where groundwater is heavily exploited for public and industrial supply. Hence, to better plan and manage the groundwater resources, medium-long term numerical modelling of groundwater flow, which takes into account climate change, population growth, and industrial and agricultural activities, is needed. The objective of this paper is to tackle three main issues: (1) the development of a robust hydro-stratigraphic model of a multi-aquifer system from a well logs database by means of a novel multi-dimensional approach which includes a hierarchical classification of the lithologies, the interpretation of cross-sections, and the interpolation of aquifer boundary surfaces; (2) the parametrization and calibration of both a steady state and a transient groundwater flow model, starting from empirical relationships (for unconfined aquifer) and step-drawdown and well tests (for semi-confined and confined aquifers) to define equivalent homogenous sub-units; and (3) the simulation of steady state and transient scenarios based on projections about global climate change and variation in abstraction and recharge rates. These issues are illustrated for the Milan metropolitan area (Northern Italy) and the conterminous Po Plain portion. The results of the model allow to analyse the major components of the regional groundwater system (i.e. public supply wells withdrawals, discharge to gaining rivers and springs, recharge from irrigation networks and vegetated areas, flow transfer between aquifers). The groundwater level rising observed in the last decades caused serious problems in the urban areas and a progressive increase in the base-flow towards the gaining rivers. Simulations including effects of future climate scenarios (2017–2030) indicate a further increase in groundwater level in the next decades at a lower rate (ca. 0.3 m/year) with respect to that of the 1970–2016 period (ca. 1 m/year), due to the combined action of decreasing withdrawals and recharge.

The experience of monitoring the land subsidence in urban areas by radar satellite interferometry on the example of St. Petersburg

2020 ◽  
Vol 64 (4) ◽  
pp. 399-408
Author(s):  
Shirshova V. ◽  
Keyword(s):  
Land Subsidence ◽  
Urban Areas ◽  
Radar Satellite

Разработана и опробована методика мониторинга на основе метода радиолокационной спутниковой интерферометрии с применением открытых данных радиолокационного спутника Sentinel-1. Обработка радиолокационных снимков была реализована на открытом программном обеспечении SNAP. В результате были получены 40 карт вертикальных смещений города Санкт-Петербург. На основе геоинформационного программного обеспечения QGIS был произведен анализ полученных карт смещений и визуализация результатов интерферометрической обработки.

Sentinel-1 InSAR survey to constrain subsidence-induced surface faulting and quantify its induced risk in major cities of central Mexico

2021 ◽  
Author(s):  
Francesca Cigna ◽  
Deodato Tapete
Keyword(s):  
Risk Assessment ◽  
Mexico City ◽  
Land Subsidence ◽  
Groundwater Resources ◽  
Urban Infrastructure ◽  
Capital City ◽  
Transport Infrastructure ◽  
Central Mexico ◽  
Groundwater Exploitation ◽  
Persistent Scatterers

<p>Several major cities in central Mexico suffer from aquifer depletion and land subsidence driven by overexploitation of groundwater resources to address increasing water demands for domestic, industrial and agricultural use. Ground settlement often combines with surface faulting, fracturing and cracking, causing damage to urban infrastructure, including private properties and public buildings, as well as transport infrastructure and utility networks. These impacts are very common and induce significant economic loss, thus representing a key topic of concern for inhabitants, authorities and stakeholders. This work provides an Interferometric Synthetic Aperture Radar (InSAR) 2014-2020 survey based on parallel processing of Sentinel-1 IW big data stacks within ESA’s Geohazards Exploitation Platform (GEP), using hosted on-demand services based on multi-temporal InSAR methods including Small BAseline Subset (SBAS) and Persistent Scatterers Interferometry (PSI). Surface faulting hazard is constrained based on differential settlement observations and the estimation of angular distortions that are produced on urban structures. The assessment of the E-W deformation field and computation of horizontal strain also allows the identification of hogging (tensile strain or extension) and sagging (compression) zones, where building cracks are more likely to develop at the highest and lowest elevations, respectively. Sentinel-1 observations agree with in-situ observations, static GPS surveying and continuous GNSS monitoring data. The distribution of field surveyed faults and fissures compared with maps of angular distortions and strain also enables the identification of areas with potentially yet-unmapped and incipient ground discontinuities. A methodology to embed such information into the process of surface faulting risk assessment for urban infrastructure is proposed and demonstrated for the Metropolitan Area of Mexico City [1], one of the fastest sinking cities globally (up to 40 cm/year subsidence rates), and the state of Aguascalientes [2], where a structurally-controlled fast subsidence process (over 10 cm/year rates) affects the namesake valley and capital city. The value of this research lies in the demonstration that InSAR data and their derived parameters are not only essential to constrain the deformation processes, but can also serve as a direct input into risk assessment to quantify (at least, as a lower bound) the percentage of properties and population at risk, and monitor how this percentage may change as land subsidence evolves.</p><p>[1] Cigna F., Tapete D. 2021. Present-day land subsidence rates, surface faulting hazard and risk in Mexico City with 2014–2020 Sentinel-1 IW InSAR. <em>Remote Sens. Environ.</em> 253, 1-19, doi:10.1016/j.rse.2020.112161</p><p>[2] Cigna F., Tapete D. 2021. Satellite InSAR survey of structurally-controlled land subsidence due to groundwater exploitation in the Aguascalientes Valley, Mexico. <em>Remote Sens. Environ.</em> 254, 1-23, doi:10.1016/j.rse.2020.112254</p>

scholarly journals Investigation of correlation of the variations in land subsidence (detected by continuous GPS measurements) and methodological data in the surrounding areas of Lake Urmia

2012 ◽  
Vol 19 (6) ◽  
pp. 675-683 ◽  
Author(s):  
K. Moghtased-Azar ◽  
A. Mirzaei ◽  
H. R. Nankali ◽  
F. Tavakoli
Keyword(s):  
Time Series ◽  
Land Subsidence ◽  
Salt Lake ◽  
Linear Trend ◽  
Groundwater Resources ◽  
Time Interval ◽  
Gps Measurements ◽  
Lake Urmia ◽  
North West ◽  
Continuous Gps

Abstract. Lake Urmia, a salt lake in the north-west of Iran, plays a valuable role in the environment, wildlife and economy of Iran and the region, but now faces great challenges for survival. The Lake is in immediate and great danger and is rapidly going to become barren desert. As a result, the increasing demands upon groundwater resources due to expanding metropolitan and agricultural areas are a serious challenge in the surrounding regions of Lake Urmia. The continuous GPS measurements around the lake illustrate significant subsidence rate between 2005 and 2009. The objective of this study was to detect and specify the non-linear correlation of land subsidence and temperature activities in the region from 2005 to 2009. For this purpose, the cross wavelet transform (XWT) was carried out between the two types of time series, namely vertical components of GPS measurements and daily temperature time series. The significant common patterns are illustrated in the high period bands from 180–218 days band (~6–7 months) from September 2007 to February 2009. Consequently, the satellite altimetry data confirmed that the maximum rate of linear trend of water variation in the lake from 2005 to 2009, is associated with time interval from September 2007 to February 2009. This event was detected by XWT as a critical interval to be holding the strong correlation between the land subsidence phenomena and surface temperature. Eventually the analysis can be used for modeling and prediction purposes and probably stave off the damage from subsidence phenomena.

scholarly journals Optimizing Reduction of Groundwater Discharge to Control Land Subsidence (Case study: Nadjafabad Aquifer)

2021 ◽  
Author(s):  
hamid Kardan moghaddam ◽  
Zahra Rahimzadeh kivi ◽  
Fatemeh Javadi ◽  
Mohammad Heydari
Keyword(s):  
Land Subsidence ◽  
Groundwater Resources ◽  
Treatment Strategies ◽  
Flow Simulation ◽  
Maximum Amount ◽  
Water Withdrawal ◽  
Ground Subsidence ◽  
Risk Zoning ◽  
Dry Conditions ◽  
The Impact

Abstract This study evaluates and predicts the ground subsidence that happens due to the haphazard operation of groundwater resources. Also, several strategies have been developed to control this unpleasant phenomenon. For this purpose, groundwater flow simulation has been conducted using MODFLOW numerical model, and subsidence simulation in Najafabad plain has been done using SUB package under three climatic scenarios for future periods. Examination of the simulation results shows that the amount of land subsidence will increase with the aquifer operation's continuation. The maximum amount of subsidence for 6 years in drought conditions will be 23 cm at the aquifer's outlet. According to the land subsidence results at the aquifer, risk zoning of the aquifer operation was done to develop a solution to reduce the withdrawal of groundwater resources to control subsidence. Therefore, risk zoning was performed using land use and the extent of operation of groundwater resources. The results showed that the north-eastern part of the aquifer has the maximum risk of subsidence. According to the obtained results from subsidence risk zoning, scenarios of reduced water withdrawal from the aquifer in its outlet were developed. The treatment strategies results showed that the maximum amount of subsidence in wet, normal and dry conditions will be 10, 14 and 18 cm, respectively. These results indicate a 14% improvement in the quantitative condition of the aquifer in wet conditions, 10% in normal conditions and 7% in dry conditions in the total aquifer of Najafabad. Improvement of conditions by simulation shows the impact of the importance of optimal utilization of groundwater resources.

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