scholarly journals Combination with precise leveling and PSInSAR observations to quantify pumping-induced land subsidence in central Taiwan

2015 ◽  
Vol 372 ◽  
pp. 77-82 ◽  
Author(s):  
C. H. Lu ◽  
C. F. Ni ◽  
C. P. Chang ◽  
J. Y. Yen ◽  
W. C. Hung
Keyword(s):  
Land Subsidence ◽  
Surface Deformation ◽  
Alluvial Deposits ◽  
Persistent Scatterer ◽  
Dry Seasons ◽  
Central Taiwan ◽  
Continuous Gps ◽  
Residential Water ◽  
Groundwater Decline ◽  
Wet And Dry Seasons

Abstract. Choushui River Fluvial Plain (CRFP) is located in the western central Taiwan, where the geomaterials are composed of alluvial deposits. Because the CRFP area receives highly variable rainfall in wet and dry seasons, the groundwater becomes the main resource of residential water. The precise leveling monitoring from 1970s indicated that the coastal areas of CRFP had been threatened by serious pumping-induced land subsidence. On the basis of relatively accurate measurements of precise leveling measurements, we used cokriging technique to incorporate a number of InSAR images to quantify the surface deformation in CRFP. More specifically, the well-developed Persistent Scatterer InSAR (PSI) was employed to process 34 Envisat images (2005–2008) and the results of PSI was then used for improving the spatial resolution of data from precise leveling. The results of cokriging estimation indicate whether the rate or the area of the land subsidence slows down gradually from 2005 to 2008. The subsidence in the northern part of CRFP was influenced by the groundwater decline in aquifer III, and the southern part was influenced by groundwater decline in aquifer II and III. The cokriging estimation was also comparable with continuous GPS data, and their correlation coefficient is 0.9603 and the root mean square is 10.56 mm yr−1.

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

2019 ◽  
Vol 11 (23) ◽  
pp. 2817 ◽  
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.

scholarly journals Recent land subsidence caused by the rapid urban development in the Hanoi urban region (Vietnam) using ALOS InSAR data

2013 ◽  
Vol 1 (6) ◽  
pp. 6155-6197 ◽  
Author(s):  
V. K. Dang ◽  
C. Doubre ◽  
C. Weber ◽  
F. Masson ◽  
N. Gourmelen
Keyword(s):  
Spatial Distribution ◽  
Land Subsidence ◽  
Surface Deformation ◽  
Red River ◽  
Urban Region ◽  
Rapid Urbanization ◽  
Building Foundation ◽  
Multi Temporal ◽  
Dry Seasons ◽  
The Mean

Abstract. Since the 1990s the land subsidence due to the rapid urbanization has been considered a severely destructive hazard in the center of Hanoi City. Although previous studies and measurements have quantified the subsiding deformation in Hanoi center, no data exist for the newly established districts in the south and the west, where construction development has been most significant and where groundwater pumping has been very intensive over the last decade. With a multi-temporal InSAR approach, we quantify the spatial distribution of the land subsidence in the whole Hanoi urban region using ALOS images over the 2007–2011 period. The map of the mean subsidence velocity reveals that the northern bank of the Red River appears stable, whereas some areas in southern bank are subsiding with a mean vertical rate up to 68 mm yr−1, especially within the three new urban districts of Hoang Mai, Ha Dong and Hoai Duc. We interpret the spatial distribution of the surface deformation as the combination of the nature of the unsaturated layer, the lowering of groundwater in the aquifers due to pumping withdrawal capacity, the increase of built-up surfaces and the type of building foundation. The time evolution deduced from the InSAR time series is consistent with previous leveling data and shows that the lowering rate of the surface slightly decreases till 2008. Then, a seasonal variation suggests that the deformation became non-stationary, with upward and downward transient displacements related to the charge and discharge of the aquifer following the changes between rainy and dry seasons.

scholarly journals Discussion on the origin of surface failures in the Valley of Aguascalientes, México

2015 ◽  
Vol 372 ◽  
pp. 235-238
Author(s):  
M. Hernández-Marín ◽  
N. González-Cervantes ◽  
J. Pacheco-Martínez ◽  
D. H. Frías-Guzmán
Keyword(s):  
Land Subsidence ◽  
Surface Deformation ◽  
Normal Faults ◽  
Groundwater Pumping ◽  
Low Intensity ◽  
Combined Stresses ◽  
Deformation Surface ◽  
Surface Discontinuities ◽  
Groundwater Decline ◽  
Key Questions

Abstract. Surface failures have been observed in the valley of Aguascalientes since the early 1980's. Although, groundwater pumping began in the early 1950's but became intensive until the late 1970's, when many of the surface failures appeared. For this reason, surface deformation (surface failures and land subsidence) has been associated to groundwater withdrawal. Recent observations, however, suggest that some of these surface discontinuities are the result of natural geologic stresses rather than those associated groundwater decline, at least in its origin. Geologically, this valley is a tectonic graben flanked by two north-to-south trending normal faults, and seismicity of low intensity has been detected into the valley evidencing that the study area is seismically active. In this work, we present and discuss evidence showing tectonic discontinuities on the surface or at a shallow depth. Evidence presented in this investigation brings up uncertainty about the purely pumping-induced origin of fissuring in the valley, and allows addressing some key questions, for instance, are the surface failures caused by the combined stresses of pumping and tectonism? Is the current tectonism sufficient to cause some surface or deep failures?

Investigation of Land Subsidence Phenomena in the wider Tirana (Albania) Region by applying Persistent Scatterer Interferometry Techniques

2021 ◽  
Author(s):  
Doris Skenderas ◽  
Constantinos Loupasakis ◽  
Ioannis Papoutsis ◽  
Stavroula Alatza ◽  
Charalampos (Haris) Kontoes
Keyword(s):  
Land Subsidence ◽  
European Space Agency ◽  
Water Withdrawal ◽  
Deformation Pattern ◽  
Persistent Scatterer Interferometry ◽  
Alluvial Deposits ◽  
Space Agency ◽  
Persistent Scatterer ◽  
Cost Efficient ◽  
The City

<p>The occurrence of land subsidence phenomenon has been investigated for the wider area of the city of Tirana, Albania.  A set of Ninety-four SAR images acquired between January 2015 and 23 of November 2019 by the European Space Agency (ESA) Sentinel1, have been processed by applying the Persistent Scatterer Interferometry (PSI).</p><p>Interpretation of PSI analysis output results, revealed subsidence deformations at the northwest and near the center of Tirana, mainly due to natural land compaction. The deformation rates reach up to 9.6 mm/yr.</p><p>The most intensive phenomena have been identified at the Laknas and Breg Shkoze- Rinas regions. In particular at the ``Mother Tereza`` National Airport of Tirana, located at the Rinas area, land subsidence ranges between 2.3mm/yr and 4.5mm/yr.  Whereas in Tirana e Re, close to the city center, less intensive subsiding movements have been identified, ranging from 1.5 to a maximum of  5.2 mm/yr.    </p><p>By evaluating geological, geotechnical, and hydrological data it was determined that except for Laknas, in all other areas, land subsidence is caused by natural compression of alluvial deposits of the Ishmi River. At the Laknas zone, besides natural compression, water withdrawal due to over pumping of ground water can be identified as well. This was proved by the piezometric surface monitoring data referring to the period 2015-2019.</p><p>Besides the interesting findings about the deformation pattern at the wider area of Tirana, the current study highlights the potential of PSI as a suitable, accurate, and cost-efficient technique for the study of land subsidence phenomena.</p>

scholarly journals GPS measurements on pre-, co- and post-seismic surface deformation at first multi-parametric geophysical observatory, Ghuttu in Garhwal Himalaya, India

2020 ◽  
Vol 10 (1) ◽  
pp. 136-144
Author(s):  
P.K. Gautam ◽  
S. Rajesh ◽  
N. Kumar ◽  
C.P. Dabral
Keyword(s):  
Time Series ◽  
Surface Deformation ◽  
Translational Motion ◽  
Anomalous Behavior ◽  
Deformation Pattern ◽  
Local Earthquakes ◽  
Position Time Series ◽  
Continuous Gps ◽  
Gps Time Series ◽  
Gps Station

Abstract We investigate the surface deformation pattern of GPS station at MPGO Ghuttu (GHUT) to find out the cause of anomalous behavior in the continuous GPS time series. Seven years (2007-2013) of GPS data has been analyzed using GAMIT/GLOBK software and generated the daily position time series. The horizontal translational motion at GHUT is 43.7 ± 1 mm/yr at an angle of 41°± 3° towards NE, while for the IGS station at LHAZ, the motion is 49.4 ±1 mm/yr at 18 ± 2.5° towards NEE. The estimated velocity at GHUT station with respect to IISC is 12 ± 1 mm/yr towards SW. Besides, we have also examined anomalous changes in the time series of GHUT before, after and during the occurrences of local earthquakes by considering the empirical strain radius; such that, a possible relationship between the strain radius and the occurrences of earthquakes have been explored. We considered seven local earthquakes on the basis of Dobrovolsky strain radius condition having magnitude from 4.5 to 5.7, which occurred from 2007 to 2011. Results show irrespective of the station strain radius, pre-seismic surface deformational anomalies are observed roughly 70 to 80 days before the occurrence of a Moderate or higher magnitude events. This has been observed for the cases of those events originated from the Uttarakashi and the Chamoli seismic zones in the Garhwal and Kumaun Himalaya. Occurrences of short (< 100 days) and long (two years) inter-seismic events in the Garhwal region plausibly regulating and diffusing the regional strain accumulation.

scholarly journals Seasonal and Temperature Dependent Variations in Proximate Parameters and Mineral Elements of Smoke-Dried Catfish (Clarias gariepinus, Burchell, 1822) using Traditional and Eco-Friendly Kilns in Lagos, Nigeria

2020 ◽  
Vol 24 (4) ◽  
pp. 639-643
Author(s):  
M.M. Ogunbambo
Keyword(s):  
Crude Protein ◽  
Clarias Gariepinus ◽  
Mineral Elements ◽  
Drying Process ◽  
Temperature Dependent ◽  
Crude Fibre ◽  
Significant Difference ◽  
Dry Seasons ◽  
Mineral Compositions ◽  
Wet And Dry Seasons

Smoke-drying Clarias gariepinus (catfish) provides animal protein and a source of livelihood in Lagos, Nigeria. Changes occurring to seasonal and mineral compositions of smoke-dried catfish using local Traditional Drum Kiln (TDK) and a newly constructed Eco-Friendly Kiln (EFK) fitted with a flame, drying and electronic components was carried out in this study. The smoke-drying process was carried out in both wet and dry seasons and smoke-dried catfish samples stored at ambient and adjusted refrigerated temperatures of 28 and 4 0C. The smoke-drying procedure was  standardized at 60 - 80 0C and kiln lasted 24 ± 3 hours. Moisture content results showed a significant difference when the catfish samples were smoke-dried using TDK and EFK and stored in ambient and controlled temperatures in both wet and dry seasons while crude protein, lipid, ash and crude fibre values were significantly different when stored only in dry season. Mineral elements phosphorus, sodium, copper, magnesium and iron showed a significant difference when stored at both temperatures and seasons using both kilns. Mineral elements were found to be most stable in smoke-dried catfish samples when stored at controlled temperatures. This work proved that standardizing smoke-drying process using both kilns resulted in good quality smoke-dried catfish but showed that higher biochemical values were obtained when EFK is used. Key words: Nigeria, Smoke-drying Kilns, Seasons, Ambient, Controlled Temperatures

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