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Monitoring of millimeter-scale deformations in Tallinn using repeated leveling and PS-InSAR analysis of Sentinel-1 data

Oja Tõnis, Gruno Anti

Advances in Geodesy and Geoinformation

2023

Vol. 72, no. 1

art. no. e33, 2023

The aim of this study was to evaluate millimeter-scale deformations in Tallinn, the capital of Estonia, by using repeated leveling data and the synthetic aperture radar (SAR) images of Sentinel-1 satellite mission. The persistent scattered interferometric SAR (PS-InSAR) analysis of images from ascending and descending orbits from June 2016 to November 2021 resulted the line-of-sight (LOS) displacement velocities in the Tallinn city center. Velocity solutions were estimated for the full period of time, but also for shorter periods to monitor deformation changes in yearly basis. The gridded LOS velocity models were used for the decomposition of east-west and vertical velocities. Additionally, the uncertainty of 2D velocity solutions was estimated by following the propagation of uncertainty. The 3D velocity of permanent GNSS station “MUS2” in Tallinn was used to unify the reference of all PS-InSAR velocity solutions. The results of the latest leveling in Tallinn city center in 2007/2008 and 2019 showed rather small subsidence rates which were in agreement with InSAR long-termsolution. However, the short-termInSAR velocity solutions revealed larger subsidence of city center with a rate about –10 mm/yr in 2016–2017, and the uplift around 5 mm/yr in 2018–2019 with relatively stable periods in 2017–2018 and 2019–2021. The inclusion of groundwater level observation data and the geological mapping information into the analysis revealed possible spatiotemporal correlation between the InSAR results and the groundwater level variations over the deep valleys buried under quaternary sediments.

Causes of groundwater level and chemistry changes in an urban area; a case study of Warsaw, Poland

Krogulec Ewa, Gruszczyński Tomasz, Kowalczyk Sebastian, Małecki Jerzy J., Porowska Dorota, Sawicka Katarzyna, Trzeciak Joanna, Wojdalska Anna, Zabłocki Sebastian, Zaszewski Daniel

Acta Geologica Polonica

2022

Vol. 72, no. 4

495--517

The presented studies focus on changes in groundwater levels and chemistry, and the identification of important factors influencing these changes on short- and long-term scales in urban areas. The results may be useful for rational and sustainable groundwater planning and management in cities. The studies concerned three aquifers: (1) the shallow Quaternary aquifer, (2) the deep Quaternary aquifer, and (3) the Oligocene aquifer in the capital city of Warsaw (Poland). The spatial variability of groundwater recharge was determined and its changes in time were characterized. The characteristics of groundwater levels were based on long-term monitoring series. The results indicate that urban development has caused overall reduction in infiltration recharge (from 54 to 51 mm/year), which is particularly clear in the city suburbs and in its centre, where land development has significantly densified during the last 30 years. Studies of groundwater levels indicate variable long-term trends. However, for the shallowest aquifer, the trends indicate a gradual decrease of the groundwater levels. In the case of the much deeper Oligocene aquifer, groundwater table rise is observed since the 1970s (averagely c. 20 m), which is related with excessive pumping. Based on the studied results, the groundwater chemistry in the subsurface aquifer indicates strong anthropogenic influence, which is reflected in multi-ionic hydrogeochemical types and the occurrence of chemical tracers typical of human activity. The Oligocene aquifer is characterized by a chemical composition indicating the influence of geogenic factors.

Identyfikacja zmian zwierciadła wód podziemnych wskutek presji antropogenicznej w regionie wodnym Warty

Dąbrowski S., Rynarzewski W., Straburzyńska-Janiszewska R., Janiszewska B., Pawlak A.

Biuletyn Państwowego Instytutu Geologicznego

2009

nr 436, z. 9/1

77-86

W artykule przedstawiono zidentyfikowane wyniki presji antropogenicznej na zbiorniki wód podziemnych w regionie wodnym Warty obejmującym powierzchnię ok. 50 tys. km2. Prezentowany problem został szczegółowo omówiony w opracowaniu dla RZGW Poznań (Dąbrowski i in., 2004), natomiast w artykule przedstawiono syntetyczne wyniki dotyczące wielkości zmian w poziomach wodonośnych kenozoiku i mezozoiku. Presja ta jest spowodowana głównie eksploatacją wód podziemnych przez ujęcia odwodnienia kopalniane w odkrywkach węgli brunatnych i surowców mineralnych oraz budowę zbiorników retencyjnych niezależnie od wcześniejszego oddziaływania melioracji i lokalnych zmian w sieci wód powierzchniowych. Objawia się to czasowymi i trwałymi zmianami poziomów wód. Identyfikację obszarów zmian antropogenicznych wód w zbiornikach wód podziemnych kenozoiku i mezozoiku poprzedzono rozpoznaniem i charakterystyką naturalnych zmian zwierciadła wód na podstawie monitoringu krajowego i lokalnych.

The article is based on the report of Hydroconsult Sp. z o.o. (Dąbrowski et al., 2004). The paper presents the results of anthropogenic pressure on groundwater reservoirs, identified in Cenozoic and Mesozoic formations of the Warta Water Region within the area of ca. 50,000 km2. The analysed anthropopression refers mainly to the exploitation of groundwater intakes, mine dewatering of brown coal outcrops and reservoir constructions. Identification of anthropogenic changes in groundwater levels within the Quaternary, Tertiary and Mesozoic groundwater reservoirs was preceded by the identification and characterization of natural groundwater table oscillations based upon the national and local groundwater monitoring data.