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Earthquake influence on groundwater levels in West Bohemia/Vogtland
Krajinová, Markéta ; Fischer, Tomáš (advisor) ; Horálek, Josef (referee)
This Batchelors thesis focuses onto possible earthquake influence on groundwater levels in West Bohemia/Vogtland area. The thesis describes geology, hydrogeology and seismic activity of the area. Further describes possible earthquake influence on ground water level and mentions world and local sightings. The area is known for its earthquake swarms up to ML=4, therefore the thesis also deals with an influence of three local earthquakes. They occurred in 2014 with hypocentre near Nový Kostel in West Bohemia and their magnitudes were ML =3,5; 4,4 and 3,6. The thesis further analyses ground water level records of 38 wells at localities: Františkovy Lázně, Lázně Kynžvart, Karlovy Vary, Německo and sokolovská pánev. A polarity of ground water level change after the earthquakes is compared to volumetric strain caused by the earthquakes. Overall agreement is found at few sites, which indicates possible effect of earthquake generated static stress change to the ground water level.
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Late Quaternary activity of slow-slip intraplate Mariánské Lázně fault as revealed by trenching and shallow geophysical survey; Bohemian Massif (Czech Republic, central Europe)
Štěpančíková, Petra ; Fischer, T. ; Hartvich, Filip ; Tábořík, Petr ; Rockwell, T. ; Stemberk, Jakub ; Široký, J. ; Sana, Hamid
The NNW-SSE trending Mariánské Lázně Fault (MLF) zone is situated in the western part of the Bohemian Massif (Czech\nRepublic, central Europe) where it intersects NE-trending Cenozoic Eger rift. The northern segment of the MLF controls the\nmorphologically pronounced mountain front of Krušné hory Mts. and eastern limit of Cenozoic Cheb basin, which is famous for\nearthquake swarms (max. ML=4.6) and CO2 emanation. We performed 2D and 3D geophysical survey (electric resistivity\ntomography, ground penetration radar) and 3D trenching to look for large surface-rupturing prehistoric earthquake responsible\nfor pronounced moutain range front. Seven excavated and six hand-dug trenches revealed a complex geology and deformation\nat the study site probably as a result of right-lateral transpression during Late Quaternary. Two Holocene earthquakes 1150-590\nBC and 780-1000 AD were inferred from 14C dating of faulted Holocene colluvium with corresponding magnitudes Mw=6.7-7.0.\nThe latter one is the youngest documented surface-rupturing event in central Europe.\n
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Recent movements on the Cordillera Blanca fault (Peru)
Sánchez Valdiviezo, Lisseth del Pilar ; Fischer, Tomáš (advisor) ; Burjánek, Jan (referee)
The studied area is located the Cordillera Blanca range (central Peru). This mountain range is, at its western foot, bordered by a 210 km long fault system bearing the same name. It is on this fault system where 3D monitoring of recent movements with the use of dilatometer TM-71 takes place. Displacements along this fault are analyzed with regard to the static stress changes caused by earthquakes. Moreover, processing and interpretation of data from ERT measurement performed across the investigated fault at Pitec locality (10 km from Huaraz) are presented. The resulting geoelectrical models of the measurement carried out in July 2016 at the mentioned locality indicate that this area is formed by rocks with very high resistivity values. It is a consequence of the presence of the moraine material (7 to 12 m thick) and of the base of the colluvial deposits composed of granites and granodiorites. At this site the fault has a dip angle of 70ř. The 3D displacement monitoring results of the studied fault at the Pitec locality indicate that the selected site is generally very stable. The dilatometer TM-71 has been in operation since 1997 and has been measuring movements on the Cordillera Blanca fault in all the three dimensions (perpendicular to the fault - opening, along the fault in horizontal plane,...
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Possibilities of hydraulic fracturing in geothermal energy exploitation
Pokorný, Jakub ; Fischer, Tomáš (advisor) ; Horálek, Josef (referee)
Hydraulic stimulation is a technique used to increase the permeability of reservoir formation by creation of new and connection of existing cracks. The aim of this bachelor thesis is to collect and explain the basic principles of continuum mechanics and fundamentals of fluid hydraulics that are an integral part of the overall understanding of the issue of stimulation and its later more detailed study. After a general introduction, these findings are put into context in terms of mechanism of rock fracturing and fluid flow in the emerging stimulated geothermal systems. This thesis is completed by placing the example of geothermal project Groß Schönebeck from the start of stimulation to the final hydraulic tests, which were carried out with the aim of assessing the efficiency of fracture permeability enhancement. Powered by TCPDF (www.tcpdf.org)
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Source Parameters of Microearthquakes and their Uncertainties
Michálek, Jan ; Fischer, Tomáš (advisor) ; Gallovič, František (referee) ; Kwiatek, Grzegorz (referee)
Title: Source Parameters of Microearthquakes and their Uncertainty Author: Jan Michálek Department: Department of Geophysics Supervisor: Doc. RNDr. Tomáš Fischer, PhD., Institute of Hydrogeology, Engineering Geology and Applied Geophysics, Charles University in Prague Abstract: The aim of this thesis is to analyze the spectral methods used for the determination of the earth- quake source parameters like the seismic moment M0 and the corner frequency fc and to apply these meth- ods to seismic data from the West Bohemian region. Considering some assumptions about the source the other important parameters like the source radius r or the stress drop in the source ∆σ can be evaluated. Determination of the parameters is performed in the spectral domain by comparing a simple Brune's source model (non-causal slip on a circular rupture; spectral slope ω−2) with the displacement of the P or S wave. The methods were applied to 56 selected earthquakes of the West Bohemian swarms from 2000 and 2008 by the absolute and relative approach in several modifications. The absolute method allows to determine not only the source parameters but also the quality factor Q (attenuation), which significantly affects the deter- mination of fc. Therefore, the absolute method was applied also as the joint inversion when Q is stabilized....
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Laboratory study of 3D elastic anisotropy of rocks
Svitek, Tomáš ; Lokajíček, Tomáš (advisor) ; Fischer, Tomáš (referee) ; Pšenčík, Ivan (referee)
12 Abstract The presented work evaluates the significance of measuring acoustic S-wave velocities for determination of elastic anisotropy of rocks. The S waves are more sensitive to anisotropic properties of a medium than the P waves. Analyzing the S-wave splitting, it is possible to determine strength of anisotropy as well as the orientation of structures responsible for the anisotropic behavior of the medium. The S waves are necessary for determining the complete tensor of elastic parameters. In order to record the S waves, the measuring head of the present apparatus has been significantly adapted. Implemented innovations provided measurements of the P waves together with two orthogonally polarized S waves. The calibration performed on homogeneous isotropic materials proved that the recorded data are accurate and of high quality. The ultrasonic measurements on spherical samples under confining pressure and recording of the S waveforms significantly improved the accuracy of the retrieved elastic parameters compared to the measurements in standard use. The analysis of the S-wave records also required modifications of the processing software and a development of new algorithms. The proposed methods were tested on synthetic data. The tests evaluated the robustness of the inversion for anisotropy as a function...
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Seismic activity in Peru
Sánchez Valdiviezo, Lisseth del Pilar ; Fischer, Tomáš (advisor) ; Jakoubková, Hana (referee)
This bachelor thesis approaches seismicity in Peru. It describes the origin of tectonic earthquakes and provides a general description of the basic concepts of seismology. This thesis work is mainly focused on a detailed characterization of seismic activity in Peru. It includes a complete description of the geodynamics of the Peruvian territory, the evolution and distribution of seismicity in this South American country and its geomorphological units.
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