|
|
Earthquake source models
Adamová, Petra ; Šílený, Jan (advisor) ; Fischer, Tomáš (referee) ; Gallovič, František (referee)
The earthquake source is routinely modeled by moment tensor description. In many cases we need more information about the source process and for that reason we occupy with higher degree moments. This approach allows us to esti- mate non-point characteristics (including some dynamic parameters): geometry of the source, duration of the source process, average slip on the fault, spatial and temporal centroid and rupture velocity vector within the point source ap- proach. This description includes 20 parameters - 6 parameters for standard moment tensor (MT) and 14 parameters for second degree moments (SDM). First, we studied synthetic tests. Large amount of significant earthquakes con- tains false non-DC component which can be caused by approximation finite source by point source. This hypothesis was proved on the case of unilateral rupture. Standard MT contains more than 20 % non-DC components which was reduced to 6 %. In the second part we applied this procedure to real data. We chose large earthquakes (Mw>6) with large non-DC component. We estimated second degree moments for them and compared them with previous studies. Moreover we restitute higher degree moments from data and proved that false non-DC component were caused by source finiteness. In the last part we applied this method to mining data and...
|
|
|
Moment-tensor inversion of earthquakes in Greece, method ISOLA
Červinková, Dana ; Šílený, Jan (referee) ; Zahradník, Jiří (advisor)
3 Title: Moment-tensor inversion of earthquakes in Greece, method ISOLA Author: Dana Červinková Department: Department of Geophysics Supervisor: Prof. RNDr. Jiří Zahradník, DrSc. Supervisor's e-mail address: jz@karel.troja.mff.cuni.cz Abstract: The possibility of obtaining a reliable moment tensor using a low-frequency waveform inversion from a single seismic station is studied. Deviatoric part of the moment tensor is described in usual way, using its orientation (angles strike, dip, rake), scalar seismic moment M0 and the double-couple percentage (DC%), and also by means of the coefficients of linear combination of elementary mechanisms. We estimate the formal error of the coefficients and study conditionality of the inverse problem. Data from earthquakes Trichonis (Mw = 5.2, April 2007) and Leonidio (Mw = 6.2, January 2008), Greece, are processed using software ISOLA (Sokos and Zahradník). The moment tensor is calculated from many stations and its stability is tested. This reference solution is compared to those independently obtained from single stations. Synthetic tests are performed to understand why the single-station estimates are sufficient for Trichonis, but not for Leonidio, paying attention to the focal depth, station azimuth and epicentral distance. It is found that the depth is crucial at...
|
|
| |
|
| |
|
| |
|
|
Recognition of electrochemical signals using artificial neuronal network
Šílený, Jan ; Kuchta, Radek (referee) ; Hubálek, Jaromír (advisor)
Automatical electrochemical measurements are sources of large data sets intended for further analysis. This work deals with classification, evaluation and processing of electrochemical signals using artificial neural networks. Due to high dimensionality of input data, an autoassociative neural network (AANN) is used in this work. This type of network performs dimensionality reduction via filtering the input data into relatively small number of principal parameters at the bottleneck output. These extracted parameters can be used for classification, evaluation and additional modelling of analyzed data trough the reconstructive part of this network. Furthermore, this work deals with implementation of a feedforward neural network in OpenCL language.
|
|
| |
|
| |
|
| |
guest ::
