Quantifying capability of a local seismic network in terms of locations and focal mechanism solutions of weak earthquakes

0465782 - ÚSMH 2017 RIV NL eng J - Journal Article
Fojtíková, Lucia - Kristeková, M. - Málek, Jiří - Sokos, E. - Csicsay, K. - Zahradník, J.
Quantifying capability of a local seismic network in terms of locations and focal mechanism solutions of weak earthquakes.
Journal of Seismology. Roč. 20, č. 1 (2016), 93-106. ISSN 1383-4649. E-ISSN 1573-157X
R&D Projects: GA ČR GAP210/12/2336
Institutional support: RVO:67985891
Keywords : Focal-mechanism uncertainty * Little Carpathians * Relative location uncertainty * Seismic network * Uncertainty mapping * Waveform inversion * Weak earthquakes
Subject RIV: DC - Siesmology, Volcanology, Earth Structure
Impact factor: 1.089, year: 2016

Extension of permanent seismic networks is usually governed by a number of technical, economic, logistic, and other factors. Planned upgrade of the network can be justified by theoretical assessment of the network capability in terms of reliable estimation of the key earthquake parameters (e.g., location and focal mechanisms). It could be useful not only for scientific purposes but also as a concrete proof during the process of acquisition of the funding needed for upgrade and operation of the network. Moreover, the theoretical assessment can also identify the configuration where no improvement can be achieved with additional stations, establishing a tradeoff between the improvement and additional expenses. This paper presents suggestion of a combination of suitable methods and their application to the Little Carpathians local seismic network (Slovakia, Central Europe) monitoring epicentral zone important from the point of seismic hazard. Three configurations of the network are considered: 13 stations existing before 2011, 3 stations already added in 2011, and 7 new planned stations. Theoretical errors of the relative location are estimated by a new method, specifically developed in this paper. The resolvability of focal mechanisms determined by waveform inversion is analyzed by a recent approach based on 6D moment-tensor error ellipsoids. We consider potential seismic events situated anywhere in the studied region, thus enabling "mapping" of the expected errors. Results clearly demonstrate that the network extension remarkably decreases the errors, mainly in the planned 23-station configuration. The already made three-station extension of the network in 2011 allowed for a few real data examples. Free software made available by the authors enables similar application in any other existing or planned networks.
Permanent Link: http://hdl.handle.net/11104/0264248