The spatial location of sources of seismic waves is one of the first tasks when transient waves from natural (uncontrolled) sources are analysed in many branches of physics, including seismology, oceanology, to name a few. It is well recognised that there is no single universal location algorithm which performs equally well in all situations. Source activity and its spatial variability in time, the geometry of recording network, the complexity and heterogeneity of wave velocity distribution are all factors influencing the performance of location algorithms. In this paper we propose a new location algorithm which exploits the reciprocity and time-inverse invariance property of the wave equation. Basing on these symmetries and using a modern finite-difference-type eikonal solver, we have developed a new very fast algorithm performing the full probabilistic (Bayesian) source location. We illustrate an efficiency of the algorithm performing an advanced error analysis for 1647 seismic events from the Rudna copper mine operating in southwestern Poland.
W pracy opisano algorytm lokalizacji źródeł emisji wstrząsów sejsmicznych w ośrodku jednorodnym i izotropowym. Lokalizacja hipocentrów wstrząsów górniczych należy do klasy zadań nieliniowej optymalizacji globalnej. Proponowana metoda składa się z kilku kroków. Po etapie algorytmu genetycznego, otrzymane rozwiązania są grupowane w klastry. Wyznaczone środki klastrów stanowią punkty startowe dla metody kierunków sprzężonych Powella (metoda lokalna). Poprawność algorytmu sprawdzono zaprojektowanym testem na danych syntetycznych oraz dokonano lokalizacji jednego rzeczywistego wstrząsu z kopalni Rudna. Dla celów testowych udostępniono skompilowany program.
EN
In this paper we describe a tremor location algorithm for homogeneous and isotropic layer. The location of the tremor hypocentre procedure belongs to global non-linear optimisation problems. The algorithm consists a few stages. After the genetic algorithm stage the clustering algorithm is launched. Evaluated clusters centres are starting points of the Powell conjugate direction procedure (local method). Location procedure were tested twice. In the first test synthetic data were generated - hypocentre coordinates were selected at random and first arrival P-wave times were evaluated at each geophone. Afterwards procedure tried to search "unknown" hypocentre location. In the second test we attempted to find the location of one of the tremors occurred in Rudna copper mine. A free working compiled trial program is available.
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