Making earth quake location estimates more accurate – HypoDD analysis of the 22 April 2013, ML=4.8 Tenk , Hungary aftershock sequence

Barbara Czecze1, Bálint Süle2, Gábor Timár1 , István Bondár2

1 Eötvös Loránd University, Department of Geophysics and Space Science, Budapest, Hungary czecze.barbara@gmail.com
2 Research Centre for Astronomy and Earth Sciences, Hungarian Academy of Sciences


Abstract - The Tenk, Hungary earthquake (ML = 4.8) occurred on 22 April 2013, which was the strongest Hungarian earthquake in the past 28 years. The routinely determined hypocenters are often suffer from phase picking errors, travel-time model errors and thus location bias. The event mislocation can be significantly reduced by multiple event relocations methods. We repicked the arrival times reported in the Hungarian National Seismological Bulletin (HNSB) to increase the consistency and accuracy of the arrival time measurements. We also added previously unpicked phases. To prepare for the double-difference analysis we obtained improved single event locations with the iLoc algorithm, and we performed waveform crosscorrelation to obtain differential travel time measurements. We used different velocity models to find the best solution and to clearly see the effect of the initial hypocenters on the outcome of the relocation. The paper demonstrates that the double-difference algorithm, hypoDD, can be effectively used even for a small cluster, provided that we have the best possible data quality. The improved locations are now the preferred solutions in the Hungarian National Seismological Bulletin.

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