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Journal of Seismology

, Volume 20, Issue 3, pp 987–999 | Cite as

Source parameters for the 2013–2015 earthquake sequence in Nógrád county, Hungary

  • Zoltán Wéber
ORIGINAL ARTICLE

Abstract

Between 2013 June and 2015 January, 35 earthquakes with local magnitude M L ranging from 1.1 to 4.2 occurred in Nógrád county, Hungary. This earthquake sequence represents above average seismic activity in the region and is the first one that was recorded by a significant number of three-component digital seismographs in the county. Using a Bayesian multiple-event location algorithm, we have estimated the hypocenters of 30 earthquakes with M L ≥1.5. The events occurred in two small regions of a few squared kilometers: one to the east of Érsekvadkert and the other at Iliny. The uncertainty of the epicenters is about 1.5–1.7 km in the E-W direction and 1.8–2.1 km in the N-S direction at the 95 % confidence level. The estimated event depths are confined to the upper 3 km of the crust. We have successfully estimated the full moment tensors of 4 M w ≥3.6 earthquakes using a probabilistic waveform inversion procedure. The non-double-couple components of the retrieved moment tensor solutions are statistically insignificant. The negligible amount of the isotropic component implies the tectonic nature of the investigated events. All of the analyzed earthquakes have strike-slip mechanism with either right-lateral slip on an approximately N-S striking or left-lateral movement on a roughly E-W striking nodal plane. The orientations of the obtained focal mechanisms are in good agreement with the main stress pattern published for the epicentral region. Both the P and T principal axes are horizontal, and the P axis is oriented along a NE-SW direction.

Keywords

Earthquake location Earthquake focal mechanism Earthquake moment tensor Bayesian inversion Waveform inversion Tectonic stress 

Notes

Acknowledgments

The author would like to thank the different organizations that operate seismological networks in the neighboring countries of Hungary for making their high quality data available. Figures were prepared using the Generic Mapping Tools software (Wessel and Smith 1998).

References

  1. Bada G, Horváth F, Dövényi P, Szafián P, Windhoffer G, Cloetingh S (2007) Present-day stress field and tectonic inversion in the Pannonian basin. Glob Planet Chang 58:165–180CrossRefGoogle Scholar
  2. Crotwell H P, Owens T J, Ritsema J (1999) The TauP Toolkit: flexible seismic travel-time and ray-path utilities. Seismol Res Lett 70:154–160CrossRefGoogle Scholar
  3. Gráczer Z, Wéber Z (2012) One-dimensional P-wave velocity model for the territory of Hungary from local earthquake data. Acta Geodaet Geophys Hung 47:344–357. doi: 10.1556/AGeod.47.2012.3.5 CrossRefGoogle Scholar
  4. Hanks T C, Kanamori H (1979) A moment-magnitude scale. J Geophys Res 84:2348–2350CrossRefGoogle Scholar
  5. Herrmann R B (2013) Computer programs in seismology: an evolving tool for instruction and research. Seism Res Lett 84:1081–1088. doi: 10.1785/0220110096 CrossRefGoogle Scholar
  6. Herrmann R B, Wang C Y (1985) A comparison of synthetic seismograms. Bull Seismol Soc Am 75:41–56Google Scholar
  7. Horváth F, Bada G, Windhoffer G, Csontos L, Dombrádi E, Dövényi P, Fodor L, Grenerczy GY, Síkhegyi F, Szafián P, Székely B, Timár G, Tóth L, Tóth T (2006) Atlas of the present-day geodynamics of the Pannonian Basin: Euroconform maps with explanatory text. Magy Geofiz 47:133–137 (in Hungarian with English abstract)Google Scholar
  8. Jost M L, Herrmann R B (1989) A student’s guide to and review of moment tensors. Seismol Res Lett 60:37–57Google Scholar
  9. Lomax A, Curtis A (2001) Fast, probabilistic earthquake location in 3D models using oct-tree importance sampling. Geophys Res Abstr 3:955Google Scholar
  10. Myers S C, Johannesson G, Hanley W (2007) A Bayesian hierarchical method for multiple-event seismic location. Geophys J Int 171:1049–1063. doi: 10.1111/j.1365-246X.2007.03555.x CrossRefGoogle Scholar
  11. Myers S C, Johannesson G, Hanley W (2009) Incorporation of probabilistic seismic phase labels into a Bayesian multiple-event seismic locator. Geophys J Int 177:193–204. doi: 10.1111/j.1365-246X.2008.04070.x CrossRefGoogle Scholar
  12. Pasyanos M E, Dreger D S, Romanowicz B (1996) Toward real-time estimation of regional moment tensors. Bull Seismol Soc Am 86:1255–1269Google Scholar
  13. Riedesel M A, Jordan T H (1989) Display and assessment of seismic moment tensors. Bull Seismol Soc Am 79:85–100Google Scholar
  14. Rubinstein R Y, Kroese D P (2008) Simulation and the Monte Carlo method. Wiley, HobokenGoogle Scholar
  15. Sipkin S A (1993) Display and assessment of earthquake focal mechanisms by vector representation. Bull Seismol Soc Am 83:1871–1880Google Scholar
  16. Wang C Y, Herrmann R B (1980) A numerical study of P-, SV-, and SH-wave generation in a plane layered medium. Bull Seismol Soc Am 70:1015–1036Google Scholar
  17. Wéber Z (2006) Probabilistic local waveform inversion for moment tensor and hypocentral location. Geophys J Int 165:607–621. doi: 10.1111/j.1365-246X.2006.02934.x CrossRefGoogle Scholar
  18. Wéber Z (2009) Estimating source time function and moment tensor from moment tensor rate functions by constrained L1 norm minimization. Geophys J Int 178:889–900. doi: 10.1111/j.1365-246X.2009.04202.x CrossRefGoogle Scholar
  19. Wéber Z (2016) Probabilistic waveform inversion for 22 earthquake moment tensors in Hungary: new constraints on the tectonic stress pattern inside the Pannonian basin. Geophys J Int 204:236–249. doi: 10.1093/gji/ggv446 CrossRefGoogle Scholar
  20. Wéber Z, Süle B (2014) Source properties of the 29 January 2011 ML 4.5 Oroszlány (Hungary) mainshock and its aftershocks. Bull Seismol Soc Am 104:113–127. doi: 10.1785/0120130152 CrossRefGoogle Scholar
  21. Wessel P, Smith W H F (1998) New, improved version of generic mapping tools released. EOS Trans Am Geophys Union 79:579CrossRefGoogle Scholar
  22. Zoback M L (1992) First and second order patterns of stress in the lithosphere: the World Stress Map Project. J Geophys Res 97:11703–11728CrossRefGoogle Scholar
  23. Zsíros T (2000) Seismicity and seismic hazard in the Carpathian Basin: Hungarian Earthquake Catalog (456–1995). MTA FKK GGKI, Budapest (in Hungarian)Google Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2016

Authors and Affiliations

  1. 1.Kövesligethy Radó Seismological Observatory, MTA CSFK GGIBudapestHungary

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