1. MICRO-SEISMICITY AND FOCAL MECHANISMS IN THE MALÉ KARPATY MTS., SLOVAKIA Lucia Fojtíková, Václav Vavryčuk, Andrej Cipciar, Ján Madarás

2. Seismic Activity in the Malé Karpaty Mts. January 9 th 1906 – the strongest earthquakes in the region in 20 th century Ms = 5.7; h=15 km, epicentral intensity Io = 8° MSK-64 Period: 1034 - 2006

3. Seismic Stations Seismic stations in Slovakia National seismic network Local seismic network LSSVS Local seismic network EBO Local seismic network EMO

4. Geological Map

5. Tectonic Sketch

6. P-wave Velocity Model 3D 1D

7. Data 44 micro-earthquakes Period 2001 - 2009 Area: 30km x 60km Magnitudes of events analyzed: 1.1 – 3.2 Hypocenter depths: 1km – 15km Seismometers - short-period: SM-3, Le3D, CMG-40T - broad-band: STS-2 Sampling frequency - 100 Hz, 20 Hz

8. An example of simple waveforms - velocity Data V14

9. Data An example of simple waveforms – displacement V14

10. Data S03 An example of complicate waveforms – velocity

11. Data An example of complicate waveforms – displacement S03

12. Data Clear polarity identification

13. Data Problematic polarity identification

14. Direct versus head waves Data

15. Locations: Epicentres

16. Locations: Hypocentres V03 Latitude [°] Longitude [°] Depth of hypocentre [km]

17. FOCMEC (Snoke, 2003): inversion from P-wave polarities AMT (Vavryčuk, 2008): inversion from P-wave amplitudes ISOLA (Sokos & Zahradník, 2009): inversion from seismograms MethodFOCMECAMTISOLA events 163643 Focal Mechanisms and Moment Tensors

18. ISOLA - AMT – FOCMEC – All Events N = 35N = 16N = 41 AMT ISOLA FOCMEC

19. Non-DC Components AMT ISOLA

20. Non-DC Components AMT ISOLA Correlation k=0.7 v p /v s = 1.46 Correlation k=0.3 v p /v s = 1.57

21. Conclusions Focal mechanism determined using three different methods are statistically similar The majority of mechanisms have the P axes clustered in the NE direction The positive correlation between ISO and CLVD can be an indicator of tensile faulting The positive values of ISO and CLVD can be an indicator of opening of faults The ISO/CLVD ratio yields the v p /v s ratio in the range of 1.46 -1.57

22. November 25, 2009, Praha Thank you for your attention