1. Comparison of travel times from quarry blasts with synthetic travel times calculated in 1-D and 3-D models of the Dobrá Voda locality
(work in progress)
P. Bulant*, M. Brož**, J. Sekereš***
*Charles University in Prague, Faculty of Mathematics and Physics, Department of Geophysics, Czech Republic
**Institute of Rock Structure and Mechanics, Academy of Sciences, Prague, Czech Republic
***PROGSEIS, s.r.o., Trnava, Slovak Republic
AIM meeting, Praha,

2. Dobrá Voda locality on a map

3. Dobrá Voda on a geological map

4. Data for the P-wave velocity model
P-wave velocity data given in the form of a very sparsely sampled 3-D velocity model consisting of 7 x 8 x 8 discrete values of P-wave velocity. The data grid is rectangular, but strongly irregular in the depth. The values of velocity are “based on profile measurements and well data”.
Data for the S-wave velocity model
S-wave velocity data given on the same grid of 7 x 8 x 8 discrete values.

5. Models suitable for ray tracing, model construction method
- smooth continuous models parametrized by B-splines
construction of a velocity model by data fitting with minimization of the Sobolev norm of the model composed of second velocity derivatives
Resulting models based on the velocity data
- 1-D smooth P- and S-wave velocity model
- 3-D smooth P- and S-wave velocity model

6. Resulting 1-D P-wave velocity model

7. P-wave rays in resulting 1-D model

8. Resulting 3-D P-wave velocity model - 23 km

9. Resulting 3-D P-wave velocity model - 15 km

10. Resulting 3-D P-wave velocity model - 10 km

11. Resulting 3-D P-wave velocity model - 5 km

12. Resulting 3-D P-wave velocity model - 0 km

13. New data – travel times from quarry blasts
- ordinary quarry blasts (for the stone production) - origin time measurements in the quarries - travel times measured by seismic stations of the regional network - 5 quarries measured until 9/2011 (Buková, Hubina, Čachtice, Jablonica, Trstín)

14. Map of the quarries in the locality

15. Quarries with blasts measured until 9/2011
Čachtice
Hubina
Jablonica
Buková
Trstín

16. Čachtice quarry blast – march 2011

17. Čachtice quarry blast – march 2011

18. Čachtice quarry blast – march 2011

19. Čachtice quarry blast – march 2011

20. Čachtice quarry blast – march 2011

21. Čachtice quarry blast – march 2011

22. Buková – recorded P-wave travel times

23. Čachtice – recorded P-wave travel times

24. Hubina – recorded P-wave travel times

25. BU+CA+HU – recorded P-wave travel times

26. Buková – recorded S-wave travel times

27. Čachtice – recorded S-wave travel times

28. Hubina – recorded S-wave travel times

29. BU+CA+HU – recorded S-wave travel times

30. Repeated travel-time measurements
Buková & Hubina :14 & 12:39 Maximum relative travel-time differences < 4%

31. Comparison of measured and synthetic P-wave travel times
Buková &
measured
1-D synthetic
rel. dif. (%)
3-D synthetic
Špačince
4.69
4.26
-9.51
4.76
1.51
Dobrá Voda
2.00
2.99
39.87
2.71
30.35
EBO
4.93
4.65
-5.79
5.25
6.32
Plavecké Podhradie
2.56
3.02
16.57
2.76
7.70
Lakšár
3.17
3.42
7.45
3.33
4.85
Hradiště
1.97
2.88
37.62
2.60
27.80
Katarínka
1.81
2.72
40.24
2.48
31.14
Lančár
3.12
4.18
29.16
3.90
22.39
Pustá Ves
3.31
4.34
26.92
4.06
20.36
Smolenice
0.74
0.87
15.56
15.74
Buková
0.37
0.16
-77.90
0.14
-89.54

32. Comparison of measured and synthetic travel times
Buková quarry m.
1-D %
3-D
Špačince
4.69
4.26
-9.51
4.76
1.51
Dobrá Voda
2.00
2.99
39.87
2.71
30.35
EBO
4.93
4.65
-5.79
5.25
6.32
Plavecké Podhradie
2.56
3.02
16.57
2.76
7.70
Lakšár
3.17
3.42
7.45
3.33
4.85
Hradiště
1.97
2.88
37.62
2.60
27.80
Katarínka
1.81
2.72
40.24
2.48
31.14
Lančár
3.12
4.18
29.16
3.90
22.39
Pustá Ves
3.31
4.34
26.92
4.06
20.36
Smolenice
0.74
0.87
15.56
15.74
Buková
0.37
0.16
-77.90
0.14
-89.54

33. Conclusions
- number of measured travel times from quarry blasts is growing - good repeatability => one measurement for each quarry sufficient - 3-D model gives better agreement with measured travel times than 1-D model - large travel-time errors => models not precise enough
Plans
- record travel times from as many quarries as possible - update the 3-D model using the measured travel times (include the measured travel times from quarry blasts into the velocity data fitting)