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, 29-30.9.2011

Dobrá Voda locality on a map

Dobrá Voda on a geological map

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.

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

Resulting 1-D P-wave velocity model

P-wave rays in resulting 1-D model

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

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

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

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

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

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)

Map of the quarries in the locality

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

Čachtice quarry blast – march 2011

Čachtice quarry blast – march 2011

Čachtice quarry blast – march 2011

Čachtice quarry blast – march 2011

Čachtice quarry blast – march 2011

Čachtice quarry blast – march 2011

Buková – recorded P-wave travel times

Čachtice – recorded P-wave travel times

Hubina – recorded P-wave travel times

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

Buková – recorded S-wave travel times

Čachtice – recorded S-wave travel times

Hubina – recorded S-wave travel times

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

Repeated travel-time measurements Buková 10.9.2007 & 2.11.2010 Hubina 2.11.2010 12:14 & 12:39 Maximum relative travel-time differences < 4%

Comparison of measured and synthetic P-wave travel times Buková 10.9.2007 & 2.11.2010 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

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

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)