1. RECEIVER FUNCTIONS analysis for Vs profiles and Moho depth estimations Andrea Licciardi (1,2) Nicola Piana Agostinetti (1) (1)Geophysics Section, Dublin Institute for Advanced Studies (2)School of Geological Sciences, University College Dublin TABOO Meeting, 23rd – 24th April 2013, Ancona

2. Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 RFs data-set

3. Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 RFs data-set Num. of recorded earthquakes Num. of selected earthquakes Num. of computed RFs

4. 1) RFs: Moho depth. The Zhu and Kanamori (2000) method Based on a weighted stack of RRFs at the predicted arrival times of Ps, PpPs, PpSs+PsPs phases Grid search in the H-Vp/Vs domain For the correct values of H and Vp/Vs the stacking function is max Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 RFs are computed with a frequency domain deconvolution (Di Bona,1998) Fq ≈ 1 Hz. Ver. Res ≈ 1 km

5. 1) RFs: Moho depth Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013

6. Trasimeno Lake Promano Pietralunga Sigillo Piccione Umbertide 1) RFs: Moho depth Piana Agostinetti et al. 2011

7. 2) RFs: mapping the ATF Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013

8. Direct P polarity reversal in the very first second of the Radial and Transverse Receiver Functions Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 2) RFs: mapping the ATF DIPPING INTERFACE HIGH VELOCITY CONTRAST

9. Evidence of ATF from RFs Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 BAZ Dist. DIP-DIRECTION The BAZ of the min amplitude on the RADIAL and of the zero energy on the TRANSVERSE gives the of the interface

10. BAZ Dist. N002 ATMI ATMC Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 AT01 DIP-DIRECTION STRIKE 2) RFs: mapping the ATF

11. Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 AT01 N002 2) RFs: mapping the ATF

12. AT05: same location as Pozzo San Donato ATVO: Monte Valentino, ~1-2km from Monte Civitello Focus on Radial RF for isotropic S-vel profile Freq ~ 1Hz = V-Res: 1km 3) High Frequency RF: comparison with borehole data Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013

13. Harmonic decomposition of the RF data-set (decoupling of isotropic/anisotropic components) K=0 analysis (i.e. isotropic) Max freq. ~ 4Hz, V-res ~ 0.25 km (?) Sharp negative arrival = velocity inversion at depth (within the first 5 km) Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 3) High Frequency RF: comparison with borehole data Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013

14. 1D Posterior distribution of seismic interfaces at depth 1D Posterior distribution for S-velocity Posterior mean Vp and Vs Fit between mean synthetic and observed RF Maximum probability for an interface at depth 3) High Frequency RF: comparison with borehole data Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013

15. Litho-discontinuities from Borehole data Interpretation (e.g. Mirabella et al 2011) Vs Discontinuities from RF data (5) (1) (2) (3) (4) (6) (1) ~200m between top Evaporites (2) Intra-Evaporites discontinuities retrieved (3) Top of the Acoustic Basement missed by ~200m, but presence of fine-layering (i.e. Ligurids) on top. Basement is not low Vs as expected (4) Intra-basement discontinuity retrieved (5) No discontinuity between Basement and Evaporites (i.e. Evaporites have low-Vs) (6) Very low-Vs top of the Acoustic Basement 3) High Frequency RF: comparison with borehole data Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013

16. 0 m ~3030 m Careful inspection of borehole data should be used to interpret the seismic discontinuities retrieved by RF analysis For example, for AT05, the Vs discontinuity at about 3800m might be associated to a sharp resistivity variation “Argilloscisti” sequence (4) ~4483 m 3) High Frequency RF: comparison with borehole data - AT05

17. Andrea Licciardi Dublin Institute for Advanced StudiesAncona 23rd April 2013 CONCLUSIONS 1.Results from RFs analysis show a complex Moho topography in between the Tyrrhenian and Adriatic domains; 2.RFs can be used to map faults with high velocity contrast in the shallow crust; 3.Velocitity profiles from high frequency RFs can be directly compared with borehole data providing additional information for geological interpretations; OUTLOOK: 1.Results from station ATVO will be compared with the available data from Monte Civitello borehole; 2.1D Vs velocity profiles will be computed at each station.