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Charles University Prague partner no. 16 (CUP)

Charles University Prague partner no. 16 (CUP). J. Zahradník, J. Jansk ý, V. Plicka. Deliverables. 12 Data base for selected stations of CUP (WP1) . Plan: attention to “classical” issues (location, focal mechanisms, strong motions) as well as

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Charles University Prague partner no. 16 (CUP)

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  1. Charles University Praguepartner no. 16 (CUP) J. Zahradník, J. Janský, V. Plicka

  2. Deliverables 12 Data base for selected stations of CUP (WP1) Plan: attention to “classical” issues (location, focal mechanisms, strong motions) as well as various transients possibly related to strain

  3. Present status: 8 CUP instruments jointly operated with UPATRAS at 4 sites • 2 stand-alone (SERG, MAMO) • 2 satellite (LOUT, PYLO) • each one with CMG-3T and 5T (weak & strong)

  4. SERG (Sergoula)

  5. MAMO (Mamousia)

  6. BB: MAMO not equal SERG MAMO, D=94 km, A=66o M5.4 Vartholomio December 2, 2002 SERG, D=102 km, A=50o

  7. at f < 0.1 we get rid of site effectsMAMO SERG 5T as good as 3T for M5.4

  8. Both CMG-3T and CMG-5T are needed (even for small local events): Example: M3.8, 13 km (SERG)

  9. 3T almost clipped 3T problem at HF 5T problem at LF

  10. Can we also contribute to studies of slow strain events ? Example: December 3, 2002 (suggested by Pascal B.) lower thermal variation in winter velocity record supplemented by “mass channel” (integrated velocity output)

  11. CMG-3T 3 days “mass channel”: an anomaly superimposed on the thermal variation EW NS

  12. Zooming anomaly on EW (1 day)

  13. ... and the corresponding velocity

  14. anomaly M3.5 earthquake increased noise ?

  15. the anomaly consists of eqs. and 4-5 minute long pulses, 10-5 m/s 4 10-6 m/s 10-5 m/s CMG3-T: 1 day (Dec. 3, 2002)

  16. Just these 4-5 minute long pulses constitute the anomaly of the mass channel.

  17. and what happens during eq. ? M3.5 Dec. 3 23:42

  18. Mass channel

  19. Velocity: signature of a sudden local tilt M3.5 10-20 km

  20. Modeling a similar event Corinth Gulf M3, distance 10km

  21. Normal instrument response of CMG-3T to abnormal input: input input output output 100-SEC VELOCIGRAPH ACCELEROGRAPH

  22. Modeling the CMG-3T response we arrive at the horizontal acceleration step of 6.10-6 m/s2 tilt step 6.10-7

  23. Note the undisturbed vertical component, typical for the tilt. low pass f < 1 Hz: data model response

  24. Dec. 3 23:42

  25. 5 min ! Following the sudden tilt (< 100 sec), accompanying the earthquake, there is a slow “strain recovery” but its amplitude is 10-30 smaller than slow pulses accompanying the preceding burst of smaller eqs.

  26. Database (V. Plicka)http:/seis30.karlov.mff.cuni.cz

  27. Database (V. Plicka)http:/seis30.karlov.mff.cuni.cz regional local transients

  28. Deliverables 16 New software for source-parameter inversion (WP1) Innovation: LF local waveforms (f < 0.1 Hz) moment tensor, uncertainty of non-DC, multiplicity in space and time synthetic and/or empirical Green fctn.

  29. Zahradník, J., Janský, J., Sokos, E., Serpetsidaki, A., Lyon-Caen, H., and Papadimitriou, P. : Modeling the ML4.7 mainshock of the February-July 2001 earthquake sequence in Aegion, Greece. (J. of Seismology, 2004) inversion of the amplitude spectra 0.1 - 0.2 Hz

  30. Iterative deconvolution of regional waveforms Zahradník, J., Serpetsidaki, A., Sokos, E., Tselentis, G-A.: Iterative deconvolution of regional waveforms and double-event interpretation of the 2003 Lefkada earthquake, Greece (Bull. Seism. Soc. Am., in press)

  31. M6 Lefkada earthquakeAug.14, 2003 5 BB stationsepic.distance<140 km

  32. Method • moment-tensor inversion (minimization of the L2 waveform misfit by the weighted least-square method) • optimization of the source position and time (maximization of the correlation by the space-time grid search) • a single point source for f < 0.1 Hz, and multiple point sources for f < 0.3 Hz

  33. Final solution: 2 main subevents,40 km and 14 sec apart explaining the two aftershock clusters

  34. Vartholomio (near Zakynthos)Dec. 2, 2002ETH-SED: Mw=5.7DC%=55 !(HRV: DC%=58,Mednet: DC%=44) Zakynthos

  35. 6 NOA stations, f=0.05 to 0.1 Hz blue: data black: synthetics for crustal model of Haslinger et al. (1999) weights proportional to 1/A were applied

  36. 100% DC matches data also well(only 0.05 worse) we cannot see the difference

  37. Going into large details: Optimum correlation is not compatible with 100% DC trial source position trial time shift

  38. Very stablestrike-dip-rakebuthighly unstableDC percentage DC%: 72 to 97 % cf. 55% (ETH)

  39. Fixing the opt. source position and increasing frequency (f < 0.3 Hz): 3 subevents 2-sec time delay between sub 1 and 2; sub 3 is unstable

  40. Subevents 1 and 2: similar strike and dip, but different rake Consider sub 1 and 2 as 100% DC (but unequal !), and sum up their moment tensors: Result: sub 1+ 2 provides DC% 77 to 93%, analogous to the previous single-source study. Multiplicity seems to explain the non-DC mechanism.

  41. Deliverables 95 New software for near-real time seismic alarms (WP8) PEXT: perturbation and extrapolation finite-extent fault, composite source modeling deterministic envelopes and accel. spectral level, stochastic HF phase; perturbed HF radiation pattern

  42. Colfiorito Mw 6.0 benchmark (M. Cocco)

  43. “Moderate” directivity GTAD CTOR

  44. Athens 1999 - PGA modeling Shake map up to 20 Hz in a few minutes on a PC

  45. Tuning maximum slip velocity against the attenuation relation

  46. Athens - synth. versus real records

  47. ... another station

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