1. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 1 Return to Passive Imaging Brad Artman June, 6 2002 Ph.D. Proposal

2. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 2 State of Affairs Claerbout’s Conjecture Terra/Helio-seismology EngineeringExploration Success

3. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 3 The nutshell Why it works As it stands Toward the goal How to finish When will all this be ready?

4. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 4 The nutshellThe nutshell –Problem –Importance –Proposal Why it works As it stands Toward the goal How to finish When will all this be ready?

5. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 5 Problem Who knows if passive seismic imaging works? –Why (not)?

6. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 6 Importance Lots of people care about the subsurface. No source required opens opportunities for: –Monitoring –Reconnaissance –Restricted access sites –Old long data sets –New long data sets

7. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 7 Proposal I propose to answer whether or not the passive seismic experiment can be used as a practicable methodology for subsurface imaging and/or monitoring. + or - I’ll tell you why.

8. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 8 The nutshell Why it worksWhy it works –Intuitive explanation –Rigorous explanation As it stands Toward the goal How to finish When will all this be ready?

9. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 9 Intuitive explanation a r1r2 r1*r1 r1*r2 b c tlag

10. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 10 Rigorous explanation I 1 U -R R Conventional reflection seismic 1 -U U P Earthquake seismology Y –R( ) R(Z) + [1+R( )] [ 1+ R(Z)] = Y U( ) U(Z) Z 1 Z 1 Z 1 1k 1+R( ) R(Z) = a U( ) U(Z) Z 1 Z 1

11. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 11 Rigorous explanation I Y –R( ) R(Z) + [1+R( )] [ 1+ R(Z)] = Y U( ) U(Z) Z 1 Z 1 Z 1 1k 1+R( ) R(Z) = a U( ) U(Z) Z 1 Z 1 1 U -R R Conventional reflection seismic 1 -U U P Earthquake seismology

12. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 12 Intuitive explanation a r1r2 r1*r1 r1*r2 b c tlag

13. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 13 Rigorous explanation II U( ) U(Z) = U(p,ω) U(p,ω) = Q(p,ω) Z 1 Q(k,ω) = Q(, ω) = |ω|U(k,ω) U(k,ω) 1 |ω|ω k Q(p,ω) = Q(, ω) ω k Q(p,ω) = |ω| Q(k,ω) q(x,t) =  (t)  u(x’,t) u(x+x’,t+t’) t’ x’    r x’,x+x’ (t) x’ DFT

14. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 14 Synthetic Tests m s

15. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 15 Cross-correlation Technique Passive Seismic Imaging applied to synthetic data, Rickett SEP-92

16. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 16 Virtual multiples a r1r2 r1*r1 r1*r2 b c tlag

17. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 17 The nutshell Why it works As it standsAs it stands –It works! –On the shoulders of giants –The race Toward the goal How to finish When will all this be ready?

18. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 18 It works! Acoustic Daylight Imaging via spectral factorization, Rickett SEP-100

19. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 19 On the shoulders of giants SEP reports 60 – 86, 100 –SEP’s Franciscan effort and analysis Schuster –Correlation migration –Drill bit source Bostock –Earthquake array seismograms Louie –Engineering characterization

20. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 20 The Race Undisclosed submission Company interest Livermore??? The earth from satellite?

21. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 21 The nutshell Why it works As it stands Toward the goalToward the goal –Is 2D possible? –Reformulation as migration –Motivation to invert –Sampling the noise-field –Shape of the noise-field –Artman GeoServices How to finish When will all this be ready?

22. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 22 Is 2D possible? Yes PGS OBC 3C Co-parallel PSD ! Is 2D possible?, Artman, SEP-111

23. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 23 Reformulation as migration I ( z, x )= Σ P ( ω,x,s) P ( ω,x,s) ω s z g z P is the wave field at each depth level, where source and receiver fields are propagated independently via SSR. z Realization: If P = P, correlation requirement of the passive seismic conjecture is fulfilled in the migration. Let the wave equation handle the unknown source. sg

24. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 24 Areal Source Wave-field Shot-profile migration of multiple reflections, Guitton, SEP-111

25. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 25 Synthetic Tests m s

26. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 26 Two horizontal planes mm m

27. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 27 Point Diffractor

28. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 28 Cost Comparison Correlations –Spatial increase: N to N (+5 O.M.) –Temporal decrease: N to N (- 4 O.M.) –Migrate (S.P.): N N N N Skipping Correlations –No spatial or frequency change: N, N –Migrate (S.P.): N N N N xy lag xy 2 t lagzxy 2 t h tz h

29. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 29 Motivation to invert

30. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 30 Sampling the noise-field Minimize storage and processing costs Bow to acquisition computer limitations

31. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 31 No

32. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 32 Shape of the noise-field

33. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 33 Artman GeoServices

34. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 34 The nutshell Why it works As it stands Toward the goal How to finishHow to finish –Brad, the sun, and your coffee table –Santa Clara Valley Seismic Experiment –Recast as deconvolution –Wave-field separation When will all this be ready?

35. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 35 Solar imaging Flare structure, density layering Tools: –Absorbing boundary layer modeling –Up-down extrapolator James Rickett

36. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 36 Crustal Seismic

37. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 37 Deconvolution Who needs physics? U = T S S = H W A U = W A = W W H T = H T Assume T is white(ish) and events are well spaced Second PEF estimation & application returns T Levinson recursion calculates the reflection coefficients

38. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 38 Wave-field separation u = E LR I Up-going wave-field Physics Surface displacements E has azimuthal dependency- this may not work.

39. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 39 Data commitments Linear acquisition: –S. California, USGS. Sept. 2002 –S.C. Valley, USGS. Sept. 2002 –3C OBC, GoM, PGS, June 2002 –Unspecified test, PGS, Sept. 2002 –Publicly available seismologic deployments Areal acquisition: –South Texas, CGG, Sept. 2002 –Sun, SOI, in-house –S.C. Valley, USGS, in-house –Moss Landing +, Artman GeoServices, in-house –Publicly available seismologic deployments

40. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 40 Time-line Summer 2002 –3D up-down extrapolator, absorbing BC’s –Image solar flare, submit for publishing –Image Moss Landing beach Urban applications? –Continue collection of outside data –SEG passive seismic workshop

41. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 41 Time-line Fall 2002 –Image Santa Clara Valley, submit for publishing –Gather/acquire data –Image data as it arrives –Physics 210: Particle mechanics

42. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 42 Time-line Winter 2002-Spring 2003 –Continue data collection and processing –Comp. Sci. 238: Parallel methods in num. analysis –Begin comparative study of successes and failures –Prepare work for publishing Summer 2003 – outside internship

43. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 43 Time-line Fall 2003 – Spring 2004 –Finalize comparative analysis –Define success parameters –Prepare for publishing Summer 2004 –Stat. 110: Stat. Methods in eng. and phys. science –Wrap up outstanding projects

44. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 44 Time-line Fall – Winter 2004 –PE 284 : Optimization –Write thesis, journal articles Spring 2004 –Finalize deliverables for graduation

45. Passive Seismic ImagingSEP/Crustal Research Group brad@sep.stanford.edu 45 Thank You