1. Christian-Albrechts-Universität Kiel 24.03.2015 - DGG-Tagung Hannover A combined elastic waveform and gravity inversion for improved density model resolution applied to the Marmousi-II model Daniel Wehner, Daniel Köhn, Denise De Nil, Sabine Schmidt, Said al Hagrey, Hans-Jürgen Götze and Wolfgang Rabbel

2. Daniel Wehner - DGG-Tagung 2015 Hannover Overview Motivation Gravity modelling Theory of FWI and Joint Inversion 2-step Joint Inversion applied to the Marmousi- II model Outlook 2

3. Daniel Wehner - DGG-Tagung 2015 Hannover True modified elastic 2D Marmousi-II model 3

4. Daniel Wehner - DGG-Tagung 2015 Hannover Initial model for FWI smoothed versions of the true model constant water- layer above constant halfspace 4

5. Daniel Wehner - DGG-Tagung 2015 Hannover Inversion with 2 Hz, 23 iterations 5

6. Daniel Wehner - DGG-Tagung 2015 Hannover Inversion with 2-5 Hz, 153 iterations 6

7. Daniel Wehner - DGG-Tagung 2015 Hannover Inversion with 2-5-10 Hz, 278 iterations 7

8. Daniel Wehner - DGG-Tagung 2015 Hannover Results for FWI with 2-5-10-20 Hz Problem well resolved 8

9. Daniel Wehner - DGG-Tagung 2015 Hannover Results for Joint Inversion 9 True model FWI alone How do we get better resolution ?

10. Daniel Wehner - DGG-Tagung 2015 Hannover Solution? Integration of GRAVITY data into seismic FWI workflow 10

11. Daniel Wehner - DGG-Tagung 2015 Hannover Solution? Integration of GRAVITY data into seismic FWI workflow 11

12. Daniel Wehner - DGG-Tagung 2015 Hannover 1. Gravity Modelling Kernel K Integration in existing FWI FD-Grid 12 Gravity of a prism

13. Daniel Wehner - DGG-Tagung 2015 Hannover 1. Gravity Modelling Cylindrical test model distance between stations: 200 m 13

14. Daniel Wehner - DGG-Tagung 2015 Hannover 1. Gravity Modelling Marmousi-II test model distance between stations: 200 m 14

15. Daniel Wehner - DGG-Tagung 2015 Hannover 2. Objective Function 15

16. Daniel Wehner - DGG-Tagung 2015 Hannover 2. Joint Objective Function 16

17. Daniel Wehner - DGG-Tagung 2015 Hannover 3. Gradient 17

18. Daniel Wehner - DGG-Tagung 2015 Hannover Application: Step 1, pure seismic FWI Inversion for all parameters 18

19. Daniel Wehner - DGG-Tagung 2015 Hannover Application: Step 2, inital model v-models kept fixed 19 Inversion for the density

20. Daniel Wehner - DGG-Tagung 2015 Hannover Application: Step 2, high λ 20

21. Daniel Wehner - DGG-Tagung 2015 Hannover Application: Step 2, high λ long wavelength model 21

22. Daniel Wehner - DGG-Tagung 2015 Hannover Application: Step 2, low λ Problem solved 22

23. Daniel Wehner - DGG-Tagung 2015 Hannover Results for Joint Inversion 23 True model FWI alone Joint Inversion

24. Daniel Wehner - DGG-Tagung 2015 Hannover Conclusion 24

25. Daniel Wehner - DGG-Tagung 2015 Hannover Thank you very much for your attention Acknowledgements: ANGUS+ research project funded by the German Federal Ministry of Education and Research (BMBF) MeProRisk-II research project funded by the Federal Ministry for the Environment, Nature Conservation, Building and Nuclear Safety (BMU) Inversions were performed on the NEC-HPC Linux-Cluster at Kiel University 25

26. Daniel Wehner - DGG-Tagung 2015 Hannover Brossier, R. [2011] Two-dimensional frequency-domain visco-elastic full waveform inversion: Parallel algorithms, optimization and performance. Computers & Geosciences, 37(4),444-455. Köhn, D., De Nil, D., Kurzmann, A., Przebindowska, A. and Bohlen T. [2012] On the influence of model parametrization in elastic full waveform tomography. Geophysical Journal International, 191(1), 325-345. Nocedal, J. and Wright, S. [2006] Numerical Optimization. Springer, New York. Plessix, R.E. and Mulder, W.A. [2004] Frequency-domain finite-difference amplitude-preserving migration. Geophysical Journal International, 157(3), 975-987. Zhdanov, M.S., Liu, X., Wilson, G.A. and Wan, L. [2011] Potential field migration for rapid imaging of gravity gradiometry data. Geophysical Prospecting, 59, 1052-1071. literature 26

27. Daniel Wehner - DGG-Tagung 2015 Hannover Comparison of density models for FWI 27 True model FWI result Absolute error

28. Daniel Wehner - DGG-Tagung 2015 Hannover Comparison of density models for Joint Inversion 28 True model Joint Inversion result Absolute error

29. Daniel Wehner - DGG-Tagung 2015 Hannover Comparison of density models for Joint Inversion 29 FWI result Joint Inversion result Absolute error

30. Daniel Wehner - DGG-Tagung 2015 Hannover Ambiguity between parameter classes from Köhn et al. (2012) 30 CTS model

31. Daniel Wehner - DGG-Tagung 2015 Hannover Influence of inverse Hessian approximation 31

32. Daniel Wehner - DGG-Tagung 2015 Hannover Influence of inverse Hessian approximation 32

33. Daniel Wehner - DGG-Tagung 2015 Hannover Gravity gradient by adjoint operator 33