Gravity inversion in spherical coordinates using tesseroids

Transcript

1. Gravity inversion
   in spherical coordinates
   using tesseroids
   Leonardo Uieda
   Valéria C. F. Barbosa
   

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2. vs
   Cartesian Spherical
   

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3. Existing inversion with tesseroids
   (Chaves and Ussami, 2013)
   ●
   Geoid height anomalies
   ●
   Space domain
   ●
   Regularization:
   – Depth-weighted Minimum Volume
   – Similarity to seismic tomography
   

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4. Adapt
   Planting anomalous densities
   (Uieda and Barbosa, 2012)
   

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5. Planting anomalous densities
   ●
   Space domain
   ●
   Multicomponent: gravity + gradients
   ●
   Non-conventional inversion
   – Growth algorithm
   – No linear systems
   – Efficient sensitivity computations
   

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7. Seed
   

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19. Synthetics
    ●
    Possible applications
    ●
    Advantages
    ●
    Shortcomings
    

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20. Lineament with dense rocks
    (magmatic)
    Inspired by Chad lineament model
    (Braitenberg et al, 2011)
    

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21. After Braitenberg et al (2011)
    

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22. After Braitenberg et al (2011)
    

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23. 10º
    N
    300 kg.m-3
    2º
    8km
    top=1 km
    

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24. gzz
    At 20 km
    

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25. Seeds
    

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26. observed predicted
    

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28. What if height=120 km?
    

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29. at 120 km
    at 20 km
    

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30. observed predicted
    

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31. at 120 km
    at 20 km
    

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32. Even higher
    height=270 km
    

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33. at 270 km
    at 120 km
    

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34. observed predicted
    

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35. at 270 km
    at 120 km
    

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36. Magmatic underplating
    Inspired by model of the Paraná basin
    by Mariani et al (2013)
    

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37. After Mariani et al (2013)
    

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38. After Mariani et al (2013)
    

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39. 10º
    N 200 kg.m-3
    15
    km
    5º
    10º
    top=30 km
    

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40. gzz at 250 km
    

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41. Seed
    

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43. What if I use wrong density?
    

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44. 150 kg.m-3
    250 kg.m-3
    

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45. In conclusion
    

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47. for tesseroids
    

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48. Works well
    

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49. height matters
    20km 250km
    

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50. correct
    dense
    correct
    dense
    

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51. Future
    ●
    Combinations of tensor components
    ●
    Dipping sources (subducting plate)
    ●
    Real data (open for collaboration)
    

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52. OPEN SOURCE
    fatiando.org
    github.com/leouieda/egu2014
    

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53. Extra
    

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54. (Hypothetical) Mantle Plume
    Inspired by synthetics in Chaves and Ussami (2013)
    

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55. After Chaves and Ussami (2013)
    

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56. top=100 km
    200 km
    700 km
    2º
    -50 kg.m-3
    

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57. gzz at 250 km
    

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58. Seed
    

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60. Joint gz + gzz?
    

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61. Same seed
    

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62. gz
    gzz
    

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63. gzz Joint
    

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64. gzz Joint
    

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65. single vs joint
    

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