advanced seismic imaging gg 6770 tomography inversion project by travis crosby
Post on 21-Dec-2015
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Advanced Seismic ImagingAdvanced Seismic ImagingGG 6770GG 6770
Tomography Inversion ProjectTomography Inversion Project
ByByTravis CrosbyTravis Crosby
Outline
• Experiment parametersExperiment parameters
• Results of unregularized tomography experimentResults of unregularized tomography experiment - Various Ray orientations - Various stopping criteria
- Noise added (±0.05% max traveltime)
• Results of regularized tomography experimentResults of regularized tomography experiment- Different lambdas
• Jackson’s Principle determination of lambdaJackson’s Principle determination of lambda
Tomography Experiment Parameters
• Real velocity model shown to the left.• 3000 units/s homogeneous starting model.• Straight rays from left to right and top to bottom.• Solve by least square steepest descent (s = [L’L] –1 L’d ), regularized and unregularized.• Ratio of knowns (441 rays) to unknowns (400 grid units) is 1.1025.• Noise added was random and 0.05% of maximum traveltime.• No preconditioning used.
Real Velocity Model
Jackson’s Principle – Determination of Lambda
Original Data
Residual 1.35e-8
Optimal lambda = 0.201
or 0.05*max(LtL) = 0.005