160 likes | 306 Views
Advanced Seismic Imaging GG 6770. Tomography Inversion Project. By Travis Crosby. Outline. Experiment parameters Results of unregularized tomography experiment - Various Ray orientations - Various stopping criteria - Noise added ( ± 0.05% max traveltime)
E N D
Advanced Seismic ImagingGG 6770 Tomography Inversion Project By Travis Crosby
Outline • Experiment parameters • Results of unregularized tomography experiment • - Various Ray orientations • - Various stopping criteria • - Noise added (±0.05% max traveltime) • Results of regularized tomography experiment • - Different lambdas • Jackson’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
Unregularized Tomography Experiment 1Rays Left to Right Rays
Unregularized Tomography Experiment 2Rays Top to Bottom Rays
Unregularized Tomography Experiment 3Rays Left to Right & Top to Bottom Rays
Unregularized Tomography Experiment 410% change stopping criteria Rays
Unregularized Tomography Experiment 51% change stopping criteria Rays
Unregularized Tomography Experiment 60.1% change stopping criteria Rays
Unregularized Tomography Experiment 70.01% change stopping criteria Rays
Unregularized Tomography Experiment 80.05% Noise Added - 0.1% change stopping criteria Rays
Regularized Tomography Experiment 90.1 Lambda Rays Unregularized
Regularized Tomography Experiment 100.01 Lambda Rays Unregularized
Jackson’s Principle – Determination of Lambda 0.05% Noise Added Original Data
Jackson’s Principle – Determination of Lambda Residual 1.35e-8 Original Data Optimal lambda = 0.201 or 0.05*max(LtL) = 0.005
Acknowledgements Much Thanks to Ruiqing He