Traveltime tomography and nonlinear constrained optimization

Conference · Sat Oct 01 04:00:00 EDT 1988

OSTI ID:6931896

Berryman, J G

Fermat's principle of least traveltime states that the first arrivals follow ray paths with the smallest overall traveltime from the point of transmission to the point of reception. This principle determines a definite convex set of feasible slowness models - depending only on the traveltime data - for the fully nonlinear traveltime inversion problem. The existence of such a convex set allows us to transform the inversion problem into a nonlinear constrained optimization problem. Fermat's principle also shows that the standard undamped least-squares solution to the inversion problem always produces a slowness model with many ray paths having traveltime shorter than the measured traveltime (an impossibility even if the trial ray paths are not the true ray paths). In a damped least-squares inversion, the damping parameter may be varied to allow efficient location of a slowness model on the feasibility boundary. 13 refs., 1 fig., 1 tab.

• Research Organization: Lawrence Livermore National Lab., CA (USA)
• DOE Contract Number: W-7405-ENG-48
• OSTI ID: 6931896
• Report Number(s): UCRL-99831; CONF-8810202-4; ON: DE89003174
• Country of Publication: United States
• Language: English

Related Subjects

99 GENERAL AND MISCELLANEOUS
990210* -- Supercomputers-- (1987-1989)
COMMUNICATIONS
CONSTRAINTS
DATA TRANSMISSION
DIAGNOSTIC TECHNIQUES
FERMAT PRINCIPLE
LEAST SQUARE FIT
MAXIMUM-LIKELIHOOD FIT
NONLINEAR PROBLEMS
NUMERICAL SOLUTION
OPTIMIZATION
TOMOGRAPHY