7/18/2005CoRA, NWRA, Inc.

Time-Distance Inversions and Kernels for Ring Diagrams

Aaron Birch

Outline:A.TD InversionsB.Kernels for Ring Diagrams

7/18/2005CoRA, NWRA, Inc.

Motivation

Kosovichev, Zhao et al.

Also holography inversions:

7/18/2005CoRA, NWRA, Inc.Couvidat et al., compare ray and Born

Also Giles comparison with normal-mode inversions

Zhao et al., 2001, test inversions

7/18/2005CoRA, NWRA, Inc.From S. Korzennik, test inversions

7/18/2005CoRA, NWRA, Inc.From S. Korzennik, test inversions

7/18/2005CoRA, NWRA, Inc.

Future Work for TD Inversions

• Kernels– Green’s functions: exact vs. normal modes– Dependence on source/damping models ?

• Regularization

• How much & what kind of averaging ?

• Magnetic Fields ?– How well does treating B as c work ?

7/18/2005CoRA, NWRA, Inc.

B. Kernels for Ring-Diagrams

• Want:

• Two steps:– Linear sensitivity of U

parameters to power– Linear sensitivity of

power to local flows

)()( xvxdxKU jiji

7/18/2005CoRA, NWRA, Inc.

Example Ring Kernel, l=300,n=4

7/18/2005CoRA, NWRA, Inc.

Blue: slice through kernelBlack: 1d undamped model

7/18/2005CoRA, NWRA, Inc.

Future Work for/with Ring Kernels

• Inversions of ring data

• Joint inversion of time-distance, holography, direct modeling, and ring data, have uniform theoretical treatment

• Model systematic effects (e.g. line of sight, Postel remapping) ?

7/18/2005CoRA, NWRA, Inc.