Abstract
P>The traveltimes of P and SH waves through the crust depend strongly on wave period. At periods longer than 10-15 s, where traveltime measurements for indirect (e.g. surface reflected and core reflected) waves are typically made, the traveltimes are shorter than predicted by ray theory. Crustal corrections, often used in global mantle tomography to isolate the effects of the crust on teleseismic traveltimes, may have a complex frequency dependence and influence finite-frequency inversions.
Crustal corrections for profiles of CRUST2.0 and the PREM reference model for the mantle may be several seconds larger or smaller than ray-theoretical values, depending on crustal thickness, crustal velocities and wave period. This variability is observed in the difference times between the seismic phases SS and S and between PP and P. It is therefore important to incorporate the effects of the crust on traveltimes in finite-frequency tomography, in order to take full advantage of the variable mantle sensitivity of body waves at different periods.
| Original language | English |
|---|---|
| Pages (from-to) | 1255-1261 |
| Number of pages | 7 |
| Journal | Geophysical Journal International |
| Volume | 179 |
| Issue number | 2 |
| DOIs | |
| Publication status | Published - Nov 2009 |
Funding
This research has been funded by NSF grant EAR-0609763. We thank Gabi Laske for providing us model CRUST2.0 via (http://mahi.ucsd.edu/Gabi/crust2.html). We thank Barbara Romanowicz and an anonymous reviewer for constructive comments that helped us improve the manuscript. Data have been provided by the IRIS/DMC and the Geoscope Data Center. Figures have been produced using the GMT software of Wessel & Smith (1995).
Keywords
- Body waves
- Seismic tomography
- Wave propagation
- Crustal structure
- EARTH MODEL
- P-WAVES
- MANTLE
- AMERICA
- CONSTRAINTS
- BENEATH
- SHEAR