The Moho map

Moho_TA_12_08.xyz

is the current map we have produced as of December 08.
The file is packed lon,lat,ZMoho, where Zmoho is crustal
thickness (i.e. depth to Moho from the surface, not from
sealevel). It represents the Moho beneath the TA stations
at the speficied longitudes and latitudes.

The velocity model used to calculate Moho
depths is based on crust2 (Bassin, C., G. Laske, and G. Masters (2000),
The current limits of resolution for surface wave tomography in 
North America, EOS Trans., 81, F897.).

The image is better toward the west, as more events are available
for analysis.  A total of 70 events with 70,000 RFs were used to
make the map. A hit count map is available on request, but is
only furnished as a matlab file. We estimate the error as ±2 km
but it actually depends more on the velocity model than on the formal
picking error.

The map will be periodically updated to extend further east, and to
densify and improve areas where additional stations become available.

At present the best reference for this model is:

Levander, A., F. Niu, and M.S. Miller, 2008, The Moho and the 
Lithosphere-Asthenosphere Boundary under the western U.S. 
from USArray PdS Receiver Functions, EOS Trans. AGU, 89(53), 
Fall Meet. Suppl., Abstract S31D-05.