10 Sept 2006 SCEC/USGS Workshop: CA 3D Seismic Velocity Model

The Role of Ambient Noise Tomography in Developingthe California 3-D Seismic Velocity Model: Brief Thoughts

Venturabasin

LA basin

CentralValley

ImperialValley

Shapiro, Stehly, Campillo, & Ritzwoller, High resolutionsurface wave tomography from ambient seismic noise,Science, 307, 615, March 11, 2005.

Oct, 2004

•Past: •application to So. CA.•group speed maps•short periods (7 - 18 s).

•Present: •refinement of the method •application to new regions•extension to phase velo-

cIties & Love waves•larger scales, longer periods•smaller scales, shorter periods•inversion for 3D Vs.

•Near Future:•joint interpretation with other data.

SCEC/USGS Workshop: CA 3D Seismic Velocity Model

Applications to New Regions (W. US Using TA/ USArray) & Inversion for a Crustal Vs Model

16 sec, group velocity, 10/04-7/06

Map by Morgan Moschetti

SCEC/USGS Workshop: CA 3D Seismic Velocity Model

16 sec, group velocity, 10/04-7/06

group velocity

gro

up

ve

loci

ty

San Joaquin Valley

Applications to New Regions (W. US Using TA/ USArray) & Inversion for a Crustal Vs Model

SCEC/USGS Workshop: CA 3D Seismic Velocity Model

16 sec, group velocity, 10/04-7/06 Preliminary crustal thickness

Applications to New Regions (W. US Using TA/ USArray) & Inversion for a Crustal Vs Model

Inversion by Morgan Moschetti

SCEC/USGS Workshop: CA 3D Seismic Velocity Model

Extension to Phase Velocities at Longer Periods: High Resolution Mantle Constraints

25 sec

Phase velocity

Ambient noise

Yang & Moschetti

25 sec

Phase velocity

Teleseismic 2-plane wave method

Yang & Forsyth

SCEC/USGS Workshop: CA 3D Seismic Velocity Model

Closing Comment on the Use of Ambient NoiseTomographyThe Role of Ambient Noise Tomography in Developing the California 3-D Seismic Velocity Model: Closing Comments

•Complements other kinds of information: homogeneously distributed provides a means to integrate models from different regions way to extrapolate the model into new areas Vs in the crust & uppermost mantle

• More useful than traditional surface wave data: significantly higher resolution shorter period, provide constraints on the crust.

•Easily introduced into inversions in which other dataare interpreted jointly and with a priori constraints.

SCEC/USGS Workshop: CA 3D Seismic Velocity Model

35.5, 242Tehachapi Mtns

SCEC/USGS Workshop: CA 3D Seismic Velocity Model

37, 242 White Mtns

SCEC/USGS Workshop: CA 3D Seismic Velocity Model