Lithospheric Structure of the Gulf of California – Salton Trough Region,
NARS-Baja Array
Working Group:Robert Clayton, CaltechDon Forsyth, BrownAntonio Gonzalez-Fernandez, CICESECraig Jones, ColoradoCecillio Rebollar, CICESEJose Romo-Jones, CICESE
Science Questions:•What is the rifting process and how does it vary from north to south in the Gulf•What is the role of the remnant slab – where does it exist.
Methods•Map of the Moho from seismic and other geophysical methods.•Map of the lithosphere/asthenosphere boundary.•Velocity Variations from tomography studies.•Flow directions from anisotropy•Current strain from earthquakes
Products•3D regional-scale velocity model•Earthquake catalogue.
Lewis et al, 2001
Ichinose et al, 1996
Receiver Functions
Receiver Functions – Southern California Seismic Network
Yan and Clayton, 2006
Crustal Thickness From Surface Waves
Yang and Forsyth, 2005
NARS-Baja / RESBAN Array
April, 2002 – April, 2007
http://www.data.scec.org/NARS-Baja/
Receiver Functions – Gulf of California
Persaud, Perez-Campos and Clayton, 2005
NARS-Baja Station NE71 – Northern Baja Pennisula
NARS-Baja Stations NE78 & NE79 – Southern Baja Peninsula
NARS-Baja Station NE75 – Central Baja Peninsula
Cross-Peninsula Profile
Lopez-Pineda et al, 2005
I II IIIAlong Peninsula Profiles
Romo, Gomez-Trevino, Esparza, Garcia-Abdesiem, and Flores-Luna, 2003
Electrical Profile
Regional 3D Velocity From Surface Waves and Receiver Functions
DiLuccio, Clayton, Persaud, Perez-Campos, 2005
Rayliegh Wave Group Velocity Dispersion Curves for Four Events
DiLuccio, Clayton and Persaud, AGU, UGM, 2005
3D Regional-scale velocity model for the Gulf of California
DiLuccio, Clayton and Persaud, AGU, UGM, 2005
Gonzalez-Fernandez et al, 2005
The 2002 Gulf of California Seismic Experiment Lizarralde et al
Column
Moho
Top
col 23.456 -117.234 123.0 SAMPLE1 lay 0.0 DEN 2700 VS 3.5 DVS 0.015 VP 5.0 DVP 0.015 TOP lay 5.0 DEN 2700 DDEN 10.0 VS 3.6 VP 6.0 DVP -0.02 lay 8.0 DEN 2800 VS 4.5 VP 7.0 MOHO
Interface Names
Column Description
Column Description
DEN, DDEN - densityVS, DVS - shear velocityVP, DVP - P-wave velocityQS, DQS - S attenuationQP, DQP - P attenuation???? - anisotropy
Parameters
Moho
Top
(lat,lon,z)
SCSN Station JCS – Rapid Variations in Moho
Rayleigh waves
Love waves
7071-R7071-L8081-R8081-L
Initial model
Flow Direction From S-Wave Anisotropy – Rayleigh Vs Love Waves
Noise CorrelationMicroseism – 6 sec – station NE81
Infrasonic – 30-100 sec – NE82
Receiver Functions of Deeper Interfaces
Perez-Campos, Persaud and Clayton, UGM, AGU 2004
Song and Helmberger, 2002