Models of crustal thickness for South America from seismic refraction, receiver functions and surface wave tomography

2013 ◽  
Vol 609 ◽  
pp. 82-96 ◽  
Author(s):  
Marcelo Assumpção ◽  
Mei Feng ◽  
Andrés Tassara ◽  
Jordi Julià
Keyword(s):  
Surface Wave ◽  
South America ◽  
Seismic Refraction ◽  
Crustal Thickness ◽  
Receiver Functions ◽  
Surface Wave Tomography ◽  
Wave Tomography

scholarly journals The lithosphere-asthenosphere boundary observed with USArray receiver functions

2012 ◽  
Vol 4 (1) ◽  
pp. 1-31 ◽  
Author(s):  
P. Kumar ◽  
X. Yuan ◽  
R. Kind ◽  
J. Mechie
Keyword(s):  
Surface Wave ◽  
Receiver Function ◽  
The United States ◽  
Receiver Functions ◽  
Function Technique ◽  
Surface Wave Tomography ◽  
Entire Area ◽  
S Receiver Function ◽  
The Usa ◽  
Wave Tomography

Abstract. The dense deployment of seismic stations so far in the western half of the United States within the USArray project provides the opportunity to study in greater detail the structure of the lithosphere-asthenosphere system. We use the S receiver function technique for this purpose which has higher resolution than surface wave tomography, is sensitive to seismic discontinuities and has no problems with multiples like P receiver functions. Only two major discontinuities are observed in the entire area down to about 300 km depth. These are the crust-mantle boundary (Moho) and a negative boundary which we correlate with the lithosphere-asthenosphere boundary (LAB) since a low velocity zone is the classical definition of the seismic observation of the asthenosphere by Gutenberg (1926). Our S receiver function LAB is at a depth of 70–80 km in large parts of westernmost North America. East of the Rocky Mountains its depth is generally between 90 and 110 km. Regions with LAB depths down to about 140 km occur in a stretch from northern Texas over the Colorado Plateau to the Columbia Basalts. These observations agree well with tomography results in the westernmost USA and at the east coast. However, in the central cratonic part of the USA the tomography LAB is near 200 km depth. At this depth no discontinuity is seen in the S receiver functions. The negative signal near 100 km depth in the central part of the USA is interpreted by Yuan and Romanowicz (2010) or Lekic and Romanowicz (2011) as a recently discovered mid lithospheric discontinuity (MLD). A solution for the discrepancy between receiver function imaging and surface wave tomography is not yet obvious and requires more high resolution studies at other cratons before a general solution may be found. Our results agree well with petrophysical models of increased water content in the asthenosphere, which predict a sharp and shallow LAB also in continents (Mierdel et al., 2007).

scholarly journals Swave velocity structure in southwest China from surface wave tomography and receiver functions

2014 ◽  
Vol 119 (2) ◽  
pp. 1061-1078 ◽  
Author(s):  
Weilai Wang ◽  
Jianping Wu ◽  
Lihua Fang ◽  
Guijuan Lai ◽  
Ting Yang ◽  
...  
Keyword(s):  
Surface Wave ◽  
Southwest China ◽  
Velocity Structure ◽  
Receiver Functions ◽  
Surface Wave Tomography ◽  
Wave Tomography

scholarly journals The lithosphere-asthenosphere boundary observed with USArray receiver functions

Solid Earth ◽  
2012 ◽  
Vol 3 (1) ◽  
pp. 149-159 ◽  
Author(s):  
P. Kumar ◽  
X. Yuan ◽  
R. Kind ◽  
J. Mechie
Keyword(s):  
Surface Wave ◽  
Receiver Function ◽  
The United States ◽  
Receiver Functions ◽  
Function Technique ◽  
Surface Wave Tomography ◽  
Entire Area ◽  
S Receiver Function ◽  
The Usa ◽  
Wave Tomography

Abstract. The dense deployment of seismic stations so far in the western half of the United States within the USArray project provides the opportunity to study in greater detail the structure of the lithosphere-asthenosphere system. We use the S receiver function technique for this purpose, which has higher resolution than surface wave tomography, is sensitive to seismic discontinuities, and is free from multiples, unlike P receiver functions. Only two major discontinuities are observed in the entire area down to about 300 km depth. These are the crust-mantle boundary (Moho) and a negative boundary, which we correlate with the lithosphere-asthenosphere boundary (LAB), since a low velocity zone is the classical definition of the seismic observation of the asthenosphere by Gutenberg (1926). Our S receiver function LAB is at a depth of 70–80 km in large parts of westernmost North America. East of the Rocky Mountains, its depth is generally between 90 and 110 km. Regions with LAB depths down to about 140 km occur in a stretch from northern Texas, over the Colorado Plateau to the Columbia basalts. These observations agree well with tomography results in the westernmost USA and on the east coast. However, in the central cratonic part of the USA, the tomography LAB is near 200 km depth. At this depth no discontinuity is seen in the S receiver functions. The negative signal near 100 km depth in the central part of the USA is interpreted by Yuan and Romanowicz (2010) and Lekic and Romanowicz (2011) as a recently discovered mid-lithospheric discontinuity (MLD). A solution for the discrepancy between receiver function imaging and surface wave tomography is not yet obvious and requires more high resolution studies at other cratons before a general solution may be found. Our results agree well with petrophysical models of increased water content in the asthenosphere, which predict a sharp and shallow LAB also in continents (Mierdel et al., 2007).

scholarly journals Surface wave tomography: global membrane waves and adjoint methods

2007 ◽  
Vol 171 (3) ◽  
pp. 1098-1117 ◽  
Author(s):  
D. Peter ◽  
C. Tape ◽  
L. Boschi ◽  
J. H. Woodhouse
Keyword(s):  
Surface Wave ◽  
Surface Wave Tomography ◽  
Adjoint Methods ◽  
Wave Tomography
Sign in / Sign up

Export Citation Format

Share Document