On the P and S Receiver Functions Used for Inverting the One-Dimensional Upper Mantle Shear-Wave Velocities

AbstractSurface velocity measurements show that the Middle East is one of the most actively deforming regions of the continents. The structure of the underlying lithosphere and convecting upper mantle can be explored by combining three types of measurement. The gravity field from satellite and surface measurements is supported by the elastic properties of the lithosphere and by the underlying mantle convection. Three dimensional shear wave velocities can be determined by tomographic inversion of surface wave velocities. The shear wave velocities of the mantle are principally controlled by temperature, rather than by composition. The mantle composition can be obtained from that of young magmas. Application of these three types of observation to the Eastern Mediterranean and Middle East shows that the lithosphere thickness in most parts is no more than 50-70 km, and that the elastic thickness is less than 5 km. Because the lithosphere is so thin and weak the pattern of the underlying convection is clearly visible in the topography and gravity, as well as controlling the volcanism. The convection pattern takes the form of spokes: lines of hot upwelling mantle, joining hubs where the upwelling is three dimensional. It is the same as that seen in high Rayleigh number laboratory and numerical experiments. The lithospheric thicknesses beneath the seafloor to the SW of the Hellenic Arc and beneath the NE part of the Arabian Shield are more than 150 km and the elastic thicknesses are 30–40 km.

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ULTRASONIC SHEAR‐WAVE VELOCITIES IN ROCKS SUBJECTED TO SIMULATED OVERBURDEN PRESSURE

Geophysics ◽

10.1190/1.1439065 ◽

1962 ◽

Vol 27 (5) ◽

pp. 590-598 ◽

Cited By ~ 10

Author(s):

M. S. King ◽

I. Fatt

Keyword(s):

Shear Wave ◽

High Pressures ◽

Applied Pressure ◽

Ultrasonic Energy ◽

Overburden Pressure ◽

Wave Velocities ◽

Shear Wave Velocities ◽

Ultrasonic Equipment ◽

The One ◽

Ultrasonic Shear

Ultrasonic equipment has been developed to measure shear‐wave velocities in small rock samples at hydrostatic pressures up to 2,400 psi. Under certain optimum conditions dilatational wave velocities can also be determined. The method employs a beam of ultrasonic energy passing through a liquid in which a quarter‐inch‐thick parallel‐sided sample of rock is rotated. From the laws of classical optics for the refraction and reflection of waves at boundaries between dissimilar media and the known velocity of sound in the liquid, the velocities in the sample may be calculated from a record of ultrasonic energy transmitted through the sample as a function of angle between the sample and the ultrasonic beam. Results obtained with this apparatus from samples of materials for which the velocity of waves has been published show good agreement with the latter. The variation of the velocity of shear waves in dry rocks with applied hydrostatic pressures up to 2,400 psi have been measured for seven sandstones, a chalk, and a limestone. The shear‐wave velocities were found to increase with an increase of the applied pressure. For five of the sandstones the increase in velocity at high pressures approached the one‐sixth power of the applied hydrostatic pressure predicted theoretically for a sphere pack model.

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Shear wave velocities in the upper mantle of the Western Alps: new constraints using array analysis of seismic surface waves

Geophysical Journal International ◽

10.1093/gji/ggx166 ◽

2017 ◽

Vol 210 (1) ◽

pp. 321-331 ◽

Cited By ~ 10

Author(s):

Chao Lyu ◽

Helle A. Pedersen ◽

Anne Paul ◽

Liang Zhao ◽

Stefano Solarino ◽

...

Keyword(s):

Surface Waves ◽

Shear Wave ◽

Upper Mantle ◽

Western Alps ◽

Array Analysis ◽

Wave Velocities ◽

Shear Wave Velocities ◽

Seismic Surface Waves

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Shear wave velocities in the Pampean flat-slab region from Rayleigh wave tomography: Implications for slab and upper mantle hydration

Journal of Geophysical Research Atmospheres ◽

10.1029/2012jb009350 ◽

2012 ◽

Vol 117 (B11) ◽

pp. n/a-n/a ◽

Cited By ~ 27

Author(s):

Ryan Porter ◽

Hersh Gilbert ◽

George Zandt ◽

Susan Beck ◽

Linda Warren ◽

...

Keyword(s):

Rayleigh Wave ◽

Shear Wave ◽

Upper Mantle ◽

Flat Slab ◽

Wave Velocities ◽

Shear Wave Velocities ◽

Wave Tomography ◽

Rayleigh Wave Tomography

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A Note on the Influence of Site Conditions on Ground Motion Values Observed for the Southeastern Illinois Earthquake of June 10, 1987

Seismological Research Letters ◽

10.1785/gssrl.64.2.149 ◽

1993 ◽

Vol 64 (2) ◽

pp. 149-156

Author(s):

M. Zhang ◽

R. Street ◽

J. Harris ◽

V.P. Drnevich

Keyword(s):

Ground Motions ◽

Soil Column ◽

Quantitative Description ◽

Response Analysis ◽

Site Conditions ◽

Sh Wave ◽

One Dimensional ◽

Wave Velocities ◽

Shear Wave Velocities ◽

The One

Abstract Site conditions (i.e., depth to bedrock and intermediate horizons within the soil column, and the shear wave velocities of-the soils and bedrock) have been investigated using and SH-wave velocity data at eight sites in Illinois and Indiana where the June 10, 1987, southeastern Illinois earthquake was recorded on blast monitors. The site effects have been calculated using the site conditions and the one dimensional response analysis program WAVES (Hart and Wilson, 1989), and it was found that the site conditions caused the peak particle accelerations to be amplified by a factor of 2.7 to 4.8. It is suggested that the records of ground motions obtained at sites not on rock be considered inadequate for usage at other sites unless accompanied by a quantitative description of the site conditions.

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