Some seismic data images, and more!

Some plots showing seismic data used to probe the Earth's interior (return to image directory page)
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SH (blue) and SV (red) components of ScS and S or Sdiff are used to study seismic anisotropy in the deep mantle. If the data are abundant and clean, this permits interpretation of deep mantle convection currents. [PDF]	The sometimes presence of an arrival between direct S and core-reflected ScS waves, called Scd (or SdS) provides direct evidence for a reflector above the CMB, and is the primary evidence for a D" layer. [PDF]	Differential analyses between ScS and S, as well as S(or Sdiff) and SKS, yield valuable information on deep mantle heterogeneity and anisotropy.  These waves are used in forward and inverse modeling. [PDF]	In some locations on the CMB, ultra-low velocity wave speeds have been detected.  Here, SPdKS is shown as delayed (red line) relative to predictions (blue line). The low velocities may be due to partially molted mantle. [PDF]	A variety of important seismic arrivals are present on the SV component of motion in the distance range from 90 to 130 degrees. Here they are compared to synthetic seismogram predictions on the left. [PDF]

Some plots showing seismic data used to probe the Earth's interior (return to image directory page)
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Azimuthal anisotropy in D" can give rise to coupling between the SH and SV components of the S wave. Here we present several regions that show such behavior. [PDF]	Station FCC of the Canadian network is shown, both in velocity (top panels) and displacement (bottom) panels. The SV precursory pulse is easily visible in the latter. [PDF]	Array analyses of seismic data permit the sometimes observability of very faint seismic waves, like PKIIKP, which reflects from the inside of the inner core. [PDF]	Again, using seismic arrays, a wave reflected from the underside of the CMB is seen as it diffracts at the CMB, called PKKPab_diff. This wave can be used to study ULVZ structure.	For decades, S waves referenced to SKS have been useful for mapping both deep mantle heterogeneity and anisotropy.  Here, shear wave splitting is investigated. [PDF]

Some plots showing seismic data used to probe the Earth's interior (return to image directory page)
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Here we see a vertical component seismogram from Pasadena CA of a deep Fiji earthquake filtered different ways. The three arrivals are P, pP, and sS.	Here are some array recordings of ScP at the ASAR short period seismic array in Australia. Many times there is a precursor in front of ScP indicating the presence of fine layering just about the CMB. [PDF]	Here is another example of ScP array recordings, this time at the Warramunga (WRA) array, in Australia. These data argue for a very localized ULVZ that is partial melt in origin. [PDF]	Array analyses permit detection of otherwise difficult to detect energy. Here, we see an S wave converted to a P-wave some 900+ km into the mantle. The figure on the left is a "vespagram". "Slowness" equates to arrival angle. [PDF]	PKP is a seismic P-wave that penetrations deep into the core of the Earth. It is often referenced to a diffracted P-wave (Pdiff). This image shows some physical scale aspects of the pair of waves. [PDF]