Abstract Regularization of seismic inversions has a strong imprint on tomographic images. We analyze recorded and spectralâelement S, Sdiff, and SS waveforms to evaluate the benefit of bodyâwave amplitudes in global tomography. Lâcurve analysis for S40RTS models with recorded and synthetic waveforms show that SSâS traveltimes and SS/S amplitude ratios have minima within the same damping parameter range. SS/S ratios for S40RTS and model GLADâM25 show the tradeâoff between scaleâlength and strength of lowermostâmantle heterogeneities. The recorded SS/Sdiff ratios are lower than predicted by 3D mantle models which may be explained by a decrease in the mean shear velocity by âź1% ${\sim} 1\%$ at the lowermost 200 km of the mantle. Our results suggest that SS/S amplitude measurements made with 3D waveforms can be used to constrain damping in linearized inversions, and amplitudes are essential for studying the size of heterogeneities.
Observations from the Little Bunker
Last updated: October 16, 2025 04:11 AM
Atmospheric COâ
424.4 ppm
+18.2
ppm/year
Atmospheric CHâ
1933.54 ppb
+12.29
ppb/year
Global Temperature
+1.48 °C
Peak: +1.73°C
World Population
8.1 billion
+67
million/year