3D and 5D reconstruction of P receiver functions via multichannel singular spectrum analysis (MSSA) for seismic structure mapping of the mantle transition zone
Abstract
Receiver functions are routinely used to obtain an estimate of the Earth's reflectivity at the crust and mantle. Single stations can represent gathers of receiver functions by a 3D data array that depends on time, distance and back-azimuth of events. Similarly, 5D arrays describe a group of stations where the two added spatial variables are the x-y coordinates of each station. In both cases, these multidimensional arrays contain complete information on the depth and impedance of the crust and mantle interfaces. However, these multidimensional arrays more often than not contain unrecorded data due to less than ideal coverage. Our work adopts multidimensional signal processing to robustly recover and denoise 3D and 5D volumes of P receiver functions simultaneously and enhance secondary conversions from the mantle transition zone. We apply our recovery algorithm to the USArray data from the Yellowstone area and efficiently recover the correct timing and polarity of mantle conversions from the 410- and 660-km seismic discontinuities, which is consistent with previous reports from this area. We find no evidence of the 520-km discontinuity in the Yellowstone region, but instead, observe a robust negative arrival within the depth range of 580-km to 610-km. This negative phase may result from an increase in water content, accumulated old oceanic material or plume residuals. Overall, our analysis shows that working with more spatial dimensions increases data redundancy, which is conducive to signal recovery. The preconditioning of the data enhances seismic records and considerably increases our ability to visualize and characterize known and suspected mantle interfaces.
- Publication:
-
AGU Fall Meeting Abstracts
- Pub Date:
- December 2019
- Bibcode:
- 2019AGUFM.S23A..06R
- Keywords:
-
- 7208 Mantle;
- SEISMOLOGY;
- 7218 Lithosphere;
- SEISMOLOGY;
- 8103 Continental cratons;
- TECTONOPHYSICS;
- 8110 Continental tectonics: general;
- TECTONOPHYSICS