Core Mantle Boundary Imaging underneath the North Atlantic Ocean using Teleseismic Noise Correlations
Lise Retailleau, Stanford University
Wednesday, August 23, 2017 at 10:30 AM
- Building 3, Rambo Auditorium
Correlations of ambient noise have been shown to be a useful tool for imaging Earth structure at a wide range of scales. Correlation functions are particularly useful on area not sampled by earthquake data. While noise based analyses were previously made with surface waves, body waves can also be extracted from correlation function even at teleseismic distances.
In this study, we analyzed the P-wave phases that travel under the North Atlantic Ocean between the US and Europe. We exploit the large set of data deployed in these regions, choosing year 2014 since the Transportable Array (USArray) was located in the Eastern part of the US. The final dataset contains roughly 900 stations distributed on both sides of the ocean.
The PcP phase reflected at the Core Mantle Boundary is particularly well reconstructed in the mid-period range (3-8 seconds) between distant arrays. We use a vespagram analysis on a set of sub-networks and compare the relative PcP to P phase arrivals with traveltime predictions to compute an image of the Core Mantle Boundary under the Northern Atlantic Ocean.