Preliminary Full-Wave Ambient Noise Seismic Tomography Results Along the South American Subduction Margin

Date: 4/25/2019

Time: 06:00 PM

Room: Grand Ballroom

The oceanic Nazca plate subducts beneath the continental South American plate, resulting in arc volcanoes and megathrust earthquakes along the convergent margin. The non-uniform distribution of subduction-related earthquakes reflects possible along-strike slab segmentation. It is therefore desirable for us to investigate what factors contribute to seismic segmentations along the margin. Seismic tomography provides a well-constrained three-dimensional slab geometry both along strike and down dip. In this study we use the finite-difference full-wave simulation and inversion to resolve a high-resolution shear velocity model of the crust and upper mantle within the entire South American subduction system. Our goal is to understand the seismic characteristics of the slab geometry of the South American subduction, and to explore the correlation between the slab geometry, volcanism, and megathrust earthquakes. The vertical components of daily ambient noises between each station pairs are cross-correlated and then stacked in order to extract Rayleigh wave empirical Green’s functions. We will calculate Rayleigh wave phase delays between the empirical Green’s functions and the synthetics. The seismic velocity model will be progressively improved by iteratively minimizing the phase delay times. The preliminary tomographic results will be presented during the meeting.

Presenting Author: Meng Liu

Authors