PyGLImER: A New Modular Software Suite to Image Crustal and Upper-Mantle
Discontinuities Using a Global Database of Ps and Sp Receiver Functions
Abstract
Over the last decades, the receiver function technique has been widely
used to image sharp discontinuities in elastic properties of the solid
Earth at regional scales. To date, very few studies have attempted to
use receiver functions for global imaging. One such endeavour has been
pursued through the project “Global Lithospheric Imaging using
Earthquake Recordings” (GLImER). Building on the advances of GLImER, we
have developed PyGLImER - a Python-based software suite capable of
creating global images from both P-to-S and S-to-P converted waves via a
comprehensive receiver function workflow. This workflow creates a
database of receiver functions by downloading seismograms from selected
earthquakes and analysing the data via a series of steps that include
pre-processing, quality control, deconvolution, and stacking. The
stacking can be performed for common conversion points or single
stations. All steps leading to the creation of receiver functions are
automated. To visualise the generated stacks, the user can choose the
desired survey area in a graphical user interface, and then explore the
selected region either through 2D cross-sections or a 3D volume. By
incorporating results from two independent seismic phases, we can
combine the advantages of both phases for imaging different
discontinuities. This results in an increased robustness and resolution
of the final image. For example, we can use constraints from S receiver
function images, which are multiple-free but relatively low resolution,
to differentiate between real lithospheric/asthenospheric structures and
multiple-induced artefacts in higher-resolution P receiver function
images. Our preliminary results agree with those from recent regional
and global studies, confirming the workflowís robustness. They also
indicate that the new workflow combining P and S receiver functions has
the potential to resolve global lithospheric discontinuities such as the
lithosphere-asthenosphere boundary (LAB) or the midlithospheric
discontinuity (MLD) more reliably than approaches using only one type of
incident phase. PyGLImER will be distributed as open-source software,
providing an easily accessible tool to rapidly generate high-resolution
images of structures in the lithosphere and asthenosphere over large
scales.