Full-Waveform Inversion of the Middle East and Its Surrounding Region

Session: Full-Waveform Inversion: Recent Advances and Applications [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

High resolution seismic images of the crust and mantle beneath regions of complex surface geological structures are necessary to gain insights on the geodynamical processes that drive plate tectonics forging these geological structures. One such region embodying various plate boundary motions and intraplate deformations is the Middle East and consequently the region is prone to significant seismic activity. Hence it is of much practical value to generate high resolution elastic P- and S-wavespeed models for the area bounded by longitudes 22E–66E and latitudes 8N–48N, to not only fine-tune our knowledge on the geological process but also to improve the ability to locate and characterize regional earthquakes more accurately. For the tomographic modeling we incorporate an adjoint method of full-waveform inversion that is well established and has become a routine tool in regional- to continental-scale earthquake seismology and has recently been applied at the scale of globe. We initiate our inversions with the first-generation global adjoint tomography model GLAD-M15 (Bozdag et al., 2016) which has transverse isotropy confined to the upper mantle. The observed data constitute 3-component seismograms of 100–150 events located and recorded within the region, carefully selected for the clarity of source time function, optimally even ray path coverage and quality controlled for signal to noise ratio. The inversion process adopts a double-difference (Yuan et al. 2016, Orsvuran et al., 2020) misfit function for the observations and synthetics. Forward and adjoint simulations are performed by the SPECFEM3D_GLOBE package (Komatitsch & Tromp 2002). In parallel to the full-waveform tomography, we attempt to search for a regional model that best fits P-wave arrival times from ISC-EHB catalogue. In a later stage the goal is to jointly invert the arrival-time and full-waveform data as a way of optimizing the use of seismic data from the sparse event/station distribution of the region.

Presenting Author: Susini Desilva

Authors