Data Processing of Surface Wave Tomography in Australia using Automated Surface Wave Phase-Velocity Measuring System (ASWMS)

Abstract

The Australian continent is divided into tectonic blocks, including Archaean and Proterozoic units in the western and central part, and Phanerozoic units in the eastern part. Surface wave tomography is an effective method of getting information about velocity variations in a particular region. Surface wave tomography was used in this project to map the subsurface of the Australian continent down to a depth of 100 km with the ASWMS (Automated Surface-Wave Phase-Velocity Measuring System). From 2010 to 2015, we gathered waveform data from 767 events and 219 permanent and temporal seismic stations dispersed across Australia. We selected a set of events that has a minimum magnitude of 6. Rayleigh wave extraction and cross-correlation between two nearby stations are among the first processing processes. Following that, the apparent phase-velocity value is calculated using the Eikonal and tomographic inversion. To generate a tomographic map with a true structural phase velocity, each phase velocity data is stacked with amplitude correction. According to current tomographic imaging studies, low-velocity values under Australia tend to be dispersed easterly, with Rayleigh velocity ranging from 3.7 to 3.9 km/s. The tectonic history and evolution of eastern Australia are related to a sequence of orogenic events that are pushing toward the continent’s eastern boundary.