Good surface vibrations help unearth resources
CSIRO’S Deep Earth Imaging future science platform team is developing the next generation of tools to craft models of the complex geology that lies deep beneath the surface.
To do this, they use as many sources of geoscientific information as possible – including electromagnetic, gravitational and seismic datasets.
Different geophysical methods will give different clues about what’s below the surface and combining them can give researchers even more information.
But finding meaningful information from the vast amount of data is challenging.
As part of the Deep Earth Imaging team, CSIRO postdoctoral fellow Cericia Martinez, is automating two dimensional (2D) seismic velocity models from seismic data to better understand Australia’s crustal geology and build a picture of the subsurface.
“We can’t always go and dig or drill a hole to figure out what’s in the subsurface, but we can use physics and maps and data to help us do that,” Dr Martinez said.
“One way we can understand what is beneath the surface is to look at how seismic vibrations travel in the subsurface.
“Just like my voice travels through the air via sound waves, seismic waves travel through rocks in the Earth’s crust.”
By sending a vibration into the Earth and measuring the time that it takes for a wave to travel through the subsurface from one location on Earth to another location on Earth, Dr Martinez says we can start to try to understand what lies hidden beneath us.
Because rocks and other subsurface features have different properties and densities, seismic waves travel at different velocities and are subject to other physical properties of waves such as reflection and refraction.
Dr Martinez has been mining the data acquired from seismic transects across the continent done by Geoscience Australia.
Her research focuses on looking at seismic travel-time data – the time it takes for seismic waves to travel through the subsurface – to identify the probable crustal architecture and geological features below.
Dr Martinez says that seismic velocity data can help to identify different subsurface features and geological units – such as water, oil and gas reservoirs and orebodies.
But there’s a problem with this data: there’s a huge volume of it, it’s very complex, and analysis of it requires lots of time and effort from experts who have very specialised skills-sets and domain knowledge.
Dr Martinez’s research incorporates geology, physics, mathematics and computer science to develop a new geophysical inversion algorithm for seismic travel-time data.
She is focusing on increased automation, classification and modelling to take away some of the time-consuming tedium of wrangling raw seismic data.