Using thunder for seismic imaging
Penn State researchers map underground structures using seismic data from lightning strikes.
1Underground exploration with seismic waves
Most of our knowledge about Earth's interior comes from observing seismic waves. These waves travel at different speeds depending on the properties of the rocks they pass through. Solid or semi-molten rock, water content, and fracture networks all affect wave propagation. Collecting data from multiple seismic events allows us to map subsurface layers with remarkable detail.
2Natural and artificial seismic sources
Seismic imaging typically uses natural events like earthquakes. However, artificial seismic waves can also be generated using explosives in specific areas. This method provides on-demand measurements without waiting for natural quakes. Both approaches have limitations in terms of cost and accessibility for continuous monitoring.
3Discovery of thunderquakes
Researchers at Penn State investigated seismic events called 'thunderquakes' caused by lightning strikes. Some lightning energy transfers into Earth's upper crust, creating minor tremors. Until now, these signals were considered too complex to provide useful data for subsurface imaging due to their noisy nature.
4Decoding complex signals
The research team developed a new model capable of analyzing thunderquake signals. Their algorithm successfully filters noise to extract meaningful geological information. During testing, the model accurately mapped underground structures beneath their campus, proving its practical application.
5Advantages of lightning data
Thunderquakes occur naturally and frequently, providing a continuous, cost-free data source. In areas with dense seismic station coverage, this method could offer a more economical and sustainable alternative to traditional techniques, especially for long-term monitoring projects.
6Potential applications
This technology could revolutionize oil and gas exploration, earthquake risk assessment, and groundwater mapping. It may also serve as a new data source for monitoring volcanic activity and other geological phenomena where conventional methods are logistically challenging.
7Technical challenges
Processing thunderquake data requires powerful computing resources and advanced algorithms. Additionally, seasonal variations in lightning activity and its uneven geographical distribution mean this method won't work equally well in all regions, particularly in arid climates.
8New era in geophysics
This research demonstrates how scientific value can be extracted from natural 'noise.' Utilizing thunderquakes for seismic imaging could significantly reduce costs in geophysical surveys while providing unprecedented amounts of data for subsurface characterization.
Original article: Ars Technica - All content — Yıldırımların sismik görüntülemede kullanımı