Thunderquakes Reveal Earth's Subsurface
Scientists use thunderquakes to study Earth's subsurface, gaining insights into geology and meteorology.
Introduction To Thunderquakes
Thunderstorms have long been known for their dramatic effects on the atmosphere, but recent research has revealed that they can also produce seismic "thunderquakes" that help scientists see beneath the Earth's surface. These thunderquakes occur when lightning strikes the ground, generating acoustic shock waves that spread beneath the surface. By studying these shock waves, researchers can gain valuable insights into the Earth's subsurface structure.Seismic Imaging With Thunderquakes
Seismic imaging is a technique used to study the Earth's subsurface structure, and it typically relies on seismic waves generated by earthquakes or human-made sources. However, thunderquakes can also be used as a source for seismic imaging, particularly in regions with limited access to traditional seismic sources. Researchers have found that thunderquakes can be applied to seismic tomography with the help of distributed acoustic sensing (DAS), which involves detecting vibrations along optical fibers. By using DAS, scientists can capture crucial seismic waves called air-coupled Rayleigh waves, which can be used to study the subsurface as far as 300 feet below the surface.Capitalizing On Fiber-Optic Cables
The use of fiber-optic cables is a key component of the DAS method, and researchers have found that these cables can be used to detect thunderquakes and study the subsurface. In a recent study, researchers shot a laser beam down a 2.5-mile-long preexisting telecommunications fiber-optic cable buried beneath Penn State University's campus. Over two years, sensors on this cable detected 458 thunderquakes, each producing seismic waves that induced tiny strains along the fiber. This allowed the researchers to see what was going on in the transition from atmospheric acoustic source to a seismic signal in very high resolution.Applications And Future Outlook
The use of thunderquakes for seismic imaging has the potential to open up new opportunities for studying the Earth's subsurface, particularly in areas that don't experience many earthquakes. The abundance of fiber-optic cables, especially in urban areas, makes it possible to expand the range of seismic imaging. Additionally, climate change is projected to increase lightning activity by up to 50 percent by 2100, which could make thunderquake imaging more accessible in the future.Real-World Implications
The ability to study the Earth's subsurface using thunderquakes has significant implications for a range of fields, including geology, meteorology, and environmental science. By gaining a better understanding of the subsurface, scientists can evaluate additional geohazards like sinkholes or landslides, assess groundwater and mining resources, and study volcanoes and magma pockets. The use of thunderquakes for seismic imaging also has the potential to provide valuable insights into the interactions between the atmosphere and Earth's surface.Conclusion And Future Directions
In conclusion, thunderquakes have the potential to be a valuable source for seismic imaging, particularly in regions with limited access to traditional seismic sources. The use of fiber-optic cables and DAS makes it possible to capture high-resolution data on the subsurface, and the abundance of fiber-optic cables makes it possible to expand the range of seismic imaging. As climate change continues to increase lightning activity, thunderquake imaging could become more accessible in the future. Further research is needed to fully explore the potential of thunderquakes for seismic imaging and to develop new methods for studying the Earth's subsurface.Sources
This is an original synthesis by Qivorane based on reporting from the outlets below.