Researchers Map 300-Foot Subsurface With 458 Thunderquakes and 2-Mile Fiber-Optic Cable
Updated
Updated · The Conversation · Aug 21
Researchers Map 300-Foot Subsurface With 458 Thunderquakes and 2-Mile Fiber-Optic Cable
3 articles · Updated · The Conversation · Aug 21
Summary
458 thunderquakes recorded over two years let researchers reconstruct underground structure to about 300 feet deep without drilling, using an old telecom fiber in State College, Pennsylvania.
A 2-mile cable was converted into more than 2,100 vibration sensors through distributed acoustic sensing, allowing the team to capture air-coupled Rayleigh waves generated when thunder's shock energy hit the ground.
Four slow-wave "weak zones" emerged beneath the test site; two match areas where satellite radar already shows active ground subsidence, consistent with fractures, voids or water in karst rock.
The approach could offer a cheaper way to monitor sinkholes, groundwater movement and contamination because buried fiber is widespread and thunderstorms provide a natural seismic source.
Researchers say the same atmosphere-to-ground process could also be tapped from sonic booms, volcanic eruptions or meteor airbursts, and potentially even on Titan.