Earthquake sensors can help forecast how hurricanes intensify

Stanford researchers have unveiled a novel method to utilize earthquake sensors for predicting hurricane intensification. Their groundbreaking study, published in Science on August 6, demonstrates how specialized microphones and seismometers can offer valuable insights into hurricanes' behavior and evolution. This discovery emerged after Hurricane Isaac made landfall in Louisiana in 2012, passing over geophysically monitored areas.

Research lead author Qing Ji, who conducted the study as a doctoral student under Eric Dunham at Stanford University, emphasizes that these geophysical instruments can significantly enhance our understanding of hurricanes. The seismometers detect ground movements, pinpointing hurricane landfall, while infrasound microphones capture low-frequency sound waves to monitor atmospheric pressure changes.

The study's findings extend beyond hurricanes, potentially revolutionizing the way we study various atmospheric phenomena, particularly those generating strong winds. Dunham, the study's senior author, highlights the unexpected connection between geophysics and atmospheric science, underscoring the study's significance.

Hurricanes, typically spanning 300-400 miles in diameter, travel thousands of miles, drawing energy from warm ocean waters. They swirl around a calm, low-pressure eye surrounded by a band of intense wind and rain known as the eyewall. Studying the boundary layer, the region closest to the ground where turbulent winds, rain, and storm surges occur, is crucial for forecasting hurricane intensity.

Traditionally, meteorologists rely on aircraft, ocean buoys, wind measurement towers, and radar to gather boundary layer data. However, these methods have limitations, such as capturing only near-surface readings or providing only snapshots of the boundary layer. Moreover, aircraft flights can pose risks to pilots.

The researchers took advantage of the underutilized seismic sensors installed in Louisiana for a different geophysical project. During Hurricane Isaac, these sensors captured valuable data, as the storm passed over them. The researchers found that the seismometers were not overwhelmed by distant seismic waves but were highly sensitive to local turbulence within a few kilometers of the storm's path.

By incorporating infrasound recordings, the researchers obtained continuous measurements of turbulent pressure fluctuations in the boundary layer. The combined dataset confirmed the storm's calm eye and intense eyewall, aligning with conventional boundary layer data. This successful study validates this innovative approach and opens up new possibilities for using such data in atmospheric science.