Pressure diffusion from high‐volume saltwater disposal wells near the Kansas‐Oklahoma border appears to have contributed to triggering earthquakes as far as 90 km away. Elevated seismicity that began in southern Kansas in 2013 is largely believed to be induced by pore pressure increase from dozens of disposal wells injecting unprecedented volumes. Earthquakes initially occurred in dense swarms near the wells, and in subsequent years migrated into surrounding areas with minimal fluid injection. By 2017, earthquakes advanced 90 km from areas surrounding the high‐volume injection wells into areas with considerable fluid injection volumes but historically consistent rates. Fluid pressure within the injection interval in southern Kansas increased subsequent to high‐volume saltwater disposal in southern Kansas and northern Oklahoma. Temporal pressure trends across central Kansas suggest that fluid migration and pressure diffusion from cumulative disposal to the south likely induced earthquakes much farther than previously documented for individual injection wells.
Geophysical detection of clandestine tunnels is a complex problem that has met with limited success. Multiple methods have been applied, spanning several decades, but a reliable solution has yet to be found. We evaluated shallow seismic data collected at a tunnel test site representative of geologic settings found along the southwestern U.S. border. Our results demonstrated the capability of using P-wave diffraction and surface-wave backscatter techniques to detect a purpose-built subterranean tunnel. Near-surface seismic data were also collected at multiple sites in Afghanistan to detect and locate subsurface anomalies, including data collected over the escape tunnel discovered in 2011 at the Sarposa Prison in Kandahar, Afghanistan, which allowed more than 480 prisoners to escape, and data from another shallow tunnel recently discovered at an undisclosed location. The final example from Afghanistan was the first time surface-based geophysical methods have detected a tunnel whose presence and location was not previously known. Seismic results directly led to the discovery of the tunnel. Interpreted tunnel locations for all examples were within less than 2 m of the actual location. Seismic surface-wave backscatter and bodywave diffraction methods showed promise for efficient data acquisition and processing for locating purposefully hidden tunnels within unconsolidated sediments.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.