In November 2021, the surface of a road in Mikasa, Hokkaido Prefecture suddenly caved in. A car fell into the large hole that formed, seriously injuring its three passengers. No underground construction work had been going on in the surrounding area, and the accident occurred without warning. Road cave-ins and other types of sinkholes happen not only in Japan but also in cities all over the world. One of the major causes is deterioration from aging pipes underground. Experts warn that multiple factors combine to cause sinkholes. In this program, we'll look at how sinkholes form as well as their countermeasures using the latest technology.
Reporter: Lemi Duncan
Dr. Kuwano using an experiment to demonstrate how sinkholes form under roads
Ground-penetrating radar can detect cavities and utility pipes underground
A 3D map of underground infrastructure based on data from ground-penetrating radar