In late 1990s, a Buffalo physicist proposed using shock waves to detect plastic land mines costing as little as $1. Years later, the idea remains a striking approach to a detection problem that defeats metal detectors

Plastic land mines are difficult to find because metal detectors may miss them entirely. Researchers at the University at Buffalo explored a different approach using weak shock waves sent through soil. Their computer simulations showed that buried objects could send back distinctive acoustic signals. Those reflected waves may reveal an object's size, shape and density. The research could offer a cheaper path toward detecting dangerous nonmetallic land mines.

Raccontata daeconomictimes.indiatimes.com