1. Huge underground cavities have opened in the north-western region of the town. 2. At the point of explosion, the nuclear fireball carves out an underground cavity . 3. There's also an underground cavity next to one of the public alleys ." 4. During the Cold War, scientists refined techniques for detecting underground cavities . 5. How quickly an underground cavity near the surface collapses is dependent on various factors. 6. But sophisticated electronic scanning gear has located two suspicious underground cavities that will be further investigated. 7. They probably make use of pre-existing underground cavities , as their legs do not show adaptations for digging. 8. "' Tunnel warfare "'is a general name for war being conducted in tunnels and other underground cavities . 9. While constructing the line in the 1970s, the tunnelers entered an underground cavity of the Neva River. 10. I remember reading about a concept to use nuclear bombs detonated in a deep underground cavity to generate power.
