A seismologist (William Leslie) has perfected a machine to predict earthquakes, and finds that one will strike California within 24 hours. But he and his mentor (Tris Coffin) are unable to convince the Governor to declare an emergency. A devastating quake occurs, and then new readings presage additional quakes all over the world. He and his assistant (Kathryn Grant) take his equipment deep into Carlsbad Caverns in hopes determining what is causing the pressure, and discover a volatile mineral previously unknown to science. Kathryn Grant as Laura Hutchinson William Leslie as Dr. David Conway Tristram Coffin as Dr. Ellis Morton Raymond Greenleaf as Gov. Chaney Charles Evans as Gen. Bortes Frank J. Scannell as Sheriff Quinn