The Night the World Exploded(1957)

With his assistant, Laura Hutchinson (Kathryn Grant), Dr. David Conway (William Leslie) develops a device to advance the fledgling science of earthquake prediction. After forecasting a large temblor that will rock California within twenty-four hours, Conway cannot persuade the Governor to act. When the prediction proves true and further tests indicate that there are more quakes to come, Conway and Laura seek to perfect their device. Subsequent tests deep within Carlsbad Caverns discover an unknown element-E-112-that is responsible for the earthquakes and threatens to destroy the globe if it ever reaches the surface. The team determines that in only four weeks until Armageddon, the race is on to neutralize the killer element before it takes a devastating toll.