Natural disaster (simulated)
A natural disaster was a crisis that occurred due to natural phenomena, as opposed to being caused by a person or unnatural force. One example included the cooling of a planet's core. (TNG: "Inheritance")
Earth had faced many natural disasters, including asteroids, volcanoes and earthquakes. (VOY: "Distant Origin")
In 2258 of the alternate reality, James T. Kirk informed Christopher Pike that the seismic activity and lightning storm occurring on and near Vulcan was not due to a natural disaster, but rather a Romulan attack. (Star Trek)
In 2268, Spock scanned the planet Cheron and found no evidence of a natural disaster having occurred, despite the large number of unburied corpses present in all the planet's cities. (TOS: "Let That Be Your Last Battlefield")
In 2364, though no living individuals were located on Minos, Natasha Yar maintained that all natural disasters had at least some survivors. (TNG: "The Arsenal of Freedom")
In 2366, Beverly Crusher speculated that tricyanate was chosen by a saboteur to contaminate Beta Agni II's water supply because it naturally occurred on the planet, and might therefore appear to be a natural disaster at first glance. (TNG: "The Most Toys")
In 2373, B'Elanna Torres speculated that a natural disaster might be behind the deactivation of a Borg cube. (VOY: "Unity")
The Etanian Order's preferred method of conquest was to simulate a natural disaster, then move in after the planet was evacuated. (VOY: "Rise")