Big Lizard: At the Garbage Dump, burn 100 tons of garbage inside an Incinerator
Earthquake: Mine 100 tons of coal (or ore)
Meteor Strike: Get 200 tourists at an Airport in one day
Tornado: Have a combined number of 24 Wind Turbines and Wind Power Plants
UFO Encounter: Ship a resource to a Space Center Great Work
Zombie Attack: Get a Diagnostic Lab to a Hospital and have 15 Sims die in a single day
Although these SimCity 2013 disasters are fun to watch, they will cause a lot of damage, so think twice before unlocking them willingly. A good idea might be to do it in the Sandbox game mode and not in your main city where you can’t save and load and undo the havoc.