The Great Earthshake (as called by the dinosaurs) was a huge earthquake that occurs in the first act of The Land Before Time. According to the Narrator it was created by two continents coliding. It took place at dawn and separated and killed many herds, including the main character's. It created a huge crack called the Great Divide, leading down to the "Big Underground". Many dinosaurs fell down the cracks, among them Sharptooth. Littlefoot and Cera nearly fell as well but Littlefoot's Mother saved them. There was also a stampede of Saurolophus, Parasaurolophus, Eudimorphodon, Ornithomimus, Dimetrodon grandis, and Velociraptor. By the earthshake's climax, one side of the divide started slowly rising up, separating herds everywhere. Among the dinosaurs stuck on the high portion included Grandma and Grandpa Longneck, Daddy Topps and Cera's mother, (all of whom survived the earthshake), while Littlefoot, Cera and Littlefoot's Mother were trapped on the lower portion.
None of the Land Before Time Earthshakes, including the Great Earthshake, had any onscreen aftershocks.
Creatures fleeing during the Earthshake.
The Earthshake separates Cera from her family.
The land ruined by the Great Earthshake, from a flashback sequence in The Great Longneck Migration