In the animated series, the artificial intelligence that ran all of the systems on the planet knew of the impending apocalypse, but obscured the data from the people. If the people knew, they would use all of the AI's resources to try and solve an unsolvable problem - and the AI needed those resources to devise an escape strategy for itself.
There's a logic to it. The computer knew that the people couldn't be saved in time, but knew that it could save itself and did so. This wasn't entirely selfish either - the AI held the records, history, art and science of the Kryptonian civilisation, and reasoned that if it survives, then not all of Krypton will be lost.
After the destruction of the planet, a
group of poor aliens survey the devastation, and find the computer core. It promptly expands its AI into the ship's hardware, kills the crew and uses the vessel to escape.
I don't know if that's "canon" or whatever, but I liked it and internalised it.