"When it came to making “Escape from LA,” Carpenter had a budget of around $50 million to work with. But while he and Russell had more time and money, Carpenter said he had the hardest time writing the screenplay for it because he felt that everything he was writing was “bullshit.” What got him to revisit Snake Plissken was that Russell was so keen on playing the character again, and they solved their script problem by moving the action to Los Angeles which was in a constant state of denial with all the earthquakes and natural disasters occurring there. They simply took the same scenario of the original movie and updated it to reflect the current state of the city while filming."
January 1, 1970
https://en.wikiquote.org/wiki/Escape_from_L.A.