If there is going to be a disaster of any scale in your story you need to remember the victims. In any real world situation where an area is heavily affected by destruction, droughts, floods, or war there will be victims. This means that when your characters successfully escape a collapsing building during an earthquake they should be able to see other people doing the same. Having these minor characters can add a lot of impact to your story and move the focus away from your main characters which is something you want to do when you want the story to be about the world more than the characters.
Victim characters don’t just have to be minor characters, they can be major characters as well. They tend to have darker backstories than other characters as well as stronger motivations. They can potentially quicken the flow of the plot. But victim characters can also not have stronger motivations than other characters. Their motivations may instead be weaker, or rather stronger but in the opposite direction due to feelings of fear, hopelessness, and embarrassment.
Finally be careful not to trivialize the plights of these characters because there will unfortunately always be people who can relate to what the characters have been through.