Each commercial launch license handed out by the FAA requires the user to have an approved mishap plan in place detailing what should happen in the event of an issue arising during a launch, and so the FAA's move to halt Starship launches is both inevitable and predictable.

The FAA has said they have to confirm that "any system, process, or procedure related to the mishap does not affect public safety" before Starship can fly again. SpaceX will also have to complete additional "environmental mitigations" before a second launch attempt, due to "debris entering adjacent properties."

This procedure will take many weeks or a few months.

SpaceX is planning to install a massive water-cooled steel plate beneath a repaired launchpad over the next 1-2 months.

This would prevent the massive engines from again blasting a large crater and spreading large boulders and debris.

What happens if a mishap occurs?
The FAA requires all licensed commercial space transportation operators to have an FAA-approved mishap plan containing processes and procedures for reporting, responding to, and investigating mishaps (14 CFR 450.173).