Well, in my opinion, this is why you have insurance.
If you are in an earthquake bad enough to cause the damage
you describe, you probably are going to have a lot of other 
things shattered as well. 
Plexiglass doesn't hold up that well if the house falls 
on it. ;_;
I personally have some cels framed in plexi, others in glass.
And all of it is covered under my insurance policy.
Here's hoping none of us will ever have to make a claim.
Ryochan