What magnitude earthquake at what distance warrants an emergency?

Question

Southern California experienced a 5.4 magnitude earthquake 30 miles away from Long Beach. Skid-dish managers triggered an emergency and all buildings were ordered evacuated. I have not seen an emergency evacuation plan which specifies any standards as to what strength earthquake should trigger an emergency call. Any Ideas?

Answer 1

It depends on the depth.  My guess would be about a 4-5 pointer.