My daughter-in-law called me from Camp Pendleton and she said they dismissed it initially thinking it was artillery fire from the Training Grounds except for it was too late in the evening.
On the note of preparation:
As a municipal agency employee we are trained through HSA to be initial responders...in addition, we put on for our church, several training incidents/exercises and provided members with Earthquake Kits sans Glocks, HK's Sigs and ammo. We did tell them that in the event of a major earthquake that it could be up to 3-4 days before they see Emergency Responders based on where they rank on the priority levels.
Soooo, for close family members and neighbors, a second response plan has been generated to prevent our cul-de-sac from resembling NOLA during Katrina...
That along with our prayers for God's protection is what we have done.