Dear XXX,
 
Thank you for your note of concern. Luckily, all of my family and friends are safe. It was a pretty scary event, though.
 
 I was awakened by an emergency alert email in the middle of the night -- at 3.08 a.m. The 6.7-magnitude quake was so big that it felt like being dropped from a high place. I got out of bed and tried to find out what was happening on TV but couldn't because there was an electrical blackout.
 
The electricity is not back yet so I'm getting news on a battery-powered radio for now. Text communication works on the smart phone so you can get in touch with me through digital communication.
 
Anyway, thank you for your friendship. I appreciate your concern. I'll write again to give you updates.

Regards,
[your name]