Hello from Japan (on behalf of the boyfriend)
Welcome to our world.
http://earthquake.usgs.gov/earthquak...quakes_all.php
Earthquakes happen all the time - they're just too minor to be felt. It is a bit concerning because the USA is in no way prepared for larger earthquakes.
And yes, a 5.8 is very strong. For the unprepared US, yes it is a big one!
Sendai Japan gets magnitude 5.0s very regularly due to the 9.0 shock. I sat through 5 magnitude 5s, a 7 and a 6.3 that was really close to the apartment. I cannot get used to the shaking. It is scary.