6.4 is not big.
9 is big.
You've never been near the epicenter of a 6.4 earthquake; in 1957 I was taking a spelling test at my elementary school when a 5.7 quake interrupted the test. The immediate jolt set some of my schoolmates to cry out as our desks (two at a desk) moved up n& down rather violently, and the hanging lights in the classroom swayed rapidly.
We were less than a mile from that quakes epicenter.
In 1989 I left work and went to a hotel adjacent to the tarmac of a general aviation airport. I parked in the back of the hotel, and as I was parking and listening to the pre game (Oak -SF world series - I was to meet my colleagues to watch the game) my 3/4 ton Dodge Van began to bounce. The radio went to static and as I stepped out of the van, the door to the hotel slammed open and guest ran out of the building.
I looked at the tarmac and could see waves going across the black top, and the light posts swing as if there was a strong wing - there was no wind and very hot afternoon).
We were over 100 miles north of that epicenter near Santa Cruz.
In Aug 2014 I was asleep about 35 miles south of Napa. I was awakened and knew immediately we were having a quake. I awoke my wife with, "L. Earthquake" before I realized the quake was not near the epicenter for it was a rolling one, meaning it was at least a 6. some distance away. We had no damage, but the City of Napa had quite a few properties damaged. That quake was 6.0