A 6.4 magnitude quake will bring down an unreinforced
masonry building [brick, unreinforced quarrystone].

A steel-girder skyscraper will be safe inside, but if you
are on the streets nearby there is danger of falling
window-panes [one windowpane falling from at least a five-story
height will cut you in half].

If you are in a well-built, wood-frame house there should be no problems,
outside of some scary moments.

What about freeways and other roadways?

A 6.4 mag quake could open up big-cracks in the asphalt or concrete roadbeds, causing
vehicles to sustain damage or, worse, ending up in pile-ups [worse, if tanker trucks
are involved hauling dangerous volatiles]

Such a quake 'could' bring down an overpass, but I understand
that the California government has reinforced most if not
all overpasses since the 1989 & 1994 quakes....So you
"should" be safe driving on or under an overpass.
[Of course I haven't initimately followed California local politics since last visiting in 1990.]

What about LA's so-called subway from downtown LA to both Long beach
and Hollywood?
I don't know...There's a risk that the tunnels may collapse...I'm not sure.

So, my California friends! Stock up on those beans, batteries, band-aids & bottled water
[and if you live in the big-cities, bullets too]

Jacob

"This planet has a 100 percent mortality rate."