One other difference between Socal and the PNW is that the risk of earthquakes in Socal has been known for much longer (eg. since at least 1812 in Santa Barbara). Thus building and construction codes have been overall somewhat better. ( I am aware that this is not universally true even in Socal.)

In the PNW, the recognition that the area is subject to even bigger quakes than California has only come in the last decade or so. As a consequence, most of the critical infrastructure in the PNW was not built with any thought whatsoever of withstanding an earthquake. The Japanese quake was a real wakeup call for the PNW. Of any country in the world, Japan was probably the most prepared for earthquakes and tsunamis. The PNW is nowhere near as ready.