Most of the apparent increase in large quakes is attributable to more and better ways of detecting and measuring them. It's difficult to conclude whether there's been an unusual increase, or whether it's a "normal" variation - or even if it's a variation.

What is known is that earthquakes can happen anywhere, anytime, and there's no accepted method for predicting them (other than fundamentalist belief and/or voodoo divination). About all that's certain is that eventually there will be an earthquake at almost any point you wish to choose, and some of them will be huge.

Recent "news" articles have pointed out that the disastrous quake in Japan killed "only" about 20,000 people. The potential would have been more than 200,000 had there been no warning, and if the cities worst hit had not had established evacuation plans with known evacuation routes to identified "safe" places, and most of the people followed instructions promptly.

It has been pointed out that fault lines in the vicinity of the US Northwest coast imply a probability of a similar quake/tsunami event "sometime." Oregon and Washington states have no plans, although a few "radicals" have begun suggesting "maybe we oughta think about it some." There has been some progress in building "quake resistant" structures in parts of the area, but no real thought to responses to tsunamis.

In the Seattle area, it's well known that much of the population lives on a "mudslide" plain that was the result of an eruption of a nearby volcano that's been "dormant" for a time but is still considered "active." (The previous mudslide was recent enough to be known within "native lore" of the current tribes in the area.) As seen with the fairly recent eruption of the smaller St Helens, prompt evacuations to safe places are about the only viable escape, and Renton, in the middle of the prior slide, has no plan for resonding to Mt. Ranier. (Maximum warning could be as short as two hours? - plenty of time.)

There are numerous places in the US where a "6P" plan could be of immense help when an expected disaster might happen, but few places where it might be helpful have a plan.

John