From what I've heard, these earthquakes along the Pacific - first in South America, now in Japan - make it more likely that there will also be a significant earthquake along the US West Coast since that is the only area along those plate boundaries that hasn't been affected yet.
I'm extremely far from being knowledgeable about this, but it makes sense...
See this Newsweek article (
http://www.newsweek.com/2011/03/13/the-scariest-earthquake-is-yet-to-come.html) for that argument. Though it seems like the scientific community thinks this is nonsense (
http://www.lifeslittlemysteries.com/bogus-claim-japan-earthquake-trigger--1488/). Anyone know more about plate tectonics?
First of all, stay away from the tabloids, AKA Newsweek, when searching for scientific knowledge. I didn't read your first link but did read the 2nd link.
Bang, Briggs, Williams as quoted in the article indicates that they are still guessing. Years ago it was the Garlock Fault rift zone, then it was the "Palmdale Bulge", then it was Parkfield as primary strain indicators used to detect what was happening along the San Andreas. Then things like the Whittier Narrows fault opened up and they USGS went WTF? Now it's the Rogers/Hayward Fault complex.
I know a thing or two about the geology because it was my major in college and because I lived close to the fault. My thesis was Regional Metamorphism in the Coastal CA Tranverse Ranges with an emphasis on the Franciscan Melange. I also had some articles submitted to and passed review but not published in CA Geology, a trade pub. The melange and transverse folding are only two of some very complex results of seismic activity. That no less than H. Kenneth Tsu remained mystified by the Fran. melange is indicative of it's complexity. The rocks tell a story, but the task is to learn the language it is written in.
As they say, seismic events on one "corner" of the plate effects only a very localized area. However, there is something peeps need to understand; the USGS, like any other govt agency, is influenced by political pressure (research funding, etc) therefore suspect. Also, given the alarmist perception in the gen'l public, they better be damned sure when they release information for dessimination to the public. Too, the USGS has been damned for being wrong. The gist is, they have very strong motivation to remain silent until certainty is absolutely proven. This silence sometimes takes the form of denying certain phenomena or events until they actually occur. In this case, denying that large scale boundary shifts are impacted by large magnitude quakes is because without certainty, they can not make a statement. And since everyone looks to the USGS or Zurn for the answers, it is prudent to deny speculation.
Now if one were to form a hypothesis on how a large quake on the island arc of Japan could trigger a quake on the NA west coast, they better include such 'minor' events as a devastating quake on the Tongan island arc trench. Or subsidence at Mendocino Ridge. (BTW: What the hell happened to the Juan de Fuca tectonic plate?)
Bottom Line: no one knows to any significant certainty. No doubt there is some very interesting research being accomplished yet after all this, we are no closer to knowing than at any time in the past.