Ok before I go any further let me state my credentials.
I have a Doctorate in Seismology.
I currently work at a well-known university as a seismology researcher.
I have published a number of peer-reviewed articles on a variety of large earthquakes around the world.
Let me clear up a few things:
1) The earthquake was initially reported as being 230km deep - this was later revised to 10km. Hence the confusion. The reason for this is that earthquake *depths* are very difficult to locate because all our seismic stations are on the surface of the earth - it leads to a trade-off between earthquake depth and origin time. As more and better data became available the depth estimate was refined to the current 10km.
2) Realistbear - what evidence do you have to disagree with the view of Scientists from the NEIC? Are you a trained seismologist? Clearly not. You can't just say 'I don't belive you' without offering an explanation why. It's like me asking an Italian to translate something from Italian and then when he comes up with an answer saying 'I don't believe you'. Let me give you some facts: Approximate number of people killed in earthquakes 2001-2010 = 694,948. Number of people killed in earthquakes 1991-200 = 54,520. Ahha you say - clearly there are more earthquakes killing more people. Lert us go back further. Number of people killed in earthquakes 1971-1980 = 362,137. Ahha you say, even that is less than now. Look at these numbers in comparison to total world population, 694,948 = 0.0107% of total population (2001-2010). 362,137 = 0.0089% of total population (1971-1980), not all that different. Go back further, 243,194 killed in 1911-1920 represents 0.0147% of total population a bit more than the modern ratio. There a a lot of graphs that show quite clearly the number of moderate (mag 7 and less) earthquakes globally is relatively constant and is certainly not increasing. This earthquake and the Christchurch earthquake fall into this category. With rising population, obviously more people are going to be exposed to earthquake risk.
3) There has been a cluster of large (mag 8+) earthquakes since 2000 (Japan was one of these). On average, globally, we get one of these every 18 months (averaged back to 1900 when accurate estimations of earthquake size become possible). There have been 13 or 14 since 2000, significantly more than average. However, there was another period during the 1950s and 1960s when a similar concentration occured, and possibly a 3rd cluster at the beginning of the 20th Century. Currently we are not sure if the concentration is anything more than chance, or if there is something that links these very large earthquakes.
4) The poles reversing is something that loads of people prattle on about. Yes, the magnetic pole is moving around by more than historical levels. Yes we are 'overdue' for a magnetic reversal. Does that mean its happening now? Course not. The earth has functioned perfectly well for a very long time, during which, occassionally, unusual events occur, what makes you think that we're suddenly living in this incredibly 'special' time when all these geological events are going to conspire against us and wreak havoc with humankind. Do you realise how ridiculously egocentric that is?
5) Supermoon. The Japan earthquake occurred about a week *before* this event. The fact that the moon is a couple of % closer to us than normal make very very little difference to the earth's crust. The reason the media made such a big deal about this particular approach is that the moon being a couple of % closer co-incided with the timing being at a full moon and the full moon being close to the horizon - both things that make the moon *appear* bigger. Whether its a full moon or not has no effect on the gravitational pull due to it. What happened last time the moon was this close? Nothing. Did the moon being this close cause the earthquake? Absolutely not.
6) Earthquake tax - we're already paying it. When insurers and re-insurers have a bad year they pass on their extra costs to customers. Japanese earthquake leads to large claims on insurers -> re-insurers have to pay out -> re-insurers put up premiums next year to cover costs -> insurers put up premiums to cover extra costs imposed on them by re-insurers -> your car insurance premium goes up next year.
7) Will the big one hit California soon? Maybe, maybe not. No one can predict exactly when and where earthquakes will hit, all we can say is that there is the potential for a large earthquake to hit California. It could happen today, it may not happen for 100 years. There is nothing to suggest that the chances are significantly altered upwards or downwards because of other earthquakes elsewhere around the globe, the supermoon, global warming, the global banking crisis or whether or not someone has made a TV documentary about it. The earth doesn't care.
8) The Oregon/Cascadia 'big one' - we think this is less likely in the near future than the California earthquake. The last Cascadia M9.0 earthquake was in 1700 and we think there's about 500 years between them. That's not to say it couldn't happen today, or in 5 years time, but if it did it would be significantly earlier than expected. If the Hayward fault in Oakland, California broke it today, it would be around when we would expect it to break.
Hope that's sorted out some wrong ideas.
