This comment concerns the recent large earthquakes that have been happening around the Pacific basin.

Terminology:
Earthquake Clusters (sometimes called Megaquake Clusters) concerns earthquakes bigger than 7.0 magnitude, and apparently happening within a short time period. On a geological scale, 10-20 years is a short time period.

Ring Of Fire: A general line of circumference drawn around the Pacific Basin, which includes a lot of earthquake and volcanic activity on the rim (perimeter). During the 1950's and 1960's scientists made a lot of progress understanding why this was happening with a theory called "Plate Tectonics". Check Wikipedia. There are 14-15 major plates covering the surface of the Earth's crust. One of the large ones is the Pacific Plate.

Now let's step forwards. Over the last decade there have been several major quakes around the Pacific rim - including some of the largest earthquakes ever seen. In addition, there have been large quakes on "nearby" tectonic plates, including in Indonesia and Haiti. This has caused the data of large quakes to clump together into a short time period. It has also caused a controversy to erupt amongst scientists over what it all means.

It is worthwhile to note that the science of seismology is a very young science. This field of science only has detailed seismology data over a century or so. If we had all the data going back for 2,000 years - we'd be in a lot better shape (!). Many scientists take the point of view that earthquakes are local phenomena, and not generally connected (except if they occur nearby one another). These people see no relationship between the cluster of big quakes, and feel it is just a random series of events.

Other scientists take the point of view that there is something going on, and some kind of major shift in the tectonic plates is taking place. Notably, the earth scientists in Russia have this point of view - hence the dire warning sent to their own leaders (if news sources can be believed).

I have been looking at this carefully. I am a structural engineer, although not a seismologist. But the two areas have a lot of overlap - we speak the same language. I find the argument that the Pacific Plate is going through a series of movements and a realignment to be compelling. I do understand that data is scarce as hens teeth. We need more.

But I think the Russians may have jumped the gun a little bit. To me, it would not be surprising to see another large quake in the northwest Pacific, in the region of Japan or the Aleutians. I certainly hope that Japan does not get a "double whammy" out of this. It would be devastating to them. But the major seismic zone which lies SE of Tokyo has not triggered yet, and we can't dismiss other fault lines between Japan and Alaska. If these fault lines do rupture, concern about the West Coast of the USA would magnify.

Pete #2

We do have historical data from excavations in and around faults which reveal at least a 10,000 year record in some areas. This is one reason there is concern about the southern one-third of the San Andreas, which is "due," more or less, for another shaker.

Earthquake prediction is a highly inexact science, as the people working in the field will state, both publicly and privately. Look at the recent miss at Parkfield a few years ago. Will California get severe earthquakes in the future? You bet your bippy we will. Does anyone know when? Definitely not, at least not with any accuracy that is useful.

So....Prepare, get your stuff together. Keep your first aid skills current. Check your home and workplace for hazards and hang on tight. These skills will come in handy in any number of other situations which also beset us (wildfires, freeway jams, etc).

I must admit I am a tad dismissive of the statements coming out of the Russian scientific establishment - just think of their stance on genetics.....

BTW, there is a very itneresting article in today's LA Times about seismological resarch on the San Andreas. I read it in an old fashioned paper edition delivered to my doorstep (charming custom from the last millennium); I am afraid I don't have the link.

I've thought about the same thing myself and it's a compelling theory. However, even if true, an "imminent" earthquake in North America in geologic time could still be many, many years away. The thought of something similar happening along the Cascadia subduction zone is frightening, to say the least. Of course, those of us in California have our own friendly neighborhood faults to fret over, too.

I saw one mention of a geologist a week ago who said that as the stress was relieved on the fault along northereastern Japan, it then transferred that stress onto a segment of the fault near Tokyo that is still locked in place. There's no way to predict when or if that stress may lead to another massive quake much closer to Tokyo.

It would be nice to have the one-minute warning system that Japan has. But I'm sure we're decades away from anything like that, if ever.

Sue