The debate continues, ‘can you predict an earthquake’ and Japan is now the center of that debate. With some scientists saying that the Mar 11 quake has loaded adjacent sections of the subduction fault while other scientists say that the extra load is very small if anything.
At the moment if you were to say there will be an earthquake in Japan tomorrow it wouldn’t even be a prediction. With all of the aftershocks that have been happening in Japan and the likelihood that this activity will continue for some time makes doing an actual prediction in Japan a bit rough. But what some people are doing is saying that the earthquakes away from the March 11 quake may not be aftershocks but cascading earthquakes in what some are calling an ‘earthquake storm‘. These earthquakes that seem to walk along a fault zone such as the Sumatra fault quakes of Dec 2004 and then March 2005 and the quakes that have followed that along the same fault, and the North Anatolian Fault that threatens Istanbul if the earthquake storm across that fault proceeds as expected.
In Japan the evidence that there may be something to the earthquake storm idea come partially from the amount of instrumentation of the Japan islands with GPS and seismic sensors. By benchmarking and measurement we can see that the Japan islands moved easterly during and since the March 11 quake. But not all of Japan moved easterly, parts of it away from the quake went west a small bit. The deformation of Japan from the March 2011 quake (from http://www.jishin.go.jp/main/chousa/11mar_sanriku-oki/p05-e.htm Geospatial Information Authority of Japan)
It would seem that the load on the fault south of the part that ruptured from the March 11 quake must have loaded more because it is pushing the southern part of Honshu west more than it was before the quake.
If we look at the area in the south on this map this added westward movement means that there is a added stress to this part of the fault. How much energy does it take to twist an nation and push two different parts of it in different directions at once? Assuming there was already some stress on the southern portion of this fault it would seem there is a lot more now.
I personally think that one part of a fault unloading with an earthquake transfer at least part of that load to the adjacent parts of the fault. In a lot of zones this is usually immediate and that next part of the zone breaks as either part of the same earthquake or in subsequent after shocks. But in other cases such as currently in Japan and Turkey this stress causes more quakes in the months or years following each part that broke before it. Other places this is a concern right now are Indonesia, Chile and New Zealand/Fiji. I hope none of these places have a huge quake such as the Japan March quake but they will all have new quakes of 7 or higher and probably in the next year or two. That is not a prediction, it’s just math.
- Japan Earthquake March 2011 (echlinm.wordpress.com)
- Scientists warn of years of aftershocks in Japan, and risks on other faults (seattletimes.nwsource.com)