Hello everyone,
back in
this post on June 7, I posted the following prediction:
This prediction is for an earthquake of magnitude 7.0 (Mw) or greater, within or at least close to the coordinates of 14 S and 76 to 77 W,
within a time window of seven days from the time of this post, which is just after 20:15 UTC on June 7, 2012.
A quake in or very close the stated zone will only be counted as a "hit" if it is at least a magnitude 6.5 Mw and is within the specified time window.
Anything less than that just is too small in terms of energy release.
I wish to state that no such quake occurred within the stated region and time frame, and so this prediction is a
no hit. Furthermore, there has
not been even one magnitude 7.0 or greater quake anywhere in the world since April 12, 2012 (a mag 7.0 in the Gulf of California) -- meaning that a
full 78 days have now passed since that last event.
While this is well beyond the long-term average of one such event approximately every 23.5 days (world-wide), it does not mean the next one has to
occur within the next few days. There have been much longer periods between magnitude 7-plus events in the last century or so, including some cases of
100+ days between such events.
I'm pointing this out to make it clear that the over-average time since the last quake (on April 12) had no bearing on my decision to make the
prediction as I did back on June 7. My prediction was based on observations and indications in the target region, and in this case I simply got it
wrong.
It was not a case of, "It's been (X) days since the last one and that's over the average, so another one is due any tick of the clock", because for
one thing, the average interval between larger quakes is just that: an average. It's primarily useful for statistical purposes. For example, while the
rate for 1/1/1900 to 12/31/1999 for mag 7.0 or bigger events was 15.53 per annum (according to the centennial list), the variation of time between
events is huge.
However, I am currently exploring a hypothesis that there could be a predictive advantage in determining when a mag 7.0 or greater quake might occur
in one special circumstance. My first rough review of longer-term data suggests that when there is a period of more than 2x the average between one
M.7.0 (or bigger) quake and the next, then the next such event
after that has a greater chance of occurring at
less than the average
interval.
Example: say there is a mag 7.0 or bigger quake, and then it's more than 47 days till the next one. [Average interval is 23.5 days, so 47 is 2x this
number.] It appears that the next large quake after that event occurs less than 23.5 days later -- more often than not -- and this seems to be so even
when "aftershock" events are excluded. (As they can often be
expected to occur pretty soon after a big shock.)
I'm still studying the data and it's a slow process because the source Centennial Quake Data Catalogue -- available
here from USGS and produced by researchers from the U of Colorado -- has the listed
quake data in a scanned-in form in the pdf. So, I have to manually assemble my own list of qualifying events (no copy and paste!) and it's very
tedious and takes a lot of time.
I expect to have some firm figures from this project available during the coming month as I now have some vacation time to work on it. So, I'll see
what an objective review of the data actually shows. If my hypothesis is right, then it could be useful in prediction work. If it's wrong then at
least it can be excluded. While I'm only into the 2nd decade of the 20th century with the data so far, the figures look encouraging. But that's only a
small percentage of the data I'm working with and so I'm not counting my chickens!
Mike
edit on 29/6/12 by JustMike because: typos. I also actually edited it dowwwwn!