Earthquake stats for the year so far have been pretty shaky indeed. As always, below is included an explanation of where averages come from. Below that you will find the statistics for the third quarter and the year totals so far. It’s been a very interesting year all the way around.
About The USGS and RHS1 Averages:
The USGS statistical averages are averages compiled from 1990 to 2000. That is when global tracking was achieved and we have no way of knowing for sure how accurately those statistics represent numbers before that time. There are scientists who did tracking, but there were also many very volatile areas that aren’t populated and it was impossible to track before. From old records we can assume that there have been more recently, but there is no way to know for sure.
We also use an RHS1 average which is 3 year statistical average which was drawn from my three year quake report from 2006, 07, 08 that I will compare the quarterly statistics to, so we can see a more current trend. At the end of this year we will add this year’s average to the three year average, making an average of 4 of 5 years since the middle of the current decade. If data can be retrieved for 2009, a year in which our site was being rebuilt from hacker/virus injection damage, we will add those in to make a current half decade statistical average.
8 Magnitude and Stronger:
We had none during the second or third quarter. We had one in the first quarter.
The USGS average is 1, if any per year. The RHS1 average is two per year.
We are holding steady at low average for these massive quakes.
7 Magnitude and Stronger:
We experienced a whopping 9 of these shakers this quarter bringing the year total in the third quarter up to 17 – which is the USGS yearly average for these massive quakes. RHS1 3 year average is 11 annually, a 35% drop from the USGS average. It looks like these are going to break both averages this year.
6 Magnitude and Stronger:
We experienced 37 of these strong quakes in the third quarter. With only 29 of these quakes in the second quarter and a the high number of 48 during the first quarter, we have now experienced 114 mag 6 quakes already as of the end of the 3rd quarter. The USGS average is 134 per year. RHS1 average is 159 annual mag 6 quakes per year. Only 20 quakes in the forth quarter will see the USGS average but 45 still need to occur to reach the RHS1 average. It looks like we will be considering this year a high or a low according to which average you want to look at.
5 Magnitude and Stronger:
There were 401 of these quakes during the 3rd quarter of the year. We experienced only 285 of these strong shakers second quarter – but we had extremely high numbers the first quarter – 565 of them! At 1251 total for this year as of the end of the third quarter, we will exceed both averages this year. USGS average is 1319 per year. The RHS1 average is only 1275 per year. Judging from my recordings so far of the 4th quarter, we already have. The only question left is by how many we will be exceeding averages.
During the first few quarters of the year most quakes were happening at depths of 10 and 35 km, indicating a crustal shift was going on. In the third quarter there were still quakes occurring at these depths but not in such a profusion as earlier in the year. The depths are becoming disperse again with no real perceivable patterns to them.
The high number of quakes this year are mainly due to some strong and lengthy aftershocks occurring after the major 7 and 8 magnitude quakes experienced near the beginning of the year.