Since I posted part 4 of Pacific Ring of Fire Seismic Events, the United States Geological Survey added one more quake to it’s “Largest and Deadliest Earthquake” list; the March 11 earthquake near Japan.

But have there been more large quakes this year, not qualifying for the USGS title of “Deadliest”, but still large, and more than normal?

According to the USGS “Significant Earthquakes of the World” list, so far this year there have been 49 magnitude 6.5, or greater quakes around the Pacific Ring.  The majority of those being near Japan.  There’s still three months left to go for 2011.

In 2010 the USGS recorded about 57 M6.5+ quakes around the Pacific Ring.  About 50 M6.5+ quakes took place in 2009.  So in the past three years it looks like about 50 M6.5+ Pacific Ring quakes per year are the norm.

I went back to “Significant Earthquakes of the World 1999”, and counted about 53 M6.5+ Pacific Ring quakes.  So, without doing more detailed research, it looks like the number of “significant” quakes around the Pacific Ring is about 50 per year, and seems to be normal.  Unless we get a sudden boost in quake activity within the next three months, it looks like 2011 will be another normal year.

What about the number of “deadliest” earthquakes, is there an upward trend?  It doesn’t seem so.  Looking at the USGS “Largest and Deadliest Earthquakes by Year 1990-2011” list, we average about one or two per year, and that’s all over the world not just the Pacific Ring.  The USGS determines the “largest and deadliest” by a combination of magnitude intensity and the number of people killed.

However, I noticed an interesting trend regarding when those “largest” deadly quakes happen; most of the dates are from Autumn to Spring, with the minority happening during Summer.  We are closer to the Sun from Fall to Spring, mmmm.