I wonder how long the typical "spike" lasts.
Actually. According to the U.S. Geological Survey we are already at what should be a normal spike for 2016. About 10 major earthquakes (6.9 or greater) and one, or two 8.0 in some years is a spike. A spike period typically ends the same year it begins. So at 11 major quakes in 2016 we are a tad over normal with five months left to go and the big one hasn't hit yet, however not all spike years are accompanied by a 8.0 or larger quake. Sorry Oklahoma, but 5.5 earthquakes aren't counted as a
major quake.
What is really disturbing is what seismologists and volcanologists are saying about volcanoes. I ran across this information while researching earthquakes. Apparently, and according to the experts, every major volcano and super caldera on Earth are now showing signs of pressure building up. I had heard this regarding Yellowstone, but I was unaware it was global. Volcanoes in Chile, Italy, the U.S., Iceland, Greece, Hawaii, Japan, and a whole lot of other countries too long to list are showing signs of major eruption events. Check the list for your country, but basically it's everywhere.
Between 2004 and 2010 the ground at the center of the Yellowstone caldera rose an unprecedented 10 inches. Water temperature in the Yellowstone River is also beginning to rise as of 2016. Quoting one volcanologist, "make no mistake about it, it's magma and it's increasing in magnitude with each passing year". "At present, the ground is rising at an unprecedented rate of about 3 inches per year". [End Quote]
When the Yellowstone caldera erupts (actually it will be more like an explosion), enough magma will be released to fill the Grand Canyon eleven times. The ash plume will stretch over 1,000 miles, and most of North America will become uninhabitable for years.