July 12, 2013 – 6,372 Years of Global Volcanic Eruptions: I downloaded all volcanic eruptions, from 4360 B.C. to 2012 A.D.; which is a total of 6,372 years. I graphed the volcanic eruptions by VEI (Volcanic Explosive Index), which is displayed above. Only 540 of the volcanoes in the NOAA database had VEI ratings, out of a total of 614 events.
The VEI is a method of eruption classification that volcanologists use to classify events, much like the Richter scale classifies earthquakes. The VEI is an exponential scale, in that one increase up the scale (which runs from 0 to 8) is a tenfold increase in destruction power. For example, a VEI 4 event is ten times stronger than a VEI 3 event. A VEI 5 event is 100 times stronger (10 X 10 = 100), while a VEI 6 is 1,000 times stronger than a VEI 3 (10 X 10 X 10 =1,000). See below for the complete Volcanic Explosive Index (VEI) scale:
Volcanoes and earthquakes are related in that the tectonic plate boundaries that cause most global earthquakes are also responsible for most volcanoes. The belt of volcanoes that surround the Pacific Ocean and the “Ring of Fire,” contains about two-thirds of the world’s active volcanoes.
Next, I graphed the volcanic eruptions by month, as shown below:
Of the 614 events in the NOAA database, only 509 had a month listed. The unusual thing about this chart is that the high of 65 for August and the low of 30 for November are beyond two standard deviations from the mean, which puts them in the statistical oddity category. Again, each research answer leads to ten new questions.
I then graphed the day of the month that the eruption fell on, as can be seen in the graph below:
The low of 7 eruptions on the 14th of the month and the high of 24 eruptions on the 17th of the month are outside the statistical reasonableness. Something else is at work here.
Volcanoes can cause destruction in more ways than earthquakes: the blast itself, avalanches, lightning, floods, gas emissions; indirect deaths from disease, starvation, exposure and desolation; lave and mudflows, pyroclastic flows, ash, bombs, steam blasts, and tsunamis.
Lastly, I graphed all eruptions from 1900 to 2012 (291) by year as seen below:
The average per year is about 2.5. The exponential trend line is slopping up. The last seven years on the graph show the following number of eruptions per year: 2006 = 7, 2007 = 2, 2008 = 4, 2009 = 2, 2010 = 7, 2011 = 9 and 2012 (thru April 13th) = 1. It looks like world-wide volcanic activity is increasing at an alarming rate. Other cycle information supports this conclusion.