It was previously thought that super volcanoes that erupted in the past were not really frequent as it was previously thought of. This claim comes from those scientists who are nowadays busy studying the areas of Snake River Canyon and Yellowstone National Park for super volcanic activities. They are saying that though the volcanic eruptions were not really very frequent, each eruption was enormous!
Geological Society of America Bulletin published a report recently. As per that report, certain studies are being carried out by various scientists along the Snake River Plain that lies between Yellowstone and Oregon. Scientists are studying stuff like radioisotope dating, paleomagnetic data, mineral chemistry and rocks in that area. This area or the Snake River Plain is thought to be the corridor of super massive volcanic activity that happened somewhere between 8 and 12 million years ago.
Scientists previously used to think that some 8 to 12 million years ago, the area stayed riddled with numerous volcanic eruptions. However, data gathered from recent research says something else. The new data says that during that period in the past, there were only a few eruptions (12 to be exact) but they were really massive. In fact, they have been tagged as super-eruptions that took place within a span of just 3 million years.
Now the question is, ‘precisely how big were these explosions?’ Dr. Thomas Knott – the lead author of the study – says that there was one super-eruption that happened 8.1 million years ago. It was, according to Knott, so massive that the volcano managed to spew out a lava sheet that spanned over 5,400 square miles or 14,000 square kilometers. This volcanic sheet that covered a part of Southern Idaho had a caldera of thickness 0.8 miles or 1.3 kilometers. So, just how big was the area covered under this volcanic sheet? If 14,000 square miles is something you cannot put in perspective then, here is a quick comparison: it is about the area of whole of Connecticut.
What about the remain 11 volcanic eruptions?
Well, the scientists say that the remaining 11 were also massive and super-eruptions. If not bigger, these 11 volcanic eruptions did create magmatic activities that had the same intensity and size as the one previously mentioned. Over time, these volcanic eruptions were responsible for subsidence of earth’s crust, which led to the formation of Snake River Basin, which is 62 miles or 100 kilometers wide.
So, what is all this fuss about? Fine! There were some serious volcanic activities millions of years ago. Why on earth should we be worried now? That’s because Yellowstone erupted thrice in last 2.1 million years and each eruption took place at a gap of 600,000 to 700,000 years. The last time it erupted was 640,000 years ago. The other 12 super volcanic eruptions took place in gaps of 250,000 years. All we need to do is simple addition. Add up the numbers and you will immediately know that we are already overdue for the next super-volcanic activity. Just when it is going to happen is not known.