In the last week, there have been two notable volcanic eruptions (Mexico and Bali) and a large flurry of micro quakes in California (that could possibly be the precursor to a major seismic event). Other volcanic episodes and mega quakes during the past century highlight the tectonic drama of the Pacific Ring Of Fire. One such volcanic eruption that has been forgotten occurred on “June 6th, 1912 when a tremendous blast sent a large cloud of ash skyward and the eruption of the previous century was underway. People in Juneau, Alaska, about 750 miles from the volcano, heard the sound of the blast – over one hour after it occurred.”
"For the next 60 hours the eruption sent tall dark columns of tephra and gas high into the atmosphere. By the time the eruption ended the surrounding land was devastated and about 30 cubic kilometers of ejecta blanketed the entire region. This is more ejecta than all of the other historic Alaska eruptions combined. It was also three times more than the 1991 eruption of Mount Pinatubo, the second largest in the 20th Century. Forty years after the eruption, investigators finally realized that Novarupta -- and not Mount Katmai (6 miles distant) had been the source of the eruption. The region was so sparsely populated that there were no witnesses. Because of the reports of the top several hundred feet of Mt. Katmai being gone, it was assumed that Katmai had blown. It turned out, however, that about one cubic mile of material collapsed into the magma chamber below Katmai -- because Novarupta had stolen vast amounts of magma that had supported Mt. Katmai. This collapse produced a crater about two miles in diameter and over 800 feet deep."
http://geology.com/novarupta/
http://volcanoes.usgs.gov/observatories/cvo/hot_stuff_expanded/katmai.html
http://pubs.usgs.gov/fs/fs075-98/images/Novarupta.gif
List of known large volcanic eruptions:
https://en.m.wikipedia.org/wiki/List_of_known_large_volcanic_eruptions
Note: Free apps showing current world wide volcanic activity and earthquakes are readily available.
