Sundin column: Volcanic eruptions, a history lesson
As I See It

With the world facing the COVID-19 pandemic, overpopulation and global warming with widespread drought and forest fires, one threat we do not have to worry about is volcanic eruptions. Other than the shallow Dotsero Crater, which was produced by a minor magma and water explosion around 4,000 years ago, Colorado has had no volcanic activity for tens of thousands of years.
Most of the world’s volcanic activity is in the Pacific Rim, which includes Indonesia, Japan, Alaska, the Pacific coasts of Canada and the United States, and Hawaii. The U.S. has the third most volcanic activity in the world, after Indonesia and Japan, with most of that being in Alaska.
Volcanic threats in the mainland U.S. are along the West Coast, including Mount Rainier and Mount St. Helens in Washington, Mount Shasta and Lassen Peak in California, and Mount Hood and South Sister Peak in Oregon, which are all classified as potentially “active volcanoes.”
The most famous volcanic eruption in human history was Mount Vesuvius near Naples, Italy, on Aug. 24, 79, which sent a pyroclastic flow onto Pompei and Herculaneum, burying them in up to 60 feet of ash and killing an estimated 16,000 people. A second eruption on Dec. 16, 1631, killed another 4,000. Since then, the nearby Naples Metropolitan District., with a population of 4.5 million, has seen 21 minor eruptions, the last of which was in 1947 during the American invasion of Italy in World War II.
The eruption of Mount Laki in Iceland on June 2, 1783, spewed 120 million tons of sulfur dioxide (and 3.7 cubic miles of lava) into the atmosphere over a span of eight months, affecting the climate of much of the northern hemisphere, creating a cold wave that destroyed crops, leading to massive deaths from starvation in Europe and of more than 15% of the populations of Japan, Egypt and Alaska. In the spring of 2010, a much-less-severe eruption of another mountain in Iceland cast an estimated 330 cubic yards of rock particles into the atmosphere, causing an enormous disruption of trans-Atlantic air travel.
The two largest and most violent, and most devastating, volcanic eruptions on record both occurred in Indonesia in the 19th century. They were heard as far away as 2,000 to 3,000 miles. Mount Tambora, on the island of Sumbawa, erupted on April 12-14, 1815, blowing the top third of the mountain away and killing 11,000 people. It put so much debris and gases into the atmosphere (36 cubic miles of rock and ash and 60 million tons of SO2 and hydrogen sulfidesulfur dioxide) that it caused crop failures resulting in the death of another 60,000 people in Indonesia. As the haze spread around the world, it cut off enough sunlight to cause crop failures throughout the world, resulting in the deaths of 200,000 people worldwide.
As a result, 1816 was called the year without a summer, and in the U.S. “eighteen hundred froze to death” due to extreme temperature drops, according to historical accounts.
Then on Aug. 26-27, 1883, Mount Krakatoa in the Sunda Strait between Sumatra and Java exploded, killing 38,000 people from the explosion and resulting tidal waves.
The next major volcanic eruption occurred on the Island of Martinique in the Caribbean Sea on May 8, 1902, when Mount Pelee exploded, sending a pyroclastic flow onto the nearby city of St. Pierre, killing the entire population of 28,000, except for one man who had been incarcerated in a deep underground cell.
On Nov. 13, 1985, an eruption of Nevada del Ruiz in Colombia created a “lahar” (a flood of mud precipitated by the melting of snow and ice at the summit) that buried the city of Amero, killing all 23,000 residents. The same thing had happened in 1845. In spite of that, they had rebuilt the city on the same spot — and guess what happened? There is now concern about a lahar from Mount Rainier descending on Puyallup, Tacoma and the surrounding communities.
Japan’s most devastating volcanic eruption resulted from an earthquake on May 21, 1792, near Nagasaki, on Kyushu (the south island of Japan). A devastating landslide 100-feet thick, traveling at 30 miles per hour, slid into the bay, generating a 330-foot high tsunami that killed 15,000 people.
The most serious volcanic eruption in the recorded history of the U.S. was the eruption of Mount St. Helens in Washington on May 18, 1980, setting off a huge landslide that reduced the height of the mountain 1,000 feet. But, because of its remote location, it killed only 57 people.
“As I See It” appears on occasion in the Post Independent and at postindependent.com. Hal Sundin lives in Glenwood Springs and is a retired environmental and structural engineer. Contact him at americron@comcast.net.

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