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Recent volcanic activity has scientists thinking

Thu., Nov. 4, 2010, midnight

A new series of volcanic eruptions within the last week has many scientists wondering if we’re going toward a new trend of increased volcanic explosions.

Indonesia’s Mount Merapi has been erupting since Oct. 26. Hot ash spewed out, followed by lava, resulting in flight cancellations and evacuations. Ash clouds reached areas as far as 18 miles away. The volcano has continued to erupt this week.

Mount Merapi is one of Indonesia’s most active volcanoes and is located near one of the world’s most densely populated areas.

In addition to the volcanic eruptions, a major 7.7 magnitude earthquake struck off the coast of Indonesia on Oct. 25, generating a tsunami that killed nearly 500 people.

On Oct. 28, two volcanoes in far eastern Russia sent huge ash clouds about 37,000 feet into the air. Airlines were forced to divert flights. Eurasia’s highest active volcano, the Klyuchevskaya Sopka, along with the Shiveluch volcano, 45 miles to the south, erupted the same day. Tokyo issued an advisory for planes to be on alert for ash clouds; the ash and dust can literally shut down engines in midflight.

Over the next few months, there may be some minor cooling in these localized areas due to the dust and ash. However, in order for significant cooling of the Earth’s temperature, we would have to see an eruption that sends the dust and ash 70,000 to 80,000 feet.

Predicting a major volcanic eruption has not quite become a reality, but much progress has been made. It seems that eruptions tend to come in bunches, as may be the case with the current eruptions. Many eruptions are often preceded by earthquakes, a swelling of the ground, the formation of cracks and the release of gases. There are also thermal infrared sensors in satellites to help detect the hot spots.

If we were to see several major eruptions within a short period of time, it’s possible that the Earth would be cooled by at least 1 to 3 degrees as all the dust and ash in the upper atmosphere would partly shield the sun’s rays and greatly disrupt worldwide weather patterns.

Temperatures did cool rather dramatically during the infamous “Year without a Summer” in 1816 following the major eruption of Mount Tambora in 1815. That explosion put an incredible eight times more volcanic material into the upper atmosphere than the recent strong eruption in June 1991 of Mount Pinatubo in the Philippines, which, by the way, briefly dropped the Earth’s temperature more than a degree in 1992.

There has been growing concern about the huge “supervolcano” in Yellowstone National Park. Although a disastrous eruption there would throw the Earth into a nuclear winter almost immediately, a major explosion is not expected for at least thousands of years, but who knows for sure.

Contact meteorologist Randy Mann at randy@

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