Five largest volcano eruptions in modern history.

The eruption of Eyjafjallajökull volcano in Iceland is having a major impact on travel and commerce in Europe and worldwide. However, as a volcanic event (in terms of scale), it barely is worth mentioning.

By the measure of the Volcanic Explosivity Index (VEI) - a sort-of Richter scale for eruptions - the current outburst is probably a 2 or a 3, experts say. In other words, eruptions like Eyjafjallajökull happen virtually every year somewhere in the world. It's a regular occurance.

The biggest eruption of the past millennium , by contrast, was a 7. Given that each number on the scale represents an eruption 10 times more powerful than the previous, that means Eyjafjallajökull is 10,000 times less powerful than one in Indonesia's Sunda Islands in 1815. [ CSM ] [ Worst Disasters by death toll ]

Top 5 : Tambora , Krakatoa, Novarupta, Pinatubo and Santa Maria.

What are the biggest volcano eruptions in recent times?

Here are the five VEI 6 and above eruptions since 1700, according to Smithsonian's Global Volcanism Program.

1. Tambora vocano eruption

April 10, 1815 - The Tambora eruption was the largest in modern history. According to the Global Volcanism Program, it was the only eruption in at least 1,000 years to rate a VEI 7.

So, exactly how big was the Tambora eruption?

The eruption of Tambora killed an estimated 92,000 people, including 10,000 from explosion and ash fall, and 82,000 from other related causes.

The concussion from the explosion was felt as far as a thousand miles away. Mt. Tambora, which was more than 13,000 feet tall before the explosion was reduced to 9,000 feet after ejecting more than 93 cubic miles of debris into the atmosphere.

The effects of the eruption were felt worldwide: 1816 became known as the “year without a summer” because of the volcanic ash in the atmosphere that lowered worldwide temperatures. It snowed in New England that June, and crop failures were common throughout Northern Europe and North America. As many as 100,000 additional deaths from starvation in these areas are thought to be traced to the eruption.

2. Krakatoa volcano eruption

Aug. 27, 1883 - The obliteration of the Indonesian island of Krakatoa in a series of eruptions ending on Aug. 27, 1883, is, in many ways, the most famous modern volcanic cataclysm. The sound of the explosion was heard some 3,000 miles away, across the Indian Ocean on Rodrigues Island.

How big was the Krakatoa eruption?

The VEI 6 eruption created a tsunami 150 feet tall, and a ship 50 miles away reported being blasted by hurricane-force winds from the eruption.

The August 1883 of Mt. Krakatoa (Krakatua) destroyed 2/3 of the island, ejecting more than six cubic miles of debris into the atmosphere. The sound of the explosion was the loudest ever documented, and was heard as far away as Australia.

Interestingly, it’s probable that no one died in the initial explosion. The casualties all came from the resulting tsunami.

3. Novarupta volcano

June 6, 1912 - The largest explosion of the 20th century happened in such a remote area of the Alaska Peninsula that scientists trying to identify exactly which volcano erupted were mistaken for nearly a half century. Only through study local geology were they eventually able to pinpoint the eruption to Novarupta.

The VEI 6 Novarupta eruption threw out more material than all other Alaskan eruptions in history – and 30 times more than Mt. St. Helens – a VEI 5 eruption. Across the Shelikof Strait on Kodiak Island, ash fell for three days, accumulating one foot in the main town.

The eruption also caused the top of Mt. Katmai, some six miles away, to collapse. As the magma chamber under Mt. Katmai emptied through Novarupta, the weight of Mt. Katmai made it fall in on itself, forming a crater two miles wide and 800 feet deep.

4. Mount Pinatubo eruption

June 15, 1991 - As the most recent VEI 6 eruption, Mt. Pinatubo demonstrated the role that science can sometimes play in limiting the damage of eruptions.

Located in the Philippines on the island of Luzon, Mt. Pinatubo had not seen any major activity for at least 500 years. But thousands of earthquakes and minor eruptions through April and May of 1991 suggested that Mt. Pinatubo was likely to erupt. Further readings suggested that gases were building within the volcano, raising the possibility of a major eruption.

Three evacuation zones were drawn up around the peak, and by the time the major eruption happened, some 66,000 people had been evacuated. Some 850 people were killed in the eruption, as compared with an estimated 92,000 after Tambora.

Curiously, direct observation of the eruption was hampered by the fact that typhoon Yunya hit the island on that same day.

5. Santa Maria eruption

Oct. 24, 1902 - The least powerful of the VEI 6 eruptions recorded since the beginning of the 1700s, the Santa Maria eruption hit the Pacific coast of Guatemala. The 1902 eruption was the first in the recorded history of the mountain, spewing ash that was detected as far away as San Francisco.