The samples were taken from both small and large eruptions.

The largest modern eruptions were in 1640, 1948 and 1971.

It was the largest eruption of violence in the country since March.

It is the second largest volcanic eruption of the 20th century.

In historic times there have been large eruptions every 250-600 years.

The largest eruption occurred the morning of December 4, 1951.

One of the largest eruptions was on January 20-24, 1913.

The largest eruption for several years occurred on May 24, 2005.

It was the 2nd largest volcanic eruption of the 20th century.

It had at least five large explosive eruptions in last 3500 years.