The samples were taken from both small and large eruptions.

Yellowstone, like many other supervolcanoes, has also had much smaller eruptions.

There were at least a dozen reported small eruptions of ash from 1831 to 1857, including a fairly large one in 1842.

During the 19th and 20th century, small phreatic eruptions occurred.

The volcano has since had small eruptions in 1991 and 2001.

At times, small eruptions happen every 20 minutes or so.

Many people like to watch the view created by the volcano when it is making small eruptions at night.

Through the night and for several days after, there were smaller eruptions.

A small eruption may have occurred in 1810 (give or take 10 years), but this event is uncertain.

The last such small eruption occurred about 80,000 years ago.