The main shield then forms, burying the smaller ones formed by the early eruptions with its lava.

An earlier eruption may have occurred around 1960.

There is no historical knowledge of earlier eruptions.

The new parks, however, are not the sole reason for the early eruption of home runs.

This was ash from the earlier eruption which had been deposited across Patagonia and stirred up by high winds.

An earlier eruption was on May 21, 1951; earlier eruptions probably occurred in 1905, 1896 and 1848.

Since the volcano's earlier eruptions are not recorded, volcanologists have used tephrochronology to date them.

Because the evidence of earlier eruptions may have been either buried or destroyed, we do not really know how often the volcano has actually erupted.

It was also the site of an earlier eruption in May 1988.

The earliest eruptions of the volcano occurred around one million years ago, explosive activity producing ignimbrite.