At their early stage mostly during the youthful age.
Yes, they often erupt again.
There are no volcanoes in the Grand Canyon.
Never.
Shield volcanoes erupt least violently cinder cone most violently and compost can erupt either way.
No. Most volcanoes have built up into mountains.
every 2 years
Yes. Composite volcanoes often produce violent eruptions.
Mexico and Central America
they arupt 2 a year
As many as it wants. Some volcanoes erupt often, some infrequently
No. Volcanoes erupt.
Some do. Most volcanoes will erupt more frequently than that, but some do go 1000 years or more between eruptions.