If you have identified all of the verbs, and named them, then, to test yourself, change them!
Do this for all of the 17 irregular verbs in the text (you can skip doubles!)
Original text:
There was a volcano = past simple
For example:
There is a volcano = to be (base form/present simple)
There was a volcano = Past Simple
There has been a volcano = Past Participle (present perfect)