Simplify the following text for a Grade 7 native English-speaking person.
Original: Plinian eruptions , also known as ` Vesuvian eruptions ' , are volcanic eruptions marked by their similarity to the eruption of Mount Vesuvius in AD 79 ( as described in a letter written by Pliny the Younger , and which killed his uncle Pliny the Elder ) .
Simplified: That eruption of Vesuvius killed Pliny the Elder , the uncle of Pliny the Younger .