Final answer:
The eruptions of Mount Pinatubo in 1991 were Plinian, not Vulcanian. Therefore, the statement is false.
Step-by-step explanation:
The statement that the eruptions of Mount Pinatubo in the Philippines in June 1991 featured stupendous Vulcanian events is false. What occurred was a series of powerful Plinian eruptions, which are characterized by a continuous gas blast eruption that projects volcanic material into the stratosphere. This type of eruption is named after the eruption of Mount Vesuvius in AD 79 that buried the city of Pompeii. The Mount Pinatubo eruption was indeed colossal, and it resulted in a significant impact on the climate, leading to a volcanic winter that reduced global temperatures. Although Mount Mayon is known for its frequent Vulcanian eruptions, Mount Pinatubo's 1991 eruption is not classified as Vulcanian.