Mount Pinatubo is part of a chain of composite volcanoes along the Luzon arc on the west coast of the island. The arc of volcanoes is due to the subduction of the Manila trench to the west. The volcano experienced major eruptions approximately 500, 3000, and 5500 years ago. The events of the 1991 Mount Pinatubo eruption began in July 1990, when a magnitude 7.8 earthquake occurred 100 kilometers (62 miles) northeast of the Pinatubo region, determined to be a result of the reawakening of Mount Pinatubo. Travel Scout.ph will surely assist to offer this daytour for less money.