Tephra deposit about 9 cm thick blankets former U.S. Clark Air Base, Philippines, about 25 km east of Mount Pinatubo. The pumice and ash fell to the ground on June 15 during the climactic eruption of Pinatubo. During the eruption, a massive typhoon made landfall and passed about 75 km northeast of the volcano. Typhoon Yuna blew tephra in all directions around the volcano, and a heavy rain saturated the tephra as it fell to the ground. Tephra-fall deposits 10-25 cm thick accumulated over a densely settled area of about 2,000 km².

For a detailed summary of the tephra-fall deposits from the 1991 eruption of Mount Pinatubo, see Tephra Falls of the 1991 Eruptions of Mount Pinatubo, a report from Fire and Mud: eruptions and lahars of Mount Pinatubo, Philippines, that is available online.