The lahars produced by Pinatubo’s eruption blocked the flow of the Mapanuepe River and created a new lake, named Mapanuepe Lake. The formation of the lake flooded the small towns of Aglao, Buhawen, and Pili. Breakout lahars continued to be a threat in the years after the lake formed, but artificial channels help to stabilize the lake’s water level.
In the series of images that accompany this section, Pinatubo’s summit crater is in the upper right corner. In the 1989 image, the maroon colors indicated moisture in the soils southwest of Pinatubo’s summit. After the eruption, the bright gray or pink colors streaming from the summit are sediment-laden lahars in the Marella River, which flows into the Santo Tomas River Valley. The lahars effectively widened this river plain, and the sediment persists, indicated by the shades of pink. The brighter mottled white and gray in the upper left of the image after the eruption gradually returned to forested green tones.
Mapanuepe Lake is the dark shape in the lower right. Southeast of the lake is the copper and gold Dizon Mines. Cleared land for the mining activity appears in pink shades in the midst of the green forested areas. The small dark shape is water at the bottom of the mine’s main open pit.
Again, a few ASTER images in this series help fill in some gaps where Landsat imagery was cloudy. The complementary imagery of the changes over time to these valleys help scientists understand more fully the trajectories of the changes.