File:SIR-C X-SAR of Mount Pinatubo.jpg

English: Mount Pinatubo Volcano,

The Philippines (P-43915) This false-color composite image of Mount Pinatubo volcano in the Philippine Islands was acquired by SIR-C/X-SAR on April 14, 1994, during the 94th orbit of the space shuttle Endeavour (STS-59). The image is centered at about 15 degrees north latitude and 121 degrees east longitude; north is at the top right corner. The area shown is approximately 45 by 68 kilometers (28 by 42 miles).

Clearly visible in this image are the steep slopes on the upper flanks of Mount Pinatubo as well as the main crater produced by the volcano's June 1991 eruption. The red color on the high slopes indicates ash deposited during the eruption; the dark drainages represent mud flows that flood the river valleys following heavy rainfall.

SIR-C/X-SAR radar images are useful in identifying areas flooded by mud flows — which are difficult to distinguish visually — and in assessing erosion and deposition rates. Dangerous mud flows of volcanic debris (called "lahars") are often generated by heavy monsoon rains; lahars can sweep down river valleys and wash out roads and villages or bury low-lying areas in several meters of mud and debris. Lahars will continue to be a severe hazard around Mount Pinatubo for the next 10 to 15 years.

The Mount Pinatubo eruption is known for its almost global effect on Earth's atmosphere and climate — a large amount of sulfur dioxide was injected into the upper atmosphere. The second SIR-C/X-SAR mission, scheduled for August 1994, will collect another image of Mount Pinatubo during the summer monsoon season to evaluate short-term changes.