On June 15, 1991, exactly three decades ago, the second largest volcanic event of the past century happened in the Philippines. The eruption of Mt. Pinatubo ejected 11 billion cubic meters of volcanic materials enough to cover Metro Manila. It was so powerful that ash particles were able to reach as far as the Indian Ocean.
Giant avalanches of high-temperature gases, ash, and rock fragments raced down the slopes of the volcano. It was more than enough to fill river systems and valleys with volcanic materials. Lahar, a forceful mixture of pyroclastic material and water (similar in consistency to wet concrete), continues to change the landscape surrounding Mt. Pinatubo.
Because of the amount of lahar, pumice, and other ejecta that came with the explosion, Mt. Pinatubo and its surrounding areas became one of the leading sources of raw materials for concrete production.
References:
Newhall, Chris, et al. The Cataclysmic 1991 Eruption of Mount Pinatubo, Philippines, Fact Sheet 113-97, USGS, pubs.usgs.gov/fs/1997/fs113-97/.
USGS. (2015, December). Pinatubo 1991 Case Study, Volcanic Ash Impact & Mitigation. Retrieved from https://volcanoes.usgs.gov/volcanic_ash/pinatubo_1991.html
Shimizu, G., Jorillo, P., Adachi, H., Lejano, B., Baarde, R., & Nakanishi, M. (2000). Development of utilization technologies for Mt. Pinatubo ejecta as prime material for concrete: Part 1-concrete material structure-property characterization. Waste Materials in Construction Wascon 2000, 21–35.
Photos courtesy of:
Albert Garcia
Terence Gonzalves