Ancient Web: A 1997 USGS Fact Sheet Mapped the Pinatubo Eruption

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When Mount Pinatubo erupted in June 1991, a remarkable part of the story was not just the size of the explosion. Scientists had warned the people living nearby. A 1997 U.S. Geological Survey page captured both the eruption and the forecast in a compact illustrated web fact sheet.

Read USGS Fact Sheet 113-97.

Written by Chris Newhall, James W. Hendley II, and Peter H. Stauffer, the page traces the warning signs back to a July 1990 earthquake, followed by March and April 1991 steam explosions, small earthquakes and volcanic gas emissions. It dates the enormous climactic eruption to June 15, 1991.

The page describes a column of ash rising about 35 kilometers, pyroclastic flows racing down valleys, and fresh deposits that could remain dangerously hot for years. It pairs photographs with a map of the volcano's damaged surroundings, including the areas affected by the later mudflows known as lahars.

The disaster kept happening after the headlines

A particularly important part of the sheet is its emphasis on long-term effects. Rain remobilized loose volcanic material into mudflows that buried settlements after the initial explosions. Some deposits were still very hot in 1996, the report says, raising risks from explosive interactions with water.

The authors credit monitoring and warnings by the Philippine Institute of Volcanology and Seismology and the USGS with saving at least 5,000 lives. They also describe damage to aircraft, American military facilities, farmland, and the displacement of local residents, including Aeta communities.

The sheet relates Pinatubo's injection of sulfur dioxide into the stratosphere to a temporary decline in average global temperatures. These figures and impact assessments are the USGS's historical 1997 account, not necessarily the final estimates that later researchers would use.

In web-publishing terms, the page is a small artifact from the era when a government report could be translated almost directly into a readable HTML document. It retains figure captions, a fact-sheet identifier, contact information, related science pages, and a notice showing maintenance through February 2005.

The specific URL may be blocked to some automated readers, although its indexed official text remains recoverable. The article concerns the historical USGS publication, not a live hazard forecast.

Explore the original report and its linked 1997 volcano fact sheets.

Part of the Ancient Web Collection.