The 1993 eruption of Colombia's Galeras volcano was a disaster.

"No one predicted there would be an eruption," said Stanley Williams, a professor of geology at Arizona State University in Phoenix, Arizona, whose firsthand account of the 1993 eruption, Surviving Galeras, was published this April.

Nearly 150 scientists were gathered in the town of Pasto, Colombia at the time of the eruption for a conference organized by Williams on the shaky science of volcanology. On January 14, 1993, Williams led 14 of his colleagues on a field trip into the mile-wide caldera to test various eruption prediction methods.

As the scientists wrapped up their studies for the day, Galeras belched. On the scale of volcanic eruptions, it was a blip—only 0.003 percent the size of the 1980 Mount St. Helens eruption. However, people died and publishers have capitalized on the harrowing tale.

Controversial Book

Victoria Bruce, a journalist, looked into the 1993 incident and heard rumblings that the scientists should not have been at the volcano at all. She tells that story in her book, In No Apparent Danger: The True Story of Volcanic Disaster at Galeras and Nevado del Ruiz, also published this April.

According to Bruce, seismic evidence in the form of screw-like shapes called tornillos on a seismograph showed up weeks prior to the eruption. Bernard Chouet, a geophysicist with the United States Geological Survey, reported in 1991 that tornillos could portend an eruption at Galeras.

Two Colombian seismologists purportedly warned Williams and colleagues about the tornillos at a meeting the night before the eruption, but the information was not shared, according to Bruce. If it had, she claims the disaster could have been avoided.

"Caught by Surprise"

Williams stands by his claim that no one, not even the Colombian seismologists Bruce refers to, predicted that the volcano was about to erupt. "Had they argued the danger was serious, I never would have considered going in there," he said. "The eruption caught everyone by surprise."

The volcanologists went into the volcano to learn how to predict when it would erupt. Such science, if ever perfected, could save hundreds of thousands of lives. Currently, 500 million people live in the shadow of the worlds 1,500 active volcanoes.

"Look at how many people live near volcanoes. We need to understand these things, we need to keep the death toll down," said Williams, who endured 17 operations to mend his body together after the Galeras eruption.