Huge volcanoes emptied lava on the surface of ancient Earth, at a much greater rate than geologists had expected. It turns out that volcanic eruptions are of the same magnitude; Compared to the largest previously known volcanic eruptions, they have occurred at least 10 times in the past 3 billion years, according to an analysis of the geological record.

These volcanic eruptions are linked to some of the most great changes that have occurred in the history of the planet. This includes the largest mass extinction event that occurred 252 million years ago, when volcanoes covered Siberia with molten rock and poisonous gases.

“The more we go back in time, the more we discover events of the same magnitude,” says Richard Ernst, a geologist at Carleton University in Ottawa, Canada, and Tomsk State University in Russia, who led the study.

Knowing when and where these volcanic eruptions occurred can help geologists locate ore deposits, reconstruct the map of the great continents, and understand how our planet's crust formed. Studying this type of volcanic activity on other planets can reveal clues about the geological history of the early Earth.

Ernst reported the findings last March to the Federation of Industries, which funded his research (see 'Earth's Largest Volcanic Eruptions'). Ernst expects to make the data publicly available by the end of this year, through a map provided by the Commission on the Geological Map of the World (CGMW) in Paris.