From rising magma to cooling lava, volcanic activity transforms landscapes above and below ground. This collection examines eruptions, calderas, geysers, geothermal systems, and the processes that move molten rock toward the surface.
When Mount Pinatubo reached its climactic eruption on June 15, 1991, the immediate landscape was overwhelmed by ash, pumice, and pyroclastic flows. Yet one of the eruption’s most important effects developed far above the Philippines. Pinatubo injected an immense cloud of sulfur dioxide into the...
Mount St. Helens had already been erupting for weeks when its most destructive event arrived on May 18, 1980. Earthquakes, steam explosions, and a growing bulge on the volcano’s north flank showed that magma was forcing its way into the edifice. Yet the decisive moment was not simply an explosion...
On June 8, 1783, the ground in southern Iceland split open along a volcanic fissure southwest of the Vatnajökull ice cap. What followed was not a brief explosion from a single summit crater. The Laki, or Lakagígar, eruption unfolded through a chain of fissures and craters, repeatedly sending...
In April 1815, Mount Tambora on the Indonesian island of Sumbawa produced the largest explosive eruption in recorded history. The immediate disaster unfolded locally: pyroclastic flows swept toward the sea, ash buried farmland, roofs collapsed, and food and water systems failed. The eruption also...
Krakatau’s climactic eruption on August 27, 1883, did more than destroy an island volcano in Indonesia’s Sunda Strait. It launched pressure waves through the atmosphere, tsunamis across the sea, seismic vibrations through the ground, and fine particles around the planet. New instruments and global...
About 74,000 years ago, the Toba volcanic system on Sumatra expelled an extraordinary volume of magma and left a caldera now occupied by Lake Toba. Ash from the Youngest Toba Tuff spread across the Indian Ocean and South Asia, creating a time marker found thousands of kilometers from the volcano....
Campi Flegrei does not rise as a single volcanic cone. It is a broad caldera woven into the western suburbs of Naples, the city of Pozzuoli, coastal neighborhoods, and the Bay of Pozzuoli. Roads, homes, rail lines, and archaeological ruins cross ground that has repeatedly moved up and down. That...
Yellowstone is often pictured as a colossal underground vat of molten rock. That image is dramatic, but it is not what geophysical measurements reveal. Beneath the caldera lies a vertically layered magmatic system in which crystals, partly molten rock, dissolved gases, and hydrothermal fluids occupy...