All over the world, scientists are discovering traces of ancient floods on a scale that dwarfs even the most severe flood disasters of recent times. What triggered these cataclysmic floods, and could they strike again? In the Channeled Scablands of Washington State, the level prairie gives way to bizarre, gargantuan rock formations: house-sized boulders seemingly dropped from the sky, a cliff carved by a waterfall twice the height of Niagara, and potholes large enough to swallow cars. Like forensic detectives at a crime scene, geologists study these strange features and reconstruct catastrophic Ice Age floods more powerful than all the world’s top ten rivers combined. NOVA follows their efforts to uncover the geologic fingerprints of other colossal megafloods in Iceland and, improbably, on the seabed of the English Channel. There, another deluge smashed through a land bridge connecting Britain and France hundreds of thousands of years ago and turned Britain into an island for the first time. These great disasters ripped through terrain and transformed continents in a matter of hours—and similar forces reawakened by climate change are posing an active threat to mountain communities throughout the world today.
NOVA follows a team of volcano sleuths as they embark on a worldwide hunt for an elusive volcanic mega-eruption that plunged the medieval earth into a deep freeze. The mystery begins when archaeologists find a hastily dug mass grave of 4,000 men, women, and children in London. At first they assume it's a plague pit from the Black Death, but when they date the bones, they're a century too early. So what killed off these families? The chronicles of that time describe a run of wild weather that devastated crops and spread famine across Europe. NOVA's expert team looks for the signature of a volcanic eruption big enough to have blasted a huge cloud of ash and sulfuric acid into the atmosphere, which chilled the entire planet. From Greenland to Antarctica, the team finds telltale "fingerprints" in ice and soil layers until, finally, they narrow down the culprit to a smoldering crater on a remote Indonesian island. Nearly 750 years ago, this volcano's colossal explosion shot a million tons of rock and ash into the atmosphere. Across the globe, it turned summer into winter. What would happen if another such cataclysm struck again today?
As part of the connecting landmass between North and South America, Mexico has long been at the center of a tectonic tug of war spanning millennia. The result is two of the world's largest, most active volcanoes--the rumbling Popocatepetl and the menacing Volcano De Colima--whose vengeful displays of wrath are increasing in frequency. Could a cataclysmic eruption be just around the corner?
Earthquakes have always been a terrifying phenomenon, and they’ve become more deadly as our cities have grown — with collapsing buildings posing one of the largest risks. But why do buildings collapse in an earthquake? And how can it be prevented? Vicki V. May explains the physics of why it is not the sturdiest buildings, but the smartest, that will remain standing.