Chalk reveals greatest underwater landslide

The cataclysmic event that wiped out the last dinosaurs also triggered the greatest underwater landslides ever, scientists report. A chunk of a giant comet or asteroid slammed into Mexico's Yucatan peninsula about 65 million years ago, setting off earthquakes with magnitudes estimated at 10 to 13. The seismic shock waves generated meter-high vibrations in Earth's crust all along the east coast of North America...