Tightly packed sediments help the Cascadia Subduction Zone generate large earthquakes, and could boost its ability to trigger a large tsunami.

Scientists probing under the seafloor off Alaska have mapped a geologic structure that they say signals potential for a major tsunami in an area that normally would be considered benign.

A new pilot program led by the Lamont-Doherty Earth Observatory aims to provide earlier and more accurate warnings of damaging ground-shaking from earthquakes and the imminent arrival of tsunamis.

For all of its violent destruction, the earthquake that struck Haiti on Jan. 12, 2010, hardly scratched the surface of the island. But scientists now say they have found some of the best clues to understanding the quake under water.