Crystal Gammon

Eruption of underwater volcano, resulting landslide recorded by submerged mic.

Quake caused by rare horizontal fault, which shifted city one foot.

Signatures in ancient rocks show continent's erosion history.

Mapping effort finds structures bridging Mariana Trench.

How these features formed has been debated.

Can't predict quakes but could provide warning.

Measurements show huge displacements of ocean floor that set off waves.

This sea rifted apart much faster than other ocean basins.