While it's possible that a ship can feel the impacts of an earthquake, it's extremely rare that damage would occur, according to Dr. Thomas Heaton, seismologist and professor of geophysics and civil engineering at the California Institute of Technology.

Being on a cruise ship during an earthquake is generally considered very safe, as water does not transmit the destructive "S-waves" (secondary waves) that cause the ground to shake and buildings to collapse. If a ship is out at sea or even in relatively deep water near the coast, the passengers may not feel the earthquake at all. The primary concern for a ship isn't the quake itself, but the potential for a tsunami. However, modern cruise ships are equipped with sophisticated seismic monitoring and satellite communication systems that receive instant alerts from global geological agencies. If a tsunami is detected, the standard protocol is for the ship to head into deep, open water, where a tsunami wave is barely a ripple on the surface; it only becomes a dangerous wall of water as it reaches the shallow coastline. If a ship is docked at a pier during an earthquake, there is a risk of the pier collapsing or the ship being buffeted against the dock, but the ship's buoyant nature still makes it one of the safest structures to be in. The greatest danger to cruise passengers during a seismic event is actually being "on shore" during an excursion in an area with poor building codes.