I spent a bit of time researching the vulnerability of the town to effects of an offshore earthquake. The is a heck of a large and potent subductive fault about 30 miles off-shore. In the 1930's a 33' tsunami came ashore and flooded the town. It's a pure regional quirk that tsunamis are slow to build up and cone ashore like a continuing high tide. See the 1995 LA MANZANILLA tsunami
http://cwis.usc.edu/dept/tsunamis/manzanillo/.
People carried their furniture and appliances to higher ground as the water seeped higher and higher. It's sounds weird but it's fact.
So don't let someone with an ancient photograph of a flooded downtown village Zihuatanejo tweak your beakie. This isn't Phuket or Japan, at least as far as a killer waves is concerned.
Mexico City is an exception of where not to build but almost all of the on-the-water villages are built on very rocky soil and a shake that would cream Mexico City is barely felt because a place is built on bedrock not gelatin grade silt.
