China cabinets, wardrobes, and bookshelves can be prone to falling into a room in an earthquake because they are often quite tall and heavy; furniture-securing items are available at your local home improvement store. Other items that need securing are appliances like hot water tanks and fridges; products designed for securing these types of appliances are also available at home improvement stores.
Hang heavy items, pictures, mirrors, etc. away from beds and couches and brace overhead lighting and fans. Make sure all flammable liquids and dangerous chemicals are stored in a secure location. Ensure electrical and gas connections are in good condition and inspect for deep cracks in ceilings and foundations.
While the technology to construct earthquake-resistant buildings has existed for many years, tsunami-proof housing is very much in its infancy. Evacuation to higher, safer, ground is pretty much the best option, but if your home is hit by a significant wave, the amount of damage that it could cause could be astronomical.