To reduce social vulnerability, various infrastructures,
or hardwares, have been implemented since the 2004
Indian Ocean and 2011 Tohoku tsunamis. Speakers to
broadcast tsunami warning messages have been installed
in coastal areas of Indonesia or Thailand. Sign boards
showing the altitude and route to evacuation places have
been installed at numerous coastal communities in the
world. New and higher seawalls have been constructed
for coastal cities, particularly to protect critical facilities
such as nuclear power plants. These kinds of infrastructure
have their lifetime and may not be maintained until
the next tsunami disaster.