Late last year we reported on the development of a completely new kind of breakwater to prevent a tsunami from hitting the coast with its full might.  Unlike other breakwaters that would otherwise hinder sea transportation and the aesthetics of the ocean, these remain at the ocean floor until called upon.

If a tsunami warning is in effect then they can rise up in a matter of minutes and disrupt the coming wave. On 28 March the first nine-meter segment of this system was constructed and successfully tested. Here is some video of the test.

Looking at the video you might suspect some complex machinery making the steel pillars rise up 13 meters from the bottom of the ocean to seven meters above it.  However, all it takes is some air.

Air is pumped in from the shore when the alarm is sounded which creates and air pocket inside the pillar causing it to become buoyant and rise to the top. When the emergency has passed, the air is simply let out and the pillar sinks back to the bottom.

This eliminates a lot of the maintenance that mechanical pillar would require.

It’s a clever solution but this segment is only nine meters of a proposed 230-meter line around Wakayama Prefecture’s peninsula. The entire breakwater is expected to be completed in 2020 at a cost of around 730M yen (US$7.8M).

Source: Naver (Japanese)
Video: YouTube – KyodoNews