Tsunami Early Warning Information Graphic


Yep - they get it in Japan.

When the recent 6 metre tsunami hit the Samoan region, killing 189 people, there unfortunately wasn’t time to warn their people.

But there was time to warn their neighbours in the South Pacific.

We failed.

New Zealand had several hours to crank-up the tsunami warning machine. The police did their best to round up people on the shoreline, but apart from that all we got was out-of-date news reports, government websites which were light on detail and the internet rife with speculation and rumours.

In New Zealand SMS (text) messages warning people in high-risk areas arrived 3 hours too late. How many people on the East Coast of New Zealand could have been killed if this was the big one? Potentially thousands.

My previous article covered how bad the information out there was at representing where the tsunami could strike, the risk and what to do. The graphics which were available were highly technical, easy to misinterpret and in most cases was retrospective data of what had actually occurred – not predictions of what was coming.

And we have to take into account human nature. In New Zealand when we hear a tsunami is coming a fair number of us just assume it’s yet another false alarm. Hundreds even go down to the shoreline to watch it coming in.

Why? Saying “go to higher ground” isn’t specific enough. Some will think that means the big sand-dune a few metres from the shoreline.

I believe we need to give people a clear message at a glance, and just enough detailed information that they’ll take it seriously.

So, while I don’t claim to be a tsunami expert, I decided to have a go at creating a ‘general public’ information graphic which could be populated with data in real-time (or by hand and published online within minutes).

I encourage your feedback, or if you are a designer, have a go at improving on my design and let me know when you do.

Here’s my first attempt (click on the image to enlarge) or download the PDF (84KB) if you want a closer look.


The left panel shows a regional breakdown of the risk level, how high/inland to go and the deadline:


The map shows the risk level, how high/inland to go and the deadline for the major population centres:


The modular design allows the information graphic to be easily reformatted for different layouts. Here’s a snap-off of the map on it’s own:


And here’s a snap-off of the regional warnings:


Information Components

Good idea.
Good idea

The purpose of the graphic is to act as an early warning system to explain the following things I thought most people would be interested in:

  • Earthquake magnitude.
  • Wave height.
  • Arrival location(s).
  • Arrival time(s).
  • Power of the wave (extent of inundation).
  • How high I need to go up or/and how far inland.

Earthquake magnitude is easy, I included that.

Wave height is variable and actually a misleading factor as people wrong assume a small (say 3m) wave is not dangerous. It actually depends on the power or force of the tsunami – a small tsunami could still go a long way inland and cause devastation. So I deliberately left wave height out.

The other questions I have done my best to answer in the graphic.


The extent of inundation was hard to represent in “birds-eye view” graphic as it depends on so many factors (such as being by a river estuary).

This could work if the map was interactive, like a Google Map where you could zoom into your region and see an overlay of the areas which are likely to be affected. I’m sure this sort of thing is coming.

Colours to Represent Risk

Another aspect I struggled with was the use of colours to represent risk.

At first I used the traditional red/orange/yellow to show risk levels. I decided this wouldn’t be useful for people with red/green colour blindness (the most common form of colour blindness).

I felt that using of shades of blue further emphasised water smashing into the shoreline, so this won in the end.

Red/Orange/Yellow or shades of Blue?



Your Thoughts?

Says it all.
Says it all.

Whether you’re a tsunami expert or not I’d love your feedback.

Keep in mind that the intention of this Information Graphic is to act as one way to communicate the risk and guide people to take action.

I realise it’s imperfect as the risks can be hard to assess due to dozens of complicating factors. But in all I believe it’s better than ‘almost nothing’ – which is what we get every time a large earthquake hits the Pacific.

PS: Thanks to Click Suite who unknowingly allowed me work-time to design this graphic last Friday while my bosses were holidaying in Fiji (I was thinking of you insanely relaxing on a beach during the tsunami season!)