Posts tagged hawaii

Depiction of the Week: Honolulu Tsunami Simulation

With the advent of the Depiction Reader, we’re starting a new feature called “Depiction of the Week”. Each week we’ll feature a depiction that you can open with either the Reader or the full version of Depiction. Are you a Depiction user with a Depiction you’d like to see featured? Click here to submit it.

This week’s depiction is this Honolulu Tsunami simulation. This depiction was originally built back on February 27, 2010. That was the day when an 8.8 magnitude quake hit just off the coast of Chile, and a tsunami warning was issued for the entire Pacific. Hawaii underwent its first tsunami evacuation since 1994, and waves of 8 to 9 feet were predicted.

Fortunately, the waves ended up being far smaller than predicted, but there were tense hours when that was unclear. During those hours, I happened to be far away from the office and my usual computers. As it happened, I was at a wedding, with nothing but my wife’s netbook. Still, I wanted to use Depiction to quickly show what the potential impact of waves of different heights could be.

Fortunately, I was able to snag some time and some wifi, and created this post with links depictions of Hilo Bay, Honolulu, and, at the request of a commenter, Kahului Bay on Maui, each with simulations of 6, 9 and 12 foot inundations.

The depiction presented here is the one created for Honolulu, with a few more elements added–specifically schools, hospitals and evacuation zones, all retrieved from the very thorough Hawaii Statewide GIS program.

A few caveats: the Depiction flood model is a very simple one, built to give a rapid potential impact (even when just using a netbook!) by showing what an increase in water level from a certain point would look like, based on the elevation data contained in the Depiction. The elevation data I used was that provided through Depiction’s Quickstart feature, and is 30-meter DEM data from the USGS (this means that the elevation was measured every 30 meters). Using higher resolution elevation data–where the elevation was measured every 10 meters, for example–would likely give different, more accurate results, though it would also increase the file size.

Honolulu Tsunami Simulation

Depiction of the Week: Honolulu Tsunami Simulation

Tsunami “what-ifs”

Fortunately, the tsunami that hit Hawaii was nothing like what was feared. The experience did provide an opportunity, though, to demonstrate how easily Depiction’s flood element can simulate things like tsunami inundation and storm surges. It’s one example of a very simple but powerful tool that Depiction has–just drop a flood in the water body, input your total feet, and Depiction will calculate the extent based on the elevation data. I just used the basic 30-meter data Depiction pulls in through a quickstart, but any data type will work, and you can get higher resolution data for much of the US, at least, from the USGS Seamless website.

The story behind my post yesterday is also moderately interesting–I was out of the house all day, at a wedding and running various other errands. The only computer I had access to was a $300 netbook that had never run Depiction. I wasn’t quite sure it would work, but once I got it installed it ran beautifully, even on 1GB of RAM.

Kim Buike also put together a short little video that demonstrates a bit more of how Depiction’s flood model can be used in tsunami simulation:

Pacific Tsunami Depictions

Last night, an 8.8 magnitude quake hit off the coast of Chile (you can download the shakemap for use in Depiction here). There is now a tsunami warning in effect for much of the Pacific. Much of Hawaii, in particular, is evacuating, as waves are expected to start hitting in just a couple hours.

I’ve quickly built a depiction with possible tsunami inundation zones for Hilo Bay, where the waves are expected to hit first. I’m hoping to build others as the day goes on.

Click here to view the Hilo Bay depiction (requires Silverlight), and click here to download the depiction file (requires Depiction).

Click here to view the Honolulu depiction , and click here to download the depiction file (requires Depiction).

Click here to view the Kaluhui Bay, Maui depiction.