HERE ON THE BIG ISLAND – We Were Prepared – and Lucky!

HERE ON THE BIG ISLAND
By Kelly Moran

We Were Prepared – and Lucky!

On the morning of a calm sunny Saturday, the 27th of February, tsunami alert sirens all around the island went off.  An earthquake in Chile, the night before, had sent shock-waves through the Pacific, and the Big Island got ready to deal with its consequences.

Tsunami Warning Centers Took Extra Caution. Photo KITV News.
Tsunami Warning Centers Took Extra Caution. Photo KITV News.

Hilo was famously socked twice in the 20th century by the force of a tsunami – more than twice, actually, but hit  really hard  in 1946 and 1960.  The tsunami in ’60 had come from an earthquake in (you guessed it) Chile, which at 9.5 was the largest  ever  recorded. This latest one, at 8.8, was only(!) the fifth-largest.

Here in Hawaii, we pay attention to tsunami alerts.  Last September, a tsunami slammed into American Samoa.  In December of 2004, a tsunami devastated several countries on the Indian Ocean.

The Pacific has a network of buoys across its expanse and along all of its coasts, linked by radio data transmission.  (The Indian Ocean does not have such a network, so the 2004 tsunami there could not be detected and warned against until it was too late.) 

DART stations consist of a bottom pressure sensor anchored to the seafloor and a companion moored surface buoy. An acoustic link transmits data from the bottom pressure sensor to the surface buoy, and then satellite links relay the data to NOAA tsunami warning centers. The DART network serves as the cornerstone to the U.S. tsunami warning system.
DART stations consist of a bottom pressure sensor anchored to the seafloor and a companion moored surface buoy. An acoustic link transmits data from the bottom pressure sensor to the surface buoy, and then satellite links relay the data to NOAA tsunami warning centers. The DART network serves as the cornerstone to the U.S. tsunami warning system. Photo: NOAA.

The Pacific sensors picked up oceanic disturbances and local rises in sea-level almost immediately after the Chilean quake.  As soon as that news reached our Civil Defense units, on Friday night (Hawaii time), they issued their warnings of a potential tsunami.  Ocean waves generated by earthquakes travel about as fast as a jetliner, some 400-500 miles per hour; so Civil Defense calculated that they would reach Hawaii around 11 a.m. Saturday morning.

The first pages of the telephone directories in Hawaii have maps of potential tsunami inundation zones on every island.  There’s even more information online, as well as news about this latest tsunami and those of the past.  It should come as no surprise that Hilo is home to a museum about tsunamis: the Pacific Tsunami Museum (www.tsunami.org/index.html#news), which I mentioned last November, in urging you to sign up for local Civil Defense alerts via cellphone text

Wonder where the tsunami evacuation zone is near you? NOAA in partnership with the State of Hawaii has developed the "Are you in a Tsunami Evacuation Zone?" to provide residents and visitors of the State of Hawai'i easy, online access to the State's tsunami evacuation zone maps. Check it out!
Wonder where the tsunami evacuation zone is near you? NOAA in partnership with the State of Hawaii has developed the "Are you in a Tsunami Evacuation Zone?" to provide residents and visitors of the State of Hawai'i easy, online access to the State's tsunami evacuation zone maps. Check it out!

The United Nations, through UNESCO, operates the International Tsunami Information Center (http://ioc3.unesco.org/itic/), and both websites have links to additional sources of news and background information.

"Tsunami, The Great Waves": This 12-page glossy brochure provides information on what a tsunami is, how fast and how big they can be, what causes them, and describes programs undertaken to mitigate this hazard, including the development of tsunami warning centers, research programmes, and safety rules describing what to do when a tsunami attack your coastline.
"Tsunami, The Great Waves": This 12-page glossy brochure provides information on what a tsunami is, how fast and how big they can be, what causes them, and describes programs undertaken to mitigate this hazard, including the development of tsunami warning centers, research programmes, and safety rules describing what to do when a tsunami attack your coastline.

So, let me tell you: We were ready!  We were also lucky.

With so much advance notice, many boat-owners sailed out to sea, to ride it out.  Retail shopkeepers had time to move vulnerable inventory uphill.  Hilo Airport, which is inside the “tsunami indundation zone,” was closed to traffic.  Mail delivery was suspended.  Hotels shifted people upstairs. (All of Hawaii’s coastal hotels, by the way, are built on sturdy piers; their lobbies have tall ceilings and no load-bearing walls, so a tsunami can surge through without undermining the structure.)

That morning, as luck would have it, there was a minus tide.  I watched Hilo Bay through binauculars, from the Davidson’s oceanfront home on Paukaa Drive, and the only effect that I saw was some waves cresting over the breakwater in the harbor.  Frankly, I’ve seen higher swells make bigger waves in a storm; but those were blue-green, with whitecaps, and had been generated by strong winds.  The waves on February 27 had been generated under the sea: they were brown from the mud (and whatever else) that they’d swept up from the Big Island’s underwater landmass.

As a result of Saturday’s tsunami, water rushes through the entrance to the Wailoa small boat harbor in Hilo. According to Mayor Billy Kenoi, the wave action generated by the temblor pulled all the water from Hilo's Wailoa River into the ocean. Photo: Hawaii Tribune-Herald.
As a result of Saturday’s tsunami, water rushes through the entrance to the Wailoa small boat harbor in Hilo. According to Mayor Billy Kenoi, the wave action generated by the temblor pulled all the water from Hilo's Wailoa River into the ocean. Photo: Hawaii Tribune-Herald.

And that was about it for the tsunami of Feb. 27, 2010.  In the end, no damage was recorded anywhere in Hawaii.  But it could have been a catastrophe.  And this little blog would have been a lot different.

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