Another of the downsides of living on an island in the middle of the ocean is the vulnerability to tsunami. Tsunami (pronounced sue-nah-me), from the Japanese tsu for harbor and nami for wave, are the waves generated by "earthquakes, landslides, volcanic eruptions, explosions, and even the impact of cosmic bodies, such as meteorites..." Note that some in the west sometimes substitute the phrase "tidal wave" for tsunami but unless the waves were caused by the tides, this is incorrect.
Hawai'i was under a tsunami watch last week Thursday due to a magnitude 8.0 (on the Moment scale, 7.9 on the Richter - see this site here that explains the different scales) earthquake near Japan. The earthquake, centered near the island of Hokkaido, caused one death and 388 injuries (see this article here for more details).
It also created a small (3ft/0.9m) tsunami that did only local damage.
However, there have been tsunami that have killed hundreds (see the list here) including 146 on April 1, 1946 on the Big Island of Hawai'i and 61 in 1960, also on the Big Island.
Tsunami are more common that most people realize. During the period from 1900 to 2001, there were almost 800 tsunami observed or recorded in the Pacific region. Of these, over 100 caused casualties and damage near the source and nine caused widespread damage throughout the Pacific. Without exception, during every year of this period, at least one tsunami was generated.
So when the Pacific Tsunami Warning Center cranks into action (see it here), we listen.
10:09 HST The center issues the first of what will be four bulletins. Bulletin 001 is an advisory that indicates a magnitude 8.1 earthquake occurred near Japan 19 minutes earlier. In the rush to get information out to the Civil Defense authorities, an incorrect estimated time of arrival (ETA) of 6:01pm ( HST) is given. In the open ocean, tsunami travel at about 500 mph (805km/hr). An ETA of 6:00pm would give us about eight hours to evacuate thousands of people living near the shore.
Based on this bulletin, all court administrators were notified of the possible arrival and perhaps the need to execute pre-arranged emergency evacuation plans.
10:27 HST Bulletin 002 corrects the ETA to 5:01pm HST. If a Pacific-wide tsunami was generated, we now have six-and-a-half hours to evacuate all near shore areas. Instituting such an evacuation is not taken lightly as the last time it was done, traffic grid lock occurred. Hence, authorities wait for confirmation of a tsunami approaching before issuing such an order. Unfortunately, as noted above, the longer you wait the less time you have to try to get people out of harms way.
11:11 HST The third bulletin raises the level of alert from an "advisory" to a "watch" as "BASED ON ALL AVAILABLE DATA A TSUNAMI MAY HAVE BEEN GENERATED BY THIS EARTHQUAKE THAT COULD BE DESTRUCTIVE ON COASTAL AREAS EVEN FAR FROM THE EPICENTER." The next step after watch (which is instituted after all 7.5 magnitude earthquakes) is warning. A warning means a tsunami has been generated and may impact an area within the hour.
12:14 HST The final bulletin canceled the watch as "THERE IS NO DESTRUCTIVE TSUNAMI THREAT TO THE STATE OF HAWAII." Had there been such a threat, authorities would have had four hours and forty-five minutes to get every man, woman, and child near the shore of every island to higher ground. Part of the evacuation plans for O'ahu County is the use of the public bus system. Unfortunately, said bus system was on strike at the time. Even if all of the bus drivers and mechanics had been able to get to their buses, many of the vehicles would not have been usable due to dead batteries or flat tires.
There are many lessons to be learned. The main one is we need to be able to move thousands of people out of the way in a relatively short period of time. How to do that remains unresolved. However, if we don't come up with a solution, hundreds more may die one day as it is a matter of when, not if, a Pacific-wide tsunami will come our way.
For more information on tsunami check out these sites here or here.
Aloha!
