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Patrick Takahashi

Patrick Takahashi

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Hawaii Tsunami, Again

Posted: 03/11/11 08:06 AM ET

A little more than a year ago I wrote in The Huffington Post on the tsunami that struck Hawaii from the 8.8 Chile earthquake. People were disappointed when, at most, there was a 2 foot tsunami.

Well, at 7:46 PM Hawaii time tonight, a massive 8.9 (revised to 9.0) earthquake struck 81 miles off Sendai (232 miles from Tokyo) in the Pacific Ocean, making this Japan's largest earthquake in 140 years. This tremor occurred in the general area of a quake two days ago which registered at 7.3. The energy release difference between these two earthquakes was around a factor of 250. For details on how to make these calculations, go to Planet Earth and Humanity.

A major tsunami is scheduled to hit Hawaii at 2:55 AM, HST. I'm being conservative, as the official time was announced to be 3:07 AM. The San Francisco expected time of arrival is 8:08 AM, PST. Historically, there is no recorded major tsunami from Japan to Hawaii or the West Coast, and waves should first make landfall on Kauai and take 20-30 minutes to travel to the Big Island. Clearly, the northwest side of the islands will be affected, but there is a wrap-around effect, and a few hotels in Waikiki began to evacuate guests, although the latest news seem to have changed the concern to just moving up to the sixth floor and higher.

Thus far, a 30 foot tsunami was experienced in Sendai, and ocean gauges seem to predict a 6 foot wave in Hawaii, which will be adjusted as further information is received. However, neither Taiwan nor the Philippines appear to have seen much of an effect so far. Thus, initial signals seem to show that the far field is not being impacted much. So, about Hawaii? When I was in high school in Honolulu a long time ago, an actual 55 foot run-up occurred on Oahu. So, we'll see.

The following then can be tracked over time. I was tempted to insert exact times, as suggested by a HuffPo editor, and I later might, but you can at least get a sense of the flow of the events:

Okay, the first report from Hawaii about minor waves on Kauai. Then, a NOAA announcement about Barbers Point (west point of Oahu, where Honolulu is located): 0.7 feet, which is about 2 feet. Sometimes the second wave can be larger, so we need to wait an hour or so longer.

As the wave moves south and east, at Kahului, Maui, the ocean is receding and the reef can be seen, which is certainly not normal. Remember, it is dark out there, and, really, no one should be reporting on something like this. Wailuku and Kahului are in a more direct path of the incoming tsunami, so this could become serious. There is an another NOAA report that the wave could be as high as 6 feet. The shape of the coastline and the bathymetry can also amplify the wave, so specific sites can be in greater jeopardy. The second wave then reached 7 feet and the third 9 feet. There are also reports of a nine-foot wave in Lahaina. This means there should have been, with a large lag, an 18 foot face difference. That's frightening. Moored boats should have been affected. Interesting that the third wave was the largest.

Further into the early morning, a three foot tsunami is now affecting Hilo. However, this tsunami city is on the opposite side of the earthquake, so Maui might well be the max for Hawaii. Kailua-Kona got it somewhat worse, as would be expected, for this town mostly faces the direction of tsunami.

Actually, when you come down to it, no major city in Hawaii faces the earthquake itself. The northwest side of all the islands are generally protected by high cliffs, although the North Shore of Oahu, where the major surf tournaments are held, could be vulnerable. Kona is threatened, but Kapalua seems to be blocked by Molokai and Lanai.

While it is not over yet, in a way it must have been a relief to officials that all those wolf cries in the past were justified this time, especially as no deaths have been recorded, yet. While several hundred perished in Sendai, the evacuation orders for Hawaii could well have saved some lives. To put things in perspective, though, that 8.9 magnitude 2004 Indian Ocean earthquake killed more than 225,000.

In the meantime, it would be wise for the West Coast of Canada and the USA to be alert, for the line of the tsunami is already moving down the coastline from north to south. Later reports indicated at least one death in Crescent City, California.

Further south, two to six foot waves appeared on the Mexican coastline and authorities are particularly worried about Easter Island and Chile because the force of the tsunami seems focused towards South America.

How's this for adventure and idiocy? My flight to Narita, Japan leaves in half an hour, so, apparently, that airport is now operational. I understand, though, that 14,000 people are stranded there. I will be touring some of the inundated sites over the next three weeks, and, hopefully, too, see some cherry blossoms.

THIS POST WILL BE REGULARLY UPDATED, although details with maps can be seen at Planet Earth and Humanity. I will, though, probably post a new article on Japan in a few days. For now, just keep up with me by clicking on my daily blog.