8.9 – Massive Earthquake Off Coast Of Japan.

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God… That’s a MASSIVE QUAKE!!!!…

Yet, it didn’t do nearly as much damage as you would expect from an 8.9. The hypocenter was pretty shallow, only 15 miles below ground, but at 80 mile from the nearest city, considering its size of the quake, it was far enough away that it did not do a great amount of damage.

Here is the shake map from the USGS Web Site.

japshake

To give you an idea of the power of this quake, here is the shake map from one of the foreshocks to this massive quake’

japshake2

At 7.2, this was a very large quake. But the 8.9 was THAT much bigger!

Then comes the Tsunami… SHIT! I’m watching the vid in disbelief. And look at the maps above. That is A LOT of coastline that is vulnerable to this Tsunami. Some of the waves have been said to be over 30 feet high! I’m not a religious man, but my prayers go out anyway.

The Tsunami generated 3 to 6 ft waves in Hawaii. That’s good news for the west coast…. With a caveat. The shape and slope of the coast line can either reduce the effect, or amplify it. Though I was studying seismology when I was a geology major, I quit the program (calc buried me) before we covered Tsunamis in dept. So I’m not an expert, but I think we’re OK here on the West Coast.

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NOTE – One thing that has always annoyed me about Earthquake news coverage is the focus on where the epicenter is and no mention of the hypocenter and the depth of the original pressure release that triggered the quake. Don’t get me wrong, obviously the focus of the epicenter is important, but so is the depth of the quake. This 8.9 quake is estimated to be 8000 times more powerful 1,100 times more powerful than the recent 6.3 quake that struck New Zeland. Christchurch was right on the epicenter, the spot over where the stress rupture occurred. But equally important was the fact that the Christchurch quake had an extremely shallow hypocenter, that was only 4.34 miles deep (7 km), and the Japan quake was 15 miles, or 24.4 km below the Earth.

Here is a write-up of a 5.3 New Zealand quake that occurred in January of this year.

This is an earthquake-report.com flash update on the following recent earthquake :

M 5.3 – Rotorua, Taupo area New Zealand

Strong earthquake with a deep hypocenter = harmless, although a lot of people could potentially to feel it. As most are asleep, we predict that only few will have been awakened by the earthquake shaking. The earthquake epicenter (not important for this kind of quake) was near highway 1 in a very active thermal area. A similar earthquake occurred a couple of weeks ago in the same area, also without damage or injuries.
35 km (25 miles) SW of Rotorua, New Zealand and 24 km NW Taupo (pop 22,469)

Magnitude : 5.3
Local time at epicenter : January 28, 2011 at 03:02:46 AM at epicenter
Depth (Hypocenter) : 154 km

And here is a write-up of the 6.8 quake that rocked the Puget Sound in Febuary 2001:

When the Puget Sound region of Washington state was jolted from its morning routine on Feb. 28 by a magnitude 6.8 Earthquake, the damage was noticeably less severe than might have been expected from such a quake, say scientists at the NSF-funded Southern California Earthquake Center (SCEC) in Los Angeles. This event, named the Nisqually earthquake, for a river delta near its epicenter, was actually larger than the devastating 1994 Northridge
earthquake in California, a magnitude 6.7 quake that became the most costly natural disaster in U.S. history.

Was the Seattle area better prepared for a major earthquake than Los Angeles? Or was the discrepancy a result of differences in the earthquakes themselves?

SCEC geologists say it is the latter. They believe much of the difference between the Nisqually and the Northridge quakes can be attributed to the Nisqually earthquake’s location — not that of its epicenter, but that of its depth, or hypocenter. The Northridge quake had a hypocentral depth of 11 miles, deep for a California earthquake, but shallow for other regions. Nisqually’s depth was some 33 miles, making its center farther away from structures than at Northridge, explaining the differences in the two quakes’ effects.

During the Japanese quake, the movement of the shallow fault line is what caused the great Tsunami. If it would have been a deeper hypocenter, maybe it wouldn’t have been so huge and devastating.

Here is some more info concerning this topic.

As long as I’m getting critical of news coverage of Earthquakes, I might as well rehash the “Temblor” controversy. 🙂

1 Comment to “8.9 – Massive Earthquake Off Coast Of Japan.”

  1. By Jeff Alberts, March 12, 2011 @ 2:40 am

    I know this is in bad taste, and I REALLY feel for the people of Japan, but the only thing missing from those images and sounds of disaster was Godzilla rising from the giant whirlpool.

    I REALLY apologize for that, honestly. But it was the first thought that bumped into my brain. I blame it on all the Japanese monster movies I was forced to watch as a teenager in the 70s.

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