Posted on 01/21/2005 7:51:32 AM PST by M. Espinola
Earthquake lore is as old as humanity. Throughout history people have believed that dogs howled or rabbits climbed onto roofs before a tremor struck. Even after the devastating Boxing Day earthquake and tsunami struck Southeast Asia, it was remarked that few if any animals seemed to have been caught in the deadly tide. Did they sense something was coming and head for the hills?
Earthquake science, though, is much younger than many think. When today's 50-year-old was in secondary school, the notion that continents drifted like paper plates floating on water was science fiction - except to a few pioneering geologists. It wasn't until the late 1960s that the theory of plate tectonics, upon which virtually all scientific efforts to predict earthquakes is based, became generally accepted. That is worth bearing in mind as attention turns to a post mortem on the tsunami catastrophe.
Before the giant tsunami hit coastlines along the Indian Ocean littoral, the greatest natural disaster to hit Asia was the Great Kanto Earthquake that leveled Tokyo in 1923, killing 140,000. Unlike the case in the United States, where people fear a repeat of the terrorist attacks of September 11, 2001, Japanese fear that another "Big One" will devastate the capital once again. The global consequences of such an event would be much more severe.
Japan spends roughly $100 million a year trying to forecast earthquakes, tsunamis and volcanic eruptions. Some observers say that it is money down the drain, since despite all this effort the authorities failed utterly to predict the Great Hanshin Earthquake, which killed 6,400 people; the 10th anniversary of that quake, January 17, this past Monday, was recently observed with ceremonies in Kobe. As the critics see it, such resources would be better spent on rescue training and stocking supplies for future disasters.
But it would be a mistake to abandon all efforts in a sphere where scientific understanding is still in its infancy. In the decade since the Kobe quake, Japan has continued to expand its warning network. There are seismometers belonging to the Meteorological Agency, universities or research institutes at about 3,800 locations nationwide. Many but not all feed data constantly to the computers of the National Earthquake Prediction Center near the northeast end of the Imperial Palace grounds in Tokyo.
This is not a research facility. Its mission is to predict the next "Big One" - not to mention little ones, tsunamis and volcanic eruptions - in time to warn the public. It operates on the assumption that any large earthquake would be preceded by smaller tremors and minute rises in land elevations. If enough precursors are recorded, a committee of scientists would convene on the premises to assess the situation and advise the prime inister whether to issue a warning or an evacuation order.
A major hole in this effort, ironically, is Tokyo itself. It is difficult for seismometers to differentiate between the small tremors caused by earth movements and those caused by the rumbling of trains and automobiles, especially at relatively shallow depths. That's why Japan's scientists concentrate most of their efforts in the Tokai region south of the capital, where four underground plates converge. They concentrate on this area because it is a place they are reasonably confident of success, where a big one might occur.
Like earthquake prediction, true earthquake proofing in construction technology is also relatively new. Few if any truly earthquake-resistant buildings existed in Kobe before the 1995 quake struck. New buildings in Tokyo must be able to withstand a shaking of at least 7.0 on the Richter scale. A recent regulation requires owners of large buildings built before 1981 to examine their buildings for earthquake resiliency, and, if they don't pass, to reinforce them or tear them down.
One of the most enduring images from the Kobe earthquake was the collapse of the Hanshin Expressway, despite claims of the Japan Highway Public Corp that its highways were safe. Anyone who has been in Tokyo knows that it has miles upon miles of expressways built on pylons, many dating back to the 1964 Tokyo Olympic Games. They often wind their way along the paths ways of old moats or over river beds.
Clearly, the safest place to build roads is flat on the ground, where they can only crack, not collapse. But in densely populated Japan, highways are raised because it is prohibitively expensive to buy land and legally difficult to persuade inhabitants to part with it. One earthquake protection measure would involve revising the complex tax code and public domain laws, so that these dangerous elevated roads do not have to be built at all.
It is folly to continue encouraging people to pour into a narrow corridor stretching between Osaka and Tokyo, when it is plainly a potential death trap. True, perhaps no part of Japan is entirely safe from earthquakes, and the most recent seismic events, such as October's Niigata-Chuetsu Earthquake, have occurred in northern Japan. But it only underscores the wisdom of spreading people and businesses away from key danger zones, such as the capital city itself.
For many years politicians have been talking about moving the capital of Japan out of quake-prone Tokyo. A head of steam built up behind that notion in the early 1990s, and by the middle of the decade, it had progressed to the point at which a committee of the Diet had identified several alternative sites. The one most frequently mentioned is in or near Sendai, the metropolis of northern Honshu. The idea had the added advantage of invigorating the somewhat economically depressed Tohoku region.
Since then the move-the-capital movement has stalled. One factor is a realization that not much of the Japanese archipelago is free from the threat of a devastating quake. Another is the vigorous opposition from the strong-willed governor of Tokyo, the conservative and nationalist politician Shintaro Ishihara.
But it may be time to get serious again, at least about some aspects of the notion. Japan is in the forefront of many modern technologies - from fiber optics to magnetic levitated trains - that would allow people to do their jobs from widely separated places. In the long-term, people may be the best quake-proofing devices of all.
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And if they could predict eathqukes, how would they use that knowledge?
We know large earthquakes are coming. Better to spend the money to make buildings and infrastructure safe when they do.
Good Afternoon That is good information Thank you
Very interesting ~ Bump!
Another one just hit Sumatra 5.6.
Since we can not pin point the exact time-frame a devastating earthquake will strike, building codes in geographic zones prone to severe seismic jolts must become stricter and rigidly enforced.
Québec - eastern Canada
It might be advised to begin 'an earthquake FR data/update list'. If anyone is interested just FR mail me.
Don't say nobody cares what you state. I was not aware of that great link you posted and furthermore if we combine efforts on this subject a number of people will become more aware domestic & global seismic activity.
As of late I was engaged in some research concerning Canadian earthquake prone areas. Here is one of the maps.
This link has some highly detailed historical earthquake maps from 1638 to 2001.
We are moving through uncharted regions of space as our galaxy moves ahead, thus encountering many unknown external challenges. The webmaster on syzygy.org believes the moon and ocean tides have a lot to do with triggering earthquakes. I tend to think external geomagnetic forces generated by the sun play a significant role.
People do not really care what I think because I am not a scientist.
I agree fully that the Earth reacts to space/solar weather.
In relation to this latest rash of major earthquakes, the root causes may actually be both,lunar, tides in conjunction with solar related external geomagnetic forces.
I received this data tonight via an e-mail update service: A magnitude 5.5 earthquake IN THE TAIWAN REGION has occurred at: 24.68N 122.35E Depth 105km Fri Jan 21 14:28:22 2005 UTC
2005/01/21 12:45 M 5.6 OFF EAST COAST OF HONSHU, JAPAN Z= 10km 34.20N 141.55E
2005/01/21 13:45 M 6.0 COAST OF ECUADOR Z= 10km 1.12S 80.71W
2005/01/21 17:54 M 5.6 MINDANAO, PHILIPPINES Z=176km 5.12N 125.23E
Below is another report dealing with the Puerto Rico and Hispaniola region:
'In a new study, geologists Jian Lin of the Woods Hole Oceanographic Institution (WHOI) and Uri Ten Brink of the US Geological Survey reported a heightened earthquake risk of the Septentrional fault zone, which cuts through the highly populated region in the Dominican Republic.
Their findings were published in the Journal of Geophysical Research from the American Geophysical Union last December.
With nearly 20 million people now living in this tourist region and a major earthquake occurring on average every 50 years, scientists say it is not a question of if it will happen but when.
The most recent major earthquake, a magnitude 8.1 in Richter scale in 1946, resulted in a tsunami that killed a reported 1,600 people. "According to our research and based on the historical records, the probability of a major earthquake that can cause tsunami in Caribbean region is very, very high," Lin told Xinhua. "This disaster, if it happens nowadays, will certainly kill much more people than it did half a century ago."
The geologically active offshore Puerto Rico and Hispaniola trenches are capable of producing earthquakes over magnitude 7.5. The Indonesian earthquake on December 26, which generated a tsunami that killed an estimated 150,000 people, came from a fault of similar structure, but was a magnitude 9.0.'
'Lin and Brink studied the geology of the northern Caribbean plate boundary, looked at historical earthquake data in the region,and used three-dimensional models to calculate the stress changes in and near the trenches after each earthquake.'
'They say stress has increased for the Hispaniola area, and that the potential threat of earthquakes and resulting possible tsunamis from the Puerto Rico and Hispaniola trenches is real and should be taken seriously.'
People will sit up and take notice when one, just a single prognostication comes in right on the money concerning a massive earthquake.
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