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03/03/2010

Natures might.

By, Uwe Paschen.
The might of nature displayed in its earthquakes, typhoons, tsunamis, hurricanes, hail storms, blizzards and many more such natural phenomenon. Those on the one hand do fascinate us and yet can be so devastating that alone mentioning them will cause many to shiver and some to relive painful even horrifying memories caused by such events. Such as the recent powerful Haiti earthquake or the one in California, Japan and the most powerful and latest, the earthquake that just struck in Chile with a magnitude on the Richter Scale of 8.8.
Chile is also where we recorded the most powerful earthquake in modern times or since we have the means to record such natural phenomenon’s that have potentially devastating consequences for Humans and any other life forms for that matter.
We live on a planet that it self may seem alive and according to the British scientist James Lovelockand his Gaia hypothesis, our earth is very much alive in deed and may even have a consciousness of some sort. Even though this may be very hypothetical, leaving some to shake their heads in disbelieve, it is not really a new idea or believe.
Many cultures believed so and still do today and if one takes the scientific approach and analyses what we can observe and understand through science and logical deductions, then it could very well be that this hypothesis may reveal it self to be true and who knows, maybe we will even be able to prove it one day.
However, today we shall stay with the facts at hand that we are able to understand and proves through science, accumulated knowledge and data, all the wile remaining grounded in logic.
Earthquakes are caused by stress factors that are due to the movement of the continental plates, those in a way swim on the Earth inner layer that is made up of magma.
Since we live on the cooled down outer crust of this planet, one may say that we live on gigantic rafts that swim on a very hot and highly dense ocean. This is why those plates or rafts move, even if slowly their mass is such that any movement is felt, at least so it seems from our perspective since our lives are rather short in contrast to the age of our planet where this has been a continuous reality for billions of years. Further we are very small and there for notice those movements in the same manner then a microbe may perceive a twitch by its host wish can be as devastating for the microbe as the earthquake can be for us.
The single most devastating earthquake as far as casualties are concerned in recorded human history did happen in "Shaanxi", China in the 16th century, causing over 830,000 fatalities. That earthquake is estimated have been of the magnitude of 8.0 or higher.
Some believe argue that we do have more earthquakes today then we ever had before, using records to prove their point, this theory is however flawed since we do have accurate and global records only for a very short time and all records prior to the 20th century where only regional and did not monitor earthquakes on a global level.
Why we have only 12-recorded earthquakes above 6.9 in magnitude in the 19th century compared to a 125 in the 20th century. Some religious groups use this in their claim that the end of times is upon us, such claims do not hold up to science or logic though.
The average number of earthquakes per annum in the range above 6.9 in magnitude is 35 earthquakes, this is what can observe since we have accurate records. In the last decade we had 354 earthquakes of those six measured between 7.0 and 7.9 in magnitude none above that. Still there are far more earthquakes world wide on a daily base it is estimated that we have more then 300,000 earthquakes, most of then can not be noticed by us, only very sensitive seismograph do record those. The very powerful earthquakes such as the resent Chile earthquake are the once that do concern us. However, those seem to happen only two to six times every century from what we can deduct from recorded data and recorded history, those records predating the 20th century are not very accurate, but historical records do give us an idea by their events how strong the earthquake may have been.
Now there are areas that are more prone to earthquakes then others are, nevertheless, an earthquake can happen anywhere because the tectonic plates keep moving since they first formed four billion years ago.
At one point, all our continents were one large land mass, that broke up into the continents we know today and those have been moving ever since in very much the same pattern.
Europe and Africa move away from the Americas by a measurable distance annually, where as North Americas, Asia and Australia are on a coalition course, off course there is a lot more to it as the map off the stress factors shows and tectonic plate movements illustrates best.
 Image generated by AFPL Ghostscript (device=pnmraw)
This is why some area such as Japan, the North American west coast and the Caribbean Islands are more prone to earthquakes then other areas would be. Those areas where we had the last four very powerful earthquakes are where the tectonic plates meet or collide. Due to their mass, the effects can be devastating for us mire mortal. Even though those movements are extremely small and slow, they can be of apocalyptic dimensions, especially when those earthquakes are followed by a tsunami such asthe tsunami of the 26th of December 2004 in the Indian ocean whose epicentre was on the west cost of Sumatra in Indonesia. This Tsunami killed nearly 230,000 people with waves as high as 10 metres. The earthquake it self had a magnitude of 9.1 on the Richter’s scale. The energy released by that particular earthquake on the Earth's surface only, ME, being the seismic potential for earth movement was estimated at 1.1×1017 joules or 26.3 megatons of TNT.
The scale below shows the hight of the 2004 tsunami wave.
                           
Tsunami waves are most frequent in the Pacific Ocean because of earthquakes in the "Ring of Fire", and an effective tsunami warning system has long been in place there. Since the 2004 Tsunami, talks are underway to establish such warning system through out the Indian Ocean and the Atlantic Ocean as well.
Not every earthquake does generate a tsunami, on March 28, 2005; a magnitude 8.7 earthquake hit roughly the same area of the Indian Ocean but did not result in a major tsunami.
Earthquakes always have an epicentre from wish the earthquake originates, most of those epicentres are located in the oceans of our planet and the waves are generated in two distinctive ways called body waves and surface waves.
“The body waves travel through the interior of the Earth. They follow raypaths refracted by the varying density and modulus (stiffness) of the Earth's interior. The density and modulus, in turn, vary according to temperature, composition, and phase. This effect is similar to the refraction oflight waves.”
“The surface waves on the other hand are analogous to water waves and travel along the Earth's surface. They travel more slowly than body waves. Because of their low frequency, long duration, and large amplitude, they can be the most destructive type of seismic wave. There are two types of surface waves: Rayleigh waves and Love waves.”
Those waves travel great distances, with a force that varies. One of the worth cased scenario is when those waves meet an obstacle, such as a bedrock from a mountain chain. From wish they are bounced back, like an echo and then meet with a second wave or after shock causing a devastating coalition of two forces as it happened on the 17th of January 1995 at 05:46H in the morning with Great Hanshin earthquake in Japan, which claimed 6300 lives. That particular earthquake measured 7 on the scale ofJapan Meteorological Agency (JMA) or 6.8 on the Moment magnitude scale (USGS), and Mj 7.3 (adjusted from 7.2) on JMA magnitude scale.
Those that lived through such devastating earthquakes as the Great Hanshin earthquake, the Haiti Earthquake or the latest earthquake in Chile, are generally left with great scars that will stay for a lifetime. Nature displays all its might time and time again through its earthquakes, typhoons, tsunamis and other phenomenon’s that fascinate us as much as they scare us.
However, nature does also give us a warning system, the trouble is though, most of us Humans are no longer able to listen, feel, or see the signs. Some still do and those know when it is time to run. Most wild animals know as well, Still farm animals do sense those early warning signs as well, even though some times latter then the wild once do. Maybe we should spend less time isolating our self’s from nature and more trying to reconnect with it, so we may hear, fell and see the warning signs our self’s as well.