Thursday, February 02, 2012

The Plate boundaries: The line of Prosperity and Fire

"Civilization exists by geological consent, subject to change without notice." - Will Durant (1885-1981), American writer, historian and philosopher.


Human civilization has come a long way from settling along the rivers like the Harappan civilization along the Indus valley to settling and cluttering along the now modern day roads - a sign of globalization and sophistication. Humans have moved from fertile valleys of water to the fiery boundaries that demarcate the Earths tectonic plates where these very roads connect and interconnect to the places of rich valuable minerals and metal resources and equally dangerous fault lines. And it is bit strange that this ground breaking discovery of plate boundaries has made little difference to how we live, as ten out of twenty major cities of the world are located along these boundaries. It is sometimes not an easy question for me to think as to why people live so close to or build their town on a disaster prone area like near a volcanoes or a fault line. It’s really disturbing sometimes to hear the news of people who passed away during the Tsunami in Japan or the Earthquakes along the Indonesian islands and the list goes on and on along the plate boundaries round the world and will still continue as the Earth's plate keeps moving against each other, but then you are faced with other questions which also carry equal weightage like why then people live near a coast where you might face the fury of a cyclone or in the arid regions of Sahara where hardly anything grows!? I was thinking about it more recently and wanted to pin down the reasons as to why people live in such places of real life danger. But it is evident from ages until now that people are willing to take such high-risk gambles for the most basic things of life especially food or food in exchange of natural mineral resources.....I guess that's how trade and civilizations began. We have been drawn to these plate boundaries or fault lines ever since the dawn of civilization not just for minerals but for water that came up in the form of springs due to faulting. The Earth's crust, on which we live and depend, is in large part a product of millions of once-active volcanoes and tremendous volumes of magma that did not erupt but instead cooled below the surface. Such persistent and widespread volcanism has resulted in many valuable natural resources throughout the world the scars of  ancient plate boundaries. So there are ancient extinct plate boundaries that criss-crosses the Earths surface apart from the present day plate boundaries or faults.The Earth has closed and opened many chapters of which we are part of the last chapters or just another chapter of the long history of our Earth. 


A simplified map with plate boundaries, earthquake, volcanoes & larger cities with more than one million inhabitants, modified after U.S.G.S. 2005. (Source: blogs.scientificamerican.com) 
There exist different views toward hazards, some may think there're hazards everywhere and it's worthless  to move around. One of the reasons in spite of  all the dangers poised by the area, is the attractions of living in a place. Japan is a very good example in this regard. It is a wealthy country with good job prospects. An economic interest is one of the main reasons for people when choosing places to live. People might live in an area such as California that's quite often affected by earthquake but because their ancestors are early settlers, the job prospects are interesting, the environment has much to offer in terms of social opportunities and natural beauty, and the climate is pleasant. 

Close to an erupting volcano the short-term spuing of destructive pyroclastic flows, heavy falls of ash, and lava flows can be complete, the extent of the damage depending upon the magnitude of eruption. Crops, forests, orchards, and animals grazing or browsing on the volcano's slopes or surrounding lowland can be leveled or buried. But that is the short-term effect. In the long run, volcanic deposits can develop into some of the richest agricultural lands on earth. Life-forms on the Earth's surface exist primarily by consent of nature's partnership -- heat from the sun, and nutrients from rocks that have been decomposed and recombined into soluble molecules by chemical reactions with moisture and gases such as carbon dioxide from the atmosphere. Volcanic rocks make some of the best soils on earth because they not only have a wide variety of common elements but are also readily chemically separable into its elemental components. Example worth mentioning in this regard is the effect of volcanoes on agricultural lands in Italy. Except for the volcanic region around Naples, farming in southern Italy is exceedingly difficult because limestone forms the basement rock and the soil is generally quite poor. But the region around Naples, which includes Mount Vesuvius, is very rich mainly because of two large eruptions 35,000 and 12000 years ago that left the region blanketed with very thick deposits of tephra which has since weathered to rich soils. Benefits of earth movements provide important nutrient rich volcanic ash that makes soil rich and farmland fertile. Volcanic ash can be considered as a time-release capsule, rich in nutrients. Volcanoes both harass and help mankind. Volcanoes can wreak havoc and devastation in the short term. However, it should be emphasized that the short-term hazards posed by volcanoes are balanced by benefits of volcanism and related processes over geologic time. For example, volcanic ash blown over thousands of square kilometers of land increases soil fertility for forests and agriculture by adding nutrients and acting as a mulch. Valuable minerals such as diamond and gold can be found in volcanic regions. . Groundwater heated by large, still-hot magma bodies can be tapped for geothermal energy. And over many thousands of years, heated groundwater has concentrated valuable minerals, including copper, tin, gold, and silver, into deposits that are mined throughout the world. Volcanic eruption also create beautiful relief feature and attract tourists.

Volcanoes can clearly cause much damage and destruction, but in the long term they also have benefited people. Over thousands to millions of years, the physical breakdown and chemical weathering of volcanic rocks have formed some of the most fertile soils on Earth. In tropical, rainy regions, such as the windward (northeastern) side of the Island of Hawaii, the formation of fertile soil and growth of lush vegetation following an eruption can be as fast as a few hundred years. Some of the earliest civilizations (for example, Greek, Etruscan, and Roman) settled on the rich, fertile volcanic soils in the Mediterranean-Aegean region. Some of the best rice-growing regions of Indonesia are in the shadow of active volcanoes. Similarly, many prime agricultural regions in the western United States have fertile soils wholly or largely of volcanic origin.


Given enough rainfall, areas buried by new lava recover quickly; revegetation can begin less than one year after the eruption. Erosion and breakdown of the volcanic material can form fertile soils over periods of tens to thousands of years. These rich soils fostered the agricultural development of the Hawaiian Islands, as represented principally by the sugar, pineapple, coffee, and macadamia nut industries.

Geothermal energy can be harnessed from the Earth's natural heat associated with active volcanoes or geologically young inactive volcanoes still giving off heat at depth. Steam from high-temperature geothermal fluids can be used to drive turbines and generate electrical power, while lower temperature fluids provide hot water for space-heating purposes, heat for greenhouses and industrial uses, and hot or warm springs at resort spas. For example, geothermal heat warms more than 70 percent of the homes in Iceland, and The Geysers geothermal field near Santa Rosa, in Northern California produces enough electricity to meet the power demands of San Francisco. The Geysers area is the largest geothermal development in the world. In addition to being an energy resource, some geothermal waters also contain sulfur, gold, silver, and mercury that can be recovered as a byproduct of energy production.

Most of the metallic minerals mined in the world, such as copper, gold, silver, lead, and zinc, are associated with magmas found deep within the roots of extinct volcanoes located above subduction zones. Rising magma does not always reach the surface to erupt; instead it may slowly cool and harden beneath the volcano to form a wide variety of crystalline rocks (generally called plutonic or granitic rocks). Some of the best examples of such deep-seated granitic rocks, later exposed by erosion, are magnificently displayed in California's Yosemite National Park. Ore deposits commonly form around the magma bodies that feed volcanoes because there is a ready supply of heat, which convectively moves and circulates ore-bearing fluids. The metals, originally scattered in trace amounts in magma or surrounding solid rocks, become concentrated by circulating hot fluids and can be redeposited, under favorable temperature and pressure conditions, to form rich mineral veins. 

The active volcanic vents along the spreading mid-ocean ridges create ideal environments for the circulation of fluids rich in minerals and for ore deposition. Water as hot as 380 degrees gushes out of geothermal springs along the spreading centers. The water has been heated during circulation by contact with the hot volcanic rocks forming the ridge. Deep-sea hot springs containing an abundance of dark-colored ore minerals (sulfides) of iron, copper, zinc, nickel, and other metals are called "black smokers." On rare occasions, such deep-sea ore deposits are later exposed in remnants of ancient oceanic crust that have been scraped off and left ("beached") on top of continental crust during past subduction processes. The Troodos Massif on the Island of Cyprus is perhaps the best known example of such ancient oceanic crust. Cyprus was an important source of copper in the ancient world, and Romans called copper the "Cyprian metal". People have been using volcanic products ever since the stone age for tools, building houses to today's road-building materials, as abrasive and cleaning agents, and as raw materials for many chemical and industrial uses. 

But many are limited by choice. Within Japan itself, the Japanese cannot move to a safer place. Also moving out means great change, some people are used to their country and are not willing to change. Family tie is a reason too. The person may own his family and friends, all living in the country. In order to keep in close relationship; he may not choose to move out.

There's no place on earth completely free from hazards. And as the world population increases, places to live will become more and more scarce and limited with already enough damages being done to the environment by cutting of our precious natural forest. Furthermore, there is danger no matter where you live. It could be from natural disasters, air pollution, or crime. Unless the phenomenon are always occurring, you get a "not in my time" attitude. Also, the area around some volcanoes is quite fertile, more important to farmers than a little 'smoke chimney'.

But it is visible apart from the boundaries of seismic areas people are now facing drought and having a difficult life inspite of the modern technologies available. Humans are now in itself a force to reckon with. We  have entered a new era of human civilization where we are changing the face of the Earth in a big way and I hope we ourselves don't write this chapter - the Anthropocene Era with a mass extinction. We are depleting the water resources and degrading the natural resources and destroying the delicate balance of the Earth. We are taking out more than what the Earth can provide, eventually stripping out life that is so essestial for life on Earth for our very own existence. Everything is linked and we should realize that we have done nothing in the formation of the Earth or in formation of life on Earth, and we are just part of the millions of years of evolution and our role is to enjoy the nature. This knowledge has humbled me to take care more of the things around me. We have been bestowed with everything in life, free by the nature so all the more it demands that we live responsibly and share with those who don't have these resources.

Today everything in life has boiled down to the bargain of economic returns from these plate boundaries in exchange of precious life, and life is not just about money. I remember what I had been hearing when I was with some very special friends I ever had in my life, they used to say was this "Man came naked from his mother's womb, so will he return as he came. He will take nothing from the fruit of his labor that he can carry in his hand. We must leave the Earth as we came into it, contentment is better than excess riches or gains". 

1 comment:

  1. Can you please list the names of the volcanoes on the faults? I have a school project and It would be a lot of help if u guys did. thanks in advance.

    Anonymous

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