The devastation caused in Turkey and northern Syria by recent earthquakes continue to dominate our news, and our thoughts inevitably go to the people who have died or been rendered homeless. There are various ludicrous rumours spreading as well: it is all the work of the Western powers; it is God’s punishment; it is the effect of climate change and so forth. So it is worth reminding ourselves how and why earthquakes occur.
It is all to do with Plate Tectonics, first validated in the Sixties. However, even in the Sixteenth century, it had been observed that the east coast of South America and the west coast of Africa looked as if they could fit together if placed adjacent to each other. So the hypothesis that the land masses of the current continents once formed one single structure started to be developed.
The theory is that when the single continent broke up around 600 million years ago, the earth’s crust became large ‘plates’ of solid crust that slide around continually on a fluid mantle. Various large plates have been identified: African, Antarctic, Eurasian, North American, South American, Pacific, and Indo-Australian.
The plate movements produce several effects at the plate boundaries.. The most well known and dramatic of these are earthquakes and volcanoes. It is easy to imagine what happens: consider two thin pieces of wafer placed on some jelly. If you bring the wafers together, what is likely to happen is that either one will climb over the other, or they might both crumble. When tectonic plates collide similar things happen: but when it is the earth’s crust that crumbles, slide against each other, or when one goes under the other , destruction of the crust take place and we notice it as earthquakes. The close correlation of plate boundaries and the sites of earthquakes and volcanoes may be seen in the two maps shown. If the plates are moving apart, the space created will be filled by the material of the mantle, called magma, and in that process volcanoes crop up.
A fascinating, animated video of earthquakes of the 21st Century can be watched at: https://en.wikipedia.org/ wiki/Lists_of_21st-century_earthquakes
In fact, plate movements produce mountain ranges as well: for example, the African plate pushing against the Eurasian plate and the Indian plate giving rise to the Alps and the Himalayas, respectively. In all this we are dealing with slow movements of just centimetres/ year, but over ‘geological timescales’— millions of years. So the plates may butt against each other without any movement for long periods, thus building up large stresses. Then when those stresses are suddenly released, it causes a violent event—an earthquake.
The amazing thing is that we have known about earthquake zones for a very long time. For decades there has been research into the prediction and prevention of earthquakes, but accurate prediction of where and when they happen has eluded seismologists. What we do have is the technology to build earthquake-resistant buildings. Even among the rubble of the recent Turkish earthquake you see the occasional building that is undamaged. Many rich countries, for example, Japan and the USA with its San Andreas fault in California, have building regulations that ensure that, in the event of an earthquake, casualties are minimal.
So ‘Hand of God’? Of course, those who believe in God as the creator of the universe will see that the Earth is just behaving according to the laws that have been ordained by the creator. Or put more simply, the planet is just obeying the laws of nature.
But God’s Hand of destruction? The destruction of life and property is almost preventable, or can be drastically reduced, through human ingenuity, even if we choose to build in earthquake zones. It is only human greed that still allows catastrophic destruction to take place: unscrupulous people, both in business and governments who cut costs at the expense of safety, and the inequitable distribution of wealth in the world, condemning the poor people of the world to unsuitable accommodation.
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