The annihilation of thousands of lives in a 7.8 magnitude earthquake in Nepal is a reminder of how precarious our human existence is on this ever-shifting planet. But an understanding of plate tectonics only began 100 years ago, with an injured German soldier
A bullet fired from a rifle in the First World War came within centimetres of killing the man who would go on to author our understanding of how the terrible forces of nature are unleashed in earthquakes, such as the one that has brought such destruction to Nepal.
The quake has its origins in an extraordinary geological process that began more than 200 million years ago, when the land mass that would become India broke away from its southern berth between the huddled prototypes of Africa, Antarctica and Australia and began its fateful northwards migration towards Asia.
In part, we know this thanks only to the poor aim of two unknown Belgian soldiers, offering hopeless resistance to the might of the German war machine as it ploughed through their country in 1914.
Born in Berlin in November 1880, astronomer and meteorologist Alfred Wegener was 33 when he was drafted into the German army in 1914. He cheated death twice: once when he was shot in the arm as the 3rd Grenadier Guards advanced into Belgium; and two weeks later when a bullet struck him in the neck.
The second wound took him out of the war for good and he used his convalescence well. In 1915 he published a controversial book called The Origin of Continents and Oceans, “a first attempt to explain the origins of large Earth features, or the continents and ocean basins, with a comprehensive principal, namely continental drift”.
Eventually, Wegener’s work would come to revolutionise the way we saw our world. But acceptance of his theory, which “came to me as far back as 1910, when considering the map of the world, under the direct impression produced by the congruence of the coastlines on either side of the Atlantic”, would move almost as slowly as the plates about which he theorised.
By the time he met his death in 1930 – killed, not unfittingly, by the force majeure of nature, succumbing to the cold while on a geological expedition to the interior of Greenland – he was still widely regarded as a crank.
Today, when the term “plate tectonics” is part of everyday language, co-opted metaphorically to illustrate everything from relationship difficulties to political upheavals, it seems incredible that our understanding of the surface dynamic that shapes our world dates back a mere 100 years, and was not universally accepted until as recently as the 1970s.
Before Wegener, it was widely believed that at various points in prehistory, the continents of the Earth had been connected by land bridges which had subsequently disappeared beneath the oceans.
How else, went the argument, to explain identical fossils found in separate and isolated locations, given the improbability of such flora or fauna having evolved independently?
Wegener was not convinced.
At the time, geological textbooks were dominated by “contraction theory” – the idea that the Earth was, in effect, shrinking. Like a drying apple, the planet’s skin was wrinkling, forming mountains and valleys, and in the process – conveniently – causing the all-important land bridges to slip beneath the oceans, leaving no trace.
But when he redrew the map of the world with the supposed land bridges in place, Wegener found that “the water displacement of the intercontinental bridges would be so enormous that … all would be flooded, today’s continents and the bridges alike”.
The supposition “that the relative position of the continents … has never altered, must be wrong”, he concluded. “The continents must have shifted.”
At one time, he suggested, North America “lay alongside Europe and formed a coherent block with it and Greenland”. Up to the beginning of the Jurassic period, Antarctica, Australia and India “lay alongside southern Africa and formed together with it and South America, a single large continent”.
It was when India separated first from Australia and then Madagascar, and began to drift closer to Asia, that the strip of land in between “became increasingly folded by the continuing approach”.
That fold, noted Wegener, “is now the largest folded range on earth, ie, the Himalaya and the many other folded chains of upland Asia”.
The process that began millions of years ago, perpetuated by the circulating currents of heat in the liquid mantle on which they float, continues today and the 7.8 magnitude earthquake that struck Nepal on Saturday was just one of a series of consequences that have shaken the region ever since.
“India and Asia collided 50 million years ago, roughly down at the Equator, and India has continued pushing northwards,” says Mike Searle, professor of earth sciences at the University of Oxford, who has spent the past 30 years studying the tectonic evolution of mountain belts and knows the region well. The India plate has been pushing under the Asia plate to the north-east at a rate of about 45mm a year, and “it’s 50 million years of earthquakes like this one that’s produced the Himalayas”.
An earthquake on this scale, 7.8 magnitude, says Professor Searle, is likely to have seen the mountains rise in height, instantaneously, by as much as five metres. The Himalayas are, in effect, “being jacked up, as they always have been – that’s why they’re so high today”.
This timeless, perpetual process of plates shifting and colliding links us all, and the UAE – which from time to time experiences its own earthquakes, chiefly as a result of the pressure point where the undersea horn of Musandam thrusts across the Strait of Hormuz – is in a way directly connected to events in the Himalayas.
Prof Searle has also done much work in Oman and the UAE, and is currently working on a project with the Petroleum Institute Abu Dhabi, carrying out structural mapping under the Musandam peninsula, down to a depth of 40 or 50 kilometres.
“We now know the timing of the formation of the Oman mountains, which was mostly 95 to 75 million years ago,” he says.
For millions of years, in fact, the Arabian plate has been advancing north-east towards the Asian plate at a rate of up to 2.3cm a year and, says Prof Searle, it is that slow motion collision that has formed the oil-bearing structures that have enriched the nations of the Gulf.
Geologically, the Oman mountains are part of the same mountain belt as the Himalayas – a gigantic crease in the surface of the Earth, created by the force of colliding plates, that runs all the way from the Alps, down through the Zagros range in Iran to Oman and then along the Himalayas and on to Burma and Sumatra.
It is the fate of the northeastward-advancing UAE, predicts Prof Searle, to find itself cast geologically upon the shores of Iran, while Oman will collide with the Makran coast of Balochistan and the Zagros Mountains will rise in stature to match the majesty of the Himalayas.
There is, however, no immediate cause for panic. The process could take anything up to 40 million years – roughly the same time again since India and Asia first collided.
Today, thanks to Wegener and those who followed him, we understand exactly what is happening when the Earth heaves and shakes, razing human dreams and buildings to the ground.
And yet, as the unfolding tragedy of Nepal so poignantly illustrates, we remain impotent in the face of the awesome power of the planet as it goes about the ancient and unstoppable business of perpetual transformation, indifferent to the consequences for the species that cling so precariously to its ever-changing surface.