Pulverised Nepal hit by cruel second quake
Just over two weeks after a catastrophic earthquake killed thousands in Nepal, an aftershock has caused yet more devastation. Why are scientists still unable to predict seismic activity?
‘When sorrows come, they come not in single spies but in battalions’, as Claudius says in Shakespeare’s Hamlet. It seems that the same could be said about earthquakes.
Just two weeks ago, an enormous quake with a magnitude of 7.9 struck Nepal, leaving 8,000 dead and hundreds of thousands homeless. With cities reduced to rubble, much of the population is living in makeshift tent cities. Now the battered country has been rocked by yet another major tremor that occurred near Mount Everest yesterday afternoon.
With a magnitude of 7.3, this earthquake is nowhere near as calamitous as the first. But because Nepal is reeling and vulnerable from the initial disaster, this second blow has fallen hard. Yesterday afternoon the death toll stood at 42 and was rising with ominous regularity.
This disaster was not entirely unexpected. Earthquakes happen when tectonic plates — the tightly-packed slabs of rock on which the Earth’s crust rests — collide, scrape against one another or drift apart. When a disruption occurs along a fault line between two plates, it can have knock-on effects in the neighbouring region. Major quakes are always followed by aftershocks, which can sometimes be as damaging as the original event.
What nobody can tell is when, where or how forcefully these shocks will strike. Despite huge advances in our understanding of our planet’s behaviour, scientists are still incapable of predicting earthquakes with any accuracy. The common toad, which can sense shifts in the earth’s chemistry days before a tremor, is a better prophet than any geologist.
This is a serious problem. If scientists could warn about an earthquake in advance, governments could take precautionary measures to minimise the damage and loss of life. Scientists from various disciplines are working on methods for predicting seismic activity better, such as measuring underground electromagnetic activity. But precise forecasts are still elusive. Indeed, it has been said that we know more about what happens in the atmosphere of Saturn than beneath the surface of our own planet.
We humans often think of ourselves as the masters of the Earth: we have penetrated the secrets of the sciences and bent whole ecosystems to our bidding. Yet we are still at the mercy of a planet whose behaviour remains a mystery. Disasters like earthquakes, some say, show how fragile humanity really is.
Have some faith in scientific progress, more optimistic rationalists respond. Our knowledge of natural phenomena like earthquakes advances further every year and it is only a matter of time before the mystery is cracked. Someday we will not only foresee seismic upheavals, but even prevent them.
- Will some parts of the natural world always remain a mystery?
- Should we give more money to research into predicting earthquakes or measures to limit the damage when they strike?
- Imagine you work for an international aid organisation. Compose a tweet persuading people to donate to the appeal for Nepal.
- Draw a diagram explaining how an earthquake works.
Some People Say...
“We’re small, nature’s big, and it’s everything we can manage to hang on and survive.”James Balog
What do you think?
Q & A
- Should I be afraid of earthquakes?
- That depends on where you live: serious earthquakes only occur near ‘fault lines’ where two tectonic plates meet. Britain has never suffered from a severe earthquake, but parts of Japan, India and Chile are risk zones. The places that suffer most are usually poor areas with unstable buildings and poor infrastructure — such as Nepal.
- Is there anything I can do to help the aid effort for Nepal?
- There is: donate to the appeal! It’s particularly urgent to fund aid in the weeks after a disaster, since many people are temporarily left without homes, food and essential medical supplies. Charities like the Red Cross are working hard to provide these services in the camps that have sprung up, but their efforts can’t continue without public generosity.
- For reference, the largest earthquake ever recorded measured just over 9.
- Lodged between India and China and dominated by the enormous Himalayan mountain range, Nepal is a poor country that is very vulnerable to natural disasters.
- Nowhere near
- Seismic activitiy is measured on a logarithmic scale, meaning that the size increases exponentially with every single-digit rise. So an 7.9 earthquake is actually about 20 times more powerful than a 7.3 one.
- Earth’s crust
- The surface of the Earth, on which we all live. In most places the continental crust is about 30 miles thick.
- Fault line
- Due to convection currents in the molten rock beneath them, tectonic plates are constantly in motion. Usually they slide along one another relatively smoothly, but occasionally they bump or hit a groove. The energy this can release causes upheavals that echo to the Earth’s surface: earthquakes.
- Beneath the surface
- We still know surprisingly little about the Earth’s core. Until fairly recently, it was thought to be liquid magma all the way down, but now we know that the centre is a crystal.