On Saturday 25th April, an earthquake of magnitude 7.9 hit Nepal, killing over 8000 people. On Tuesday 12th May a second earthquake of magnitude 7.3 hit Nepal, just over 2 weeks after the initial quake.
I wrote an article (read it here) the day the first earthquake hit Nepal. Since then the death toll has risen to over 8000. We now know that the focus of the earthquake was about 15 km deep (considered shallow and is likely to cause more damage than an earthquake with a deeper focus), lasted about 20 seconds, and nearly 18000 people were injured.
There were 41 aftershocks between the 25th and 27th April, with magnitudes ranging between 4.0 and 6.6. It is normal to experience aftershocks in the days after a large earthquake, with the magnitude of these earthquakes normally decreasing as time passes after the initial quake. What is not so normal, is what followed last Tuesday.
On 12th May, a 7.3 magnitude earthquake occurred. With another shallow focus (18.5 km deep), the tremors were felt up to 2500 km away. Just a few minutes later, an aftershock of magnitude 6.3 followed, which could be felt as far away as New Delhi, India. The death toll of this quake is now above 100 people, and is still slowly rising.
So what has caused all of these earthquakes?
Nepal lies on a boundary between two tectonic plates: the Indian Plate and Eurasian Plate. The collision of these two plates caused the formation of the Himalayas 50 million years ago (see picture below). The two plates are still moving towards each other, at about 45mm a year. When plates are moving towards or along side each other, they sometimes stick, and pressure builds up, as the convection currents in the mantle below move. Eventually this pressure is released in a series of earthquakes.
While the earthquake on 12th May was a lot larger and later than aftershocks of the earthquake on 25th April would have been expected, it is still considered an aftershock as they occurred on the same fault, although the original earthquake was further west than the one that followed last Tuesday.
What can you do to help?
After the first quake, Rugby School sent many tents and sleeping bags out to Nepal (see picture below), and all the pupils are making donations today, following the second quake, which will be put together and sent off.
A quick google search comes up with many different ways that you can donate to help the people of Nepal, but The Guardian have summarised most of the ways here.
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| Formation of the Himalayas |
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| The tents and sleeping bags donated by Rugby School, all boxed up, ready to be sent to Nepal |
Emily Lauterpacht
