Nepal is a mountainous nation between India and Tibet known for its hiking opportunities,
wildlife parks and temples. Trekkers visit its Himalayan Mountains to follow the Annapurna
circuit or trails around Mt. Everest. If you are a trekker or an adventurous person then you
must have heard of Nepal a small nation located in the vicinity of Himalayas.
Nepal is located on the boundary of two major tectonic plates (Indian plate and Eurasian
plate), so it has suffered large earthquakes in recent history. In past century, four quakes of
magnitude more than 6.0 have occurred and have caused widespread damage and loss of life.
In 1934 a magnitude-8.0 earthquake, known as the Nepal-Bihar earthquake, killed about
10,600 people and seriously damaged the capital, Kathmandu. It remains the most deadly
earthquake in Nepal’s history. More recently, a magnitude-6.9 quake killed almost 1,500
people in August 1988.
So what happened on Saturday (25th April, 2015) that shook the entire Nepal with the
magnitude of 7.9 causing around 4000 people dead, 7000 injured and demolition of the
historical monument Dharahar tower is that a chunk of rock about 9 miles below the earth’s
surface shifted, unleashing a shock wave, as powerful as the explosion of more than 20
thermo-nuclear weapons those ripped through the Kathmandu valley.
The junction of the India and Eurasia tectonic plates is the cause of earthquakes in
the Himalayan region. The Indian plate is moving to north under the Eurasian plate at a rate
of 45 mm a year, in a process which is known as “thrust fault” and this is what builds the
Himalayan mountain range.
After an earthquake, the plates resume moving and the clock resets. Nepal lies on a so-
called thrust fault, where one tectonic plate forces itself on top of another. The fault runs
along the 1,400-mile range, and the constant collision of the India and Eurasia plates pushes
up the height of the peaks by about a centimetre each year.
And with this incident, Nepal has gone taller by 80 centimetres.
Despite the seeming regularity of severe earthquakes in Nepal, it isn’t possible to predict
when one will happen. Historic records and modern measurements of tectonic plate
movement show that if the pressure builds in the region in a way that is generally consistent
and homogeneous, the region should expect a severe earthquake every four to five decades.
Geologists are saying that it was a tragedy waiting to happen. Geophysicists have long
monitored how fast the Earth’s plates are moving, and the entire subcontinent of India is
being driven slowly but surely underneath Nepal and Tibet at a speed of around 1.8 inches
per year. It’s the reason Everest exists.
In the 81 years since the 1934 Bihar earthquake, the land mass of India has been pushed
about 12 feet into Nepal. The bigger the area that slips, and the larger the pent-up energy, the
greater the damage.
Saturday’s slip took place over an area about 1,000 to 2,000 square miles over a zone
spanning the cities of Kathmandu and Pokhara in one direction, and almost the entire
Himalaya mountain width in the other. A part of India slid about one to 10 feet northwards
and underneath Nepal in a matter of seconds.
About 1.45 million people live in Kathmandu, the majority in poorly constructed homes
not designed to withstand the kind of shaking seen on Saturday. Studies have long predicted
that the Kathmandu area was due a magnitude-8 earthquake, or higher — one study predicted
between 21,000 and 42,000 fatalities if a magnitude-8.1 earthquake had struck the area.
(Fortunately, Saturday’s shaking was half that intensity).
Still, this catastrophe comes at a delicate time for Nepal as it emerges from a long-running
civil war and its economy has been improving steadily. We have to hope that recovery from
both can somehow take place despite the enormous challenges.
Let’s pray for Nepal.