exactly is going on underground when the Earth moves so violently?

The Theory of Plate tectonics was put forward in the mid-20th century based on decades of

earlier research. One scientist, Alfred Wegener first suggested the concept of continental

drift in 1912 - the idea that land masses can move across the earth’s surfaces. But

he didn’t know the mechanism behind the movement. Throughout the 50s, 60s and 70s

more pieces of the puzzle fell into place. Including ideas like sea-floor spreading,

and global crustal motion.

Now scientists know that the Earth is made up of several layers, the mantle and the crust

make up the outermost shell, the Lithosphere. This crust is broken up into 7 or 8 major

tectonic plates which float on top of another layer called the asthenosphere. The molten

rock beneath them move them around like a conveyer belt. Sometimes the plates meet up

and move towards each other forming a convergent boundary, when they move apart, it’s a divergent

boundary, when they slide past each other it’s a transform.

When plates slide over, under or past each other it creates a lot of pressure which can

be released as a volcanic eruption or an Earthquake.

Nepal sits on a volatile zone. The Indian plate broke off from Madagascar 90 million

years ago. Around 50 million years ago it hit the Eurasian plate. This forced the Indian

plate to take a dive, while the other plate thrusted upwards creating the Himalayas. When

two plates meet like this, it’s called a thrust fault.

Millions of years later, they’re still crashing into each other. The Indian plate subducts,

or is sliding beneath the other plate, and moves North 2 inches (5 centimeters) a year.

This builds up enormous amounts of pressure. When all that pressure is released, it can

mean disaster.

This region is weirdly used to earthquakes, for some reason. They seem to experience large

quakes every 75 years or so, like clockwork. And this one was right on cue, the last major

Earthquake struck in 1934. But this recent earthquake was shallow, at only 15 kilometres

deep. While a 7 magnitude earthquake is devastating on its own, a shallow depth means more shaking

at the surface and more damage.

At the time of this taping, the death toll from this catastrophic earthquake’s death

toll is over 4-thousand and is expected to rise. Buildings, temples and homes have been

toppled as many remain in need of help. Recovery efforts are underway with aid and humanitarian

organizations mobilizing to provide much needed support, but they need help. In response to

the tragic earthquake, Discovery Communications will be making a $250,000 donation to relief

efforts. And we hope that you too can support the people of Nepal by visiting GlobalGiving’s

Nepal Earthquake Relief Fund page. We’ve got a link below in the description. Thanks

for watching DNews.