April 28 – Nepal Event

Today’s factismal: The earthquake that hit Tibet this weekend was the twenty-first most powerful earthquake in the past decade.

There is no doubt that the earthquake which hit Tibet this weekend was a disaster. With a main shock that measured Mw 7.8, it released the same amount of energy as 504 Hiroshima bombs; that’s enough energy to power a typical household for 332,871 years or a hurricane for 53 seconds. That energy did enormous damage to the area, mostly because the buildings there are mainly built of brick and masonry neither of which stand up well to shaking. And the shaking from this event was larger than normal because the earthquake was abnormally shallow (just about 10 miles deep). But the temblor was actually not that strong as earthquakes go. In the past decade alone,t here have been twenty events stronger than this one (and five that were just as strong).

Recent earthquakes near the M 7.8 event (Image courtesy IRIS)

Recent earthquakes near the M 7.8 event
(Image courtesy IRIS)

Over the next few months, there will be more earthquakes in this area as the strain caused by this one slowly dissipates. There will be about five earthquakes that are larger than M6, about a dozen that are larger than M5, close to one hundred that are larger than M4, and more than a thousand that are larger than M3. (Earthquakes smaller than M3 are typically too small to feel and so don’t count.) Though that sounds like a lot of events, it really isn’t. That’s because the energy released by each event isn’t the same; it would take 32 M5 events to release the same amount of energy as 1 M6. So all of those later earthquakes will only release about 1/5th the energy of the first one!

A magnitude 7.8 earthquake releases 64 times as much energy as a 6.6

A magnitude 7.8 earthquake releases 64 times as much energy as a 6.6

So why was there an earthquake? If you’ve kept up with the Secret Science Society, you already know the answer. Nepal is located at a place where two plates are colliding and making a mountain range. What is unusual is that both the India Plate and the Eurasian Plate are made up of continental material. Since the stuff making up the continents is less dense than the stuff making up the oceans and the mantles, it is very difficult to subduct. As a result, the material is piling up in a giant mass, creating the highest mountain range and plateau in the world. But that piling up comes at a price – lots and lots of earthquakes.

And those earthquakes cause damage. Lots and lots of damage. Not just buildings, but lives. This event killed over 3,000 people and injured many thousands more. So this time, I’m not going to ask you to do citizen science. Instead, I’m going to ask you to do something that will help the people of Nepal. Please give to the World Help fund (here’s their rating on Charity Navigator). The money you give will go to help the people of Nepal restart their lives and rebuild their homes. To learn more, go to:
http://www.worldhelp.net/

One thought on “April 28 – Nepal Event

  1. Pingback: May 5 – Whole Lot A Shakin’ Goin’ On | Little facts about science

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