Indonesia quake surprises scientists

2012-04-12 09:54

kalahari.com

Los Angeles - The massive earthquake off Indonesia surprised scientists: Usually this type of jolt isn't this powerful.

The biggest earthquakes tend to occur in subduction zones where one plate of the Earth's crust dives under another. This grind produced the 2004 magnitude-9.1 Indian Ocean disaster and the magnitude-9 Japan quake last year.

Wednesday's magnitude-8.6 occurred along a strike-slip fault line similar to California's San Andreas Fault. Scientists say it's rare for strike-slip quakes, in which blocks of rocks slide horizontally past each other, to be this large.

"It's clearly a bit of an odd duck," said seismologist Susan Hough of the US Geological Survey in Pasadena, Calif.

As one of the world's most seismically active places, Indonesia is located on the Pacific "Ring of Fire", an arc of volcanos and fault lines encircling the Pacific Basin. Pressure builds up in the rocks over time and is eventually released in an earthquake.

Wednesday's quake was followed by a magnitude-8.2 aftershock. Both were strike-slip quakes.

"A week ago, we wouldn't have thought we could have a strike-slip earthquake of this size. This is very, very large," said Kevin Furlong, a professor of geosciences at Penn State University.

So large, in fact, that the main shock went into the history books. Record-keeping by the USGS National Earthquake Information Centre ranks Wednesday's shaker as the 11th largest since 1900. It's probably the largest strike-slip event though there's debate about whether a similar-sized Tibet quake in 1950 was the same kind.

A preliminary analysis indicates one side of the fault lurched 70 feet past the other - a major reason for the quake's size. By contrast, during the 1906 magnitude-7.8 San Francisco earthquake along the San Andreas -perhaps the best known strike-slip event - the ground shifted 15 feet.

The Sumatra coast has been rattled by three strong strike-slip quakes since 2004, but Wednesday's was the largest.


- SAPA
Read more on:    indonesia  |  tsunamis
NEXT ON NEWS24X
SHARE:

Read News24’s Comments Policy

24.com publishes all comments posted on articles provided that they adhere to our Comments Policy. Should you wish to report a comment for editorial review, please do so by clicking the 'Report Comment' button to the right of each comment.

Comment on this story
3 comments
Add your comment
Comment 0 characters remaining
 

Inside News24

 
/Wine
 

You HAVE to see this MTB Tsunami Fip!

You might not know what a Tsunami Flip is, but just watching this will turn your eyes into saucers. Check out this first-ever MTB Tsunami Flip in contest here.

 
 

Where were you when you last felt alive?

Bear Grylls’ top 10 things kids should do outdoors
Mountain unicycling – say WHAT?
Top tips to ensure you’re running right
Stand-up paddle boarding a great workout

Jobs in Cape Town [change area]

Jobs in Western Cape region

Luxury Brand Manager

Cape Town
Peoplefinder Career Placements

Senior Mechanical Engineer

Cape Town
Communicate Cape Town Engineering
R550 000 - R800 000 Per Year

Intermediate Software Tester

Cape Town
Communicate Cape Town IT
R25 000 Per Month

Property [change area]

Travel - Look, Book, Go!

Magical Massinga

Spend 5 nights at the gorgeous Massinga Beach Lodge in Mozambique and only pay for 4 from R13 220 per person sharing. Includes return flights, accommodation, transfers and romantic turndown. Book now!

Kalahari.com - shop online today

Deal of the week!

20% off Afrikaans books, music and DVDs. Offer valid while stocks last. Shop now!

Save up to R1000 on Hisense smartphones!

View the large range of Hisense smartphones. Buy today and save up to R1000!

Hot gaming titles – available for pre-order!

Call of Duty: Advanced Warfare Day Zero Edition, Far Cry 4, Grand Theft Auto 5 and more. Pre-order now!

Get a free eBook

Buy 3 eBooks and get the cheapest FREE. Offer valid while stocks last. Shop now!

Bargain box – 60% off

Reduced prices, very limited stock. While stocks last. Hurry and shop now!

OLX Free Classifieds [change area]

Samsung Galaxy s4

Mobile, Cell Phones in South Africa, Western Cape, Cape Town. Date October 24

Best bargain in big bay

Real Estate, Houses - Apartments for Sale in South Africa, Western Cape, Cape Town. Date October 25

VW Golf 6, 1.6 Trendline (Excellent condition)

Vehicles, Cars in South Africa, Western Cape, Cape Town. Date October 25

Horoscopes
Aquarius
Aquarius

Pushing too hard and doing too much may have left you feeling drained and overwhelmed. You may need time out to recharge and reset...read more

There are new stories on the homepage. Click here to see them.
 
English
Afrikaans
isiZulu

Hello 

Create Profile

Creating your profile will enable you to submit photos and stories to get published on News24.


Please provide a username for your profile page:

This username must be unique, cannot be edited and will be used in the URL to your profile page across the entire 24.com network.

Settings

Location Settings

News24 allows you to edit the display of certain components based on a location. If you wish to personalise the page based on your preferences, please select a location for each component and click "Submit" in order for the changes to take affect.








Facebook Sign-In

Hi News addict,

Join the News24 Community to be involved in breaking the news.

Log in with Facebook to comment and personalise news, weather and listings.