Haiti Earthquake Was the 'Big One' Says Top Seismologist

[G_j]

http://news.yahoo.com/s/time/20100113/wl_time/08599195328400

Haiti Earthquake Was the 'Big One' Says Top Seismologist

By EBEN HARRELL / LONDON 7 mins ago

The British Geological Survey in Edinburgh has been one of the leading geoscience research centers in the world since its founding in 1835. To understand more about the 7.0-magnitude earthquake that devastated Haiti on Tuesday, TIME spoke with one of the survey's seismologists, Roger Musson, about the science behind the seismic event.

What sort of earthquake was this?

An earthquake is the sudden release of energy along a fault line in the earth's crust as rocks break in response to stress. There are three types, and they depend on the sort of movement along the fault. This was what we call a strike-slip, or transform, earthquake, where one side of the fault slides horizontally past the other one.(See pictures of the devastating earthquake in Haiti.)

Which fault produced this earthquake?

It is rather baroquely called the Enriquillo-Plaintain Garden fault. It is a major plate boundary fault and is analogous to the San Andreas fault in California. It starts around the southern border between Haiti and the Dominican Republic and runs west until it reaches Jamaica.

Was it the most destructive type of earthquake?

A thrust earthquake, in which one side of the fault goes up, is the type that produces truly enormous events like the Sumatra earthquake of 2004. But strike-slip faults often run through populated areas, so they can be the most damaging to humans.(Read "Haiti Death Toll May Be in the Thousands.")

People talk about waiting for the Big One in California. Was this a similar earthquake for this fault?

This was the Big One. The fault has been more or less locked for 200 years. Seismologists were unsure as to whether it would produce one Big One or several smaller ones. We seem to have the answer.

..more..

[malaise]

1. Check #46

http://www.democraticunderground.com/discuss/duboard.php?az=view_all&address=389x7451284

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Frightening

[G_j]

5. locked up for 200 yrs.

they've had dozens of aftershocks, some very powerful.
:-(

[malaise]

6. The worst part for us is that we may just be next

We're on the same fault. I think I'll stay outdoors tomorrow - the 103rd anniversary of the great Kingston earthquake.

[G_j]

7. you are in Jamaica?

wow,

you missed all the snow..

[malaise]

9. Thankfully

I miss it every year even when the siblings offer us free tickets just to get us there for winter. I can't handle the cold.

[Hekate]

2. Californians all shudder in sympathy, believe me. nt

[malaise]

3. They're finding people alive

http://news.bbc.co.uk/2/hi/americas/8457921.stm

[Hekate]

4. I know search and rescue teams with specially trained dogs are on their way from California...

... it might be too early for them to be already there. I have a feeling the people involved started packing their bags as soon as they saw the news of the earthquake. It's always a wonderful thing when survivors are found and extracted by anyone, but these teams (both the human and dog) live for that.

Hekate

[defendandprotect]

8. k

[amborin]

10. the Enriquillo fault:

http://www.usatoday.com/tech/science/2010-01-13-Haiti-geoscience_N.htm?csp=34

[Mendocino]

11. The Enriquillo-Plantain Garden Fault Zone

and the parallel Septentrional-Orient Fault Zone both cross the Island of Hispaniola. They compress the land forming mountains up to 3087 meters, almost two miles high. There are powerful forces at work here.

Edit- didn't check spelling.

[G_j]

12. two miles high

so the mountains have been pushed up at edge of the fault?

[Mendocino]

13. The northern fault (Septentrional or SOFZ)

has been the primary, but evidence is showing that the southern (Enriquillo) is becoming more and more dominant. It was the EPGFZ that slide shifted.

The mountains have been pushed up by the interaction of the two over time. I should point out that the highest mountains are in the Dominican half of the island. Haiti itself has high peaks about in the 2700 meter range, around 8200 feet.