Was the 2010 Haiti Earthquake triggered by deforestation and the 2008 hurricanes?

By: Dr. Jeff Masters , 2:57 PM GMT on December 20, 2010

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Major earthquakes occur when the stress on rocks between two tectonic plates reaches a critical breaking point, allowing the earth to move along the connecting fault. While the slow creep of the tectonic plates makes earthquakes inevitable along major faults, the timing and exact location of the quake epicenter can be influenced by outside forces pushing down on Earth's crust. For example, the sloshing of water into the Eastern Pacific during El Niño events has been linked to magnitude 4, 5, and 6 earthquakes on the seafloor below, due to the extra weight of water caused by local sea level rise. Sea level rise due to rapid melting of Earth's ice sheets could also potentially trigger earthquakes, though it is unknown at what melting rate such an effect might become significant.


Figure 1. Google Earth image of Haiti taken November 8, 2010, showing the capital of Port-Au-Prince and the mountainous region to its west where the epicenter of the 2010 earthquake was. Note the brown color of the mountains, where all the vegetation has been stripped off, leaving bare slopes subject to extreme erosion. Heavy rains in recent years have washed huge amounts of sediment into the Leogane Delta to the north.


Figure 2. Zoom-in view of the Leogane Delta region of Figure 1, showing the large expansion in the Delta's area between 2002 and 2010. High amounts of sediments have been eroded from Haiti's deforested mountains and deposited in the Delta. Recent expansion of the river channel due to runoff from Hurricane Tomas' rains is apparent in the 2010 image. Image credit: Google Earth, Digital Globe, GeoEye.

At last week's American Geophysical Union (AGU) meeting last week in San Francisco, Shimon Wdowinsky of the University of Miami proposed a different method whereby unusual strains on the crust might trigger an earthquake. In a talk titled, Triggering of the 2010 Haiti earthquake by hurricanes and possibly deforestation , Wdowinsky studied the stresses on Earth's crust over the epicenter of the mighty January 12, 2010 Haiti earthquake that killed over 200,000 people. This quake was centered in a mountainous area of southwest Haiti that has undergone severe deforestation—over 98% of the trees have been felled on the mountain in recent decades, allowing extreme erosion to occur during Haiti's frequent heavy rainfall events. Since 1975, the erosion rate in these mountains has been 6 mm/year, compared to the typical erosion rate of less than 1 mm/yr in forested tropical mountains. Satellite imagery (Figure 2) reveals that the eroded material has built up significantly in the Leogane Delta to the north of the earthquake's epicenter. In the 2008 hurricane season, four storms--Fay, Gustav, Hanna, and Ike--dumped heavy rains on the impoverished nation. The bare, rugged hillsides let flood waters rampage into large areas of the country, killing over 1,000, destroying 22,702 homes, and damaging another 84,625. About 800,000 people were affected--8% of Haiti's total population. The flood wiped out 70% of Haiti's crops, resulting in dozens of deaths of children due to malnutrition in the months following the storms. Damage was estimated at over $1 billion, the costliest natural disaster in Haitian history. The damage amounted to over 5% of the country's $17 billion GDP, a staggering blow for a nation so poor. Tragically, the hurricanes of 2008 may have set up Haiti for an ever larger disaster. Wdowinsky computed that the amount of mass eroded away from the mountains over the epicenter of the 2010 earthquake was sufficient to cause crustal strains capable of causing a vertically-oriented slippage along a previously unknown fault. This type of motion is quite unusual in this region, as most quakes in Haiti tend to be of the strike-slip variety, where the tectonic plates slide horizontally past each other. The fact that the 2010 Haiti quake occurred along a vertically moving fault lends support to the idea that the slippage was triggered due to mass stripped off the mountains by erosion over the epicenter, combined with the extra weight of the extra sediment deposited in the Leogane Delta clamping down on the northern portion of the fault. Wdowinsky gave two other examples in Taiwan where earthquakes followed several months after the passage of tropical cyclones that dumped heavy rains over mountainous regions. His theory of tropical cyclone-triggered quakes deserves consideration, and provides another excellent reason to curb excessive deforestation!


Figure 3. Two of 2008's four tropical cyclones that ravaged Haiti: Tropical Storm Hanna (right) and Hurricane Gustav (left). Image taken at 10:40 am EDT September 1, 2008. Image credit: NASA/GSFC.

Christmas in Haiti
Portlight.org will brighten the lives of hundreds of kids in Haiti this week, thanks to their successful Christmas in Haiti fundraiser. Portlight raised $1800 to buy toys, candies, and other assorted goodies. The shipment left Charleston last week, and will arrive in time for Christmas. Thanks to everyone who helped support this worthy effort!

Jeff Masters

Stuff for Haiti (Portlight)
Stuff for Haiti
Ms. Mae (Portlight)
Ms. Mae

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KeryInNola - He suffers from rectal cranial inversion.
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That is really crappy of you, KoolMowDee. Although I hope everything comes out ok for you.
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KOTG.... u gotta stop, man... I need those stomach muscles to eat dinner with.... lol
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Quoting MrMixon:
Oh geez - for those of you "armchair-geologists" who doubt that massive sediment redistribution could cause earthquakes (and this IS a massive redistribution of sediment), I urge you to gather your evidence and publish a paper refuting the paper referenced by Dr. Masters....


Well the incidents you cited were due to fluid injection for the most part. Might it be possible that that occurred in Haiti. The river that feeds the lagoon appears to jog west along the south side of a ridge that just might correlate with a fault line. This would provide a path for water to seep deep into the earth. Is that what you are saying?

I can think of examples where movements of earth of greater magnitude than this by man in earthquake zones have not led to large earthquakes. Hong Kong comes to mind. I measured the air field they built out into the harbor and it is much larger than this delta enlargement. Magna mountain southwest of Salt Lake City comes to mind also. Magna was a mountain and is now a hole as deep as the mountain was high. The polder in the Netherlands comes to mind too.

Haiti will always have earthquakes. The real problem is that the Haitians are building on sediment which amplifies the effect of any earthquake. Mexico City has the same problem.

But I agree, 98% deforestation is deforestation gone too far if there is no reforestation.
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Remember: Don't Insult the Alligator till after you cross the river.
Member Since: July 15, 2006 Posts: 170 Comments: 53548
I thought that line was between genius and mental illness...
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KOTG - You are in rare form tonight...

BTW, 95L - This just isn't funny anymore.
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<
Member Since: July 15, 2006 Posts: 170 Comments: 53548
Uh-oh: it snowed in Australia today--right in the middle of summer. Sure evidence of _ _ _ _ _ _ _ _ _ _?

http://www.canberratimes.com.au/news/local/news/general/mother-natures-white-christmas-bid/2030921. aspx

http://www.huffingtonpost.com/2010/12/20/australia-summer-marked-b_n_799110.html

Member Since: November 8, 2009 Posts: 4 Comments: 13509
Quoting DoverWxwatchter:
Extract from calusakat's post 274

I do not have to prove my position regarding your AGW hypothesis. Just because you say it is so, that does not make it so.

That's because you can't. Your claims go against all reputable scientific evidence. You and I both know that your denier statements are false and have no backup.




Sigh...

More AGW Talking Points.

Haven't you a brain of your own?

It is your total and complete responsibility to convince me and the rest of us that your position is the proper one. If you don't convince us, that is your fault and your fault alone.

All we have to do is sit back and yawn. We have no need to prove anything.

As an AGW lemming you are one of the ones who must come to the table with the NEW ideas, not us. Your Chicken Little mantra, 'The sky is falling, the sky is falling!!!!.', is not, in any way, proof that your position is correct. At best, it only proves how desperate you are to get your way.

Sadly your methodology is to commit foul after foul as you conform to the AGW Talking Points booklet.

The ball is in your court.


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>
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<
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Quoting AstroHurricane001:


Didn't you say that last winter too? LOL.


Yes!!!! Evil is eternal.... ; )
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Quoting presslord:
snow is evil...it is of the Devil...


Didn't you say that last winter too? LOL.
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WHAT???



OK, this is the system I said looked well-developed just a few days ago. Probably not going to become anything significant though.
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there from earlier in the season mostly were on in the chat room they have many names but stupid is the only thing they are or have become
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1
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276. JLPR2
Quoting JFLORIDA:



Its weired its basically being ignored here in the US. Sounds like a bad scene and something unfortunate waiting to happen.

More:


Tensions mounted last week leading up to a two-day student walkout when Capitol Security, a private security firm contracted by the university for $1.5 million, demolished entrance gates to the campus. Hired guards were young with little or no training or evaluation, bore no identification badges and some were armed with sticks and pipes in a climate of intimidation perhaps not seen since dockworkers strikes of the 1940s. Many of the guards had been recruited from marginalized Afro-Puerto Rican communities, such as Villa CaDona in Loza, which has been the site of documented police abuses, lending a disturbing dimension of institutionalized racism, according to community leaders there.

Several violent incidents were reported, including a student who was seriously beaten and injured by guards. One video purportedly of students breaking security van windows was repeatedly aired in the local media as the justification for the police occupation of the campus, just as students had peacefully concluded the two-day walkout last Wednesday evening.

According to Ramrez, Fortuo's public statements targeting leftists, designated protest areas off campus and protest prohibitions are violations of constitutionally-protected First Amendment rights. The police presence and heavily-equipped riot squads also create a climate of intimidation that restricts expression, he added.





Yes, the tension is getting worse and worse each day, since the police officials are working long hours at the university watch and recently they lost some sort of benefit so they are probably hitting the students, seeing them as the ones guilty of their work load.
Today has been the most aggressive day so far and the violence was started by the police. :\
If only I had a bazooka... LOL!
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Jeff co-founded the Weather Underground in 1995 while working on his Ph.D. He flew with the NOAA Hurricane Hunters from 1986-1990.

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