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

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

The headline and the provocative repost are both from meteorologist — and former NOAA Hurricane Hunter — Jeff Masters of the Weather Underground:

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 Ni±o 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

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

  1. Mike says:

    While theoretically interesting, the Haiti earthquake would have still happened, just a few years later than it did. The real issue is the development practices that allowed it to be so deadly. These are not unrelated to the development practices to lead to the deforestation – so there is a connection at the level.

    Masters wrote: “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.” As glaciers melt the pressure on the land below decreases and allows the land to rise. This can trigger earthquakes too. Earthquakes in Greenland or Antarctica probably won’t impact humans, but melting ice caps on some volcanoes near populated areas are a concern. It think C.P. had a post on this some time ago.

    It is interesting to see how interconnected various earth systems are.

  2. M says:

    “While theoretically interesting, the Haiti earthquake would have still happened, just a few years later than it did.”

    I was wondering about that – eg, the kind of disaster which is going to happen sometime, somewhere, and therefore little variations don’t matter so much (eg, with a hurricane, if you happen to have driven a large boat in front of it and it landfalls 100 miles to the west of where it would otherwise have been) to disasters whose frequencies or natures change because of interference (eg, increased intensity of the average hurricane due to global warming).

    If I read the post right, this earthquake is in the latter category: ie, a vertically oriented slippage event would not have occurred at all without the deforestation/hurricane/delta combination. How well-founded this hypothesis is is another question, but I don’t think it falls into the “just theoretical” category.

    -M

  3. David B. Benson says:

    Fairly clear than the mass redistribution from LGM to the Holocene helped to trigger numerous volcanoes; probably some severe earthquakes as well.

  4. Mike says:

    M: Good point. Thanks.

  5. David B. Benson says:

    M & Mike — Even with the forest those mountains erode at about 1/6th the rate when denuded. Eventually there would have anyway been enough erosion and delta formation to trigger the earthquake.

  6. Rabid Doomsayer says:

    If the loss of ice mass could trigger earthquakes and volcanic activity, how will earth quakes and volcanic activity affect the stability of the remaining ice sheet? Another feedback?

    Given that the Antarctic region has the biggest number of volcanoes with undetermined status the issue could be important. Where and when might also be important.

    I am really glad it is not my job to do the modelling. Talk about uncertainty factors.

  7. catman306 says:

    “It is interesting to see how interconnected various earth systems are.”
    Interconnected in ways we have yet to learn about. (unknown unknowns)
    That’s why a stable, self-regulated system is precious. Well, we had one. Nice, wasn’t it?

  8. David B. Benson says:

    Rabid Doomsayer — Ice sheets are really, really big while volcanoes & earthquakes are not.

  9. From Peru says:

    If there is melting in Antartica, and if the Glacial Isostatic Adjustment trigger big eartquakes (that is, over 8.5 Moment Magnitude) could the tsunami destroy an ice shelf?

    What will a Sumatra 2004-like earthquake triggered tsunami do the ice shelves in Antartica (I think of the big ones, like the Ross Ice Shelf)?

    Could result in an abrupt collapse of the West Antarctic Ice Shelf?

  10. David B. Benson says:

    From Peru — I already answered that sort of question @8.

    No, I think even the largest earthquake is too small to have much of an impact.

  11. Prokaryotes says:

    When deforestation erosion, heavy rains, landslides, hurricane/storm pressure could trigger the quake or further increase the chance of a future quake, the opposite with planting trees – following roots and natural Co2 weathering, a balanced climate would help to stabilize and prevent earthquakes.

  12. David B. Benson says:

    Prokaryotes @11 — I’m all for afforestation and reforestation, but this will have no impact whatsoever on the frequency of occurance of earthquakes. Earthquake energy comes solely from plate tectonics and that won’t change, trees or no.

  13. Prokaryotes says:

    David B. Benson, are you sure?

    “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.

    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,”

    So, if you do reforestation you lower the influence of an outside force – a stress factor on the tectonic plate.

  14. Prokaryotes says:

    What happens if all 1 billion chinese jump at once?

  15. Muoncounter says:

    The Port au Prince earthquake occurred at a depth of 13 km below the surface. A USGS map of historical seismicity shows a large number of prior earthquakes in the area. While there was no prior large earthquake, it is beyond a stretch of the imagination to put the ’cause’ of this event on any surface disturbance.

  16. monkey says:

    I am skeptical of this as earthquakes are a geological event not climate related thus any correlation seems speculative at best. Not all natural disasters can be linked to climate change. Natural disasters always have and always will occur no matter what. Climate change simply increases the risk of certain types (i.e. drought, hurricane, floods, wildfires etc.) but they would still happen with or without just less frequently perhaps (or maybe there is no correlation, although as time passes this should be come clearer either way). Volcanoes and earthquakes by contrast likely have little to do with AGW. Ironically volcanoes if large enough might be a blessing in disguise as they create global cooling due to blocking the sunlight so if large enough it could offset global warming or even cause global cooling if massive enough (the last volcano massive enough to do this occurred 26,000 years ago).

  17. Inverse says:

    Chaos theory would fit well with this. Although I expect its just another bunch of Climate unrelated scientist looking for a % of the gravy boat.

  18. Wonhyo says:

    There’s been record rainfall in Southern California the last few days. Could So. Cal. experience an earthquake triggered by the same mechanism hypothesized for the Haiti quake?

  19. Rabid Doomsayer says:

    David Benson,
    Right now and perhaps for the near future the ice sheet is very solid. A major volcanoe would probably puch a hole through the ice sheet but no more. After the ice sheets were weakenened it could be the final straw for a largish area. I know a very vague response, but it all depends on things unknown.

  20. A face in the clouds says:

    Some people along the Gulf Coast still wonder if there was a relationship between the 2005 hurricane season and the 5.8 – 6.0 quake in the Central Gulf in the fall of 2006.

    Some down there also wonder if the Haiti quake contributed in any way to the BP spill.

    They’ll be asking again next time I’m down there, so I’m all ears.

  21. Paulm says:

    If the ice sheets melting cause volcanic activity, this activity can probably directly result in earthquake activity in that region that would not otherwise have occured on a meaningful time scale.

    These earthquake will result in the gas hydrates becoming more unstable and releasing more methane. The resulting landslides and tsunamis will also destabilize ice sheets, glaciers and permafrost. All positive feedbacks.

  22. Paulm says:

    Welcome to Planet Eaarth series….
    Eastern Canada is the reality of Climate Warming and shows whats in store in the future for many coastal communities.

    Storm warnings continue for Eastern Canada
    http://www.cbc.ca/canada/new-brunswick/story/2010/12/22/nb-storm-surge-recovery-540.html

    A powerful storm battered communities along the Atlantic coast on Tuesday, leaving behind a trail of washed out roads, swamped wharves and thousands of residents in all four provinces without electricity.

    The east coast of New Brunswick was among the hardest hit regions. …only days after a different weather pattern caused extreme flooding and similar destruction in southwestern New Brunswick

    …He said the storm and the rising water was like nothing he has ever witnessed before in the area. “Nope, never [and] hopefully never see it again,” Barney said.

  23. fj3 says:

    Eden Concept: Residents of Eden with a net-zero cost-of-living have a very high quality-of-life!

    Unfortunately, residents of Haiti have the opposite.

  24. Redistribution of mass from the upside of a fault to the downside stresses the fault. If enough mass is redistributed a large earthquake may result.

    The island of Hawaii has earthquakes as large as M 8 caused by vertical forces that result from the accumulation of lava flows.

    Many of the comments here reflect ignorance of elementary geophysics. The USGS explains Hawaiian earthquakes on their web site.

  25. David B. Benson says:

    Prokaryotes & others — Averaged over the entire globe and a suitably long time, say 100,000 years, nothing but tectonics matters for earthquakes. Tectonics of course includes volcano activity. The surficial mass redistribution only effects the detailed timing of fault activity, not the long term rates.

  26. Prokaryotes says:

    David B. Benson said “nothing but tectonics matters for earthquakes.”

    No & Yes, gravitation is another outside stressor for tectonics, which is affected by mass distribution. Alls the ice melt going on, will trigger tectonics, which otherwise wouldn’t. Mountains lose their glue and the earth gravitational field is changing from ice melt/sea level rise.

  27. Barry says:

    David Benson (#27), it is my understanding that stresses can be relieved in many ways depending on many factors. A big quake isn’t a given.

    It seems at least possible that the stresses on this Haiti fault could have been released in a series smaller earthquakes if the loading/unloading happened slower. I think that is the whole point of the rapid loading scenario talked about in the article.

    Muoncounter (#15) says the area has been subject to repeated small quakes in the past but never a large one.

    I don’t think anyone can say for sure that the fault would, or would not, have failed in a similar magnitude event regardless of erosion rates.

    Wdowinsky’s idea seems at least plausible to me.

  28. David B. Benson says:

    Prokaryotes — You are picking nits. That just effects timing.

    Barry — Good point. The stress might be relieved in a series of small earthquakes rather than one larger one. Many deatils (that I don’t know) would have to be considered to evaluate the geophysical likelihood of that.

  29. Matto says:

    Okay, let’s take a look at some numbers here shall we?

    Haiti 2010 earthquake – 7.0 M, 217,000-230,000 Deaths
    Chile 2010 earthquake – 8.8 M, 521 Deaths
    NewZealand earthquake – 7.1 M, 1 Death

    Using some roundabout way to frame this as if climate change caused the deaths in Haiti and not centuries of historical inequity, horribly unfair trade relationships and the resulting lack of development is distracting from the real issues.

  30. Prokaryotes says:

    Ok, it effects timing, but here 250 million years ago siberia saw 100.000 of thousand of years volcanic activities but it settled.
    And the tuff times of pangea are over. And without an climate shift with following ice melt trigger, the tectonics would stay more calm, agree?

  31. Prokaryotes says:

    Reforestation and farming are crucial to Haiti’s long-term recovery http://www.pennlive.com/editorials/index.ssf/2010/01/reforestation_and_farming_are.html

    Commentary: Haiti rebuilding plans must include reforestation http://www.mcclatchydc.com/2010/02/04/83516/commentary-haiti-rebuilding-plans.html

    Profiting From Biodiversity
    We can see plainly in Haiti what happens when the biology of a nation is largely destroyed; indeed it is clear that for the country to have any hope in its future Haiti needs substantial ecosystem restoration and reforestation. http://www.nytimes.com/2010/10/21/opinion/21iht-edlovejoy.html

  32. Prokaryotes says:

    Haitian Farmers Reject Monsanto Donation
    The Peasant Movement of Papay, a group of Haitian farmers, has committed to burning 60,000 seed sacks (475 tons) of hybrid corn and vegetable seeds donated by Monsanto in the wake of the devastating earthquake earlier this year. http://www.foodsafetynews.com/2010/06/haitian-farmers-burn-monsanto-hybrid-seeds/

  33. Nico says:

    I’m wondering what the effects of all that oil drained out of the gulf so quickly will be. Is it causing the swarm earthquakes now happening in Southern California?? Or maybe something else down the road? It WAS nice while we had a balanced eco-system…

  34. I know this is really boring and you are skipping to the next comment, but I just wanted to throw you a big thanks – you cleared up some things for me!