photo: Colin Crowley/Creative Commons
Yet another reason why deforestation is bad: So much of Haiti's mountainsides have been eroded away because of deforestation and hurricanes that it may have stressed Earth's crust, triggering the earthquake that killed over 200,000 people last year. Amazing, but as Mongabay reports, according to analysis by a geologist at the University of Miami presented at the American Geophysical Union meeting last month, it well may be true--and it's happened elsewhere before.
Typical deforestation in Haiti, photo: Tree For The Future/Creative Commons
The meeting was on December 20th and Jeff Masters reported on it at Wunder Blog. Here's the relevant passage on the linkage between deforestation, sediment and earthquakes:
[Shimon] 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.
Masters pulled the above image from Google Earth, showing sediment deposition in the Leogane Delta of Haiti from 2002 to 2010. Very telling.
As Wdowinksy's presentation highlights, in southwest Haiti over 98% of the forest cover has been removed in recent decades, leading to erosion six times the normal level for forested tropical areas.
As for the part about this sort of thing happening before, Wdowinksky cited examples from Taiwan where earthquakes followed strong storms in mountainous areas.
Deforestation Increased Severity of Pakistan Flooding
Stopping short of earthquakes, but still in the devastating natural disaster realm, let's remember that rampant deforestation in Pakistan directly contributed to the severity of flooding seen there last summer. With the hills and mountains stripped of much tree cover, erosion increased, in places dragging remaining tree cover down causing blockages, damaging dams and increasing flooding.
photo: DVIDSHUB/Creative Commons
A quick calculation on the number of people whose lives were disrupted or killed in both these events, both with deforestation at the center: 4 million people in Pakistan left homeless, including a couple thousand killed + 800,000 people affected by the Haiti earthquake (8% of the nation's population), including 200,000+ dead = roughly 5 million people victims of deforestation-related natural disasters.
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More on Deforestation:
New Google Earth Layer Shows Global Deforestation
Amazon Deforestation Down 51 Percent From This Time Last Year: So, What's Working?
10 Countries With the Highest Deforestation Rates in the World
More on the Haiti Earthquake:
Help For Haiti Earthquake Aftermath. Giving Green.
Comparing Haiti and Chile: Did Building Codes Save Lives?
Haiti's Rebuild May Be Biochar's Big Breakthrough