Most of you know the latest on the situation in Haiti itself, but a few ex pats, like Jessi Stit in Malawi, don't seem to get a lot of news so at the end on this entry you'll find an update.
The geologic situation in Hispaniola
[The following information is drawn from an article in Science, volume 327, 22 Jan 2010, p398, (go to www.sciencemag.org), and from USGS sources]
In 1979, a siesmologist named William McCann published a world-wide survey of the regions where there is a highest probablity of rupture of a fault in an earthquake. Hispaniola (Haiti/Dominican Republic) was identified as one of them.
The Caraibbean plate (South American side) and the North American plate slide past one another relentlessly at roughly 20 mm per year about a fault that passes through the southern edge of Cuba and along the southern edge of Hispaniola. This fault is much like the San Andreas fault in southen California. Unfortunately for Hispaniola, the two continental plates actually form two parallel faults here, one along the southern edge of the island, the other along the northern edge, pinning Hispaniola in a double grinding East-West twist.
A further misfortune of this double grinding is that it is causes relatively shallow earthquakes that create more physical damage than deep earthquakes. A third misfortune is that Port au Prince, much like Mexico City, is built on sandy sediments that fill a valley rather than on rock. When an earthquake hits, the sandy ground shakes like a bowl of jello. It actually behaves in a fluid-like manner grossly magnifying the shaking effect.
In the period of the 1700's there were major earthquakes along the southern edge of Hispaniola, in fact there was a 6.6 quake in Port au Prince in 1701. On October 18, 1751 a very large quake of 8.0 broke the fault in the southern ocean off shore to the East, the faulting then triggered a 7.5 quake in Haiti to the east of Port au Price, further breaking the fault on November 21. This quake destroyed Port au Prince. Then on June 3, 1770 another 7.5 quake occurred in the Port au Prince area, again destroying the city. In the early 1800's an 8.0 quake occurred on the northern fault in Haiti.
This is often the pattern, a part of the fault breaks and this transfers the stress in the fault to unbroken regions which may then eventually rupture in a domino effect.
In the aftermath of the 1751 quake 30,000 people died of hunger and disease.
As a result of the 1751 and 1770 quakes, at that time Haiti outlawed masonry house construction, allowing only wood construction. This obviously was not continued.
The 1770 earthquake of 7.5 magnitude formed the fault that partially broke this past January. The 1770 quake was five times more powerful than the 2010 quake.
In the past 240 years, the two plates have contined to march past each other at a steady 22 mm/year pace but locked together in Hispaniola and building up more and more unrelieved shearing stress in the Haiti-Cuba fault system. The plates have moved, more or less, 17 feet past each other with no major rupture to relieve the stress.
Dangerous times?
This earthquake on the scale of earthquakes was relatively moderate. Unfortunately, it may well be a precursor to an even larger one. The fault is a sleeping giant. After 250 years, is it turning in its sleep to get more comfortable for a while?
If you are interested in the seismology of the Caribbean, or your own backyard, I encourage you to go to the USGS site . You will see the Virgin Islands to the East are constantly active with small quakes, and appreciate why there is a volcano there.
Update for those expats living in caves:
Right now supplies and equipment appear to coming in at a fast rate. Monetary donations seem high.
The biggest issues look like the inability to move supplies inward from the airport and the absence of tents. Most people are still sleeping in the street, damaged housing or makeshift housing. Food supplies, medicine and water are getting in. There is an effort to move people into the countryside out of the city. Crime (looting) is beginning to increase in Port au Prince.
The seaport itself was heavily damaged but I think it has been repaired enough to take on some deepwater ships again. The roads are either full of debris, people or damaged and they have to use limited amounts of heavy equipment to move things. The injuries and inability to provide immediate health care, and destruction of most medical facilities is still a big issue. Over 100,000 people have been killed and buried in mass graves, or still are rotting in the streets and destroyed buildings. I imagine the toll will go higher.
There are bodies in the ruins and the potential for serious public health issues is great. Compounding this, as you may expect, there are many crushing injuries that require amputation, as well as head trauma. People remain untreated for long periods, leading to infection and gangrene; and the likelihood of poor/doubtful recovery. It was absolutely horrible to see seriously injured people all lined up on blankets lying on the sidewalk or in the courtyard of places where the few medical teams are. They may lay there for several days.
The US military has hospital ships off shore and are trying to meet some of the need.
Authorities are trying to move people out of Port au Prince into the country side to relieve the excessive crowding.
The infrastructure, as I can tell (water supplies, roads, etc) was already in very bad shape and now is basically worthless.
I have described it as if we are watching one of the twin towers collapse helpless to help - but in horribly painful slow motion. So much damage was done and the events have been launched in the area of health that can't be reversed, while we stand and watch holding all the medicine, equipment in our hands to help if we could.
I worry a lot about what will happen in Port au Prince - dysentery, cholera, etc, I may be the pessimist tho. I heard on PBS radio yesterday that the two major pre-existing medical problems in Haiti are tuberculosis and HIV/AIDS. The Tuberculosis sanitarium was destroyed; much of the HIV/AIDs vectors were in the prison in town and that was destroyed and all the inmates have fled. People is the countryside who have HIV/AIDs are still managing to get to treatment but I can't speak for Port au Prince, itself. Other than the escaped prisoners, it appears many HIV/AIDS positive people are able to connect with treatment.
I immediately thought about heading down, looking for the right connection, but as I followed what is happening, I came to the realization, with some help from friends, I'd be in the way until I can connect with the right organization and we can get enough physical presence to create space to help. I think very soon it will be time to go though, and am still struggling with whether to take off and help or stay in seminary. Sometimes action is a better form of praying than sitting and studying.
I worry the most about whether this quake is a precursor to an even larger one in the relatvely near future.
Henry
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