A tale of two earthquakes...

[Krazy P]

Or why the advance of civilization and growth is good.

Haiti... 220,000 dead

Chile ... 1,000 dead (maybe?)

The difference?

Aside from the obvious differences in the quake and location, the salient difference is the infrastructure, building codes and so forth. A direct result of the positive outcomes of a higher standard of living and the progress of civilization.

[plotthickens]

And Chile has multiple income streams which has allowed these things to happen.

[darynthe]

I read that the Chilean earthquake was about 1000 stronger than Haiti's.

However the epicenter was farther from the urban centers affected.

This to say that indeed the standard of living makes all the difference in the world.

I will bitch about one thing: I hear that first world will provide the money to the reconstruction of Haiti. And then in the meeting the big guys had in Montreal to rebuild Haiti, they swore that they will let Haiti do the reconstruction as they see fit.

What the hell? If it is my money I will oversee and decide the use of it. Why should the foreign goverments to trust the locals with such a huge ammount of resources when they haven't been able to deal with things so far? The history of Haiti is one of the bloodiest ever. Corruption, murder. Rape wasn't illegal until recently.

I am in for helping Haiti, I am just frustrated that they probably will end making a mess of it and it won't work out in the end.

[Synchronicity]

The Chilean earthquake was a little under 100 times stronger in magnitude than the Haitian earthquake (8.8 vs 7.0). Haiti has a higher death toll partly because of poor building codes, but mostly because the origin of the Haitian earthquake was significantly closer, both in depth and surface distance, to Haiti's population centers.

[Mogura]

This is an excellent article that does a pretty good job of explaining it:

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No, the apocalypse is not coming. No, the two earthquakes are not linked in any way. And no, Pat Robertson, you can't blame the Devil or the French. The real answers, for those comfortable with science and the Enlightenment, are tectonics and poverty.

An article about earthquake-proof buildings:

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[Aronnax]

Chile has dealt with earthquakes for a long time, many of the Confined Masonry (To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.) building techniques were developed in Chile. For those who don't find PDFs of engineering reports irresistible I'll summarize: They build a lot of their structures out of concrete masonry units (CMU) like many developing world nations but they "confine" the walls with reinforced concrete (RC) columns and beams to deal with lateral loading (brick walls are weak laterally for obvious reasons).

Haiti uses CMUs, concrete and rebar but the pieces aren't put together in the same manner. There are problems with voids in concrete, undersized and/or an absence of rebar but some of the problems are also directly related to building techniques. Overuse of CMU as interior fill increases building mass without significantly increasing strength. Unattached concrete slab roofs and exposed rebar simply shouldn't be done. A combination of systemic poverty and decades of government corruption makes this a terribly difficult problem to address.

[nacht]

The Chilean earthquake was a little under 100 times stronger in magnitude than the Haitian earthquake (8.8 vs 7.0).


The difference in power between two moment magnitudes is 10^(1.5*(m1-m2)). Thus the difference between the Chilean earthquake and the Haitian earthquake was a factor of a little over 500, not a little under 100.

[Mogura]

Interesting science stuff...

The magnitude-8.8 earthquake that rocked the west coast of Chile last month was violent enough to move the city of Concepcion at least 10 feet to the west and the capital, Santiago, about 11 inches to the west-southwest, researchers said.

NASA scientists have also credited the quake with shifting the Earth's axis enough to create shorter days. The change is negligible, but still worth noting: Each day should be 1.26 microseconds shorter, according to preliminary calculations. A microsecond is one-millionth of a second.

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[Synchronicity]

The difference in power between two moment magnitudes is 10^(1.5*(m1-m2)). Thus the difference between the Chilean earthquake and the Haitian earthquake was a factor of a little over 500, not a little under 100.

Could you explain that formula? Richter magnitudes are scaled logarithmically, which means a difference of 1.8 on a log scale would equate to 10^1.8 on a linear scale, which is just under 100. Perhaps you are thinking of the amounts of energy released by the two quakes, which I believe were separated by a factor of about 500. I don't know the specific formula used to calculate that.

[nacht]

Could you explain that formula? Richter magnitudes are scaled logarithmically, which means a difference of 1.8 on a log scale would equate to 10^1.8 on a linear scale, which is just under 100.


First clarification needed, though it doesn't affect the raw calculations in this case, is that the values in question aren't Richter exactly. They are on the Moment magnitude scale (To view links or images in this forum your post count must be 2 or greater. You currently have 0 posts.).

Second issue is that while both are log-10, there's a scaling constant of (3/2) involved with Richter magnitudes as well, so the difference in power is calculated the same way: 10^(1.5*(m1-m2)). So a difference of magnitude of 1.8 comes out to around 501.


Perhaps you are thinking of the amounts of energy released by the two quakes, which I believe were separated by a factor of about 500. I don't know the specific formula used to calculate that.

That is exactly the number being calculated, but the amount of energy released is how much stronger the quake is.