Good Question

The Chile earthquake, 8.8 on the Richter scale, was by far the largest. But a little noticed 7.0 quake struck near Japan's Ryukyu islands just a few hours earlier, triggering its own tsunami warnings.

The Jan. 12 temblor in Haiti was also 7.0, about 500 times less powerful than the Chile quake, though it appears to have killed many more people. That prompts yet another question: Why did a much larger quake cause much less destruction?

Not as hard to answer, as one might think...

What makes modern quakes particularly devastating are megacities located near seismically active zones. "Earthquakes don't kill people, buildings kill people," says David Wald of the National Earthquake Information Center of the USGS.

That is especially true in poorer countries where many buildings are shoddily designed and constructed from weak materials, or they simply fail to meet basic building standards. That was the case in Haiti, where the death toll is estimated to exceed 220,000—much greater than what is thought to have occurred in Chile, even though the Haiti quake was far less powerful. Chile enforces strict building codes, partly because it has endured several major temblors, including the highest magnitude quake on record, 9.5, in 1960.

You mean stacking cardboard houses like milk crates doesn't cut it, when the Earth starts shaking?  But much like building New Orleans in a bowl, Port-au-Prince will be rebuilt and it's surviving residents will pay only a passing interest to safety and building standards, because it's too much work to build it right.

Comments

[Monnie]

The Chilean EQ epicenter was over 20 miles beneath the surface, while Haiti's was a relatively shallow one. The depth makes a BIG difference in surface shaking.

Not meant to denigrate the differences in building construction and infrastructure.

[Wonder Woman]

Thanks Monnie. More information and perspective is always better.

I had no idea that depth matters but when I think about it, it makes perfect sense.

[Texas Canuck]

I'm not going into any size or depth matters ;-) but there are a lot of differences between Chili & Haiti quakes. There are even different ways the earth shakes, i.e. surface, body and yes, even love waves. A good chunk of Chili actually sunk 6 feet and NASA says the earth's axis actually shifted and out day got shorter. The only thing truly common is the need of survivors to loot TVs.

[Monnie]

WW,

All those cubic miles of rock act like a shock absorber. Chile was really lucky---an 8.8 close to the surface would have wrecked that entire area and killed many more people.

Texas Canuck,

You're always good for a double entendre.

Love waves? No "deep throat"?

I

[Fenris Badwulf]

Interesting how these earthquakes keep happening.

Back in my university days, I had a prof tell me that that earthquakes can trigger other earthquakes, especially the shallow ones. Now I wish I could find a link to back this up.

And, I have cancelled my plans to visit LA.