As many of you know, three days ago California was hit with a magnitude 6.5 earthquake that originated 30 miles off the coast of Eureka/San Fransisco. Yesterday came more devastating news that a magnitude 7.0 earthquake struck only 10 miles away from the capital Haiti, Port Au Prince. (I didn’t think this was supposed to happen until 2012…)
EDIT: Thanks Deborah, for correcting my facts. I feel foolish for posting before being 100 sure of things. Thanks for commenting with your expertise.
Immediately I was struck with by the differences between these two quakes. Although Haiti experienced a much stronger, and closer, rumble – it also experienced a LOT more casualties and damage. So far the toll stands at 30 injured in California, no deaths, while the toll for Haiti is potentially (and unfortunately, likely) thousands dead.
What is the reason for such a huge difference?
Wealth. (and Luck)
Haiti is one of the worlds most struggling countries and economies, while C.A. is one of the richest, in the US and in the world.
When you have money you can build things stronger and repair them faster. This is truly a disaster for the country.
The luck factor comes in when you look at where the quakes actually struck – California’s quake was 30 miles off the coast so the state only got the worst of the edges – while, Haiti’s was directly on the island, and was also more powerful.
At this time of crisis both places need our prayers and aid. If you are interested in donating $5 via text message to Haiti visit the Yele.org website to find out how. You can also donate via the Redcross.org website, in $10 increments.
Maps from Earthquake.usgs.gov
Related posts:
{ 11 comments… read them below or add one }
A brief correction by probably the only seismologist reading your blog (and first time commenter!):
CA's earthquake was off the coast of Eureka (north of San Francisco), not LA! Earthquakes of that size happen pretty often in that area, but it is lightly populated compared to much of California. Many Californians don't even know when a large earthquake occurs up there — most people are unaware of the M7.2 in 1992 in the same area (also very little damage) but they have heard of the M6.7 Northridge (1994, LA) and M6.9 Loma Prieta (1989, SF).
I would argue that while wealth is a HUGE factor (particularly along the lines of infrastructure and building codes), the population density is also a major difference. An M7 earthquake 30 miles off the coast of LA would cause significant problems.
I made a donation today to CARE ( http://www.care.org/ ) in support of the relief efforts.
Also, congratulations on hitting 0. That's a huge accomplishment!
Yes, had the earthquake actually been near LA I imagine it would have caused major damage. These two earthquakes seem vastly different. I wonder if Deborah might comment on what an M7 earthquake 10 miles off the coast of LA could do!
I also wanted to offer my congratulations on you guys hitting 0. Great job!
Also, I will be donating to Heifer International ( http://www.heifer.org ). They are not a first responder charity but will use the funds to provide the tools and resources for the survivors to rebuild their lives.
The larger offshore faults near LA haven't had large earthquakes in historic times, so it is unclear what size earthquakes they are capable of producing.
The biggest general hazard in southern CA is the rupture of the San Andreas Fault from near the border with Mexico towards Los Angeles. This section of the fault hasn't had a major earthquake in a long time (200+ years, I believe), and is likely to produce a high M7 earthquake. There is a neat simulation on youtube ( http://www.youtube.com/watch?v=xioHswbahPc ) showing the rupture starting in the south and heading towards the north. If it happens similarly to this, it will be bad for all of southern CA — but especially Los Angeles, which has a region of relatively loose sediments.
Population density is also a key issue, you are correct. Thanks for your comments, seismology is fascinating.
Heifer International is a good cause as well. We've donated to them in the past, and I am sure they will do everything they can to help the rebuilt people of Haiti get control of their lives and food situation again.
Thanks!
Am I correct in thinking that a quake as bad as the one in Haiti hadn't occured in over 150 years? I imagine that the San Andreas Fault breaking would be absolutely devastating!
How well can we predict plate movements and earthquakes? (any chance to be prepared for something massive?)
Haiti hadn't had a large earthquake since before 1800.
The San Andreas Fault has ruptured in pieces historically (check out this cool figure: http://www.geo.utep.edu/pub/bkonter/research/SAF_… ) but the southernmost part hasn't had a large earthquake in a very long time.
We know from GPS and other types of measurements how the plates are moving overall, but it is a very complicated system. It's not the simple picture kids are taught where there are X number of plates moving around — there are many microplates (small plates) that affect movement and there is deformation going on at the plate boundaries and within the plates as well.
In addition, we are unable to measure the state of stress on a fault (which would perhaps be a good predictor) from the surface — we would have to drill into the fault a few km deep — and that value of stress varies everywhere, so that is not a reasonable thing to measure (way too expensive and time consuming and always changing everywhere, so the measurements would be largely incomplete).
What we are somewhat capable of is predicting *what* will happen when the earthquake does occur (which it inevitably will), rather than *when* it will occur. Such studies enable us to perhaps improve building codes where we predict larger motion and make sure the public is aware of what to do in an earthquake.
We can also forecast the likelihood of large earthquakes given past events, but this is like the weather forecasting — it's not always right, plus we usually do it on a 30-year timescale (rather than the 5+ days of the weather forecast).
CA is pretty good at spreading earthquake awareness — everyone associates CA with earthquakes and most people in CA understand a bit about what to do to be prepared. But did you know that many other places in the US are fairly high risk as well?
http://pubs.usgs.gov/fs/2005/3038/images/seismic-…
I just learned (from cnn.com) that a 5.7 quake hit Venezuela; is it common to have three "big" earthquakes so close in timing? Or does it just seem that way because they are actually being reported now?
It's not unusual at all. There are several M5 and M6 earthquakes every day worldwide. The one in Venezuela may very well be related to the Haiti earthquake since they are so close together (stress release from one earthquake can cause earthquakes nearby, hence why we get aftershocks) but it is usually difficult to absolutely say one large earthquake was the cause of another large earthquake unless they are close enough to be considered 'aftershocks'.
There was a 6.0 yesterday near the Mariana islands and a 6.2 on Saturday, neither of which made the news… they generally aren't 'newsworthy' unless they are over a M7 (and even then you often won't hear about them) or unless there are more than several hundred fatalities.
I get an email every time an earthquake larger than M5.5 occurs anywhere in the world; several of these show up everyday!