What are the chances of an earthquake in California being as damaging as the Haiti earthquake?
Jan 23, 2010
in
Earthquake Questions
I know that California sits on many fault lines, but if the same magnitude quake that hit Haiti recently hit San Francisco for example, would there be as much damage/deaths?
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4 comments
sd3r on January 23, 2010 at 11:04 pm
no, a similar magnitude won’t do as much damage here, California has different building codes. actually, make that California HAS building codes.
compare the Northridge quake (1994) at 6.7, ok less than the 7.0 to hit Haiti, but compare the 57 deaths, ~9000 injured in California to the suspected 200,000 deaths in Haiti.
California will probably see an 8.0 someday. that’s the day you don’t want to be caught on a bridge or near/in a tall glass structure.
Mark V on January 23, 2010 at 11:04 pm
I need to clarify something. *NO* scientist has predicted that California or a piece thereof will "break off" from the rest of the continent in a horrible calamity. It physically cannot happen. I’d love to devote the rest of this answer to explaining, in depth, the various reasons what that was a really stupid thing to say. But I’ll save you the time to read it. Just accept that that was a BS answer/statement, with absolutely no piece of truth to it whatsoever.
The actual chances of an earthquake happening in California are no better or worse than they were in Haiti. The chances of an earthquake happening here being the same or worse insofar as damage and death is low.
First of all, earthquakes of that magnitude are very, very rare in California because of the way that the San Andreas Fault Zone does let off built up strain in continuous (thousands) of small earthquakes that not even dogs notice, up to the occasional 4.0 Richter magnitude, which are basically the level at which those of us living here even begin to notice or care about. The release of strain by these smaller and more frequent earthquakes offsets the possibility of such a serious build-up of strain along a fault face (faults lock along a large two-dimensional face, not just a single point). I won’t tell you that it can’t happen, I’m just explaining how the SAFZ works, in a general sense.
Second, not just San Francisco, but all of our major cities learned from the disastrous Great San Francisco of 1906. We know where to put our buildings with regard to solid bedrock and unconsolidated sediment. How to build a type of structure for various places to best survive a seismic event. Our building codes and engineering designs and locations have only improved over the course of more than 100 years. My primary day-to-day job is to locate suitable foundation rock, study them, design for them, and supervise construction of whatever structure is being built (bridges, aqueducts, roads, office buildings…). Part of designing for those structures usually includes some kind of seismic isolation system, which allows a building to absorb and sway with surface waves that would have otherwise been far more damaging. Yet, even without these SISs, beyond my job, the civil and structural engineers who I work with design fantastic structures. I won’t go into all of the details, but there are many, many ways in which those shocks can be mitigated — and are. Older structures have been, and still continue, to be retrofitted.
Third, as populated as San Diego, Los Angeles, and San Francisco are, it’s nothing compared to what poor Port-au-Prince had: about 35,200 people per square kilometer. Of those of you who prefer Imperial, US units, that’s about 91,000 people in one square mile!! Los Angeles is only 3,100 per square kilometer (8,200 sq mi), and your specific question, San Francisco, while still more dense, only 6,700 per square kilometer (17,000 sq mi). That’s only 18% as dense as the unfortunate city in Haiti. Now, put this against the fact that in our cities, our buildings are spaced apart (even in cities), they aren’t stacked willy-nilly on top of each other, etc. So when they do come down, they don’t crush thousands of people if for no other reason than there aren’t enough people close to one of those rare falling buildings to kill.
Fourth, while our infrastructures are still rather backward (quality of electric and telephone lines, water and gas mains), they will not be damaged and destroyed to the same level as the Haitian infrastructure. Roads will still be clear enough for firetrucks and heavy equipment to move around. In-place emergency management structures and plans. Large amounts of medical, food, water, shelter, search-and-rescue crews, and other necessary aid arriving within only hours, and along a logistics train that will remain essentially unbroken from source to damage area.
Finally, rebuilding. We have more money, and California is an easy location to plow out the debris and bring in new construction material.
It wouldn’t be nearly as bad as the Port-au-Prince earthquake. I don’t intend to speak poorly of them, just stating facts.
But last — I’m not trying to tell you that a very bad earthquake can’t happen, or that if it happens, it won’t suck. Just that it won’t be as bad, and those are the reasons why.
Andrew on January 23, 2010 at 11:04 pm
Some scientists predict that the coast of California will break off at some point in the future. This could be devastating but since it lies on San Andreas Fault, the magnitude will not be that severe since a Transform boundary "rubs" against plates it wont be too devastating.
Jack T on January 23, 2010 at 11:04 pm
virgn just look up the san fransisco quake of 1903..give you an idea ..go to wiki or google..simple all the data is at your disposial..thee is some old footage taken as well..go for it good luck.