You're right, but over the course of a building's lifespan, the "chance" is greater, right? So the chance of a terrorist attack against salesforce tower this year is less than the chance it might happen sometime in the next 30 years. I'm not good at statistics, though.
Anyway, this is why we have a lot of earthquake preparedness, though the chance is 5% in the next 30 years.
It's not a "constant worry," so much as a plan. There's non-negligible chance of terrorist attack, so they architect in such a way to prevent it being catastrophic. There's a non-negligible chance of your office catching fire, so they put green exit signs at the door. That sort of thing.
Not even close. USGS estimates over the next 30 years are:
72% probability of a M6.7 or higher
51% probability of a M7.0 or higher
20% probability of a M7.5 or higher
And?? California building codes have improved alot since the 1980s or so. I remember the 1989 LA earthquake as I drove through the aftermath to visit my grandma about 2 weeks after, I live on the Central coast.
That tells me our building codes are pretty damn good.
I work at ucsb and the catilina islands recently had a 5.2 about 2 weeks ago and the building shook abit. But all in all unless we suffer an 8.0+ I'm not terribly worried (knock on wood). To put that another way, realistically for any moderate sized earthquake CA is generally well prepared in terms of architecture, unless the big one hits ... In which case just kiss your butt goodbye.
I do wish, even for the big one, that CA invested in an early warning system like Japan has ... Imagine a 5-50 seconds warning of an earthquake, that would save lives, not stricter building codes:
https://youtu.be/OXXZouxPT7U
An early warning system might be nice, but stricter building codes are what is going to save lives. Japan has those too.
It's also worth pointing out that there has arguably not been a large quake close to a major city center in California since 1906 (for some values of "large" and "close"). The 1994 Northridge quake, which did some $15B in damage, was probably the best recent preview we have. Loma Prieta certainly did serious damage, despite being (as I recall) some 75 miles from San Francisco.
The real test is when the Calaveras Fault that runs up the east side of the SF Bay breaks. The last time was 1868, when there wasn't much there; estimated magnitude was 6.3 to 6.7. A quake of that size on that fault now — and it's getting to be likely, in the next two or three decades — is going to make a hell of a mess. We'll find out then how well a lot of things hold up.
Anyway, this is why we have a lot of earthquake preparedness, though the chance is 5% in the next 30 years.
It's not a "constant worry," so much as a plan. There's non-negligible chance of terrorist attack, so they architect in such a way to prevent it being catastrophic. There's a non-negligible chance of your office catching fire, so they put green exit signs at the door. That sort of thing.