3 ms·

Major earthquake overdue in California's Eastern Sierra, study finds

29 points by smaili 11y ago

vhost- 11y ago
I remember about a year before I left Reno we were having multiple earthquakes daily that I could feel. No one really knew what was going on and we all thought our city was falling in a hole. https://en.m.wikipedia.org/wiki/2008_Reno_earthquakes https://en.m.wikipedia.org/wiki/2008_Reno_earthquakes
- baus 11y ago
  I live on the south side of Tahoe, and I can remember some pretty significant jolts up here. One time my ex GF thought a bear jumped on the roof!
disposeofnick9 11y ago
Qualitatively, the South / Peninsula SF Bay Area hasn't had many significant earthquakes in recent years compared with the 80's-90's. I remember the 89 Loma Prieta doing algebra homework at 5:04 pm in the setting sun, shaking that kept on going for seemingly an eternity (lost half the contents of our pool) and aftershocks all night.
secfirstmd 11y ago
As a matter of curiosity, do investors in California take the high chance of an earthquake into account?
- eip 11y ago
  If they did do you think they would let entire startup teams live and work on reclaimed landfill in the SF bay?
cossatot 11y ago
I can't find any published research by Dr. Kent on this (and the abstracts from the referenced conference aren't on the website yet) but there are some important things to keep in mind when considering this type of thing: 1) Earthquakes do not occur uniformly spaced in time. It's not clear what the distribution of inter-event times is, but it's often considered to be a Poisson, Gamma, or other bespoke distribution based on the physics involved [1]. 2a) Earthquakes that happen on a fault in a complex fault network like the Sierra Frontal Fault (part of the Walker Lane / Eastern California Shear Zone system) do not occur independently; there is abundant evidence and physical reasoning to show that an earthquake on one fault or section of a fault may trigger nearby earthquakes [2]. 2b) This triggering probably just adjusts the inter-event time for a given fault segment, i.e. turning the clock forward or back [3]. This can basically lead to 'clustering' of earthquakes on a fault system. 3) We don't really know from the LA Times article whether the baseline earthquake rate was determined over a timeframe that was dominated by a cluster; i.e. insufficiently long sampling time to determine the real rate. Finding evidence of earthquakes hundreds to thousands of years ago, and then characterizing their age and magnitude, is really hard. There are big sample bias problems in a lot of these datasets, and it takes a lot of effort ($$) to minimize it but it never goes away. So be skeptical when you hear that an earthquake is 'overdue'. It is almost always a mischaracterization of what is actually going on, and rarely by the scientists involved... [1]: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.133.9909&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.133... [2]: http://www.ipgp.fr/~armijo/paraseminario/Stein-97.pdf http://www.ipgp.fr/~armijo/paraseminario/Stein-97.pdf [3]: http://onlinelibrary.wiley.com/doi/10.1029/2004JB003405/full http://onlinelibrary.wiley.com/doi/10.1029/2004JB003405/full
Maultasche 11y ago
I remember that when I was growing up, seismologists were telling us that there would be a really big quake any day now. Decades later and they're still saying the same thing. There have been some significant quakes in the meantime, but not the huge one that has been continuously predicted. The seismologists are probably right, but it's really difficult to accurately predict the timing of earthquakes. The earth will sit around doing absolutely nothing for decades and then suddenly lurch violently without warning. The seismologists keep saying it, and someday it will end up happening, but that could be tomorrow or it could be centuries from now.

29 points by smaili 11y ago

I remember about a year before I left Reno we were having multiple earthquakes daily that I could feel. No one really knew what was going on and we all thought our city was falling in a hole. https://en.m.wikipedia.org/wiki/2008_Reno_earthquakes https://en.m.wikipedia.org/wiki/2008_Reno_earthquakes

baus 11y ago
I live on the south side of Tahoe, and I can remember some pretty significant jolts up here. One time my ex GF thought a bear jumped on the roof!

disposeofnick9 11y ago

Qualitatively, the South / Peninsula SF Bay Area hasn't had many significant earthquakes in recent years compared with the 80's-90's. I remember the 89 Loma Prieta doing algebra homework at 5:04 pm in the setting sun, shaking that kept on going for seemingly an eternity (lost half the contents of our pool) and aftershocks all night.

secfirstmd 11y ago

As a matter of curiosity, do investors in California take the high chance of an earthquake into account?

eip 11y ago
If they did do you think they would let entire startup teams live and work on reclaimed landfill in the SF bay?

cossatot 11y ago

I can't find any published research by Dr. Kent on this (and the abstracts from the referenced conference aren't on the website yet) but there are some important things to keep in mind when considering this type of thing: 1) Earthquakes do not occur uniformly spaced in time. It's not clear what the distribution of inter-event times is, but it's often considered to be a Poisson, Gamma, or other bespoke distribution based on the physics involved [1]. 2a) Earthquakes that happen on a fault in a complex fault network like the Sierra Frontal Fault (part of the Walker Lane / Eastern California Shear Zone system) do not occur independently; there is abundant evidence and physical reasoning to show that an earthquake on one fault or section of a fault may trigger nearby earthquakes [2]. 2b) This triggering probably just adjusts the inter-event time for a given fault segment, i.e. turning the clock forward or back [3]. This can basically lead to 'clustering' of earthquakes on a fault system. 3) We don't really know from the LA Times article whether the baseline earthquake rate was determined over a timeframe that was dominated by a cluster; i.e. insufficiently long sampling time to determine the real rate. Finding evidence of earthquakes hundreds to thousands of years ago, and then characterizing their age and magnitude, is really hard. There are big sample bias problems in a lot of these datasets, and it takes a lot of effort ($$) to minimize it but it never goes away. So be skeptical when you hear that an earthquake is 'overdue'. It is almost always a mischaracterization of what is actually going on, and rarely by the scientists involved... [1]: http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.133.9909&rep=rep1&type=pdf http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.133... [2]: http://www.ipgp.fr/~armijo/paraseminario/Stein-97.pdf http://www.ipgp.fr/~armijo/paraseminario/Stein-97.pdf [3]: http://onlinelibrary.wiley.com/doi/10.1029/2004JB003405/full http://onlinelibrary.wiley.com/doi/10.1029/2004JB003405/full

Maultasche 11y ago

I remember that when I was growing up, seismologists were telling us that there would be a really big quake any day now. Decades later and they're still saying the same thing. There have been some significant quakes in the meantime, but not the huge one that has been continuously predicted. The seismologists are probably right, but it's really difficult to accurately predict the timing of earthquakes. The earth will sit around doing absolutely nothing for decades and then suddenly lurch violently without warning. The seismologists keep saying it, and someday it will end up happening, but that could be tomorrow or it could be centuries from now.