6 ms·

Definitely good to be prepared, but AFAIK there is no such thing as being "statistically overdue" for an earthquake.

by dangom 7y ago

specialp 7y ago
Yeah there is. It is not like saying that if black hit on roulette 10x in a row that one would be statistically overdue for red. Because those are completely independent events with equal probability on each trial. With earthquakes if statically speaking a massive earthquake hits on a roughly 1 in 500 year interval, the stresses at the plate boundary are much more likely to be greater at year 600 than at year 1 after a massive earthquake. https://earthquake.usgs.gov/earthquakes/events/1906calif/18april/eqmodels.php https://earthquake.usgs.gov/earthquakes/events/1906calif/18a...
- deleted 7y ago
  [deleted]
- kirrent 7y ago
  If only earthquake modelling was so simple as to say you were overdue for an earthquake simply based on accumulated stress. Unfortunately, the Gutenberg-Richter law is not prescriptive, but a time independent statistical observation which assumes independent events, which is why saying you're due for another one is very much like gambler's fallacy. Of course we know that there are underlying physical processes which make means there should be some underlying dependence to be found, and there are attempts at time-dependent models out there, but for our purposes independence works. If you're interested in the statistics around recurrence times, can I recommend this [1]? It's fairly well written and clear and it deals with this issue fairly comprehensively and directly. [1] - http://www.crm.cat/en/About/People/Researchers/ACorral/Documents/corral_dependence_times_independencd_magnitudes_tp06.pdf http://www.crm.cat/en/About/People/Researchers/ACorral/Docum...
- vkhn 7y ago
  There is no law of averages.
- dangom 7y ago
  Quoting from Corral 2006: "the longer since the last earthquake, the longer the expected time till the next". "the belief that the longer the time to get an earthquake,the bigger its size, is false".
ksdale 7y ago
I believe the parent is referring to the fact that there have been large earthquakes with remarkable regularity in the PNW every ~500 years for the past few thousand years, and it's been well over 500 years since the last one.
PeterisP 7y ago
I'm not that informed about geology, but as far as I understand, earthquakes are not independent random events but a result of stress accumulation on faultlines over time and released in sudden bursts i.e. earthquakes; and if a particular faultline has not had a release in a long time, then this means that when it happens, the next earthquake is likely to be stronger.

Definitely good to be prepared, but AFAIK there is no such thing as being "statistically overdue" for an earthquake.

by dangom 7y ago

Definitely good to be prepared, but AFAIK there is no such thing as being "statistically overdue" for an earthquake.

Yeah there is. It is not like saying that if black hit on roulette 10x in a row that one would be statistically overdue for red. Because those are completely independent events with equal probability on each trial. With earthquakes if statically speaking a massive earthquake hits on a roughly 1 in 500 year interval, the stresses at the plate boundary are much more likely to be greater at year 600 than at year 1 after a massive earthquake. https://earthquake.usgs.gov/earthquakes/events/1906calif/18april/eqmodels.php https://earthquake.usgs.gov/earthquakes/events/1906calif/18a...

deleted 7y ago
[deleted]
kirrent 7y ago
If only earthquake modelling was so simple as to say you were overdue for an earthquake simply based on accumulated stress. Unfortunately, the Gutenberg-Richter law is not prescriptive, but a time independent statistical observation which assumes independent events, which is why saying you're due for another one is very much like gambler's fallacy. Of course we know that there are underlying physical processes which make means there should be some underlying dependence to be found, and there are attempts at time-dependent models out there, but for our purposes independence works. If you're interested in the statistics around recurrence times, can I recommend this [1]? It's fairly well written and clear and it deals with this issue fairly comprehensively and directly. [1] - http://www.crm.cat/en/About/People/Researchers/ACorral/Documents/corral_dependence_times_independencd_magnitudes_tp06.pdf http://www.crm.cat/en/About/People/Researchers/ACorral/Docum...
vkhn 7y ago
There is no law of averages.
dangom 7y ago
Quoting from Corral 2006: "the longer since the last earthquake, the longer the expected time till the next". "the belief that the longer the time to get an earthquake,the bigger its size, is false".

ksdale 7y ago

I believe the parent is referring to the fact that there have been large earthquakes with remarkable regularity in the PNW every ~500 years for the past few thousand years, and it's been well over 500 years since the last one.

PeterisP 7y ago

I'm not that informed about geology, but as far as I understand, earthquakes are not independent random events but a result of stress accumulation on faultlines over time and released in sudden bursts i.e. earthquakes; and if a particular faultline has not had a release in a long time, then this means that when it happens, the next earthquake is likely to be stronger.