3 ms·

Have there been any studies done on how one may affect/trigger the other?

mjevans 10y ago
What type of study are you proposing exactly? The best data we have at the moment would be records of geologic events that have a strong correlation to earth quakes and seeing how they line up between the two different areas. My gut tells me to expect, usually not co-incidence, but as they are part of the same larger system, possible co-incidence (and likely at a much more catastrophic level when something THAT LARGE does happen).
- deskamess 10y ago
  Not knowledgeable enough about quakes to propose a study. As you and a sibling comment have stated I was just wondering if the 'they are geographically close enough and could affect each other' intuition may have merit.
jballanc 10y ago
I believe the fact that seismic events can trigger other seismic events along the same fault system is well known. What is still up for debate is how soon, how far away, and how large. I've heard it said that the only way you can tell if an earthquake is a fore-shock or the main event is to wait. For example, I've always loved this visualization of the seismic events leading up to the major Japanese earthquake of 2011: https://www.youtube.com/watch?v=NSBjEvPH2j4 https://www.youtube.com/watch?v=NSBjEvPH2j4 . See if you can identify the main quake when it happens. I bet you're wrong!
cossatot 10y ago
Cascadia subduction zone events don't seem to trigger large earthquakes in the faults above the subduction zone: http://onlinelibrary.wiley.com/doi/10.1002/2013JB010635/epdf http://onlinelibrary.wiley.com/doi/10.1002/2013JB010635/epdf And the 1857 and 1906 M7+ events on the San Andreas did not cause earthquakes in the Pacific Northwest. However, dynamic triggering of earthquakes does happen: http://lanl.gov/orgs/ees/ees11/geophysics/nonlinear/2005/Nature2005GJ.pdf http://lanl.gov/orgs/ees/ees11/geophysics/nonlinear/2005/Nat... Note that this type of triggering (by passing seismic waves) is, in the absolute sense, really unlikely to specifically nucleate a M7+ earthquake; otherwise there would be chains of huge earthquakes every time there's a big earthquake in Tonga (which is all the time). However, the relative likelihood is increased substantially. There is a lot of research on earthquake triggering (both 'static' and 'dynamic') much of which is publicly available on Google Scholar (or sci-hub...). Static (or 'Coulomb') triggering is the most physically comprehensible; dynamic triggering, where passing seismic waves cause new quakes, is statistically supported but hard to understand mechanistically. The basics of static triggering are that, if you think of the earth's upper crust as a compressed elastic (e.g. rubber, but far more rigid) sheet, when a tear in it happens (an earthquake) it changes the distribution of stress/forces in the elastic sheet. Some regions will be stressed more, particularly around the edges of the tear, and some will be stressed less. The areas that are stressed more by the new tear tend to have more earthquakes following the first one. This is largely a local (i.e. 10s of km) phenomenon. The big paper on this is here: http://www.ipgp.fr/~king/Geoffrey_King/Publications_files/King1994%20BSSA.pdf http://www.ipgp.fr/~king/Geoffrey_King/Publications_files/Ki...

What type of study are you proposing exactly? The best data we have at the moment would be records of geologic events that have a strong correlation to earth quakes and seeing how they line up between the two different areas. My gut tells me to expect, usually not co-incidence, but as they are part of the same larger system, possible co-incidence (and likely at a much more catastrophic level when something THAT LARGE does happen).

deskamess 10y ago
Not knowledgeable enough about quakes to propose a study. As you and a sibling comment have stated I was just wondering if the 'they are geographically close enough and could affect each other' intuition may have merit.

jballanc 10y ago

I believe the fact that seismic events can trigger other seismic events along the same fault system is well known. What is still up for debate is how soon, how far away, and how large. I've heard it said that the only way you can tell if an earthquake is a fore-shock or the main event is to wait. For example, I've always loved this visualization of the seismic events leading up to the major Japanese earthquake of 2011: https://www.youtube.com/watch?v=NSBjEvPH2j4 https://www.youtube.com/watch?v=NSBjEvPH2j4 . See if you can identify the main quake when it happens. I bet you're wrong!

cossatot 10y ago

Cascadia subduction zone events don't seem to trigger large earthquakes in the faults above the subduction zone: http://onlinelibrary.wiley.com/doi/10.1002/2013JB010635/epdf http://onlinelibrary.wiley.com/doi/10.1002/2013JB010635/epdf And the 1857 and 1906 M7+ events on the San Andreas did not cause earthquakes in the Pacific Northwest. However, dynamic triggering of earthquakes does happen: http://lanl.gov/orgs/ees/ees11/geophysics/nonlinear/2005/Nature2005GJ.pdf http://lanl.gov/orgs/ees/ees11/geophysics/nonlinear/2005/Nat... Note that this type of triggering (by passing seismic waves) is, in the absolute sense, really unlikely to specifically nucleate a M7+ earthquake; otherwise there would be chains of huge earthquakes every time there's a big earthquake in Tonga (which is all the time). However, the relative likelihood is increased substantially. There is a lot of research on earthquake triggering (both 'static' and 'dynamic') much of which is publicly available on Google Scholar (or sci-hub...). Static (or 'Coulomb') triggering is the most physically comprehensible; dynamic triggering, where passing seismic waves cause new quakes, is statistically supported but hard to understand mechanistically. The basics of static triggering are that, if you think of the earth's upper crust as a compressed elastic (e.g. rubber, but far more rigid) sheet, when a tear in it happens (an earthquake) it changes the distribution of stress/forces in the elastic sheet. Some regions will be stressed more, particularly around the edges of the tear, and some will be stressed less. The areas that are stressed more by the new tear tend to have more earthquakes following the first one. This is largely a local (i.e. 10s of km) phenomenon. The big paper on this is here: http://www.ipgp.fr/~king/Geoffrey_King/Publications_files/King1994%20BSSA.pdf http://www.ipgp.fr/~king/Geoffrey_King/Publications_files/Ki...