Eli5: Why can’t earthquakes be predicted with accuracy?
In: 2
Because earthquakes are not part of a lengthy process that we can observe with enough detail to see when it happens. We know the idea of how earthquakes happen, but we can’t predict it with any kind of confidence because seismometers only measure shocks already in progress. You can’t see when the plates are going to grind, when the mantle shifts. We can’t look underground and see it, measure it in any kind if detail.
Because there are too many variables involved. We can get average slip rates and recurrence intervals for faults over long periods but that can only give us a rough idea of how long it’ll be before another. If a fault averages 5 mm/yr of slip, then maybe in 100 years an earthquake will happen and it’ll slip 0.5 m or maybe the earthquake hits in 1000 years and it slips 5 m.
It all depends on the regional stresses, other faults nearby, how “sticky” the fault is, and more. The best we can do right now is look at the long-term data, use high-precision GPS to monitor the movement of the plates on either side of the fault, and make some guesses about how big it can get and how long it’ll be before one of that size occurs. Seismologists and others are working on forecasting earthquakes, but there are just so many variables that we simply don’t have the capability to accurately measure and/or account for.
Because there are too many variables involved. We can get average slip rates and recurrence intervals for faults over long periods but that can only give us a rough idea of how long it’ll be before another. If a fault averages 5 mm/yr of slip, then maybe in 100 years an earthquake will happen and it’ll slip 0.5 m or maybe the earthquake hits in 1000 years and it slips 5 m.
It all depends on the regional stresses, other faults nearby, how “sticky” the fault is, and more. The best we can do right now is look at the long-term data, use high-precision GPS to monitor the movement of the plates on either side of the fault, and make some guesses about how big it can get and how long it’ll be before one of that size occurs. Seismologists and others are working on forecasting earthquakes, but there are just so many variables that we simply don’t have the capability to accurately measure and/or account for.
Earthquakes happen the same way ropes snap; you know the robe is overstressed but you don’t know how long it can hold out.
Other earthquakes can momentarily or permanently transfer their load into a target. It’s like if a snake rope tired to the heavy load breaks. The other types tied to the heavy now have to make up the difference .
To understand more clearly get a hard bake, as opposed to soft, cookie. Snap it at half as carefully as you can. Now put both halfs of the cookie on a flat smooth surface and mate the cookie back together. Now slide one of the cookie segments along the other one. Maybe do the exercise with a couple cookies to get a fair feel. You know the interface between the cookies will give way and crumble, but you don’t know when.
The plates of the Earth’s crust mate like big cookies. Big jagged cookies.
And while some earthquake faults have a part up top, you can see, the two cookies rubbing together are doing that deep underground; several miles depth where we can’t actually measure or see their condition.
Because earthquakes are not part of a lengthy process that we can observe with enough detail to see when it happens. We know the idea of how earthquakes happen, but we can’t predict it with any kind of confidence because seismometers only measure shocks already in progress. You can’t see when the plates are going to grind, when the mantle shifts. We can’t look underground and see it, measure it in any kind if detail.
Because earthquakes are not part of a lengthy process that we can observe with enough detail to see when it happens. We know the idea of how earthquakes happen, but we can’t predict it with any kind of confidence because seismometers only measure shocks already in progress. You can’t see when the plates are going to grind, when the mantle shifts. We can’t look underground and see it, measure it in any kind if detail.
Because there are too many variables involved. We can get average slip rates and recurrence intervals for faults over long periods but that can only give us a rough idea of how long it’ll be before another. If a fault averages 5 mm/yr of slip, then maybe in 100 years an earthquake will happen and it’ll slip 0.5 m or maybe the earthquake hits in 1000 years and it slips 5 m.
It all depends on the regional stresses, other faults nearby, how “sticky” the fault is, and more. The best we can do right now is look at the long-term data, use high-precision GPS to monitor the movement of the plates on either side of the fault, and make some guesses about how big it can get and how long it’ll be before one of that size occurs. Seismologists and others are working on forecasting earthquakes, but there are just so many variables that we simply don’t have the capability to accurately measure and/or account for.
Earthquakes happen the same way ropes snap; you know the robe is overstressed but you don’t know how long it can hold out.
Other earthquakes can momentarily or permanently transfer their load into a target. It’s like if a snake rope tired to the heavy load breaks. The other types tied to the heavy now have to make up the difference .
To understand more clearly get a hard bake, as opposed to soft, cookie. Snap it at half as carefully as you can. Now put both halfs of the cookie on a flat smooth surface and mate the cookie back together. Now slide one of the cookie segments along the other one. Maybe do the exercise with a couple cookies to get a fair feel. You know the interface between the cookies will give way and crumble, but you don’t know when.
The plates of the Earth’s crust mate like big cookies. Big jagged cookies.
And while some earthquake faults have a part up top, you can see, the two cookies rubbing together are doing that deep underground; several miles depth where we can’t actually measure or see their condition.
Earthquakes happen the same way ropes snap; you know the robe is overstressed but you don’t know how long it can hold out.
Other earthquakes can momentarily or permanently transfer their load into a target. It’s like if a snake rope tired to the heavy load breaks. The other types tied to the heavy now have to make up the difference .
To understand more clearly get a hard bake, as opposed to soft, cookie. Snap it at half as carefully as you can. Now put both halfs of the cookie on a flat smooth surface and mate the cookie back together. Now slide one of the cookie segments along the other one. Maybe do the exercise with a couple cookies to get a fair feel. You know the interface between the cookies will give way and crumble, but you don’t know when.
The plates of the Earth’s crust mate like big cookies. Big jagged cookies.
And while some earthquake faults have a part up top, you can see, the two cookies rubbing together are doing that deep underground; several miles depth where we can’t actually measure or see their condition.
Scientists in Italy were convicted for not being accurate earthquake predictors. See: [https://www.science.org/content/article/why-italian-earthquake-scientists-were-exonerated#:~:text=Six%20scientists%20convicted%20of%20manslaughter,a%20seventh%20defendant%20last%20November](https://www.science.org/content/article/why-italian-earthquake-scientists-were-exonerated#:~:text=Six%20scientists%20convicted%20of%20manslaughter,a%20seventh%20defendant%20last%20November).
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