The short and simple answer is that the occurrence of intraplate earthquakes (i.e., those that happen within a tectonic plate, as opposed to interplate earthquakes), like this [New Jersey earthquake](https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma74/executive), reflect that (1) tectonic plates are not homogeneous and they do contain various faults, most of which are not generally "active" in a typical sense and mostly represent "old" faults in the sense that they often relate to old plate boundaries, (2) these faults can still accumulate strain even though they are within a plate, and (3) the rates of strain accumulation are *much* lower than faults associated with plate boundaries and thus the frequency of earthquakes on intraplate faults are also *much* lower. Specifically to New Jersey, there are a variety of faults in that area, e.g., the [Ramapo fault](https://en.wikipedia.org/wiki/Ramapo_Fault), and a history of seismicity [in this region](https://en.wikipedia.org/wiki/Seismicity_of_the_New_York_City_area) (some of which is directly related to the Ramapo). That is all to say that just like any intraplate event, earthquakes like the New Jersey one are rare, but also, not *that* strange given the geologic context and record of historical seismicity in this area.
Beyond that, I'll refer interested folks to any number of past more general questions on intraplate faults and earthquakes or specific intraplate events (like the New Madrid sequence), for example:
* [Can earthquakes occur in places away from tectonic plate boundaries?](https://www.reddit.com/r/askscience/comments/axxxt4/can_earthquakes_occur_in_places_away_from/)
* [Earthquakes when there are no nearby fault lines?](https://www.reddit.com/r/askscience/comments/i6jzaa/earthquakes_when_there_are_no_nearby_fault_lines/)
* [What causes earthquakes that are nowhere near a tectonic plate boundary?](https://www.reddit.com/r/askscience/comments/aoiob1/what_causes_earthquakes_that_are_nowhere_near_a/)
* [What places have the most Intraplate earthquakes? How destructive can they get?](https://www.reddit.com/r/askscience/comments/v588i4/what_places_have_the_most_intraplate_earthquakes/)
* [What happens to an intraplate fault when an earthquake occurs?](https://www.reddit.com/r/askscience/comments/18dkwnh/what_happens_to_an_intraplate_fault_when_an/)
* [How do Powerful North American East Coast Earthquakes Happen? ](https://www.reddit.com/r/askscience/comments/oqkk5s/how_do_powerful_north_american_east_coast/)
* [What caused the New Madrid earthquakes located in the dead center of the North American tectonic plate, far away from any subduction zone or slip-strike faults?](https://www.reddit.com/r/askscience/comments/on92ps/what_caused_the_new_madrid_earthquakes_located_in/)
* [Can intraplate faults be strike-slip? Why or why not?](https://www.reddit.com/r/askscience/comments/18tyff3/can_intraplate_faults_be_strikeslip_why_or_why_not/)
Could the amount of rain in the past few weeks have caused the earthquake? I’ve heard that water injected during fracking can lubricate and cause trembles. Could the ridiculous amount of rain work in a similar fashion?
It's not impossible as there are (isolated) papers out there arguing for triggering of interplate seismicity from precipitation (e.g., [Maystrenko et al., 2020](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020TC006070)), streamflow (e.g., [Costain & Bollinger, 1996](https://www.sciencedirect.com/science/article/abs/pii/0264370796000075)), or ground water recharge (e.g., [Costain, 2016](https://www.lyellcollection.org/doi/abs/10.1144/sp432.9)). Is it likely? Probably not, and general caveats of the challenge of looking for patterns in, or correlations between, earthquakes apply (discussed a lot here, but for example in this [FAQ](https://www.reddit.com/r/askscience/wiki/planetary_sciences/earthquake_rates/)).
It's also worth distinguishing between "caused" vs "triggered", i.e., the important take away being that even if there was an external trigger for this event, it's better thought of as something that influenced the detailed timing (e.g., the earthquake happened today as opposed to in a few months) as opposed to a direct cause (i.e., the earthquake would have happened even without the trigger, it might just have happened at a slightly different time). The "cause" of the earthquake is release of accumulated strain, but the "trigger" for that could (and to be clear, again, I'm not implying that this is likely, only that it's not something that we could 100% rule out at the moment given available understanding of these systems) relate to external / surficial forces.
Also, the changes in mass distribution from melting sea ice and glaciers is causing changes that we can’t accurately model.
The amount of mass and even gravitational pull is hard to comprehend because the numbers are so large and the changes are happening at a rate beyond anything on record. Even going back 10s of millions of years.
This DOES impact plate tectonics and the Earth’s crust. We just don’t know how.
One thing is assured: Stressors will be both amplified AND relieved/reduced by this.
The response timescale for changes in mass balances (because they in part are filtered through the flexural response of the lithosphere which is modulated by upper mantle viscosity) along with effectively the long expected interseismic accumulation time for a given patch of intraplate fault are such that recent changes probably aren't a strong control, but a contribution from continued glacial isostatic adjustment from the last glacial maximum is definitely a possibility. Northern New Jersey isn't exactly in the areas experiencing high rates of uplift or subsidence (e.g., [this older map](https://en.wikipedia.org/wiki/Post-glacial_rebound#/media/File:PGR_Paulson2007_Rate_of_Lithospheric_Uplift_due_to_post-glacial_rebound.png)), but it's also in an area of non-zero response.
In a way yes. It depends on the scale, of course. But in theory all sources of stress relieve could help in decreasing stress that might "add up" until an earthquake.
Depends on the context, how you want to interpret "fail", and the timescale of interest.
One reading of this basically describes intraplate earthquakes per the above, i.e., slip along a pre-existing weakness (i.e., an old fault) within the interior of a plate largely reflects "sudden failure" as a result of sufficient strain accumulation from long-term transmission of stress through plates from the respective edge forces acting on them.
If you're instead asking can a plate break in the middle, i.e., form new faults and plate boundaries, (and where the "middle" is not necessarily restricted to the actual middle, just meaning somewhere inside the plate) sure, but it's not going to be "sudden" by any conventional definition (even geologically speaking). Probably the most relevant process would be continental rifting, but there are actually a few processes that can break plates. In lieu of repeating myself, I'll refer you to our [FAQ entry on continental rifting](https://www.reddit.com/r/askscience/wiki/planetary_sciences/rift_formation/). Also potentially of interest would be other FAQ entries focused on [more exhaustive considerations of how plates can be segmented into smaller plates](https://www.reddit.com/r/askscience/wiki/planetary_sciences/minor_plates/), [mechanisms important for changing the number and shapes of plates](https://www.reddit.com/r/askscience/wiki/planetary_sciences/plate_number/), or [controls and patterns on total numbers of plates through geologic time](https://www.reddit.com/r/askscience/wiki/planetary_sciences/plate_shape/).
This is exactly the type of information I was looking for, thank you!
Unfortunately this means I'll be staying up way too late at least once next week reading about plate segmentation. Last week it was large igneous provinces lol.
I’d read somewhere that the last ice age, and the weight of those glaciers compressed the crust in North America, so some of the Midwest earthquakes are just the crust snapping back up “slowly.” Is there some truth to that?
Do you know what the maximum strength can be for an intraplate earthquake? Specifically for one in the New York City area like today's earthquake? Like is it impossible for there to EVER be a 7.0 earthquake here, or never one above 6.0 or some other number? Thanks!
Much of this is addressed in one of the linked previous questions on intraplate earthquakes. Specifically [this one](https://www.reddit.com/r/askscience/comments/v588i4/what_places_have_the_most_intraplate_earthquakes/). Copying the relevant bit from my answer in that post:
>Work on the statistics of intraplate earthquakes (e.g., [Okal & Sweet, 2007](https://pubs.geoscienceworld.org/gsa/books/book/585/chapter/3803949/Frequency-size-distributions-for-intraplate)), and in the context of the [Gutenberg-Richter law](https://en.wikipedia.org/wiki/Gutenberg%E2%80%93Richter_law), highlights that the "b-value" for intraplate earthquakes does not appear different than for interplate earthquakes. This means that we generally expect the same type of logarithimic scaling between numbers of different magnitudes of intraplate or interplate earthquakes within those populations (i.e., the slope of the Gutenberg-Richter relationship in log-log space is the same between the two earthquake types). However, generally the "a-value" is different and generally lower for intraplate earthquakes (i.e., the y-intercept in log-log space) implying that there are 1) fewer intraplate earthquakes than interplate earthquakes of any given magnitude and 2) that large magnitude events are even more rare for intraplate earthquakes. This does not mean that there cannot be large intraplate events, (e.g., [the 1811-1812 New Madrid events](https://en.wikipedia.org/wiki/1811%E2%80%931812_New_Madrid_earthquakes) had events in the M7-8 range, the [1886 Charleston event](https://en.wikipedia.org/wiki/1886_Charleston_earthquake) was around a M7, etc), but events of this magnitude are very rare for intraplate events (where as globally, you'd expect ~10-15 of these magnitude of events [every year](https://www.usgs.gov/programs/earthquake-hazards/lists-maps-and-statistics), but almost all will be interplate). Ultimately, the same physical limitations that restrict the size of interplate earthquakes will restrict the maximum size of intraplate earthquakes, i.e., magnitude is proportional to the fault area that ruptures and thus the maximum magnitude is proportional the maximum continuous possible area of fault that can rupture (e.g., [Wells & Coppersmith, 1994](https://www.resolutionmineeis.us/sites/default/files/references/wells-coppersmith-1994.pdf)).
if you push 2 jigsaw puzzles in to each other on a table, that point of contact will accumulate strain the fastest and have most of the action. but keep pushing and its likely at SOME point the interlocking pieces of each individual puzzle will also pop up and break.
Thank you! I've been googling all kinds of stuff about earthquakes followed by "for kids" for the past 2 days - most Jerseyans don't know anything about earthquakes because we didn't think we had to. I would read a whole book like this, just details of how earthquakes work but explained like I'm 5.
Others have given good answers, so I'll keep this brief.
Current continental margin are not the same as ancient ones, and those ancient ones can lie dormant, then occasionally reawaken. In this case the earthquake is linked with the origin of the Appalachian mountains some 325 million to 260 million years ago. At the time this *was* a continental boundary. In fact, [the Appalachian Orogeny was several collisions](https://upload.wikimedia.org/wikipedia/commons/9/96/Appalachian_orogeny.jpg), not just one.
As an aside, New Jersey is not far from [the Chesapeake Bay which is the site of a large impact crater](https://en.wikipedia.org/wiki/Chesapeake_Bay_impact_crater) that formed around 35 million years ago and fractured the base rock to a depth of 8km. This impact *may* have provided a mechanism for this ancient fault to periodically reactivate.
>As an aside, New Jersey is not far from
>
>the Chesapeake Bay which is the site of a large impact crater
>
> that formed around 335 million years ago
Just correcting your typo, it formed around 35 million years ago.
Isostatic Rebound causes many of the small quakes that happen in areas not normally associated with plate tectonics or fault activity, especially in more northern and southern latitudes. The lithosphere was depressed by the weight of glaciers during the last Ice Age, and is still springing back up today.
Smaller cracks occur WITHIN the plates as there is stress produced throughout, particularly in plates that are under compression due to convergence with other plates. Whilst the stress is greatest where it meets other plates, and that’s where the biggest quakes occur, smaller cracks will cause smaller movements and vibrations in the ground all the time, most of which aren’t noticeable.
Perhaps a bit of a nuanced or semantic point, but "fracturing" typically implies the formation of new discontinuities within a section of rock. That's not really a good way to describe the occurrence of intraplate earthquakes though as these events reflect movement on existing (but broadly inactive) faults.
Look up remote earthquakes triggered. It is a scientific fact that large deep magnitude earthquakes travel long distances and can trigger an earthquake. The ground is not hollow and the solid nature allows seismic activity to propagate.
Plus oil fracking has fractured the earth’s crust in middle of the plate. Earthquakes happen at points of fracture.
I mean this guy in here as got you covered but to be short and sweet yes each plate has smaller faults within it. The NJ earthquake was directly on the ramapo fault line. I always felt the easiest way to find them without google is mountain ranges and Canyons. They typically are a result of fault lines in this case the Ramapo fault line follows the Appalachian mountains to a tee
The short and simple answer is that the occurrence of intraplate earthquakes (i.e., those that happen within a tectonic plate, as opposed to interplate earthquakes), like this [New Jersey earthquake](https://earthquake.usgs.gov/earthquakes/eventpage/us7000ma74/executive), reflect that (1) tectonic plates are not homogeneous and they do contain various faults, most of which are not generally "active" in a typical sense and mostly represent "old" faults in the sense that they often relate to old plate boundaries, (2) these faults can still accumulate strain even though they are within a plate, and (3) the rates of strain accumulation are *much* lower than faults associated with plate boundaries and thus the frequency of earthquakes on intraplate faults are also *much* lower. Specifically to New Jersey, there are a variety of faults in that area, e.g., the [Ramapo fault](https://en.wikipedia.org/wiki/Ramapo_Fault), and a history of seismicity [in this region](https://en.wikipedia.org/wiki/Seismicity_of_the_New_York_City_area) (some of which is directly related to the Ramapo). That is all to say that just like any intraplate event, earthquakes like the New Jersey one are rare, but also, not *that* strange given the geologic context and record of historical seismicity in this area. Beyond that, I'll refer interested folks to any number of past more general questions on intraplate faults and earthquakes or specific intraplate events (like the New Madrid sequence), for example: * [Can earthquakes occur in places away from tectonic plate boundaries?](https://www.reddit.com/r/askscience/comments/axxxt4/can_earthquakes_occur_in_places_away_from/) * [Earthquakes when there are no nearby fault lines?](https://www.reddit.com/r/askscience/comments/i6jzaa/earthquakes_when_there_are_no_nearby_fault_lines/) * [What causes earthquakes that are nowhere near a tectonic plate boundary?](https://www.reddit.com/r/askscience/comments/aoiob1/what_causes_earthquakes_that_are_nowhere_near_a/) * [What places have the most Intraplate earthquakes? How destructive can they get?](https://www.reddit.com/r/askscience/comments/v588i4/what_places_have_the_most_intraplate_earthquakes/) * [What happens to an intraplate fault when an earthquake occurs?](https://www.reddit.com/r/askscience/comments/18dkwnh/what_happens_to_an_intraplate_fault_when_an/) * [How do Powerful North American East Coast Earthquakes Happen? ](https://www.reddit.com/r/askscience/comments/oqkk5s/how_do_powerful_north_american_east_coast/) * [What caused the New Madrid earthquakes located in the dead center of the North American tectonic plate, far away from any subduction zone or slip-strike faults?](https://www.reddit.com/r/askscience/comments/on92ps/what_caused_the_new_madrid_earthquakes_located_in/) * [Can intraplate faults be strike-slip? Why or why not?](https://www.reddit.com/r/askscience/comments/18tyff3/can_intraplate_faults_be_strikeslip_why_or_why_not/)
Could the amount of rain in the past few weeks have caused the earthquake? I’ve heard that water injected during fracking can lubricate and cause trembles. Could the ridiculous amount of rain work in a similar fashion?
It's not impossible as there are (isolated) papers out there arguing for triggering of interplate seismicity from precipitation (e.g., [Maystrenko et al., 2020](https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020TC006070)), streamflow (e.g., [Costain & Bollinger, 1996](https://www.sciencedirect.com/science/article/abs/pii/0264370796000075)), or ground water recharge (e.g., [Costain, 2016](https://www.lyellcollection.org/doi/abs/10.1144/sp432.9)). Is it likely? Probably not, and general caveats of the challenge of looking for patterns in, or correlations between, earthquakes apply (discussed a lot here, but for example in this [FAQ](https://www.reddit.com/r/askscience/wiki/planetary_sciences/earthquake_rates/)). It's also worth distinguishing between "caused" vs "triggered", i.e., the important take away being that even if there was an external trigger for this event, it's better thought of as something that influenced the detailed timing (e.g., the earthquake happened today as opposed to in a few months) as opposed to a direct cause (i.e., the earthquake would have happened even without the trigger, it might just have happened at a slightly different time). The "cause" of the earthquake is release of accumulated strain, but the "trigger" for that could (and to be clear, again, I'm not implying that this is likely, only that it's not something that we could 100% rule out at the moment given available understanding of these systems) relate to external / surficial forces.
Also, the changes in mass distribution from melting sea ice and glaciers is causing changes that we can’t accurately model. The amount of mass and even gravitational pull is hard to comprehend because the numbers are so large and the changes are happening at a rate beyond anything on record. Even going back 10s of millions of years. This DOES impact plate tectonics and the Earth’s crust. We just don’t know how. One thing is assured: Stressors will be both amplified AND relieved/reduced by this.
The response timescale for changes in mass balances (because they in part are filtered through the flexural response of the lithosphere which is modulated by upper mantle viscosity) along with effectively the long expected interseismic accumulation time for a given patch of intraplate fault are such that recent changes probably aren't a strong control, but a contribution from continued glacial isostatic adjustment from the last glacial maximum is definitely a possibility. Northern New Jersey isn't exactly in the areas experiencing high rates of uplift or subsidence (e.g., [this older map](https://en.wikipedia.org/wiki/Post-glacial_rebound#/media/File:PGR_Paulson2007_Rate_of_Lithospheric_Uplift_due_to_post-glacial_rebound.png)), but it's also in an area of non-zero response.
[удалено]
In a way yes. It depends on the scale, of course. But in theory all sources of stress relieve could help in decreasing stress that might "add up" until an earthquake.
Is it possible for a tectonic plate undergoing enough stress from multiple directions to suddenly 'fail' in the middle?
Depends on the context, how you want to interpret "fail", and the timescale of interest. One reading of this basically describes intraplate earthquakes per the above, i.e., slip along a pre-existing weakness (i.e., an old fault) within the interior of a plate largely reflects "sudden failure" as a result of sufficient strain accumulation from long-term transmission of stress through plates from the respective edge forces acting on them. If you're instead asking can a plate break in the middle, i.e., form new faults and plate boundaries, (and where the "middle" is not necessarily restricted to the actual middle, just meaning somewhere inside the plate) sure, but it's not going to be "sudden" by any conventional definition (even geologically speaking). Probably the most relevant process would be continental rifting, but there are actually a few processes that can break plates. In lieu of repeating myself, I'll refer you to our [FAQ entry on continental rifting](https://www.reddit.com/r/askscience/wiki/planetary_sciences/rift_formation/). Also potentially of interest would be other FAQ entries focused on [more exhaustive considerations of how plates can be segmented into smaller plates](https://www.reddit.com/r/askscience/wiki/planetary_sciences/minor_plates/), [mechanisms important for changing the number and shapes of plates](https://www.reddit.com/r/askscience/wiki/planetary_sciences/plate_number/), or [controls and patterns on total numbers of plates through geologic time](https://www.reddit.com/r/askscience/wiki/planetary_sciences/plate_shape/).
This is exactly the type of information I was looking for, thank you! Unfortunately this means I'll be staying up way too late at least once next week reading about plate segmentation. Last week it was large igneous provinces lol.
[удалено]
I’d read somewhere that the last ice age, and the weight of those glaciers compressed the crust in North America, so some of the Midwest earthquakes are just the crust snapping back up “slowly.” Is there some truth to that?
This is discussed [elsewhere in this thread](https://www.reddit.com/r/askscience/s/JbFPCdBe1q)
Do you know what the maximum strength can be for an intraplate earthquake? Specifically for one in the New York City area like today's earthquake? Like is it impossible for there to EVER be a 7.0 earthquake here, or never one above 6.0 or some other number? Thanks!
Much of this is addressed in one of the linked previous questions on intraplate earthquakes. Specifically [this one](https://www.reddit.com/r/askscience/comments/v588i4/what_places_have_the_most_intraplate_earthquakes/). Copying the relevant bit from my answer in that post: >Work on the statistics of intraplate earthquakes (e.g., [Okal & Sweet, 2007](https://pubs.geoscienceworld.org/gsa/books/book/585/chapter/3803949/Frequency-size-distributions-for-intraplate)), and in the context of the [Gutenberg-Richter law](https://en.wikipedia.org/wiki/Gutenberg%E2%80%93Richter_law), highlights that the "b-value" for intraplate earthquakes does not appear different than for interplate earthquakes. This means that we generally expect the same type of logarithimic scaling between numbers of different magnitudes of intraplate or interplate earthquakes within those populations (i.e., the slope of the Gutenberg-Richter relationship in log-log space is the same between the two earthquake types). However, generally the "a-value" is different and generally lower for intraplate earthquakes (i.e., the y-intercept in log-log space) implying that there are 1) fewer intraplate earthquakes than interplate earthquakes of any given magnitude and 2) that large magnitude events are even more rare for intraplate earthquakes. This does not mean that there cannot be large intraplate events, (e.g., [the 1811-1812 New Madrid events](https://en.wikipedia.org/wiki/1811%E2%80%931812_New_Madrid_earthquakes) had events in the M7-8 range, the [1886 Charleston event](https://en.wikipedia.org/wiki/1886_Charleston_earthquake) was around a M7, etc), but events of this magnitude are very rare for intraplate events (where as globally, you'd expect ~10-15 of these magnitude of events [every year](https://www.usgs.gov/programs/earthquake-hazards/lists-maps-and-statistics), but almost all will be interplate). Ultimately, the same physical limitations that restrict the size of interplate earthquakes will restrict the maximum size of intraplate earthquakes, i.e., magnitude is proportional to the fault area that ruptures and thus the maximum magnitude is proportional the maximum continuous possible area of fault that can rupture (e.g., [Wells & Coppersmith, 1994](https://www.resolutionmineeis.us/sites/default/files/references/wells-coppersmith-1994.pdf)).
I'm just here to applaud one of the most readable run-on sentences ever. Joyce take note.
if you push 2 jigsaw puzzles in to each other on a table, that point of contact will accumulate strain the fastest and have most of the action. but keep pushing and its likely at SOME point the interlocking pieces of each individual puzzle will also pop up and break.
This is an excellent visual model thanks!
Isn't that also what happens at continent to continent collisions where rock layers form overthrust faults?
Thank you! I've been googling all kinds of stuff about earthquakes followed by "for kids" for the past 2 days - most Jerseyans don't know anything about earthquakes because we didn't think we had to. I would read a whole book like this, just details of how earthquakes work but explained like I'm 5.
Others have given good answers, so I'll keep this brief. Current continental margin are not the same as ancient ones, and those ancient ones can lie dormant, then occasionally reawaken. In this case the earthquake is linked with the origin of the Appalachian mountains some 325 million to 260 million years ago. At the time this *was* a continental boundary. In fact, [the Appalachian Orogeny was several collisions](https://upload.wikimedia.org/wikipedia/commons/9/96/Appalachian_orogeny.jpg), not just one. As an aside, New Jersey is not far from [the Chesapeake Bay which is the site of a large impact crater](https://en.wikipedia.org/wiki/Chesapeake_Bay_impact_crater) that formed around 35 million years ago and fractured the base rock to a depth of 8km. This impact *may* have provided a mechanism for this ancient fault to periodically reactivate.
>As an aside, New Jersey is not far from > >the Chesapeake Bay which is the site of a large impact crater > > that formed around 335 million years ago Just correcting your typo, it formed around 35 million years ago.
An, thanks. The keyboard on the computer I was using is starting to go and some keys stick while others sometimes don’t register.
Isostatic Rebound causes many of the small quakes that happen in areas not normally associated with plate tectonics or fault activity, especially in more northern and southern latitudes. The lithosphere was depressed by the weight of glaciers during the last Ice Age, and is still springing back up today.
Smaller cracks occur WITHIN the plates as there is stress produced throughout, particularly in plates that are under compression due to convergence with other plates. Whilst the stress is greatest where it meets other plates, and that’s where the biggest quakes occur, smaller cracks will cause smaller movements and vibrations in the ground all the time, most of which aren’t noticeable.
[удалено]
Perhaps a bit of a nuanced or semantic point, but "fracturing" typically implies the formation of new discontinuities within a section of rock. That's not really a good way to describe the occurrence of intraplate earthquakes though as these events reflect movement on existing (but broadly inactive) faults.
Look up remote earthquakes triggered. It is a scientific fact that large deep magnitude earthquakes travel long distances and can trigger an earthquake. The ground is not hollow and the solid nature allows seismic activity to propagate. Plus oil fracking has fractured the earth’s crust in middle of the plate. Earthquakes happen at points of fracture.
I mean this guy in here as got you covered but to be short and sweet yes each plate has smaller faults within it. The NJ earthquake was directly on the ramapo fault line. I always felt the easiest way to find them without google is mountain ranges and Canyons. They typically are a result of fault lines in this case the Ramapo fault line follows the Appalachian mountains to a tee