https://www.usgs.gov/faqs/what-probability-earthquake-a-fore... Suggests 5% for larger quake to follow within week. But overall most sources I could find suggested it's hard to know, needs more research
1: https://www.reddit.com/r/askscience/comments/10wecl8/do_litt...
Myth 5 is "Small Earthquakes Relieve Pressure and Prevent Larger Ones"
The long term absence of stress relief small quakes on a known fault line might be bad news, or no news at all, statistics are where the difference is here, not in particular events. See also, 'the big one' and various theories around it.
The above link does not answer that question. It is relating stress release to "fault strength", or the maximum shear stress that can be withstood by the fault. There is an incidental relationship with depth that plays a role.
The video linked nearby (on criticality) also does not address the question at issue.
I'm only replying because I work adjacent to this area, and my understanding is that the idea that small EQ's release stress is a myth. Here [1] is another link, listed as #1 in the "Myths" category. And you can dig up quotes from none other than Lucy Jones [2] saying that this is a myth.
I don't work directly in this area, so I'm not willing to say absolutely no. But I'd really like to see a head-on reference supporting the claim that it's not a myth.
So the statement "EQs release stress" is true and it follows that adding the modifier "small" to the front doesn't change this.
It should also be immediately apparent that it would be very surprising if there were not statistical implications as a result of this. So surprising in fact that I would suggest that the burden of evidence should fall on those claiming that any such statistical effects are unexpected.
Like how buying a Porsche costs money, and leaves you poorer than before you bought it, but when you see stranger buy a Porsche, you update towards believing that they're wealthy rather than poor.
Disclaimer: I am not a geoscientist.
In reality I think (layman's impression) that there's rough (post hoc) evidence for both things. Foreshocks followed by noticably larger EQs as well as trains of progressively smaller EQs.
To me a myth is something that isn't true at all, not something that we do not have data on to be able to rule it out completely or that may be an influence just not a capital one. I think the most generous reading of the 'myth' claim would be that the energy available in the smaller quakes is too low to have a meaningful effect on releasing energy from a larger quake and I'll buy that. But at the same time an absence of such fore-shocks in an area where earthquakes are known to happen indicates that stress may be been building up over a longer time and that stress would be released in the next bigger quake if and when it happens.
This too may not be a big enough difference due to the immense increase in energy present in larger events (the scale is logarithmic). But its effect is quite probably still non-zero and for it to be a myth it would have to be zero.
Myth = the sun rotates around the earth
Myth = unicorns exist
Myth = the earth is 6000 years old
Those are directly falsifiable, and we know all of these to be categorical falsehoods.
Smaller earthquakes can - depending on local crust composition and other environmental factors - affect the amount of energy released in a larger one following, is not necessarily a significant effect (though even this would be tricky to establish) but I find it hard to believe they are completely unrelated though the effect may not be large.
Insignificant effect != Myth
(Related, and profound apologies for the fb.com link: https://www.facebook.com/DLJCSS/posts/small-quakes-do-not-pr...)
(Source: Work with Earth science domain experts in $dayjob, and am often surprised when my basic intuitive arguments turn out to be wrong.)
Your link addresses a different claim than the one I made. So far we have release of stress (true by definition), statistical correlation (foreshocks and aftershocks), and reduction of a future event (your link).
As to objections about relative quantities, earthquake swarms exist. I think it's going to be just about impossible to make claims that are correct while also being applicable to all scenarios. A more limited claim that a particular quake or activity in a particular region does not exhibit a certain sort of relationship is going to be much more defensible.
(stresses build up and are often released through many small, unfelt earthquakes (25:54). If these small movements don't dissipate the stress, it can accumulate and lead to a powerful chain reaction (26:25) * disclaimer I used YouTube's built-in AI to find/summarize the timestamps, as I couldn't remember offhand where it was when I previously watched this.
It's worth noting that they are mostly interested in critical phenomena in general, and earthquakes are kind of a drive-by application, treated along with fires and sand piles.
They do hint around the edges, but they don't head-on make the claim for earthquakes that small EQs materially lessen stress buildup and thereby make larger EQ's less likely.
I was looking for a credential of one of the people they interview, to see if they are really a solid earth person or more of a critical phenomena person -- their names aren't easy to find. This particular myth ("small earthquakes relieve stress") is a bit of a stinker in the solid earth community, and I think a solid earth person would be quite careful about their words as they discuss this.