Research finds quakes can systematically trigger other ones on opposite side of Earth
CORVALLIS, Ore. – New research shows that a big earthquake can not only cause other quakes, but large ones, and on the opposite side of the Earth.
The findings, published Aug. 2 in Nature Scientific Reports, are an important step toward improved short-term earthquake forecasting and risk assessment.
Scientists at Oregon State University looked at 44 years of seismic data and found clear evidence that temblors of magnitude 6.5 or larger trigger other quakes of magnitude 5.0 or larger.
It had been thought that aftershocks – smaller magnitude quakes that occur in the same region as the initial quake as the surrounding crust adjusts after the fault perturbation – and smaller earthquakes at great distances – were the main global effects of very large earthquakes.
But the OSU analysis of seismic data from 1973 through 2016 – an analysis that excluded data from aftershock zones – using larger time windows than in previous studies, provided discernible evidence that in the three days following one large quake, other earthquakes were more likely to occur.
Each test case in the study represented a single three-day window “injected” with a large-magnitude (6.5 or greater) earthquake suspected of inducing other quakes, and accompanying each case was a control group of 5,355 three-day periods that didn’t have the quake injection.
“The test cases showed a clearly detectable increase over background rates,” said the study’s corresponding author, Robert O’Malley, a researcher in the OSU College of Agricultural Sciences. “Earthquakes are part of a cycle of tectonic stress buildup and release. As fault zones near the end of this seismic cycle, tipping points may be reached and triggering can occur.”
The higher the magnitude, the more likely a quake is to trigger another quake. Higher-magnitude quakes, which have been happening with more frequency in recent years, also seem to be triggered more often than lower-magnitude ones.
A tremblor is most likely to induce another quake within 30 degrees of the original quake’s antipode – the point directly opposite it on the other side of the globe.
“The understanding of the mechanics of how one earthquake could initiate another while being widely separated in distance and time is still largely speculative,” O’Malley said. “But irrespective of the specific mechanics involved, evidence shows that triggering does take place, followed by a period of quiescence and recharge.”
Earthquake magnitude is measured on a logarithmic 1-10 scale – each whole number represents a 10-fold increase in measured amplitude, and a 31-fold increase in released energy.
The largest recorded earthquake was a 1960 temblor in Chile that measured 9.5. The 2011 quake that ravaged the Fukushima nuclear power plant in Japan measured 9.0.
In 1700, an approximate magnitude 9.0 earthquake hit the Cascadia Subduction Zone – a fault that stretches along the West Coast of North American from British Columbia to California.
Collaborating with O’Malley were Michael Behrenfeld of the College of Agricultural Sciences, Debashis Mondal of the College of Science and Chris Goldfinger of the College of Earth, Ocean and Atmospheric Sciences.
The paper:
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After the great Andaman Boxing day quake, the one causing the tsunami that drowned a hundred thousand, the Earth reverberated for hours like a struck bell. No surprise that such big quakes can destabilise faults at the far end of the globe.
There is something else to consider in aftereffects from large quakes. The current grouping up in North Alaska is a good example of how a strong teleseismic quake can lead to a dampening of the overall global quake count for days or many days after the initial large quake.
The huge quake count at Hawaii also had a global effect while it was running. Interesting to note that the 24/hr global rate of 2.5+ mag quakes rose around 50% last week when the series of quakes in Hawaii finally came to an end early last week, after a 4 month run. The last 24 hours is the first day without a 2.5+ mag quake in Hawaii since early April. Then this 6.4 quake in Kaktovik Alaska which struck almost 24 hours ago also dampened the global count around 40%, excluding the several hundred plus quakes per 24/hr at the Alaskan location.
There is no mechanism for an earthquake in one part of the globe to suppress earthquakes in another part of the globe.
Goldminor,
Are you suggesting that pressure waves emanating from low magnitude quakes are acting to relieve stresses non-catastrophically so that minor quakes are suppressed, but higher amplitude waves due to major quakes have the opposite effect, triggering other major quakes?
If it is more than a coincidence then there should be thousands of similar cases associated with volcanic activity. Excluding low-magnitude quakes within some small radius of volcanic activity should cause those time periods to show a decreased count globally, compared to periods without major volcanic activity.
I first took note of this effect during the March 2011 quake in Japan. For many weeks after that quake there were very few quakes anywhere else around the globe greater than 2.5 mag. Unfortunately, most of my notes from that time period were all lost as I kept a daily count at the time for over a year.
Any quake rated as a teleseismic quake can affect the total global rate from my observations. The global rate is still a bit below average with the exception of the rate in Alaska of 80/24hrs and globally 20/24hrs, sixty hours after the strong quake.
Waves traveling from one spot around the world will arrive at the antipode at the same time, adjusting for the density and thickness of the media through which they pass. This means the arrival point where the incoming waves “sum” will be offset to the same extent there is a signal delay through the materials
It appears the biggest difference one can find moves the summation point 30 degrees.
It sounds like a rogue wave: the sum of multiple wavelets at one point to give a brief, significant jarring. Wherever there are predisposed concentrations of stress within that window, the coincidence of waves would push it over the edge.
Very interesting, and with sufficient knowledge about the Earth’s interior, a viable prediction mechanism. Cool!
Only if you know how much stress has built up in the faults at the antipode and how close any of them are to breaking.
Mods, I had an interesting post on the big Peruvian quake of 2007 maybe triggering the cave in of the Crandall Canyon coal mine in Utah that killed a number of miners and rescuers. For some reason it was disappeared. I tried to advise of this quake/mine cave in in an email to the inquiry, but got no acknowlegement back. My point was, it doesnt have to be at the antipodes. The big quake in Qom, Iran that killed 25,000 people also was followed by several notable quakes near and far. You only need a situation where an incipient quake, or cave in or bridge collapse etc. needs only a nudge. Common sense is enough data for this sort of thing.
Clearly from the figure above, the Earth is flat.
The earthquake’s wave propagation is function of the earth’s internal structure. Analysis of a particular type of a wave that penetrates the inner core (shown in green in the animation below) from data associated with numerous major earthquakes has concluded that the Earth’s inner core is lopsided and it rotates at a slightly different angular velocity than the rest (the inner core’s differential rotation). It is thought that it may be responsible for the slow drift of the South Atlantic anomaly westwards, as well as gradual reduction in the magnetic field intensity across Americas and the increase in the eastern hemisphere.
https://youtu.be/Fr1jjl32iCU
I sure would like to see similar verbiage, like this:
“The understanding of whether human activity is warming the planet is still largely speculative.”
“Each test case in the study represented a single three-day window “injected” with a large-magnitude (6.5 or greater) earthquake suspected of inducing other quakes, and accompanying each case was a control group of 5,355 three-day periods that didn’t have the quake injection.”
What is this “injected”? Thought this was based upon observations.
It sounds as though, in theory, if someone exploded a large nuclear device, or several, on the floor of the Indian Ocean off the coast of South Africa, they could induce a large earthquake in California, sending it into the Pacific.
Not likely, but perhaps the plot line of a future James Bond movie….but I wonder how many would be rooting for the bad guys in this scenario.
It would be rather difficult to implement. To get good energy transfer the bomb should be underground which is hard in deep ocean. An air explosion where the fireball does not reach the ground does not have much of a seismic footprint. The 50 MT “Tsar Bomba” where the fireball did not quite reach the ground only had a magnitude of about 5.
‘The findings, published Aug. 2 in Nature Scientific Reports, are an important step toward improved short-term earthquake forecasting and risk assessment.’
Not really. This is gross speculation.
Not quite speculation. The focussing effect is quite real. But it would be very short term forecasting. The seismic waves arrive at the antipodes 20 to 40 minutes after the original quake.
Could enough time for people to evacuate sea coasts and get to higher ground.
I would if on the Pacific coast when warning arrived. Of course, I’d run into everyone else trying to do the same.
Which is why, were I to live on the coast, I’d buy an electric helicopter.
Correlation ain’t causation. It may be that some states of Earth’s magma have greater likelihood of triggering major quakes at widely separated points on the surface than others. That seems at least as likely as attributing the cause of the latter quakes to the earlier ones.
The paper is speculation because of a major impediment, namely, that earthquakes can be caused by different mechanisms. For example, the Hawaii island chain pushing up through the Pacific can be envisioned as having coincident earthquake noise. OTOH earthquakes happen in the middle of stable, old, tectonic plates on land. Further, there are shallow earthquakes that likely happen with rock metamorphism such as dewatering/dehydration of sediment piles. Even isostatic adjustment is probably noisy with quakes.
There is no compelling logic to implicate the antipode. (There is, unrelatedly, an interesting story from the cold war missile era, that ballistic missiles launched in any direction from the main site then in Russia would converge on the antipode S-E of New Zealand , a good location to shoot them down.
Shooting down is the best way to treat this earthquake paper. Geoff
“OTOH earthquakes happen in the middle of stable, old, tectonic plates on land.”
Very rarely though (except in connection with (de)glaciation). And isostatic adjustment is actually remarkably quiet seismically except immediately after deglaciation. Check Fennoscandia or the Canadian Shield. Lots of isostatic adjustment, very little seismic activity.
And the seismic focussing effect is definitely real:
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4461126/
And I don’t see this as being much help in forecasting earthquakes. Let’s say there is a really big one in the Indian Ocean. What do you do? Send out a warning “there might be a quake in California/Cascadia in ten minutes”?
Also note that the seismic energy by itself is far too weak to cause earthquakes. But it may be enough to trigger earthquakes when the strain on a fault is very close to breaking point, and cause a quake to happen slightly earlier than it would have done otherwise.
Very large impacts (much larger than Chicxulub) can focus enough energy at the antipodal point to directly cause tectonic effects. The chaotic terrain antipodal to the Caloris basin on Mercury is a prime example.
And why should anyone send ICBM:s from Russia to the US by way of New Zealand? It is much easier by way of the Arctic.
tty,
What is up? You are normally smarter than this.
Ballistic missiles are not steered after liftoff. They are launched at various directions to hit targets. If left to go far enough, they all cross the antipode. Nowhere else to go.
Re quakes, I gave but a few examples of types. Does not matter if a type is rare, for the paper discussed. To me, the critical bit is energy. The trigger energy, by analogy to a gun, need not be large. The destructive energy is in the cordite. Meaning, you can have lots of quake triggers over a time, but unless the quake locality has cordite potential, it is a non event. The art of prior measurement of such potential is far from adequate, not from lack of effort, but because it is so difficult.
So the paper really deals with nothing useful. Geoff.
“Ballistic missiles are not steered after liftoff.”
ICBM:s most definitely are. The evolution of inertial navigation was very largely driven by the need to precision steer ICBM:s. It is true that early ICBM:s were purely ballistic after burnout, but for more modern MIRV:ed missiles the “bus” was steered until all the MIRV:s had separated.
And if you think a bit you will realize that there are two great circle courses between any two points. One (the longer) will pass the antipodal point. The other, shorter, will not. ICBM trajectories almost invariably use the shorter route for obvious reasons (less energy needed, better precision, shorter flight time).
The Soviet Union did develop the R36ORB missile with FOBS (Fractional Orbit) capability which theoretically could have used “the long way around” to attack from the south, but it is doubtful if this was ever implemented. The missile was retired in 1983.
ICBMs also have blow out panels to stop them or change direction before MIRVed warhead separation.
OK, tty, good to see the thinking cap is still on.
You know enough to have realized that I was talking about the early days before steering. We used to distinguish between ballistic missiles and guided missiles. It is not important, it was but an interest comment.
Corporately, in our mineral exploration days, we were involved in the technology of inertial and other navigation types via the need to be able to know the path of a diamond drill hole going at times up to 3,000 metres below the surface. Those strong looking, heavy drill rods actually behave more like spaghetti al dente. If, as often happens, the path goes through or near magnetic rocks like those with magnetite or pyrrhotite for example, then using a compass technique to get a bearing is out of the available technology. We were into laser ring methods but this was before they could be made small enough to prevent catastrophic laser light loss on tight bends. Life can be interesting when you have earned the scientific freedom to imagine “What if?”
We also used to wonder what newly-engineered printing device for our 1960s computers would replace the ASR33 tty Later we learned with fascination about the accuracy of guidance of cheap plastic ink jet printer heads, far better control than we had imagined possible. We learned a lot about miniaturization.
Do keep writing enjoyable, correct comments, tty Geoff.
Not unexpected. It is well established that seismic energy is focussed near the antipodal point. Google “Caloris Basin” and “chaotic terrain” for a well-known extreme example.
It has even been suggested that the huge main pulse of the Deccan flood basalt was triggered by the (antipodal) Chicxulub impact
The authors of this paper need a tutorial on probability. The annual frequency of M5.0 or greater earthquakes is around 1,600. How many earthquakes to expect in any 3-day period?
1600/(365/3) = 13
30 deg. latitude = 2070 mi.
surface area = (3.1416) 2070^2 = 13.46 million sq. mi.
Now spread that 13 earthquakes evenly over Earth’s total surface area (197 million sq. mi.)
197/13 = 15.15 million sq. mi.
That’s bigger than 13.46 million sq. mi.
Therefore, you expect to get an M5.0 or greater earthquake in your target area by chance alone. The probability is P = 1
P < 1 = 13.46/15.15 = 0.89
Once again from today, on 14Aug18:
In Greece since the 1970s, someone appeared very observant and connected the earthquakes in West Central America with earthquakes in Greece. He was particularly successful in determining the time of the earthquake in Greece (+/- one day) and size. For the epicenter, additional in situ work was needed to identify precursor phenomena. The methodology was very successful but the creator was remained unknown because he was not a scientist, he was a skier teacher!!
It is apparently happening on the Sun too.
https://www.youtube.com/watch?v=LlPP6negemo
Comet hitting Sun triggers eruption on the opposite side of Sun.