The Sun Doesn’t Cause Earthquakes

by Jason Major on April 12, 2013

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SDO/AIA image of the Sun from April 12

SDO/AIA image of the Sun from April 12

If that title seems like an obvious statement to you, it’s ok… it seems pretty obvious to me too. But there are those who have been suggesting — for quite some time, actually — that earthquakes can be triggered or strengthened by solar activity; that, in fact, exceptionally powerful solar flares, coronal mass ejections, and other outpourings from our home star can cause the planet’s crust to shift, shake, and shudder.

Except that that’s simply not true — at least, not according to a recent study by researchers from the USGS.

Researchers Dr. Jeffrey Love from the United States Geological Survey and Dr. Jeremy Thomas from Northwest Research Associates compared historical data of solar activity with earthquake occurrences around the world and found no definitive correlations… nothing to suggest that one directly influenced the other.

“Recently there’s been a lot of interest in this subject from the popular press, probably because of a couple of larger and very devastating earthquakes. This motivated us to investigate for ourselves whether or not it was true.”

– Jeffrey Love, USGS Research Geophysicist

Even when an earthquake may have been found to occur on the same day as increased solar activity, at other times during even stronger quakes the Sun may have been relatively quiet, and vice versa.

Damage in Anchorage from an earthquake on March 27, 1964. Solar activity at the time was unexceptional. (U.S. Army photo)

Damage in Anchorage from an earthquake on March 27, 1964. Solar activity at the time was unexceptional. (U.S. Army photo)

“There have been some earthquakes like the 9.5 magnitude Chile quake in 1960 where, sure enough, there were more sunspots and more geomagnetic activity than on average,” said Dr. Love. “But then for the Alaska earthquake in 1964 everything was lower than normal. There’s no obvious pattern between solar activity and seismicity, so our results were inconclusive.”

Basically, even though our planet orbits within the Sun’s outer atmosphere and we are subject to the space weather it creates — and there’s still a lot to be learned about that — observations do not indicate any connection between sunspots, flares, and CMEs and the shifting of our planet’s crust (regardless of what some may like to suggest.)

“It’s natural for scientists to want to see relationships between things,” said Love. “Of course, that doesn’t mean that a relationship actually exists!”

The team’s findings were published in the March 16, 2013 online edition of Geophysical Research Letters.

Read more in Harriet Jarlett’s article on Planet Earth Online, and for results from another study see Dr. Ryan O’Milligan’s article on TheSunToday.org.

(Oh, and the Moon doesn’t cause earthquakes either.)

About 

A graphic designer in Rhode Island, Jason writes about space exploration on his blog Lights In The Dark, Discovery News, and, of course, here on Universe Today. Ad astra!

ozonator April 12, 2013 at 5:50 AM

Big data sets are hard to find.

Martin J Green April 12, 2013 at 6:25 AM

No one knows for sure so this is just an assumption until further data/theory proves otherwise. Physics does not rule out that there could be a correlation.

Kai Henningsen April 12, 2013 at 6:46 AM

Solar activity influence earthquakes? Umm … seems to me that would be completely drowned by the signal from solar gravity. You know, the thing that causes a slight difference in our tides (as, it’s not completely drowned by the much stronger effect from the moon).

Given that tides shift not only the water, but also the land – and that earthquakes happen when one large piece of land moves against another – it seems fairly likely that tidal effects influence earthquakes. Of course, we have those all the time, and influence is not the same as trigger, so it’s not clear to me how you would show the effect, but I’m pretty sure it must be there.

Sun weather? Not so much. Well ok, if you get picky, the movements of my fingers writing this comment have a similar (though much, much lower) gravitational effect, and thus also influence earthquakes, so why not sun spots? Except, I don’t see anyone being able to measure an effect this small anytime soon … and given the larger effects mentioned, it seems completely irrelevant.

Of course, irrelevant doesn’t help sell books.

Me April 12, 2013 at 8:36 AM

Well said. I have been involved w/our star close to 40 years. I have heard over the years the suggestion the gravitational forces of our star ‘might’ cause earthquakes. I doubt ‘only’ the sun itself causes quakes. No one really knows for sure factually. There are so many variables in science all we can do is try to give the best estimates possible until proven factual. …take care.

Jason Major April 12, 2013 at 1:36 PM

I don’t see why we’d have to look to the Sun for earthquake causality when tectonic and volcanic activity (and even a little fracking) do just fine on their own.

Kai Henningsen April 13, 2013 at 4:02 PM

Of course, I said “influence”, not “cause”, for a reason. Then again, if you look at the Jovian moons, it would seem that gravity from Jupiter is much closer to the causing end of the spectrum over there.

Simply put, the tidal effects (most from the moon, second largest contributor being the sun) permanently flex the crust up and down, and I expect without that effect, the time between quakes would probably be longer … and the quakes larger. The terrestrial forces would need longer to build up enough force to get things moving, but there would then be a larger buildup when it finally happens.

Johan Deknudt April 12, 2013 at 3:01 PM

I always theorized Sunspot activty is more influenced by the gravitational effect from Jupiter. when you lay sunspot activity and the intervals of Jupiters’ perihelium next to each other. you’ll notice they are overlapping. wich corresponds to 11 years.

Mike Petersen April 12, 2013 at 6:51 AM

Those who believe sunspot activity can cause earthquakes are the same ones who believe that passing comets can do the same.

Gerald R Everett April 12, 2013 at 11:11 AM

Yea but the inconsiderate thing doesn’t prevent them either.

Friv 2 April 12, 2013 at 1:57 PM

Of course, we have those all the time, and influence is not the same as trigger, so it’s not clear to me how you would show the effect, but I’m pretty sure it must be there.

vv April 12, 2013 at 5:23 PM

Dear UT & community, Ideas are what they are, ideas. May not be an obvious or correct one but must be discussed. We are looking for a vaccine against AIDS. We were not going to start this quest because it seemed impossible?

Jason Major April 12, 2013 at 11:41 PM

This is exactly what Drs Love and Thomas did — they took an idea and tested it via recorded observations. When no specific pattern linking solar activity and quakes was seen, the reasonable assumption is that there is no correlation. Should something show up in the future that makes the association in a significant way, then this will have to be reconciled. That’s just good science.

vv April 13, 2013 at 12:24 PM

I don’t question the publication; I question the journalism and commenters. Think first, is a good motto for everyone!

Tim Amato April 12, 2013 at 5:35 PM

If you think of the oceans tides from the moon and sun’s gravity; that is the overwhelming -external- force on the earths crust. Actually, the earths internal core may have its own tidal action putting forces on our crust.

spell7 April 12, 2013 at 6:10 PM

Taken at face value, I would agree that it should be obvious that sunspot activity shouldn’t have an effect on earthquake activity. Much like similar claims about a full moon or “supermoon” which are headline garbage.
The arguments regarding gravitation effects, tides etc. are good but tend to be more “steady state” type effects that should be orders of magnitude larger than anything else. I’ve had enough science and engineering training to know that small, transient influences can have a measurable effect by shifting a system slightly away from steady state.
If an article were published tomorrow suggesting that either through thermal or magnetic interactions, a VERY small correlation could be found linking earthquake activity to CMEs and sunspots, I would probably think it interesting and read on before pitching out as garbage. I know CMEs can significantly distort the geomagnetic field but I am ignorant of how that affects the source of the magnetic field. I’m just as ignorant of any possible thermal effects from a CME. That ignorance could make such an article seem plausible to me especially if some supporting data were included. If the article claimed significant correlation, I wouldn’t make it past the title/abstract.

Kai Henningsen April 13, 2013 at 4:20 PM

“steady state”? Not very steady. The tidal effect on land is smaller than on the ocean (0.2m as opposed to 1m) because land is stiffer, but flexing land 0.2m (about two thirds of a foot, for the US readers) vertically every 12 and a bit hours is still a lot of movement. I expect it makes it much harder for land pieces to hold other land pieces in place against terrestrial forces.

Which is a good thing. I’d rather have many small quakes then few large ones.

spell7 April 15, 2013 at 2:07 PM

By “steady state” I mean the system has reached a regular pattern of behaviour. Kind of like a pendulum swinging – it is a steady, periodic effect that can be predicted and modeled.
Imagine a pendulum in a grandfather clock. Let’s say that the door was left open so that any air currents generated by someone walking by can flow around the pendulum. Gravity is by far the dominate force driving the motion but the slight push of the air when someone walks by can change one or two swings of the pendulum by a measureable amount before it returns to the steady state oscillation. If you looked a little deeper, you would find that despite returning to the normal predictable motion, the clock may now be slighty ahead or behind on the time if only a tiny fraction of a second.

Aqua4U April 12, 2013 at 11:13 PM

I guess it could happen if there were layers in the Earth’s crust that were superconducting and the CME was big enough?

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