Mind Your Declination!

[MarkBC]

If you use an old-school physical compass for navigation (I still have a Silva Ranger in the bottom of my main daypack) make sure you're adjusting the declination regularly. The times they are a changin'!

The Magnetic North Pole Is Rapidly Moving Because of Some Blobs
from Popular Mechanics

That the magnetic pole is moving rapidly isn't real new news, but I think the explanation for it is.

The scientific journal article -- in Nature Geoscience -- that was the source for the PM article:
Recent north magnetic pole acceleration towards Siberia caused by flux lobe elongation

For centuries, the magnetic north pole has been safely in the care of our friendly neighbor to the north. But if it falls into Russian hands...!

"The magnetic north pole has shifted over time since scientists first identified its location in 1831.

LIVERMORE ET AL. NATURE GEOSCIENCE (2020"

 

[ski3pin]

Gosh, Julie and I were just reading and studying this this morning. Our declination east has dropped from 13.5 to 13 degrees.

This is another example of us riding on a dynamic planet!

 

[Foy]

My buddy Steve earned the nickname "Magellan" about 45 years ago by moving from an exploration project in the Blue Ridge of NC to the Green Mountains of Vermont and not correcting the declination on his Brunton. The second he crossed a topofil line left by one of his co-workers on a grid they were putting in, they hung the moniker on him and he's still got it today. The grid lines were supposed to be parallel to one another and 500' apart.

Foy

 

[AWG_Pics]

My buddy Steve earned the nickname "Magellan" about 45 years ago by moving from an exploration project in the Blue Ridge of NC to the Green Mountains of Vermont and not correcting the declination on his Brunton. The second he crossed a topofil line left by one of his co-workers on a grid they were putting in, they hung the moniker on him and he's still got it today. The grid lines were supposed to be parallel to one another and 500' apart.

Foy

Ahh, the eternal shame of relying on old information and dead reckoning. I hail from the days of paper maps, siledas, inertial navigation and the aforementioned dead reckoning. GPS has certainly changed things. But I still have my old brunton, and just updated the declination setting a couple of months ago.

I recall having misplaced a valley and a couple of mountains in central Idaho back in the 1980's. Some puzzling over topo maps, shooting azimuths with the brunton and triple checking everything eventually set me right. Perhaps a lost art?

 

[ski3pin]

<snip>
. Some puzzling over topo maps, shooting azimuths with the brunton and triple checking everything eventually set me right. Perhaps a lost art?

Not a lost art around here.

 

[MarkBC]

Not a lost art around here.

I learned how to navigate with map and compass in Boy Scouts -- Orienteering Merit Badge, I think. I used it for real a few times hiking/backpacking back in the day -- figuring my location by taking bearings on landmarks with compass and triangulating on a topo map.
I haven't done that in a long time... but I still remember how -- could if I had to.

 

[takesiteasy]

Declination is not the only possible problem with compasses. Foy (and Magellan) in particular will appreciate this: somewhere I have a photo of my brother and I in the woods of northern Minnesota with our compasses pointing north at each other either side of a large boulder full of magnetite- a common problem here in the land of iron ore. Plays havoc with navigation in the deep woods, haha.

 

[ski3pin]

Interesting side discussion is this: is the accelerated movement an indicator of a coming long overdue pole reversal?

 

[MarkBC]

Interesting side discussion is this: is the accelerated movement an indicator of a coming long overdue pole reversal?

I hope not... . Correct me if I'm wrong, but I think that while the poles are reversing the magnetic field is down for a while. That's bad for life -- no protection against various bad particles from the Sun and elsewhere.

 

[AWG_Pics]

Interesting side discussion is this: is the accelerated movement an indicator of a coming long overdue pole reversal?

You are right, there have been many magnetic field reversals throughout earth history -- what we don't know is how long they take to reverse and what adverse effects the reversal process may cause. I am hoping, with not much evidence, for a near instantaneous reversal. Or better yet, maybe it will hold off for another century or two!

 

[ski3pin]

Nova had an episode years ago called Magnetic Storm that we found fascinating. One section showed layers of basalt high up on Steens Mountain that indicated a rapid sequence of pole reversals. Minerals in the rock aligned with the magnetic field as the rock cooled. The program also showed modeling of the magnetic field. I suspect this has become much more detailed and refined since then.

I wonder if there are studies out there that tie past reversals to other global events.

I find all this so fascinating. The earth is a great place to live.

 

[MarkBC]

....

I find all this so fascinating. The earth is a great place to live.

I agree. The earth is my favorite planet!

One of the best things I did -- decades ago -- was taking a geology class from the local community college: "Geology of Southeast Oregon". This was a regular for-credit geology class, but I took it as audit...to avoid testing anxiety!
Besides in-class stuff we did a 4-day field trip (camping) in southeast Oregon covering Abert Rim, Hart Mt, Steens Mt and Pueblo Mt. Mostly about all the faulting, etc, that formed the region's terrain.
Love that stuff!

 

[PaulT]

I find all this so fascinating. The earth is a great place to live.

We've all made a very wise choice.

Paul

 

[Foy]

Declination is not the only possible problem with compasses. Foy (and Magellan) in particular will appreciate this: somewhere I have a photo of my brother and I in the woods of northern Minnesota with our compasses pointing north at each other either side of a large boulder full of magnetite- a common problem here in the land of iron ore. Plays havoc with navigation in the deep woods, haha.

"Local magnetic disturbances" are fairly common. Hard rock explorationists deal with them much more frequently since we were so often working in terrains already known to be mineralized. We encountered lots of disturbances next door to you in Michigan's UP while working in the Marquette and Iron Mountain iron ranges. As you and your brother found, there are outcrops of high iron content of ore or near-ore grade Pesky glaciers had a nasty habit of plucking them out of outcrop and dropping them miles and miles downrange.

Foy