Author Topic: Surveying and solar storms  (Read 3303 times)

Online SamT

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Surveying and solar storms
« on: February 19, 2011, 04:22:39 pm »

http://www.bbc.co.uk/news/science-environment-12493980

is this weekend perhaps not the best weekend to be surveying ????

I seem to remember John Beck talking about a whole day of Peak Cavern surveying having been a complete waste of time since the readings were all over the place on account of a solar storm.

How bad does it get, anyone with any other experience of this ???

Offline robjones

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Re: Surveying and solar storms
« Reply #1 on: February 19, 2011, 06:34:55 pm »
My father-in-law spent a summer surveying in Alaska in the 1950s and on completion found that the data was virtually useless because they had been working on the increasingly bulging flank of a volcano - it blew a few months after they left. Not a frequent problem for surveyors in the UK fortunately.

Offline Anon

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Re: Surveying and solar storms
« Reply #2 on: February 19, 2011, 08:09:19 pm »
Depends how long the effects last for, the flares from earlier in the week were supposed to have hit a few days back (if what I read was correct).. We are now heading towards a period of increased solar activity so anything is possible!

Offline Les W

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Re: Surveying and solar storms
« Reply #3 on: February 19, 2011, 09:49:19 pm »
I will ask the cave surveyors at the Wessex if it affected their training course today. I hope they considered it at least.
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Online SamT

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Re: Surveying and solar storms
« Reply #4 on: February 19, 2011, 10:14:36 pm »
a quick google revealed someone who'd already googled for me.. to quote...

Quote
I was googling about it a little and I found multiple sites saying that there is a high probability and documented episodes where compasses went crazy or showed differences in their readings.

http://news.bbc.co.uk/2/hi/science/nature/3223739.stm
Quote
The geomagnetic storm has caused compasses to swing wildly.
The direction of magnetic north changed by several degrees during the storm
The compass variation at the Lerwick geomagnetic observatory in Scotland changed by 5.1 degrees in only 25 minutes at about 0630 GMT

http://www.thenakedscientists.com/HT...interview/897/
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It was known that the more sunspots there were on the sun, the more unreliable the compass readings were.

http://www.solarstorms.org/SRefStorms.html
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November 18, 1882 - The Transit of Venus Storm - It produced a compass bearing deflection of nearly 2 degrees

http://earthsci.org/education/fieldsk/declin.htm
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The influence of solar magnetic activity on the compass can best be described as a probability. During severe magnetic storms, compass needles at high latitudes have been observed swinging wildly.

http://en.wikipedia.org/wiki/Geomagnetic_storm
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Possibly the most closely studied of the variable Sun's biological effects has been the degradation of homing pigeons' navigational abilities during geomagnetic storms. Pigeons and other migratory animals, such as dolphins and whales, have internal biological compasses composed of the mineral magnetite wrapped in bundles of nerve cells


I've just giggled out loud to think that a surveying course took place this weekend.  :lol:

As you say Les, I hope they at least considered it, either that, or they are all wondering why they were all crap at surveying  :lol:

Online SamT

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Re: Surveying and solar storms
« Reply #5 on: February 19, 2011, 10:17:08 pm »

This was in 2003...

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The compass variation at the Lerwick geomagnetic observatory in Scotland changed by 5.1 degrees in only 25 minutes at about 0630 GMT


Offline Peter Burgess

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Re: Surveying and solar storms
« Reply #6 on: February 19, 2011, 10:20:05 pm »
Taking check bearings will tell you straight away if there is a problem, and taking one before and after your session will tell you if there has been any variation during the time of the surveying. In fact, I can't think of a better weekend to do a course as detecting a variation is probably quite rare.

Offline Les W

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Re: Surveying and solar storms
« Reply #7 on: February 19, 2011, 10:26:51 pm »
Taking check bearings will tell you straight away if there is a problem, and taking one before and after your session will tell you if there has been any variation during the time of the surveying. In fact, I can't think of a better weekend to do a course as detecting a variation is probably quite rare.
Although if the variances are that fast then you might do a before and after bearing and have the storm whilst underground and not know anything was amiss (although this is unlikely there used to be 9 day long Daren Cilau underground camps, any surveying of new discoveries ought to have been checked against any known magnetic storms that might have occurred at the time)
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Offline Peter Burgess

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Re: Surveying and solar storms
« Reply #8 on: February 19, 2011, 11:34:04 pm »
Having done a considerable amount of simple mine surveying since about 1980, I can only recall one evening when we found our checks showed a variation of  about 1 degree. Mind you, we didn't always do the checks. Maybe the odd occasion when we found survey loops not closing too well, and having to go back and redo them, might have had a natural cause, but was more likely us having a bad day.

Offline graham

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Re: Surveying and solar storms
« Reply #9 on: February 20, 2011, 06:47:05 am »
I am willing to bet that they were not taking field measurements at 06.30 GMT.
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Online SamT

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Re: Surveying and solar storms
« Reply #10 on: February 20, 2011, 10:08:43 am »
I am willing to bet that they were not taking field measurements at 06.30 GMT.

I'll raise you, and bet that they didn't travel back in time to 2003 either.  :read:

Offline graham

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Re: Surveying and solar storms
« Reply #11 on: February 20, 2011, 10:44:30 am »
I am willing to bet that they were not taking field measurements at 06.30 GMT.

I'll raise you, and bet that they didn't travel back in time to 2003 either.  :read:

I wouldn't put anything past Andrew and Wookey.
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Offline footleg

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Re: Surveying and solar storms
« Reply #12 on: February 21, 2011, 12:53:26 pm »
So it is true, I spent a weekend learning about the dark side of surveying (therion). As it turned out, our loop closure in a loop between the main and trademans entrances of Goatchurch closed with only a small error (I don't have the data at work today to be more specific). So at least during the period we were there (Saturday afternoon) there was not any wild variation in magnetic north at that location. There may of course have been a constant deviation during the time we were there. If anyone would like the survey data to compare with their own data taken on a different occasion then just ask me.

Offline Duncan Price

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Re: Surveying and solar storms
« Reply #13 on: February 21, 2011, 11:19:06 pm »
Interesting - Footleg was our mentor while myself and Dickon did the surveying.  We did two loops - one underground (which we cocked up due to misplacing a from-station) and one which included a surface leg.  Closure was very good - again I don't have the stats but it emphasises the need to check pre- & post- survey.

Conveniently for me; where I'm currently working has a concrete entrance pipe alligned due Grid N-S...  just take  a shot on going in and out.

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Offline robjones

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Re: Surveying and solar storms
« Reply #14 on: February 22, 2011, 07:17:56 pm »
My surveying lecturer* drilled into us that the closer a closed loop came to perfection in terms of closure, the greater the chance there were errors contributing.

When you have accumulated a lot of closed loop survey data with a consistent set of equipment and in broadly similar benvironments, it can be instructive to examine the misclosures; any that are well-below your norm probably contain errors...

[*R.A.Yates, UCW Aberystwyth; his famous line, awaited - and duly delivered each year - in one of the introductory lectures on chainwork: 'The leader leads and the follower follows.']

Offline manrabbit

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Re: Surveying and solar storms
« Reply #15 on: February 22, 2011, 07:39:14 pm »
What is being affected here, is it the needle of your compass or is it the earth's magnetic field. If a solar flare is have a direct effect on your compass needle is this effect as great deep underground?  :-\
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Offline Les W

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Re: Surveying and solar storms
« Reply #16 on: February 22, 2011, 08:18:24 pm »
It is the earth's magnetic field that is distorted by solar storms. The needle (or card) in a compass is just indicating the direction of that field. If the field changes then the compass shows a different direction. The earth's magnetic field doesn't really change with depth (the range of depths you will experience on or under the earth's surface, a potential maximum of about 8km, is not actually very much compared to the range between the depth to the core and to the furthest extent of the magnetic field in outer space (Thousands of Km))
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Offline Duncan Price

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Re: Surveying and solar storms
« Reply #17 on: February 23, 2011, 12:39:30 am »
I checked my compass against a known datum tonight.  I was the same as previous.

Wearing a watch or holding other metalwork close to the (electronic) compass incorporates larger errors.

Duncan