Please LIKE and SUBSCRIBE. I also appreciate your continual support of these geology education videos. To do so, click on the "Thanks" button just above (right of Download button) or by going here: www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8 Or: www.buymeacoffee.com/shawnwillsey
Thank you, Shawn, for being able to create a practical application out in the field for this. I had never heard of a Brunton compass, yet alone handled one. I found it complex but I think if I rewatch it a couple of times I will get the steps needed to take a full strike and dip reading.
Message from Nick today. Sat, Nov 16 at 1 pm update: More good news to report. Liz is waking up occasionally in her bed and seems to be recognizing our voices/faces. Saying things like “OK”, “frick”, “dammit”, “can you undo me?”. Occasional grins and tiny head shakes when somebody says something funny or familiar. She is mostly under heavy sedation - and these next two days are the most intense regarding recovery from major brain surgery. All three boys are here, plus Cori and Clara. Baby Luca is with his dad mostly in our Air BnB nearby. We are still feeling really good here….so much so that we are starting to think about logistics for the next week and beyond. The most crucial and intense phase is behind us and we are grateful all of the excellent care and emotional messages from you all via text, etc.
Thanks for another clear video. You need to be a juggler to get the camera and the compass working at the same time! I had never seen a Brunton compass before - a very simple and clever tool! It was very useful to tack on the video at the end, showing things in a real-life situation! Thank you also for answering a question that I had asked in the previous GEOL101 video on how one defines the strike angle - answer: use the right hard rule! And, of course, if I need to come see you in your lab, I now have a pretty good idea where that is (A06, unless GeoCompass was wrong). 😲 😉
John McPhee wrote about incompetent people at the USGS who did not know strike from dip. They were sent to "penal quadrangles" in Louisiana where they would encounter neither.
As a complete amateur, I plan to use my cell phone for measuring strike & dip if I ever want to. Unfortunately nearly everywhere I go to look at rocks is out of cell phone range, so can't really count on it. What i was wondering though is, if you want an accurate reading on a real Brunton,, don't you have to calibrate it for magnetic declination? (I assume the Rock'd app, which has the "brunton" I'm using, does this itself since it knows where the phone is located) (when it's working).
Yes, I opted not to discuss magnetic declination as that is a whole extra episode, potentially. My Brunton is set to local mag declination and I assume the iphone app also factors this in based on location,
Your phone's compass and accelerometers should work without cell reception, though your phone or the app may not correctly adjust for declination (if it does that at all) without being able to look up the location's exact declination from the internet (with cell reception).
My Brunton had the same crack. It's from closing it with the little thingy pointing the wrong way. It could still be used for strike and dip, but using it to find location was pretty tough. Plus no GPS. Had to replace the mirror.
Hi Shawn. Thanks for the great review. I have two Brunton style compasses. One is an original Brunton I bought over 50 years ago when I was a graduate student and I paid a lot of money for it. I bought a Chinese look-alike for next to nothing about 5 years ago. The Chinese version is actually a very good compass, very good with every feature the "real thing, has but it came with a really terrible hinge. I improved the hinge with a brass rod and a little blacksmithing and the hinge is now as solid as a ... ah ... solid as a rock. The real Brunton is heavy and fragile (being of metal and real glass), but the Chinese version is light and very rugged. Guess which one I have on display and which one I carry with me when outside exploring? The only real downside to the Chinese Brunton (besides having to fix the hinge) is that it is NOT a "real" Brunton. That can be so embarrassing when the other geologists in the group notice. Not having a cracked mirror is a dead giveaway that it's not the real thing. By the way, I've always found the vernier on the clinometer to be a rather absurd attempt at a precision that just isn't there.
One word of caution when using a phone or tablet app: If you're using a protective cover which contains magnets, the displayed compass directions can be very inaccurate. For instance, the indications on my iPad can be in error by more than 90° in azimuth if the cover is folded flat against the rear of the device. Opening the cover flat gives a more accurate reading, but it's still off by several degrees.
Thanks for the demo, Shawn. Have you considered asking your students to help you when you don’t have enough hands. It would be great experience and extra credit. Tripods work great too. Maybe you’ve considered these and they aren’t workable. Drones can also video you as well.
I noticed your azimuth ring displaced a bit... perhaps 15 or 16 degrees. i assume it's compensating for declination (or what aviators call variation). So my question is are strike values reported in relation to true north or magnetic north? In north america variation can be 20 degrees or more and shifts continuously... id say thats pretty important yet although you may have i didnt hear you mention it.
@@shawnwillsey Understand wanting to focus on the operation of the tool, but imho knowing to correctly record or adjust for mag vs true is fundamental to reading azimuths correctly (twitchy from spending so much time trying to recover historical readings where they didn't) - Jen
In your demonstration of measuring dip (at 9:45), my eyes see the index line as close to 30 degrees, but between 20 and 30, not 30 and 40. So I believe the correct dip should be about 29 degrees or more accurately greater than 29 but less than 30 degrees. Again at 18:04 (although the camera focus is off), I see the index line as being between 30 and 40, so I think the dip should be about 39 degrees. Since my reading is constantly different than yours, I would appreciate it if you would comment on how I am misreading the inclinometer.
You're likely not misreading it, instead it is an issue with the parallax (as in, the dial is raised above the measurement surface - the phone is to the right of Shawn, so he reads it at a different angle than visible from the camera. As we can see here, this can impact readings, so it's important to read dials dead-on whenever possible!
Thank you for the lesson on how to use a Brunton. I inherited my grandfather's and have it on display, but as an engineer I've always wondered how to use it. Seems like erosion can give you all sorts of strike readings in a localized area. Presumably you have to use the sighting features to average over a longer distance.
Please LIKE and SUBSCRIBE. I also appreciate your continual support of these geology education videos. To do so, click on the "Thanks" button just above (right of Download button) or by going here: www.paypal.com/donate/?hosted_button_id=EWUSLG3GBS5W8 Or: www.buymeacoffee.com/shawnwillsey
Thanks for all the hard work on these videos!
My pleasure!
Thank you, Shawn, for being able to create a practical application out in the field for this. I had never heard of a Brunton compass, yet alone handled one. I found it complex but I think if I rewatch it a couple of times I will get the steps needed to take a full strike and dip reading.
Let us all pray for the speedy recovery of Nick Zentner's wife.
Message from Nick today.
Sat, Nov 16 at 1 pm update: More good news to report. Liz is waking up occasionally in her bed and seems to be recognizing our voices/faces. Saying things like “OK”, “frick”, “dammit”, “can you undo me?”. Occasional grins and tiny head shakes when somebody says something funny or familiar. She is mostly under heavy sedation - and these next two days are the most intense regarding recovery from major brain surgery. All three boys are here, plus Cori and Clara. Baby Luca is with his dad mostly in our Air BnB nearby. We are still feeling really good here….so much so that we are starting to think about logistics for the next week and beyond. The most crucial and intense phase is behind us and we are grateful all of the excellent care and emotional messages from you all via text, etc.
@@shawnwillsey Thanks you for this! needed some good news tonight
Oh thank you so much for this update. 🤞🏻❤
Yes, thank you, for this update on Liz’s situation.
@@shawnwillseyThank you for the update from Nick.
Thanks!
Even I, was able to follow. Thx Professor!
Thanks for another clear video. You need to be a juggler to get the camera and the compass working at the same time! I had never seen a Brunton compass before - a very simple and clever tool! It was very useful to tack on the video at the end, showing things in a real-life situation!
Thank you also for answering a question that I had asked in the previous GEOL101 video on how one defines the strike angle - answer: use the right hard rule!
And, of course, if I need to come see you in your lab, I now have a pretty good idea where that is (A06, unless GeoCompass was wrong). 😲 😉
Ahhh-ha (lightbulb moment)! Now I get it. Thanks for presenting this.
Thanks, Shawn, this video was indeed very helpful!🙂
John McPhee wrote about incompetent people at the USGS who did not know strike from dip. They were sent to "penal quadrangles" in Louisiana where they would encounter neither.
McPhee is one of my all-time favorite authors. Creative non-fiction at its best!
As a complete amateur, I plan to use my cell phone for measuring strike & dip if I ever want to. Unfortunately nearly everywhere I go to look at rocks is out of cell phone range, so can't really count on it. What i was wondering though is, if you want an accurate reading on a real Brunton,, don't you have to calibrate it for magnetic declination? (I assume the Rock'd app, which has the "brunton" I'm using, does this itself since it knows where the phone is located) (when it's working).
Yes, I opted not to discuss magnetic declination as that is a whole extra episode, potentially. My Brunton is set to local mag declination and I assume the iphone app also factors this in based on location,
Your phone's compass and accelerometers should work without cell reception, though your phone or the app may not correctly adjust for declination (if it does that at all) without being able to look up the location's exact declination from the internet (with cell reception).
My Brunton had the same crack. It's from closing it with the little thingy pointing the wrong way. It could still be used for strike and dip, but using it to find location was pretty tough. Plus no GPS. Had to replace the mirror.
Luv the right hand rule, first time I've seen that Doc. The apps, wow, field methods have definitely changed lol.
YES thank you
Hi Shawn. Thanks for the great review.
I have two Brunton style compasses. One is an original Brunton I bought over 50 years ago when I was a graduate student and I paid a lot of money for it. I bought a Chinese look-alike for next to nothing about 5 years ago. The Chinese version is actually a very good compass, very good with every feature the "real thing, has but it came with a really terrible hinge. I improved the hinge with a brass rod and a little blacksmithing and the hinge is now as solid as a ... ah ... solid as a rock. The real Brunton is heavy and fragile (being of metal and real glass), but the Chinese version is light and very rugged. Guess which one I have on display and which one I carry with me when outside exploring? The only real downside to the Chinese Brunton (besides having to fix the hinge) is that it is NOT a "real" Brunton. That can be so embarrassing when the other geologists in the group notice. Not having a cracked mirror is a dead giveaway that it's not the real thing. By the way, I've always found the vernier on the clinometer to be a rather absurd attempt at a precision that just isn't there.
Thanks for sharing your compass stories, I love the ingenuity with the hinge!
Reminds me of Dr. Holmes class at NAU!
Super informative video. I know my geology and physics, but am sorely lacking in field work.
Ahh, *now* I remember. Thanks Shawn!
😄rings a bell with me too!
Pretty cool instument
Pls make another video on joints, lineament, and how to measure their attitude.
One word of caution when using a phone or tablet app: If you're using a protective cover which contains magnets, the displayed compass directions can be very inaccurate. For instance, the indications on my iPad can be in error by more than 90° in azimuth if the cover is folded flat against the rear of the device. Opening the cover flat gives a more accurate reading, but it's still off by several degrees.
Hi from Dorset UK. Great - Im useless at this 😂
Hurrah! Getting hoped-for information.
The faithful old Brunton. Mine is green
Thanks for the demo, Shawn. Have you considered asking your students to help you when you don’t have enough hands. It would be great experience and extra credit. Tripods work great too. Maybe you’ve considered these and they aren’t workable. Drones can also video you as well.
I hope I could experience using this down the road
Maybe a carry tripod for the camera? Lots of UA-camrs use them. Great video though, very educational. 👍
I noticed your azimuth ring displaced a bit... perhaps 15 or 16 degrees. i assume it's compensating for declination (or what aviators call variation). So my question is are strike values reported in relation to true north or magnetic north? In north america variation can be 20 degrees or more and shifts continuously... id say thats pretty important yet although you may have i didnt hear you mention it.
The Coconino sandstone seems to have a dip of 22-28 degrees!
I seem to remember using a small board with a triangular cutout to approximate or extend the bedding plane. Is that still done?
how good is the Xgeology geological compass. on amazon. for $50.
Not sure. I've never used it. Check reviews, maybe?
I'm assuming that declination of magnetic north to true north is above the 101 level?
He set his Brunton and right hand already, let's implement the KISS principle here
Brunton already set to local mag declination. I didn't want to go down that rabbit hole and explain it all at this level
@@shawnwillsey Understand wanting to focus on the operation of the tool, but imho knowing to correctly record or adjust for mag vs true is fundamental to reading azimuths correctly (twitchy from spending so much time trying to recover historical readings where they didn't) - Jen
In your demonstration of measuring dip (at 9:45), my eyes see the index line as close to 30 degrees, but between 20 and 30, not 30 and 40. So I believe the correct dip should be about 29 degrees or more accurately greater than 29 but less than 30 degrees. Again at 18:04 (although the camera focus is off), I see the index line as being between 30 and 40, so I think the dip should be about 39 degrees. Since my reading is constantly different than yours, I would appreciate it if you would comment on how I am misreading the inclinometer.
You're likely not misreading it, instead it is an issue with the parallax (as in, the dial is raised above the measurement surface - the phone is to the right of Shawn, so he reads it at a different angle than visible from the camera. As we can see here, this can impact readings, so it's important to read dials dead-on whenever possible!
Yes, about a 29 degree dip for rock plane in class and about 40 or so degrees in field.
Why does EAST lie 90 degrees clockwise from SOUTH on that compass?
Not sure. I just stick to the compass needle and the azimuth readings.
I watched a geologist use his field notebook to get a good reading.
Yes, you can use a clipboard or notebook as a plane and hold it parallel to bedding to get a good reading.
The official tool but not the best. Try a sighting inclimator.
Thank you for the lesson on how to use a Brunton. I inherited my grandfather's and have it on display, but as an engineer I've always wondered how to use it.
Seems like erosion can give you all sorts of strike readings in a localized area. Presumably you have to use the sighting features to average over a longer distance.
pretty cool. ,how does the relate to finding gold. is there a way i can send pictures to you. ,email. please. thank you.