May 30, 2014
GPS in the Eastern Sierra, Year Six (and Counting)
At the end of May, I made my annual pilgrimage to SNARL, the Sierra Nevada Aquatic Research Lab, at the base of Mount Morrison in the Eastern Sierra. Big heart. The purpose: teaching Indiana University undergrads about GPS. The bonuses, starting with the drive down: mountain views.
This is my sixth year helping out with the class, which has been going for I think 12. I get grandmothered in as GPS instructor/engineer, which actually fits my current job quite well. The class is taught by my Indiana University master's advisor, Michael Hamburger, and John Rupp, from the Indiana Geological Survey. They are helped out by an Associate Instructor and together hold court over 15 students for a California mountain adventure.
What I love about this class (other than the amazing scenery): Unlike most geology field courses, it is an *intro* course, open to non-majors. This year, there were three geology majors, a history and political science major, a few biology majors, an environmental management major, and a speech pathology major, among others. And because it's Indiana University, in the heart of the midwest, many of these students have never seen these mountains before. Some have never really seen *any* mountains before. So every day is a wonderful new discovery. They get to ride a gondola for the first time, up Mammoth Mountain. They glissade for the first time, they see Death Valley for the first time, they soak in hot springs for the first time. And, they eat Linda's cooking for the first time. (Linda's been doing the catering since the beginning or almost the beginning of the course some twelve years ago, and it's an amazing thing. Don't come with any expectation of losing weight. The hiking is more than balanced out by Linda's desserts. Sigh.)
Oh, and they do GPS for the first time! (The most important thing, right?) One day of the course is surveying day, and we measure a line of survey markers up and across a fault using leveling (old school) and GPS (new school), so they can compare the techniques. The fault is the Hilton Creek fault, but we measure its displacement across McGee Creek, just a hair south of the field station where we stay. (Turns out faults don't care about their namesakes when they rupture).
This is how the day is supposed to go:
"Wow, we spent a lot of time trying to located these (small, hidden) survey markers amidst the sage brush and scrubby trees, and even though the written directions from years past seem pretty good it took forever. But that GPS stuff—WOW! It got us right to the point!"
To explain: We use what's called real-time kinematic methods, or RTK, which means we have a base station (GPS) that communicates with our rover (also GPS) via radios. We tell the base station where it is. No, base station, even if you think you're over there, you're not! You're right here! And so it can actually calculate the errors in its position. Because our rover and base are close together (a few km at most), they share the same error sources. Mainly, the satellite signals are going to travel through the same slice of atmosphere to reach our instruments, which means they're going to be delayed by the same amount to our base and rover, and that error essentially cancels out. It's convenient. And I program in the locations of the survey points beforehand, so *theoretically* we can navigate right to the points. And by "right to," I mean we should get within 2-3 centimeters, or about an inch. It's cool when it works.
And it *would* have worked this time if I had just chosen good coordinates. I happened to use coordinates from a year where the survey was bad for some reason. I had maybe eight years to choose from, and two were bad, and I used one of them. So in the field we were off by one meter, then two, then five. Not very impressive. But that was only a side goal of the survey. The main goal was to re-measure the positions of the markers to see if they'd changed.
[I like to teach one student in each group how to run the controller, and then they teach the next person, and so on, until everyone has used it to measure a marker. When possible, I have the old group teach the new group when we switch off. They always do great.]
And, the students seemed to like it. Some of them were totally grooving on it. The first group I had helped me set up the base station, and they were waaaaaay into it. A couple of the students even matched the equipment.
The idea of the survey is that we'll see motion on the fault, if there is any between surveys. So far, no luck. But I feel like we did a good job of surveying this year, so if there had been any motions, we'd have seen it. Michael and I manage to almost-but-not-quite work our way out of the tangle of data every year to make some sense of it, but with one or two days and an Excel spreadsheet and undoubtedly small motions, if any at all, we've never really had a "wow" product to show the students. By the next day they're on to the next thing, anyway, so I don't think they mind. But it would be really nice to show some real, meaningful results from the survey.
As it is, I attempt to entertain them with a few lectures—one to show how GPS works and what makes our fancy high-precision stuff different from the GPS in their smartphones, and another to show applications of GPS. Earthquakes! Volcanoes! Even hurricanes, snow depth, soil moisture, drought, and glaciers! And I show off about the Plate Boundary Observatory, which includes several sites within almost spitting distance of the field station where we stay.
[Leveling. More precise in the vertical, but it *only* gives the vertical. Plus, we cruise right past them once we're set up. Plus, we can navigate right to the markers...usually. Still, if there are changes, but the changes are very small, leveling might be the way to go.]
And then, at the end of the exhausting days, we eat Linda's food and soak in those hot springs and giggle in the "executive suite" dorm room like we're in... well, college. Or maybe junior high.
And maybe, just maybe (it's not uncommon), one or two of the students who weren't geology majors decide to study geology, or a student ends up in something else with an Earth science or environmental focus. One went on to study environmental law. The 2008 group started a Facebook page, and posts still show up periodically about the ecology or geology of the Eastern Sierra. We have yet to rope in a geodesist. But I like to think that the students at least have a better idea of what technology can do for us when it comes to understanding and mitigating hazards.
A major bonus for ME is getting to hang out with my dear friend Anne Hereford, who helped teach the class for six years and still comes out to visit. Here, we're taking Sunday afternoon off to hike up Convict Creek after lunch on the lake with the class. AMAZING geology. Just plain beautiful, whether you understand the folds or not. And the company was pretty darn okay, too.
Epilogue Part 2:
The drive back north is almost as nice as the drive back south, except the destination is not quite as nice. Hope to see you next year, Sierra class.
May 10, 2014
So I am eating soup—the same soup I've been eating the past few days—and as I'm eating it I realize I don't really want to use a spoon, because it's a a blended soup, and so I thoroughly lick off the spoon and reach out from the couch to drop the spoon onto my satchel beside me. Where there's.... another spoon. Because I did the exact same thing yesterday, and didn't remember until I saw the spoon.
The same thing happened yesterday. Where *did* I put that fork? I washed it, and then where did it end up? So I washed another one. And didn't want to put it in the drying rack for some reason. So I put it on top of an upturned clean bowl. Right next to another clean fork.
The best, though, was earlier this week when I got myself some tea. I drink a lot of tea. When I drink tea, if I use a tea bag, and if that tea bag has a tag, I tear off the tag. I tear off the tag because I don't like when it gets accidentally tugged into the tea when I'm pouring in the water, and then I have to fish the tag out with my fingers from the tea I'm about to drink. So I get up from my desk, pick up my mug, go to the sink down the hall, pull out yesterday's dry tea bag and toss it in the compost bin, get a new tea bag, pull off the tag, and read the tag while I fill my mug with water. Sometimes I like the quote or phrase on the tag. If I do, I feel like I should keep it with me somehow and read it again sometime, so I put it in my back pocket. I liked this one. I put it in. But I realized as I was putting it in that it was silly to do so because the last I remembered putting my hand in my pocket I found a mass of not-so-legible tea-tag fuzz. There was one other very intact tea tag in there, so I pulled it out.
At least I'm consistent.