Summer Underway

June 24th, 2010

The second week for me here is almost completed, and although things are pretty quiet here I've been keeping plenty busy! We finally got our matlab software GUI to download and convert all our MT data from Berkeley (magneto-telluric: refers to both magnetic and electric fields measured). Its been a pretty steep learning curve in UNIX and networking and public key cryptography. The network administrator for the crustal geophysics group is a grad student who, go figure, is out in the field (thanks again, Kelsey ; ) ). But one learns more by doing it themselves right?  Then there's the actual signal analysis, which I've only begun to scratch the surface of... All the electric and magnetic data is buried in noise for the 22 hours every day that BART is running. BART is the local Bay Area transit system, which powers their trains by sending current on the 'third rail.' Go figure, sending huge amounts of electric current along the ground at high voltage without any shielding would throw off our highly sensitive measuring equipment (We're talking about hundreds of square kilometers of area that this affects!). 

On another note, I've (hopefully) settled on ideas for a project that I can call my own over the summer. While the seismometers have been well calibrated and tested, the magnetic coils in the ground haven't been checked in awhile. MT equipment is very well developed and used in industry as an exploratory technique, but not as often permanently installed to look at long term trends. We fully understand how they work and how well they should respond to a local magnetic field, but we're not sure if some of the connections have degraded over time, nor do we understand all the finer points of its setup (ex: is it better to bury the coil, or mount it on a concrete slab? Both will measure local variations, but what to what magnitude in SI units?).  So, I've been challenged to design an induction coil to create our own magnetic field -- start with a 9V car battery and make a low-freq (~1Hz) magnetic field. Then we take it to the sites and see if what is measured is what we expect. I'm excited by this project because it should provide a good range of activities, from designing basic circuitry, to field deployment, to computer analysis (it'll take a little work to filter out the field we create from all the other noise, and then compare magnitudes). And all very hands on, which I definitely appreciate!

On a more personal note, I'm having a good time settling in to the bay area! I've been getting to know my undergrad counterpart (a stanford undergrad working on the same project), as well as the other students in our offices. I'm staying with family, which is always nice, and my girlfriend is in the area working for the summer at a German summer school/camp. I signed up for membership at a local rock climbing gym, and also just picked up a used road-bike to help with the daily commute -- should be solid couple hours of exercise each day.  

Tomorrow should be my first day really getting dirty out in the field, shovel in hand. We'll be driving up to the Marin Headlands (just north of the golden gate bridge). We need to pull up one of the buried magnetic coils there and swap it with a working one. Time to get to work...