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Homestake Meeting Minutes, 07/14/16

Attending: Gary, Ross, Levi, Vuk, Daniel, Pat, Tanner

Agenda:

• Homestake array status
  • RR cabling issue: probably rodent activity. Fix would most likely require replacing cables.
  • WTP mass rail issue Gary suspects that the platform has tilted in one direction, so that the instrument is not leveled any longer. We would probably need to have a sensor ready just in case though.
  • Do we need a maintenance trip asap? Cost roughly $20 per station per day, so next 50 days would cost us $2000, which is about the same as the cost of a trip to fix these. On the other hand, do we gain much from the extra 2 months of data from these 2 stations.

• Planning the September trip to remove surface stations
  • have to leave each site in the state we found it. Have to extract the insulation from the vaults, and we have to remove the pole. The pole might be hard in some cases, in most cases just pulling one guy wire would do it (since they are shallow, may have to dig some more). A couple of sites may be harder since they are deeper - for them, may have to dig more and maybe hit the concrete.
  • Gary: could clean up up to 5 stations per day. But have to service the balers in parallel with this. And we have to check the orientation of the sensors, to get another data point.
  • Also have to clean all of the equipment (remove mud etc), pack them into their boxes. We should ship them in December, along with all the others.
  • We should allow a full week: arrive on Sunday and leave on Friday or Saturday.
  • Dates in September: Gary would prefer the second half of Sept. Pat OK. Daniel: weeks of Sep 19 and 26 are ok. Ross: will be taking classes, but could miss some.
  • What about the tools: let's take inventory in Sept, and decide what to leave in the lab and what to ship back to UMN.
  • Week of Sep 26 looks like the best choice. Follow up via email, Vuk will check with the lab.

• Data analysis updates
  • Preliminary Love Wave Recoveries: pdf
    • Vuk: next step
    • Vuk: how do we verify this algorithm with data? Maybe compare to other techniques?
    • Gary: could look for noise from a nearby mine, there is a lot of activity there. But this is at higher frequencies, 1-10 Hz.
  • Gary: working on the active source data from the surface weight drops. Now at the stage of measuring arrival times at different stations from individual shots. Had to rearrange the data to make sure the shots are matched at different stations, have to do it interactively. Hoping to get something together for an AGU abstract, Aug 1. Estimating ~30,000-40,000 measurements so have to do it efficiently.
  • Ross: trying to study the elliptical particle motion, debugging an older piece of code to do it. More next time.
  • Daniel: have visiting summer student who spent 2 weeks at Boise working on the inversion problem for the near-surface structure. Should be able to show it next time. Trying to decide now how to push this further.
  • Daniel: Boise state group has tools to estimate directions from active source data, which may help Ross/Gary in their efforts. Gabe is the graduate student to talk to.
  • Try to think more about what what papers we should publish. Plan to have a discussion at the next meeting. Vuk will email about this.