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Homestake Telecon Minutes, 02/25/16



  • Homestake array
    • status of stations (WTP, Yates, 800)
    • planning next visit: April 15-24
      • No access on Apr 11 (Mon) and Apr 22 (Fri).
      • Replace instruments at 800 and Yates.
      • Harvest data from balers.
      • Clean out the insulation panels being stored in the room at the #4 Winze wye on the 4850L.
      • Terry and Pat will go.
      • Should have one spare instrument, Pat and Tanner should follow up. Need another Guralp from PASSCAL, Gary to follow up on it.
      • Assume to download 4 Balers/day, so need 6 days for the whole array. Checked inventory, looks like we should have 10+ spare balers.
  • Data analysis updates
    • Results of the Geochemical Analysis of Homestake Wave Speeds PowerPoint
      • Victor: should follow up on the minerals for which we don't have data. Levi to email the group about them.
      • Velocity does not seem to depend on the depth, so the observed depth dependence of the velocity must come from porosity of the rock, fractures etc.
    • Indiana group results - S velocities and start of event catalogfeb25-2016.pptx
      • Shear wave speed measurements at 2000 level: ~3500 m/s in the Homestake formation, ~3300 m/s in Ellison, and ~3700 m/s in the mixed rock environment near Ross.
      • Victor: any bias due to being close to the tunnel? Gary: possibly, fracturing is probably higher near the tunnels.
      • Gary: looking at anisotropy, but can't tell yet. Need to look at the geology, Levi's work could help with this. Difficult to distinguish anisotropy from heterogeneity in the rock.
      • Event catalog: seeing ~10 events per day, mostly mining explosions in the region. Not all are recovered correctly, need a full array analysis for this.
      • Many large signals with large S-wave contribution from these mining explosions, although one wouldn't expect large S-wave components generated in these explosions.
    • Rayleigh wave planning (Tanner) slides
      • Daniel can help with estimating Rayleigh wave amplitudes, Tanner will follow up with him offline.
      • Daniel: probably best to filter the data in a narrow band around a specific frequency, and then do the fitting. In this way you avoid dealing with different speeds at different frequencies.
groups/homestake/meetings/20160225.txt · Last modified: 2016/02/25 11:48 by mandic