Homestake Meeting Minutes, 04/13/18

Attending: Gary, Pat, Victor, Vuk, Daniel

Agenda:

  * Next Meeting: May 11
  * Data analysis topics
    * Data corrections, frame production (Gary/Daniel/Pat)
    * Event catalog (Gary/Ross)
    * Radiometer updates (Pat, Andrew)  {{:groups:homestake:meetings:rwave_pe_and_radiometer.pdf|{{:groups:homestake:meetings:rwave_pe_and_radiometer.pdf|}}}}
      * Pat: eigenfunctions measured above 0.2 Hz, not much signal below it. Gary agrees.
      * Vuk: Correction of equation on slide 6.
      * Daniel: for data points where there is a binary distribution (some retro and some pro), should we try to force the retro solution? This could change the mean and the median.
      * Pat: not sure, had the same question. Will follow up via email.
      * Victor/Daniel: if v(f) is a power law, then the coefficients of the biexponential eigenfunctions are independent of frequency.
      * Pat: velocity at low frequencies is maybe not modelled well with a linear or a power law. Maybe there are better choices?
      * Victor: usually people don't fit velocity vs frequency with a parametrized curve, instead they use their data (or don't use some frequencies).
      * Victor/Pat: could try to fix velocities from other estimates, and only estimate other parameters
      * Vuk: it seems posteriors and priors are similar, not constraining the eigenfunctions more than we already did before the measurements.
      * Victor: yes, the paper could simply state that the data is consistent with the model.
      * Vuk: Maybe we can get away with some simpler statistical statement, showing that the model is consistent with the data?
      * Victor: would be nice, but would not be the selling point of the paper.
      * Vuk: let's then proceed with what we have. If we come up with a simple statistical test we can add it...
    * Parameter estimation for Rayleigh and Love (Pat) 
    * Teleseismic events and Wiener filtering (Daniel, Michael)
    * Very-long-periods (Ross)
    * Velocity from noise correlations (Daniel)
      * Model selection?
    * Pull together all velocity measurements to start making comparisons (all)

  * Papers
    * Homestake Array Summary paper:
      * Leads: Vuk, Gary, Victor
      * Submitted to Seism. Research Lett.:  Still waiting. Vuk to check with the editor...

    * Active excitation overview paper
      * Leads: Gary, Ross
      * Others: Victor, Daniel,…
      * {{:groups:homestake:meetings:maintext.pdf|Draft}}.

    * Surface Active Excitation
      * Leads: Victor, Boise
      * Others: Gary, Ross
      * Plan to invite the Boise group to give us a presentation in Sep or Oct 2017, when they are ready with their paper.

    * Underground Active Excitation:
      * Lead: Gary, Ross

    * Parameter estimation for the Rayleigh and Love eigenfunctions (amplitude vs depth dependence).
      * Leads: Pat, Daniel
      * Also contributing: Victor, Vuk, Levi

    * Estimating directional and modal composition of the seismic noise. (Pat, Levi, Vuk)
      * Leads: Pat, Vuk, Levi

    * Wiener filter application
      * Leads: Jan, Michael    
      * Latest version: {{:groups:homestake:meetings:wiener_v7.pdf|Draft}}. 
      * Michael: draft produced after discussing with Victor. Will iterate again to make it more suitable for geophysics community. Moved text around to emphasize geo aspects more. Target: Journal of Geophysical Research: Solid Earth. Physics implications are in the conclusion only.
      * Victor: this is the standard journal for geophysics research, so the emphasis should be on geophysics. It is OK to add on implications for physics.

    * Teleseismic EQs and near-surface scattering
      * Leads: Daniel, Victor

    * Time-variable velocity changes
      * Lead: Victor, not started yet

    * Very low frequency harmonics (Ross)
    * 3D PDF of Homestake geometry - draft for active source experiment paper {{:groups:homestake:meetings:homestakeexperiment.pdf|}}