Homestake Meeting Minutes, 10/18/17

Attending: Daniel, Ross, Pat, Andrew, Vuk, Michael

Agenda:

  * Next Meeting: Vuk will circulate doodle poll, it seems there are conflicts with current time.
  * Data analysis topics
    * Data corrections, frame production (Gary/Daniel/Pat)
      * Has data in IRIS been updated? Check with Gary?
    * Event catalog (Gary/Ross)
    * Radiometer updates (Pat, Andrew)
      * Pat posted some results: http://homepages.spa.umn.edu/~meyers/homestake/r_wave_checks_october_18/Homestake%20EQ%20r-wave%20investigations.html
      * looking at the transverse to vertical phase, to find the Rayleigh wave (90 degree phase).
      * tried to run the radiometer on the data around 1.5 Hz, which seems to be coming from a direction about 68 degrees east of north. Find that radiometer gives 22 degrees north of east, which seems consistent. Some concerns: the data at this frequency has periodic turn ons/offs, so it may be local, in which case the waves would not be plane waves. 
      * Looked at earthquakes too, but not ready to present.
      * Plan to present at the next meeting, will try to have some slides with applications to different data.
    * Parameter estimation for Rayleigh and Love (Pat) 
    * Teleseismic events and Wiener filtering (Daniel, Michael)
    * Very-long-periods (Ross)
      * Circulated a figure comparing power in Homestake and Pinon flat arrays. Up to 1000x better noise in the Homestake array at 2mHz, depending on the frequency. {{:groups:homestake:meetings:ross_comparison_vertical.png|figure}}
      * Will use this for the methods paper, didn't see the very long periods in the Pinon Flats. Will use to demonstrate why Homestake data can reveal these periods.
      * Method paper is nearly done, will also write a results paper
    * 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
      * target: Seism. Research Lett., 6000 words, 10 figures.
      * Paper should be in a very mature state. Vuk will take another look, check emails from Gary, and if there are no issues will submit.

    * Active excitation overview paper
      * Leads: Gary, Ross
      * Others: Victor, Daniel,…
      * Will discuss at the next call.

    * 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
      * Novel, but maybe insufficient for a publication. Could use the eigenfunction measurement for Rayleigh and assume something about Rayleigh field to make preliminary estimates of the Newtonian noise. 

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

    * Wiener filter application
      * Leads: Jan, Michael    
      * Michael with check with Jan, there may be more work to be done on it before circulation.

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

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

    * Very low frequency harmonics (Ross)