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.
    • 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)