Homestake Meeting Minutes, 06/29/17

Attending: Gary, Andrew, Victor, Pat, Vuk

Agenda:

• Next Meeting: July 27
• Data analysis topics
  • Data corrections, frame production (Gary/Daniel/Pat)
    • Pat: Frames at Caltech now. Michael knows about it, working on the Wiener filter paper.
  • Event catalog (Gary/Ross)
    • Gary: should be done in a couple of weeks, fixing some of the errors. Will include the 6 months we are using for the paper, not the entire dataset. This is the issue of time, and also is when we start losing the DEAD station.
  • Radiometer updates (Pat, Andrew)
    • Pat and Andrew spent some time understanding the frequency range over which the radiometer method could work. 10-20 km on the long-end for wavelengths, above that the directional information only comes from polarization and not phase. On the short wavelength end, looking at the topology maps, will do a 2D fourier transform to get a sense of it.
  • Parameter estimation for Rayleigh and Love (Pat)
  • Teleseismic events and Wiener filtering (Daniel, Michael)
  • Gary: Ross has been working on the very-long-periods, comparing the noise levels of our array and another at Pinon Flat (also very quiet array) - ours is about 20x lower than Pinon Flat in the very low frequency band (hour long periods). Ross is working on a paper on this. Could try to make a presentation at the next call.

• Papers
  • Homestake Array Summary paper: pdf and with comments
    • Leads: Vuk, Gary, Victor
    • target: Seism. Research Lett., 6000 words, 10 figures.
    • Vuk: getting very close.
    • Gary: agrees
    • Victor: would like to read it again.
    • Gary will work on the paper today, Victor will continue. Vuk and Victor will meet on July 11 or 12 to finish it off, after which we have to go through the internal LIGO review.
    • Vuk will write to Michael and Jan to let them know about this, so that they can adjust the Wiener filter paper if necessary.
    • Victor: should add a comment about DEAD. Pat will confirm it and send the suggested text around.

• 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
  • Victor will talk to Lee about it. Results exist, have a velocity structure. Might be hard to publish a paper on that only. May need some implication aspect.
  • Gary: should check if Gabe will take the lead on this, may want it for his thesis.
  • Gary: could consider putting some of this into the paper that Ross and Gary are working on. But needs to be discussed.

• 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
  • Victor: this is novel, but it might be insufficient for a publication. Maybe enough for a short paper.
  • Victor/Vuk: should think more about it, how it would look on its own vs combining with radiometer.
  • Pat: could also use the eigenfunction measurement for Rayleigh and assume something about Rayleigh field to make preliminary estimates of the Newtonian noise. Should discuss this with Jan.

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

• Wiener filter application
  • Leads: Jan, Michael

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

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

• Very low frequency harmonics (Ross)