This is an old revision of the document!

Homestake Meeting Minutes, 01/18/18

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

Agenda:

• Next Meeting: Feb 16?
• Data analysis topics
  • Data corrections, frame production (Gary/Daniel/Pat)
  • Event catalog (Gary/Ross)
  • Radiometer updates (Pat, Andrew) radiometer_update_2.pdf
    • Ran radiometer and simple phase beam-forming on 1.4 Hz transient feature. Observed the two methods to agree well. Expect it to be human-generated, seems to be aligned with local mining work, direction of Terry Peak.
    • At 1.5 Hz expect the wavelength ~3km, should see them underground as well, but we don't seem to. Is it possible that eigenfunctions are such that the amplitude is significantly lower?
    • Ross: Could compare the blast events from this mine, and compare the waveforms on the surface and deep underground.
    • Gary: good idea.
    • Daniel: velocity of 2.8 km/s, implies this is surface wave…
    • Vuk: could also look at distant stations to check locality of the effect.
    • Gary: could follow up with Jaret.
    • Pat: will try to add deep stations.
  • 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.

• Active excitation overview paper
  • Leads: Gary, Ross
  • Others: Victor, Daniel,…
  • Draft of the paper exists, as a report for IRIS. Gary will be adopting it to a publication. Don't have a particular date in mind.

• 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: wiener_v4.pdf.
    • Addressing comments from previous meetings, added an appendix including 0.1 Hz (which does not show bi-modality) and 0.4 Hz (which is more complex) - both as expected. Modified the coherence-vs-amplitude plot, including both Homestake and Sweetwater arrays.
  • Daniel's slides: 2018-01-18_bowden.pdf.
• Teleseismic EQs and near-surface scattering
  • Leads: Daniel, Victor

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

• Very low frequency harmonics (Ross)