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groups:homestake:meetings:20171208 [2017/12/07 16:32] – created mandicgroups:homestake:meetings:20171208 [2017/12/08 13:19] (current) mandic
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 Homestake Meeting Minutes, 12/08/17 Homestake Meeting Minutes, 12/08/17
  
-Attending: +Attending: Andrew, Jan, Pat, Ross, Vuk, Daniel, Michael, Gary
  
 Agenda: Agenda:
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       * Others: Victor, Daniel,…       * 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.       * 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.
 +      * Vuk: Gary reports via email that he expects to be working on this paper over the holiday break.
  
     * Surface Active Excitation     * Surface Active Excitation
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     * Wiener filter application     * Wiener filter application
       * Leads: Jan, Michael           * Leads: Jan, Michael    
-      * Vuk: +      * Latest version: {{:groups:homestake:meetings:wiener.pdf|}}. Needs minor modifications of figure 6, and still need to rewrite conclusions. 
 +      * Vuk: Why can't you measure seismic speed below 1.2 Hz. 
 +      * Jan: Not clear, the method should work, it looks like there is a lot of variability around 1Hz, potentially different wave modes. 
 +      * New point in the paper: evidence of the presence of body waves at 0.2 Hz, based on the speed measurement. Body waves seem to dominate on some days. In fact, it seems there is a continuous body wave background and on some weeks a stronger Rayleigh background overcomes it. Important for GW detectors. 
 +      * Vuk: suggest to emphasize this to Victor and Gary via email, their response could help place this result in existing geo literature. ALso suggest to plot Fig 6 as a scatter plot, which should appear as -45 degree line. 
 +      * Daniel: where would body waves come from? 
 +      * Jan: not sure. 
 +      * Jan: also have very good Wiener subtraction. Should we try a more visible journal, like Nature geophysics? 
 +      * Vuk: worth considering, depends on what is known about body vs Rayleigh background. Also, it seems we don't need the depth aspect of this array is not needed for Fig 6.  
 +      * Jan: correct, could try another array like Sweatwater. 
 +      * Vuk: Could we use an estimate of Rayleigh wave speed from elsewhere? And plot lambda/4 on the Figure 5. 
 +      * Ross/Pat: could try to estimate the speed from mining blast data. Pat working on this now, Ross did a study in the past. 
 +      * Jan: Could use shear wave speed, which was measured, and convert based on some assumption on the poisson ratio. This could be a value for now, that could be updated later from other analyses. 
 +      * Gary: could use the mine blasts. Have very solid data on shear wave speed from the active excitation at 2000. But this is on the scale 10-100m, but don't know it at a larger scale, but wouldn't expect it to very much. You can also get uncertainty on these velocity measurements.  
 +      * Jan will send an email summarizing these results. We should discuss how to proceed via email, if necessary we'll schedule another call before the winter break...
  
     * Teleseismic EQs and near-surface scattering     * Teleseismic EQs and near-surface scattering
groups/homestake/meetings/20171208.1512685970.txt.gz · Last modified: 2017/12/07 16:32 by mandic