Homestake Meeting Minutes, 11/03/16

Attending: Daniel, Gary, Ross, Pat, Victor, Voon, Vuk, Terry

Agenda:

• Status of the seismic array:
  • No issues to report.
• Planning next Homestake visit, Nov 27 - Dec 5
  • Vuk: Workplan and decommissioning document sent to Jaret, waiting to hear back. Also communicated with PASSCAL about the shipment, forwarded some of the questions to Jaret.
  • Terry: what do we do with the left-over equipment? Vuk: will play it by ear, will have to decide on item-by-item.
  • Some of the batteries etc we may want to keep, other things we can give away.
  • Daniel/Gary: they will direct us where to dispose of things.
  • Pat: waiting to get confirmation from house owners, car rental OK.
  • Vuk: renting a second car.
  • Vuk: should we ask PASSCAL for their inventory? Gary: yes, we should ask for it, they have barcodes etc. Vuk will email Pnina.
  • Vuk: we also have our inventory, we can use the two to track the equipment.
  • Vuk: there is also old (legacy) equipment that we will need to extract and decide what to do.
• Data Analysis Updates
  • Ross: has been building a catalog of 2015 data (along with 10 other stations from the region), found about 450 events in the second half of 2015 (Gary already did the first half). Used software to locate the events, using a cross-corr tool to study them. Some events are small and hard to identify, but trying to measure the phase velocity across the array.
  • Gary: looking for things that could be located with regional data, so missing the very small events in the data. Otherwise there would be thousands of events that could be seen by the Homestake array that are not seen by regional stations. So these 450 events are some large explosions in mines and teleseisms. May have to backtrack and redo the first half of the year.
  • Ross: identified a couple of regionals from Oklahoma.
  • Vuk: How should we make this available?
  • Gary: could be made available easily right away. Making a large catalog to include all of the local events would take a long time and a lot of work.
  • Gary: the catalog could be placed on the wiki, or we could put it in a repository and send the link to everyone.
  • Vuk: we can do both, and keep a cleaned-up version on the wiki.
• Gary: Weight drop analysis: weightdropstatusreportnov3-16.pptx
  • Almost done with this first-order data analysis. Have data only to the nearest second, so made a code that looks at the cross correlations of data from the array to get the better timing. Needs to complete the last line of shots. Computed the timing corrections for each DUGL seismometer, for each shot. With the timing corrected, can now start looking at the wave speed in different directions - lining up traces against each other to get the time-delays for each station. Observe similar structure for some places, and different structure at other places. Probably has to do with surface effects and path effects. Want to make figures like this for AGU. Boise State is looking at the surface data that may give us a model for the top, which could help us understand the deeper data.