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groups:homestake:meetings:20140123

Meeting Minutes, 01/23/2014

Attending: Tanner, Eric, Riccardo, Gwynne, Nelson, Victor, Michael, Vuk

Homestake wiki: https://zzz.physics.umn.edu/groups/homestake/home

Our agenda:

1) Homestake update

Vuk: no news yet, trying to connect with Bryce. Will try to keep everyone informed via email.

2) UMN test setup

Tanner: continuing to set up the prototype at UMN, connected the digitizer, the bailer, and a computer to a local network switch. Can control them, see the data from the seismometer etc. At the moment don't have the GPS hooked up, since the lab is in the basement. Will move to a different lab with a window, with the hope that we can get the GPS signal and get the whole system to work.

3) Analysis of existing data

```  a) Frames/miniSEED files (Shivaraj, Tanner, Michael)
b) Wiener filtering (Michael, Jan)
Michael: no news.

c) Estimation algorithms (Shivaraj, Eric)
Eric: posted slides:
https://zzz.physics.umn.edu/_media/groups/homestake/meetings/homestake_orfs_eric20140123.pdf

Eric: Going back to the beginning and trying to rebuild the radiometer algorithm to
understand it better now, and to make things easier in the future. Studying the overlap
reduction between seismometers, following the formalism from the gravitational-wave field.
Assume isotropic distribution of eg P-waves only or S-waves only, two detectors some distance
apart, look at different detector orientations. Normalization of the overlap reduction function
such that at low frequency it shows the fraction of the power detected, so it approaches 1/3
(due to 3D nature of the siimulated field).
Victor: similar studies have been done in the past, showing that lower frequencies are
correlated over longer distances. There is also a difference between surface and body waves.
Eric: Next, will develop the code to simulate different seismic noise fields, stochastic
rather than sinusoidal. Should allow adding different modes in the future, with different
directionality and different frequency content.
Victor: should also worry about heterogeneity.
Vuk: definitely should include it, although it may be more important and high than at low frequencies.
Eric: will also redo the map-computation code, including the spherical harmonic decomposition
code copied from the GW field.

```