With the microseism being elevated over the weekend--looked at the floor seismo wrt the HEPI L4Cs.  We'd really like to help with microseism noise but it is a tough problem.  However, something just doesn't seem right.

Looked at coherence between the floor sts2 and BS HEPI X Y Z Blend inputs.  Strong coherence with Z but X & Y pretty poor.  Looking at the locally oriented sensors and whoa, strong coherence with the diagonally oriented HEPI L4Cs split between the X & Y...  See attached.

The upper left panel has the coherence with the cartesian basis blend inputs.  Strong in Z but oor in X & Y.  The lower left panel  has the local basis horizontals with the X ground signal: Strong in H1 and H3, the sensors oriented NE to SW (building crane basis.)  The H2 & H4 sensors, oriented Nw to SE show little to no coherence.  The upper right panel looks at the horizontal local sensors wrt the Y ground motion and the result is the opposite: strong signal with the H2 & H4 L4C but little to none in the H1 & H3 signals.  The lower right shows the strong coherence in all the Z local L4C signals with the Z signal from the floor seismometer.

Since the Z signal has good coherence, I don't think there is any problem with the model path, maybe?

Since the Local to Cartesian transformation has equal magnitudes (the local sensors are oriented at 45 degrees to the LIGO referencef frame, I don't believe the matrices are to blame. These values are correct based on T1000388.

This leads me to conclude the the ground STS2 must be oriented incorrecty or its internal U V W transformation to X Y Z is messed up.  This will certainly cause issues with sensor correction etc.