Polarization anomalies at various stations


The table below shows the results from polarization analysis of long-period surface waves using the method described by Ekstrom and Busby (SRL, 2008). The horizontal components have been rotated to maximize the correlation between the observed and predicted seismograms for moderate and large earthquakes. The table shows the median (aqua blue) of the rotation angle (the anomaly), as well as the range (navy blue) for the second and third quartiles of the distribution of angles.

The table below gives the channel names and station orientation for the horizontal components, the wave type (Surface-wave or Mantle-wave), a response epoch identifier, the times of the first and last observations used, the total number of observations, and the number of polarization measurements used in the estimate of the sensor orientation. Estimates based on fewer than 5 measurements are less reliable. The orientation anomaly is measured against the reported orientation (Az-1, Az-2). A positive value for the anomaly reflects a counter-clockwise rotation of the sensor compared to the reported value.

Ranked by polarization anomaly

Ascii file with the data

Arrival-angle anomalies
Station Channels T Epoch min time max time Az-1 Az-2 # obs. # used -90- -26 -25- -21 -20- -16 -15- -11 -10- -8 -7- -5 -4- -2 -1- 1 2- 4 5- 7 8- 10 11- 15 16- 20 21- 25 26- 90
PFO-II LH1-00 LH2-00 M 0001 2010.116 2010.199 0.0 88.5 10 1 x x x x x x -2 x x x x x x x x
PFO-II LH1-00 LH2-00 M 0003 2010.272 2012.149 0.0 88.5 88 11 x x x x x x x 1 x x x x x x x
PFO-II LH1-00 LH2-00 M 0004 2012.208 2012.208 0.0 88.5 1 0 x x x x x x x x x x x x x x x
PFO-II LH1-00 LH2-00 M 0005 2012.210 2012.227 0.0 88.5 3 0 x x x x x x x x x x x x x x x
PFO-II LH1-00 LH2-00 M 0006 2012.239 2013.298 358.0 88.5 64 4 x x x x x x -2 x x x x x x x x
PFO-II LH1-00 LH2-00 M 0007 2013.316 2014.133 358.0 88.5 32 7 x x x x x -5 x x x x x x x x x
PFO-II LH1-00 LH2-00 M 0008 2014.144 2015.267 358.0 88.5 62 7 x x x x x x -3 x x x x x x x x
PFO-II LH1-00 LH2-00 M 0009 2015.293 2015.351 359.9 88.5 17 2 x x x x x x x x x 5 x x x x x
PFO-II LH1-10 LH2-10 M 0001 2010.116 2010.199 358.3 88.5 14 1 x x x x x x x -1 x x x x x x x
PFO-II LH1-10 LH2-10 M 0002 2010.204 2013.298 358.3 88.5 168 34 x x x x x x x -1 x x x x x x x
PFO-II LH1-10 LH2-10 M 0003 2013.316 2015.351 358.3 88.5 111 20 x x x x x x x -1 x x x x x x x
PFO-II LHN-00 LHE-00 M 0014 2008.252 2008.255 0.0 90.0 4 0 x x x x x x x x x x x x x x x
PFO-II LHN-00 LHE-00 M 0015 2008.273 2009.049 0.0 90.0 15 9 x x x x x x -2 x x x x x x x x
PFO-II LHN-00 LHE-00 M 0016 2009.065 2009.174 0.0 90.0 8 3 x x x x x x -4 x x x x x x x x
PFO-II LHN-00 LHE-00 M 0017 2009.196 2010.103 0.0 90.0 49 11 x x x x x x x x 4 x x x x x x
PFO-II LHN-10 LHE-10 M 0006 2008.252 2008.321 0.0 90.0 9 1 x x x x x x -4 x x x x x x x x
PFO-II LHN-10 LHE-10 M 0007 2008.329 2010.103 0.0 90.0 67 15 x x x x x x x 0 x x x x x x x