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 S 0001 2010.111 2010.199 0.0 88.5 38 8 x x x x x x -3 x x x x x x x x
PFO-II LH1-00 LH2-00 S 0002 2010.200 2010.202 0.0 88.5 5 1 x x x x x x x x 4 x x x x x x
PFO-II LH1-00 LH2-00 S 0003 2010.259 2012.181 0.0 88.5 590 65 x x x x x x x 0 x x x x x x x
PFO-II LH1-00 LH2-00 S 0004 2012.185 2012.208 0.0 88.5 19 1 x x x x x x x x x x x 13 x x x
PFO-II LH1-00 LH2-00 S 0005 2012.210 2012.232 0.0 88.5 20 3 x x x x -8 x x x x x x x x x x
PFO-II LH1-00 LH2-00 S 0006 2012.237 2013.303 358.0 88.5 339 53 x x x x x x -4 x x x x x x x x
PFO-II LH1-00 LH2-00 S 0007 2013.311 2014.138 358.0 88.5 158 21 x x x x x x x 0 x x x x x x x
PFO-II LH1-00 LH2-00 S 0008 2014.139 2015.278 358.0 88.5 344 64 x x x x x x x 0 x x x x x x x
PFO-II LH1-00 LH2-00 S 0009 2015.284 2015.365 359.9 88.5 65 9 x x x x x x -3 x x x x x x x x
PFO-II LH1-10 LH2-10 S 0001 2010.111 2010.202 358.3 88.5 70 9 x x x x x -5 x x x x x x x x x
PFO-II LH1-10 LH2-10 S 0002 2010.206 2013.303 358.3 88.5 1005 216 x x x x x x -2 x x x x x x x x
PFO-II LH1-10 LH2-10 S 0003 2013.311 2015.365 358.3 88.5 568 129 x x x x x x x -1 x x x x x x x
PFO-II LHN-00 LHE-00 S 0014 2008.169 2008.262 0.0 90.0 28 2 x x x x x x -3 x x x x x x x x
PFO-II LHN-00 LHE-00 S 0015 2008.268 2009.049 0.0 90.0 139 24 x x x x x x x 1 x x x x x x x
PFO-II LHN-00 LHE-00 S 0016 2009.053 2009.179 0.0 90.0 74 9 x x x x x x x 0 x x x x x x x
PFO-II LHN-00 LHE-00 S 0017 2009.182 2010.107 0.0 90.0 282 55 x x x x x x x x 3 x x x x x x
PFO-II LHN-10 LHE-10 S 0006 2008.169 2008.324 0.0 90.0 81 14 x x x x x x x 1 x x x x x x x
PFO-II LHN-10 LHE-10 S 0007 2008.326 2010.107 0.0 90.0 442 64 x x x x x x x x 2 x x x x x x