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
H2O-H2 LH1-00 LH2-00 S 0011 2000.001 2000.028 78.5 168.5 13 0 x x x x x x x x x x x x x x x
H2O-H2 LH1-00 LH2-00 S 0012 2000.037 2001.156 78.5 168.5 175 2 x x x x x x x x x x 8 x x x x
H2O-H2 LH1-00 LH2-00 S 0014 2001.165 2001.166 78.5 168.5 2 0 x x x x x x x x x x x x x x x
H2O-H2 LH1-00 LH2-00 S 0015 2001.174 2001.189 78.5 168.5 12 0 x x x x x x x x x x x x x x x
H2O-H2 LH1-00 LH2-00 S 0016 2001.203 2001.361 78.5 168.5 47 1 x x x x x x x x x x x 11 x x x