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
BJI-CD LHN LHE S 0001 1986.206 1993.155 358.0 88.0 801 159 x x x x x -5 x x x x x x x x x
BJI-CD LHN LHE S 0003 1993.163 1994.103 178.0 268.0 104 24 x x x x x -5 x x x x x x x x x
ENH-CD LHN LHE S 0001 1989.176 1997.232 0.0 90.0 467 140 x x x x x x x x 2 x x x x x x
HIA-CD LHN LHE S 0001 1987.065 1994.324 357.0 87.0 907 229 x x x x x x -2 x x x x x x x x
KMI-CD LHN LHE S 0001 1986.235 1996.107 0.0 90.0 1060 270 x x x x x x -4 x x x x x x x x
LSA-CD LHN LHE S 0001 1992.002 1994.364 0.0 90.0 396 53 x x x x x x x x x 6 x x x x x
LZH-CD LHN LHE S 0001 1986.293 1987.289 180.0 270.0 146 28 x x x x x x x -1 x x x x x x x
LZH-CD LHN LHE S 0002 1987.298 1999.345 0.0 90.0 1272 212 x x x x x x -4 x x x x x x x x
MDJ-CD LHN LHE S 0001 1986.341 1988.051 0.0 90.0 22 3 x x x x -9 x x x x x x x x x x
MDJ-CD LHN LHE S 0003 1989.101 1989.291 0.0 90.0 59 18 x x x x x x -2 x x x x x x x x
MDJ-CD LHN LHE S 0005 1991.158 1996.309 0.0 90.0 543 117 x x x x x x x 0 x x x x x x x
QIZ-CD LHN LHE S 0001 1992.139 1999.363 0.0 90.0 733 192 x x x x x x x -1 x x x x x x x
SSE-CD LHN LHE S 0001 1986.179 1996.255 353.0 82.0 452 91 x x x x x x -2 x x x x x x x x
WMQ-CD LHN LHE S 0001 1986.295 1994.364 0.0 90.0 954 216 x x x x x x x -1 x x x x x x x