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 M 0001 1986.296 1993.144 358.0 88.0 247 24 x x x x x -7 x x x x x x x x x
BJI-CD LHN LHE M 0003 1993.169 1994.090 178.0 268.0 33 5 x x x x x -7 x x x x x x x x x
ENH-CD LHN LHE M 0001 1992.146 1997.220 0.0 90.0 150 39 x x x x x x x 0 x x x x x x x
HIA-CD LHN LHE M 0001 1987.065 1994.319 357.0 87.0 279 111 x x x x x x -3 x x x x x x x x
KMI-CD LHN LHE M 0001 1987.003 1996.107 0.0 90.0 324 100 x x x x x x x -1 x x x x x x x
LSA-CD LHN LHE M 0001 1992.020 1994.362 0.0 90.0 123 17 x x x x x x x x x x 8 x x x x
LZH-CD LHN LHE M 0001 1986.293 1987.289 180.0 270.0 44 2 x x x x x x -4 x x x x x x x x
LZH-CD LHN LHE M 0002 1987.298 1999.345 0.0 90.0 402 60 x x x x x x -4 x x x x x x x x
MDJ-CD LHN LHE M 0001 1987.115 1988.037 0.0 90.0 6 3 x x x x x x x x x x x 11 x x x
MDJ-CD LHN LHE M 0003 1989.101 1989.291 0.0 90.0 12 7 x x x x x x x x x 5 x x x x x
MDJ-CD LHN LHE M 0005 1991.158 1996.293 0.0 90.0 175 42 x x x x x x x -1 x x x x x x x
QIZ-CD LHN LHE M 0001 1992.146 1999.363 0.0 90.0 234 67 x x x x x x x -1 x x x x x x x
SSE-CD LHN LHE M 0001 1986.179 1996.218 353.0 82.0 144 15 x x x x x x x x 3 x x x x x x
WMQ-CD LHN LHE M 0001 1986.296 1994.362 0.0 90.0 295 104 x x x x x x x -1 x x x x x x x