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
DAG-GE LHN LHE S 0005 2009.001 2010.016 0.0 90.0 430 18 x x x x x x x 1 x x x x x x x
DAG-GE LHN LHE S 0007 2010.018 2018.365 0.0 90.0 3548 142 x x x x x x x 1 x x x x x x x
SUMG-GE LHN-10 LHE-10 S 0001 2017.142 2018.365 0.0 90.0 657 69 x x x x x x x x 3 x x x x x x
SUMG-GE LHN LHE S 0004 2009.001 2010.199 0.0 90.0 642 12 x x x x x x x -1 x x x x x x x
SUMG-GE LHN LHE S 0006 2010.201 2012.198 0.0 90.0 869 46 x x x x x x -4 x x x x x x x x
SUMG-GE LHN LHE S 0007 2012.200 2013.203 0.0 90.0 429 56 x x x x x x -4 x x x x x x x x
SUMG-GE LHN LHE S 0008 2013.207 2017.136 0.0 90.0 1446 111 x x x x x x x x x x 8 x x x x
SUMG-GE LHN LHE S 0010 2017.142 2018.365 0.0 90.0 615 47 x x x x x x -4 x x x x x x x x