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.

Alphabetical listing

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-AZ LHN LHE S 0010 2011.321 2013.273 0.0 90.0 535 16 x x x x x -5 x x x x x x x x x
PFO-AZ LHN LHE S 0012 2014.319 2015.365 0.0 90.0 318 11 x x x x x -5 x x x x x x x x x
PFO-AZ LHN LHE S 0008 2006.002 2010.285 0.0 90.0 1513 43 x x x x x x -3 x x x x x x x x
PFO-AZ LHN LHE S 0009 2011.133 2011.319 0.0 90.0 175 7 x x x x x x -3 x x x x x x x x
PFO-AZ LHN LHE S 0011 2013.274 2014.317 0.0 90.0 319 22 x x x x x x x 0 x x x x x x x
MONP2-AZ LHN LHE S 0001 2007.297 2011.210 0.0 90.0 1229 193 x x x x x x x 0 x x x x x x x
MONP2-AZ LHN LHE S 0002 2011.211 2015.365 0.0 90.0 1281 208 x x x x x x x 1 x x x x x x x
MONP-AZ LHN LHE S 0006 2006.002 2007.043 0.0 90.0 325 14 x x x x x x x x 2 x x x x x x
MONP-AZ LHN LHE S 0007 2007.045 2007.296 0.0 90.0 243 5 x x x x x x x x 3 x x x x x x