LDEO Seismology: USArray Polarization

Polarization anomalies on USArray stations

The tables below shows the summary results from a polarization analysis of long-period surface waves recorded on USArray and other broadband stations.

**Statistics of sensor-rotation angles (by station-response epoch)**
Network	# Obs.	0-3 degrees	4-6 degrees	7-9 degrees	10-90 degrees
TA	1054	93.6%	5.5%	0.9%	0.0%
US	75	58.7%	22.7%	8.0%	10.7%
IU	26	96.2%	0.0%	3.8%	0.0%
CI	79	59.5%	16.5	11.4%	12.7%
BK	22	86.4%	9.1%	4.5%	0.0%

Outliers (by station-response epoch)

The figure shows the stations for which the median polarization anomaly is greater than 6 degrees.

Statistics of sensor-rotation angles (by station)
Network # Obs. 0-3 degrees 4-6 degrees 7-9 degrees 10-90 degrees

TA 845 95.6% 4.1% 0.2% 0.0%

US 66 57.6% 21.2% 9.1% 12.1%

IU 24 95.8% 0.0% 4.2% 0.0%

CI 41 51.2% 29.3% 7.3% 12.2%

BK 19 94.7% 5.3% 0.0% 0.0%

**Statistics of sensor-rotation angles (by station)**
Network	# Obs.	0-3 degrees	4-6 degrees	7-9 degrees	10-90 degrees
TA	845	95.6%	4.1%	0.2%	0.0%
US	66	57.6%	21.2%	9.1%	12.1%
IU	24	95.8%	0.0%	4.2%	0.0%
CI	41	51.2%	29.3%	7.3%	12.2%
BK	19	94.7%	5.3%	0.0%	0.0%

Outliers (by station)

The figure shows the stations for which the median polarization anomaly is greater than 6 degrees.