Station details:
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Code: QUA2
Latitude:  42.27889
Longitude:  -72.35250
Elevation:   168.0
Depth: 
Name: Belchertown
Region: Massachusetts,U.S.A.
Status: 

        
Arrival picks statistics
Travel Time Analysis
On the top graph every dot represents the median residual for one month of data. The green line is the overall median; the orange line shows the standard deviation (smad) based on the median absolute deviation (mad), whilst the red line shows twice the standard deviation (2 * smad).
The bottom graph shows the number of residuals for each month. The red columns show the number of residuals whose median (for that month) is outside two standard deviations from the overall median (2 * smad).
Red dots indicate a possible clock error.
Travel time residuals
 

Station comments:
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opened 19960814
BB station

Data at the ISC for 22 years between 1997 and 2018.