Station details:
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Code: GRA1
Latitude:  49.69190
Longitude:   11.22170
Elevation:   500.0
Depth: 
Name: Grafenberg Array
Region: Bayern,Germany
Status: 

        
GRA1 is an alternative code for GRF

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
Amplitude analysis
 On the top graph every dot represents the median value for that 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 (if present) shows twice the standard deviation (2 * smad).
The bottom graph shows the number of observations for each month. Any red columns show those observations whose monthly median value is greater than twice the standard deviation (2 * smad) from the overall (running) median (shown in the top graph by red dots).

Red dots indicate a possible calibration error.
 

Station comments:
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opened 197603

Data at the ISC for 34 years between 1984 and 2025.