Station details:
================

Code: HRF
Latitude:  46.59430
Longitude: -112.04400
Elevation:  1256.0
Depth: 
Name: Holter Research Foundation--Helena
Region: Montana,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.
 

Station comments:
=================

Holter Research Foundation - Helena
closed 198308
reopened and moved slightly 198408

Data at the ISC for 4 years between 1980 and 2020.