In many cases, the log files had to be edited by hand to report correct event pairs in order to make the correct time change to the header. All of the log files have names of the form I.** where ** is the DAS number of the Reftek at the sites. Specific lines in the log files containing `phase error' or `DSP clock set' event reports should have contained all essential timing correction information. Normally, the corrections contain a seconds and a milliseconds portion of time offset. However, for almost all of our cases, the milliseconds portion was not recorded in the log file. Moreover, if the offset was positive, a whole second was erroneously added. These errors were corrected by manually editing the log files so that they reported the correct phase error. The corrected phase errors were then used by refrate and clockcor to correct the start time in the event headers, as before. The modified and original log files have been stored together with the data set.
There still remain some problems with the absolute timing in the seismograms which have not been modified but should be easy to observe in the data. The one-second (leap second) and 10-second (time pulse) errors were not removed during the data processing from the stations with Omega timing receivers. See Table 1 for the stations where these timing errors can be expected.
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