The data centers apply corrections to incorrectly timed data at the time of publication. Individual users apply corrections to data already distributed. The SEED data format, as it exists now, is only capable of cataloging a single, summary, timing correction. Thus, SEED cannot contain the timing correction discussed here while still maintaining the historical record of any other type of applied timing correction. Generalized solutions have been proposed ranging from external tables to changing SEED itself.
Discussions are ongoing.
However, the existing SEED structure does allow in Field 16 of the Fixed Section of Data Header for a single time correction. As this field has not been previously utilized for the ASL data, we plan to publish corrected data as soon as complicated forward and backwards compatibility issues of data distribution have been solved. We will issue a general notification when we have derived satisfactory solutions to these issues. Multishear software also provides an unambiguous bit flag set within each data packet to indicate that the timing correction is in place. Multishear should be phased into all GSN stations maintained by the ASL over the next two years.