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Discrepancy in magnitude from database search

June 14, 2004

We have discovered an inconsistency between the magnitudes reported in the new database search of the UC Berkeley earthquake catalogs ( http://www.ncedc.org/db/Search/PI/dbselect.html) and the older, flat file search ( http://www.ncedc.org/ncedc/catalog-search.html). The inconsistency arose during the conversion of the catalog from an older PC-based database. The magnitudes currently reported in the database search were computed using a older set of station adjustments and thus differ from the magnitudes reported in the flat file search.

We are currently looking into the best way to resolve this inconsistency. For the present, we advise users for whom magnitude is a critical parameter to use the flat file search.

The NCEDC is a joint project of the University of California, Berkeley and the USGS. Please send us email at ncedcinfo@ncedc.org or fill out our comments form if you have questions or comments about these changes.