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BDSN HH & HL data now continuous

September 25, 2004

As of September 25, the NCEDC is archiving continuous data from the BDSN HH and HL channels. In the past, we had archived waveform snippets or triggers for events for the HH and HL channels, while archiving BH and lower data rates continuously (with a few exceptions such as after large earthquakes such as the Denali and San Simeon events).

With this change in policy, the NCEDC will archive all data transmitted to the BSL. In general, we will not make efforts to fill in missing data from the HH and HL channels, unless the gaps occur in a record of interest. Our usual efforts to provide continuous data for the other channels will be the same.

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