Site Map/Alternate Navigation Skip to Main Content

NCEDC archives continuous HRSN data following the 2003/12/22 San Simeon earthquake

February 27, 2004

The NCEDC is archiving continuous high frequency data from the HRSN borehole network due to increased seismic activity following the magnitude 6.5 San Simeon Earthquake of December 22, 2003.

The NCEDC normally archives continuous 20 Hz data channnels (BPx) as well as triggered 250 Hz high-rate (DPx) data channels from the HRSN (BP network) borehole network in Parkfield. However, in response to a significant increase in earthquake detections by the HRSN network related to the San Simeon earthquake, the NCEDC is archiving continuous data from all data channels for the entire HRSN network starting on day 2003.355, the day before the earthquake, until seismic detections from the HRSN network drop to a reasonable level.

During time of normal seismic activity, continuous 20 Hz data and triggered 250 Hz data is transmitted in near-real time from the HRSN network operations center in Parkfield to the UC Berkeley Seismological Laboratory and the NCEDC. However the HRSN network has triggered ~ 50,000 times in the 68 days since between 2003.356 and 2004.059. Due to the increased seismic activity, we are writing the continuous HRSN data on tapes in Parkfield, and archiving the data from the tapes. Tape processing has introduced a delay of a month or more in the data archiving system as compared to the 1-3 day delay in archiving telemetered data.

Due to intermittent power problems with the solar powered stations and repeater site between the the HRSN stations and the central data collection site in Parkfield, there may be gaps in the continuous data from some sites.

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.