BDSN/NHFN/MPBO Seismic Data

The archival of current BDSN (Chapter 3), NHFN (Chapter 5), and Mini-PBO (Chapter 8) (all stations using the network code BK) seismic data is an ongoing task. These data are telemetered from more than 42 seismic data loggers in real-time to the BSL, where they are written to disk files. Each day, an extraction process creates a daily archive by retrieving all continuous and event-triggered data for the previous day. The daily archive is run through quality control procedures to correct any timing errors, triggered data is reselected based on the REDI, NCSN, and BSL earthquake catalogs, and the resulting daily collection of data is archived at the NCEDC.

All data acquired from the BDSN/NHFN/MPBO Quanterra data loggers are archived at the NCEDC. The NCEDC has made an effort to archive older digital data, and the 16-bit BDSN digital broadband data from 1987-1991 have been converted to MiniSEED and are now online. In late June 2002, the NCEDC initiated a project to convert the remaining 16-bit BDSN data (MHC, SAO, and PKD1) from late 1991 through mid-1992 to MiniSEED. An undergraduate student was hired to read the old tapes and to work on the conversion. All remaining 20 Hz 16 bit BDSN data has been converted to MiniSEED, and we are working on the decimation procedures to create the 1 Hz data channels. Data acquired by portable 24-bit RefTek recorders before the installation of Quanterra data loggers at NHFN sites has not yet been converted to MiniSEED and archived. Figure 11.3 illustrates the data completeness level of the core BDSN stations.

In September 2004, we began to archive continuous high frequency data (80 Hz and 100 Hz) from all of the BDSN broadband, strong motion, and strainmeter sensors.

Figure 11.3: Chart showing the availability of BDSN/NHFN/MPBO (BK networkc) data at the NCEDC for the 1 Hz and 20 or 40 Hz channels from 01/01/1996 - 09/01/2005. The data availability from these networks is better than 95% at nearly all stations. Notable exceptions are ELFS and HELL (BDSN/USArray sites with problematic satellite telemetry), MNRC (operated for the first year with only dialup telemetry before the installation of continuous telemetry), YBIB (lost AC power before decomissioning the site), and W02B (experienced significant radio problems). In general, a difference between the 1 and 20 or 40 Hz data is indicative of one or more significant telemetry problems. Following a major telemetry outage, BSL staff will recover 1 Hz continuous data but only event data for the higher rate data channels.
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