Seismic Data Management at the Canadian National Data Centre

Jim Lyons

Geological Survey of Canada

Outline

Evolution of the National Seismic Network

POLARIS (cooperating network)

CNDC processing

Waveform archive

Data dissemination

Ongoing challenges

Evolution of the CNSN - 1

1st Digital Data: regional seismograph networks:

operated Eastern Canada Telemetred Network (ECTN) and WCTN (in southwest BC), from 1975 1995

only “event files” comprising triggered stations with fixed pre- and post-trigger header/trailer were kept for computer-based analysis & archive

archived on 12" SONY WORM optical disks

data stored as 10-minute Full SEED volumes

Evolution of the CNSN - 2

1st archive of continuous data:

Yellowknife Array Upgrade 1988-9

CNSN Upgrade

Rollout started in 1992, based on new in-house digitizer (GD-1)

CNSN packet structure, data compression scheme and serial transmission protocol

Evolution of the CNSN - 3

CNSN Upgrade we reverted from SEED to a simple file format

“Canadian Archive” (CA) ½ hour network volumes based on a contiguous array of CNSN data packets with short header

• maintains full original data integrity including checksum, SOH and error/status codes

• excellent compression (subsequently adopted by CTBTO for data payload in CD-1.x format)

Evolution of the CNSN - 4

YKA revisited

started converting YKA data packets to CNSN packets in Yellowknife and transmitting as a real time stream to Ottawa for processing alongside CNSN data

allowed consolidation of CNSN & YKA onto common acquisition/archive systems

Evolution of the CNSN - 5

CNSN station map - 2005

POLARIS Network - 1

Portable Observatories for Lithospheric Analysis and Research

Investigating Seismicity

“a Canadian geophysical research consortium focused on investigation of the structure and dynamics of the Earth's lithosphere and the prediction of earthquake ground motion”

POLARIS Network - 2

initially to comprise 90 BB seismographs in 3 sub-arrays, using NMX digitizers and Libra VSAT satellite telemetry

subsequently augmented to ~105 HBB Libra sets with 3 VSAT earthstation downlinks

deployments to last 4-5 years

includes co-located MT systems; GPS to come

POLARIS Network - 3

GSC Role:

acquire, archive and disseminate waveform data

• we reformat real-time data streams on-the fly to pseudo-CNSN packets and process/archive alongside CNSN data (daily volume now exceeds CNSN)

• host POLARIS website ( www.polarisnet.ca )

• house and operate two NMX VSAT hubs

Canadian Seismograph Stations

CNDCProcessing Overview

Waveform Archive - 1

robotic DLT-tape library system installed in 1999

allowed us to put all waveform holdings (near) on-line

reformatted all earlier data formats to CA

developed standard tools to handle and reformat (SEED, CD-1, GSE-2.0, IMS-1.0, Mk2, Integer)

Waveform Archive - 2

moved to 12 TB all-disc system in April 2005

now all-online (no tape access delays)

CD Archive Holdings

1 TB = 10244 bytes

Data Dissemination - 1

Continuous data:

as CTBT NDC, forward IMS Primary SHI data to Vienna IDC in CD-1 format (currently ~194 MB/day)

share real-time data with USGS/NEIC (10), PTWC/ATWC (9), Montana Bureau of Mines (MB - 2) and UWashington (6) via orb2ew (Internet)

10 FDSN stations to IRIS-DMC (daily ftp)

Data Dissemination - 2

Request data:

AutoDRM has run continuously since May 1994

NetDC since 2004

Event archive

developed Web interfaces to ease usage

Data Dissemination - 3

CNDC AutoDRM Data Shipments Number of requests processed Volume in GB (1GB = 10243 B)

Event Selection

Ongoing challenges

serving non-specialist clients

archive and dissemination of non-seismic data (Infrasound, MT and GPS data)*

tracking network metadata over time*

automated quality control and display*

Global Infrasound

Archive(G I N A)

stored in CSS-3.0 wf format

convert to SEED, MSEED, SAC, & Integer on demand

Magneto-telluric Data

Tracking Network Metadata

tracking the complete history of Canadian and foreign stations of interest wrt: agency, affiliation(s), network/deployment(s), location, timing, instrumentation, and response over time has required rethinking our db schema

adopted some features of CSS-3.0 db schema

now reviewing and implementing some Antelope extensions to CSS (e.g., stage table)

CNSN Station Book - 1

CNSN Station Book - 2

CNSN Station Book - 3

Automatic Quality Control

need to track various measures of data quality including availability (completeness), timeliness (latency), stn timing, signal degradation (waveform quality), and metadata quality (e.g., degree to which response is known and trusted)

how to automate and display for potential data users?

RUDY

Bitter cold and wind affecting power (TEG) at YKW4

Station Quality Plot

Conclusion

While the seismological community is reasonably well served, a number of challenges remain:

making data useful to a broader range of people

managing an increasingly heterogeneous data set

automating and displaying data quality

Hopefully we can both contribute to and gain by the GEOSS initiatives.

The End