Seismological Research Letters; September/October 2006; v. 77; no. 5;
p. 559-571; DOI: 10.1785/gssrl.77.5.559
© 2006 Seismological Society of America
On the Identification and Documentation of Timing Errors: An Example at the KBS Station, Spitsbergen
Steven J. Gibbons
NORSAR
| The first 20% of the full text of this article appears below.
|
 |
INTRODUCTION
|
|---|
The availability of high-quality digital seismic data has never been better
than it is today. Through consortia such as the Incorporated Research
Institutions for Seismology (IRIS) and Observatories and Research Facilities
for European Seismology (ORFEUS), waveform data from stations of many
worldwide networks are available via the Internet to the international
community of seismologists. When a user examines a segment of data, it is
assumed that the time displayed is the exact time in Coordinated Universal
Time (UTC) at which the motion was recorded. In general, when retrieving data
segments from a waveform repository, there is no independent confirmation of
the validity of the time stamp. In this paper, I discuss a case where a user
discovered an erroneous time stamp on data from a single-site station. A
fortuitous source of repeating seismic signals, together with data from
another nearby station, facilitated measurement of the timing anomaly during
the period in question. Erroneous timing on seismograms might be more
widespread than assumed; the identification and documentation of such cases
requires more attention.
The IRIS/GEOFON/AWI seismic station at King's Bay Station (KBS) is situated
near Ny Ålesund, King's Bay, on the Arctic island of Spitsbergen
(figure 1). The location is
important in the context of nuclear-explosion monitoring due to the relative
proximity of the Russian island of Novaya Zemlya, the site of numerous
Soviet-era nuclear tests, the last known event being on 24 October 1990. Also
on Spitsbergen, a highly sensitive small-aperture seismic array, SPITS, became
operational in 1994 and is now a designated Auxiliary Seismic Array (AS72) of
the International Monitoring System (IMS) of the Comprehensive Nuclear
Test-Ban-Treaty Organization (CTBTO). However, the KBS station is still of
great importance given both the high quality of the continuous seismic data
and the availability of the historical data recorded at . . . [Full Text of this Article]
NORSAR
P.O. Box 53
N-2027 Kjeller,
Norway.
steven@norsar.no
Copyright © 2009 by Seismological Society of America