 |
| Titel |
Static corrections for enhanced signal detection at IMS seismic arrays |
| VerfasserIn |
Neil Wilkins, James Wookey, Neil Selby |
| Konferenz |
EGU General Assembly 2016
|
| Medientyp |
Artikel
|
| Sprache |
en
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 18 (2016) |
| Datensatznummer |
250132555
|
| Publikation (Nr.) |
 EGU/EGU2016-13072.pdf |
|
|
|
|
|
| Zusammenfassung |
| Seismic monitoring forms an important part of the International Monitoring System (IMS)
for verifying the Comprehensive nuclear Test Ban Treaty (CTBT). Analysis of
seismic data can be used to discriminate between nuclear explosions and the tens of
thousands of natural earthquakes of similar magnitude that occur every year. This is
known as “forensic seismology”, and techniques include measuring the P-to-S wave
amplitude ratio, the body-to-surface wave magnitude ratio (mb/Ms), and source
depth.
Measurement of these seismic discriminants requires very high signal-to-noise ratio
(SNR) data, and this has led to the development and deployment of seismic arrays as part of
the IMS. Array processing methodologies such as stacking can be used, but optimum SNR
improvement needs an accurate estimate of the arrival time of the particular seismic
phase.
To enhance the imaging capability of IMS arrays, we aim to develop site-specific static
corrections to the arrival time as a function of frequency, slowness and backazimuth. Here,
we present initial results for the IMS TORD array in Niger.
Vespagrams are calculated for various events using the F-statistic to clearly identify
seismic phases and measure their arrival times. Observed arrival times are compared with
those predicted by 1D and 3D velocity models, and residuals are calculated for a range of
backazimuths and slownesses. Finally, we demonstrate the improvement in signal fidelity
provided by these corrections. |
|
|
|
|
|
|