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| Titel |
Usability of Seismic Noise Cross-Correlations for Local-Scale Networks |
| VerfasserIn |
T. Megies, H. Igel, J. Wassermann |
| Konferenz |
EGU General Assembly 2010
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 12 (2010) |
| Datensatznummer |
250035503
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| Zusammenfassung |
| The cross-correlation technique to reconstruct Green’s functions from ambient seismic noise
is tested for its usability with short-period data of the local-scale network at Mt. Hochstaufen,
SE Germany. Processing schemes mainly developed for low-frequency data are adapted to the
short-period data.
The reconstructed Green’s functions are stacked on different time scales and the usability
for different applications is tested:
Daily Green’s function stacks are used for quality control in order to detect and correct
for errors in the time-stamping of the recorded data. These errors include drifting digitizer
clocks due to loss of GPS reception (up to 10-1Â seconds per day) as well as sudden
one-second offsets in GPS timing. Monthly stacks are used for interferometric analysis in
order to assess small relative variations of the seismic wave velocity of about ± 0.7Â %.
Observed precipitation rates and earthquake swarm activity are found to correlate well with
the estimated velocity variations.
Finally, stacking all available data for every pair of stations, preliminary observations on
the usability for local surface wave tomography are made. The results indicate that the modal
content of the high-frequency anthropogenic part of the noise field is more complex than with
the low-frequency natural part, and the supposedly strongly fractured and karstified source
region of the earthquake swarms affects the propagation of coherent surface wave trains at
certain frequencies. |
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