 |
| Titel |
Improving Seismic Monitoring in Northern Switzerland |
| VerfasserIn |
Katrin Plenkers, Stephan Husen, Michael Schnellmann |
| Konferenz |
EGU General Assembly 2013
|
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 15 (2013) |
| Datensatznummer |
250075157
|
|
|
|
|
|
| Zusammenfassung |
| We currently densify the existing Swiss Digital Seismic Network in northern Switzerland by
additional 10 stations. The new network aims at observing seismicity in northern Switzerland
with a completeness of Mc = 1.0 and a location error < 0.5 km in epicenter and < 2 km in
focal depth.
Monitoring of weak seismic events in this region is challenging, because the area of
interest is densely populated and geology is dominated by the Swiss molasse basin. A optimal
network-design and a thoughtful choice for station-sites is, therefore, mandatory. To help
with decision making we developed a multi-step assessment-scheme that takes into
account local noise level, geology, infrastructure, and costs necessary to realize the
station.
The assessment scheme is weighting the different parameters and the most
promising sites are identified. In a first step, all potential sites are classified based on
information from topographic maps and site inspection. In a second step, local noise
conditions are measured at selected sites. Finally, the most promising sites are classified
taking into account results from the test measurements and updated information
on local geology, availability of electricity and data transmission, and installation
costs.
The first station went into operation in September 2012. In this study, we present lessons
learnt during the network realization. We review the proposed assessment-scheme and
demonstrate potentials and limitations for seismic monitoring in such an environment.
We find that the step-wise search for the optimum installation site was successful. Test
measurements conducted and analyzed for the assessment-scheme are representative for the
performance of the later installed stations. In one case a significantly improved
installation was possible, because the test measurement revealed noise sources that
could be diminished. The assessment scheme allowed to compare station from
different regions, which was especially helpful in judging, whether the site condition in
sufficient.
In areas of high ambient noise, seismometers were installed in boreholes at about 120 m
depth. We present a comparison of ambient noise measurements at the surface and in the
borehole to demonstrate the gain in signal-to-noise ratio in the frequency range 1 Hz to 40
Hz. |
|
|
|
|
|
|