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Bernardi et al., 2005

Bernardi F., Braunmiller J., Giardini D., 2005. Seismic Moment from Regional Surface-Wave Amplitudes: Applications to Digital and Analog Seismograms. Bull. Seism. Soc. Am. 95, 408-418. https://doi.org/10.1785/0120040048

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Abstract

Accurate, consistent earthquake size estimates are fundamental for seismic hazard evaluation. In central Europe, seismic activity is low and long-term seismicity, available as intensities from written historical records, has to be included for meaningful assessments. We determined seismic moments M0 of 25 stronger twentieth-century events in Switzerland from surface-wave amplitude measurements. These M0 can be used to calibrate intensity-moment relations applicable to preinstrumental data. We derived the amplitude-moment relation using digital data from 18 earthquakes in and near Switzerland where independent M0 estimates exist. The surface-wave amplitudes were measured at empirically determined distance varying reference periods TΔ. For amplitudes measured at TΔ, the distance attenuation term of the surface-wave magnitude relation S(Δ) = log (A/T)max + 1.66 log Δ is independent of distance. For log M0 = MS + CE, we get log M0 = S(Δ) + 14.90. Uncertainties of ±0.3 for the 14.90-constant correspond to a factor of 2 M0 uncertainty, which was verified with independent data. Our relation allows fast, direct M0 determination for current earthquakes, and after recalibration of the constant, the relation can be applied anywhere. We applied our relation to analog seismograms from early-instrumental earthquakes in Switzerland that were collected from several European observatories. Amplitude measurements from scans were performed at large amplifications and corrected for differences between TΔ and actual measurement periods. The resulting magnitudes range from Mw = 4.6 to 5.8 for the largest earthquake in Switzerland during the twentieth century. Uncertainties for the early-instrumental events are on the order of 0.4 magnitude units.

Nell'archivio ci sono In the archive there are 12 terremoti provenienti da questo studio: earthquakes considered from this study:


   
molto grandiextra large
   
grandilarge
   
medimedium
   
piccolismall
   
molto piccolivery small
non parametrizzatinot determined
falsifake
 

Clicca sulla riga per individuare il terremoto sulla mappa o sulla lente per ottenere più informazioni.Click the row to highlight the earthquake on the map or the lens to obtain more information.

  DataDate    Area epicentraleEpicentral area    MDPs   Imax  EQ in
CPTI15
EQ in
CPTI15
Riferim. in
CPTI15
CPTI15
reference
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1905 04 29 01 59Massif du Mont-Blanc (VS)  -  -    
1905 12 25 17 05Domat/Ems (GR)  -  -    
1915 08 25 02 13Martigny (VS)  -  -    
1924 04 15 12 49Brig (VS)  -  -    
1946 01 25 17 32Ayent (VS)  -  -    
1946 05 30 03 41Ayent (VS)  -  -    
1954 05 19 09 35Mayens de My (VS)  -  -    
1960 03 23 23 10Brig (VS)  -  -    
1961 08 09 13 10San Valentino (Italy)  -  -    
1968 06 27 15 43Chablais (France)  -  -    
1968 08 19 00 36Chablais (France)  -  -    
1996 07 15 00 13Epagny (France)  -  -