Magnification of undamped seismographs and the analysis of the 1906 San Francisco earthquake record obtained on the Vicentini seismograph in Zagreb (Croatia) |
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| Authors: | Marijan Herak Ivo Allegretti Seweryn J Duda |
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| Institution: | Department of Geophysics, Faculty of Sciences, University of Zagreb, Horvatovac bb, 10000 Zagreb, Croatia;Institute of Geophysics, Hamburg University, Bundesstrase 55, 20146 Hamburg, Germany |
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| Abstract: | A method to estimate the dynamic magnification of nonlinear seismographs is presented. The method was tested by applying it to the record of the 1906 San Francisco earthquake seismogram obtained on the Vicentini seismograph in Zagreb, in order to reconstruct the ground motion amplitudes. The magnitudes inferred from the corrected Vicentini recording of P- and surface waves are internally consistent ( m b= 7.74, M s= 8.48) and agree with the values published in various catalogues, within the error limits of magnitude determination for individual events. The corrected P-waveform is compatible with a rupture slip profile exhibiting several distinct maxima along the 300 km-long section of the San Andreas fault, in accordance with recent studies and contemporary geodetic measurements. |
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