silvanos you have to find out in what unit the original reports are. if mm on the seismogram, then you have to convert that to true ground displacement in using the response function. in some bulletins, the seismogram observations have already been corrected to ground . i also suggest you download the events from ISC, there you will probably find correct amplitudes and magnitudes.
jens ________________________________ From: Silvanos Fiama <[email protected]> Sent: Sunday, May 29, 2022 2:57 PM To: [email protected] <[email protected]> Cc: Jens Havskov <[email protected]> Subject: help I am Fiama Bondo Silvanos, junior researcher (Bac+5) at CRSN-Lwiro (Department of Geophysics) and does research in seismology. I have a project on the relocation of earthquakes between 1955 and 1970 in the Kivu rift. I already know how to relocate by using in nordiq format the phases of the waves appearing in the IRSAC bulletins and reading sheets. but I experience difficulties for the revaluation of the magnitudes. the seismometers used are analog during this period are the old WooA Anderson, old benioffs and the phases and the amplitudes (film and paper recorder respectively) were measured in mm and are in the bulletins that I retrieved to recalculate the magnitudes. Could you guide me on how to use these amplitudes in mm under seisan to reevaluate the magnitudes? My first technique was to convert to nanometer (nm) and then divide the amplitudes by 2800 for the benioffs for the all component and keep the amplitudes converted to nm for the WA (E and W components). But this technique gives largely high magnitudes for old WA. could you help me? you can see the jointed file > > FIAMA BONDO Silvanos > CRSN-LWiro. >
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