11:00 AM - 11:15 AM
[S05-2-03] Instrumental polarities of the most important historical seismographs of the Euro-Mediterranean area
One of the many critical issues in the use of historical seismograms is the knowledge of the polarity of the seismographs with mechanical and galvanometric recording system.
This information is not easy to find and rarely appears in the seismological literature or seismic bulletins. Periodical collection, on a global scale, of this and other information of instrumental parameters is not always reliable or it do not refer to the same definition of polarity.
The considerable efforts to use scientifically historical instrumental records (i.e. pre-WWSSN), to calculate for example the focal mechanism are often made vain due to the uncertain reliability of information on the polarity of the historical instruments.
For the most popular historical instruments that have operated in the Euro-Mediterranean during the period 1910 – 1980 we determined the instrumental polarity comparing those expected for a set of 10 earthquakes of known mechanism with those read on over 700 seismograms.
This information is not easy to find and rarely appears in the seismological literature or seismic bulletins. Periodical collection, on a global scale, of this and other information of instrumental parameters is not always reliable or it do not refer to the same definition of polarity.
The considerable efforts to use scientifically historical instrumental records (i.e. pre-WWSSN), to calculate for example the focal mechanism are often made vain due to the uncertain reliability of information on the polarity of the historical instruments.
For the most popular historical instruments that have operated in the Euro-Mediterranean during the period 1910 – 1980 we determined the instrumental polarity comparing those expected for a set of 10 earthquakes of known mechanism with those read on over 700 seismograms.