Deprem Araştırma Bülteni (17. Sayı)
Aletsel Sismolojide Bazı Ana Yöntemler ve Uygulamalar.

Başarır L. E.


It was desirable to give some basic methods in the field,of instrumental seismology and their applications on the avaliable instruments at the Kandilli Observatory. These will be especially on the seismograph systems and their calibration techniques. This study is not involved with the systems including galvanometer. The methods which are the subjects of this paper are very recently to calculate damping factor of long period seismograph systems on critical damping. For this purpose, several seismograms obtained at different times were investigated and it was found that there was a disagreement (max. + 0.11) in the calculate damping factors. According to our consideration the differences are due to noise and digitizing errors. In this study, seismometer transfer function was evaluated numerically for various damping factors and natural frequencies were calculated by computer. Taking this into account, impulsive responses have been computed using inverse fast Fourier transform. As a matter of fact, this technique gives a good understanding of the behaviour of seismometer. Bence, one can realize how the seismometer time characteristics will effect the seismograms. Calibration methods have also been applied to Istanbul Kandilli Observatory (ISK) short period Geotech Seismograph systems to find damping factor, natural frequency, electromotor constant of the seismometer and sensitivity. It was found that various system constants could vary considerably from the values given in the manual. These results show the necessity of the calibration of the systems at least once a year.