Old Network

The instrumental period of seismology has begun in Georgia in the end of XIX century In 1899 the Tiflis (now Tbilisi) seismic station has been founded in the former Caucasian district of Russian Empire. The horizontal Rebert-Ellert pendulum has been installed on the station. The first seismogram has been recorded 6 December 1899. This gives start to the development of seismology in Caucasus.

 August 11 1903, Earthquake in Greece 36.00N-23.00E.
Recorded in TBILISI Seismic Station on Rebert-Ellert Seismograph

After the well-known Shemacha earthquakes, The Permanent Central Commission of Seismicity (PCCS) in Russia founded seven seismic stations in the Caucasus region. The horizontal Omori-Boshi pendulum with mechanical registration was installed in Batumi, Shemaxa, Axalkalaki, Borjomi, Derbent and Zurnabad in 1903-1908. The Bulletins of the PCCS also were published. The following moments of phases were indicated for each earthquakes (mean European time): the beginning of weak oscillations (flicker) of the pendulum T; the beginning of the oscillations C; the beginning of the strong oscillations R; amplification (minimum) of the oscillations M; the end of the oscillation F; and the double-trace amplitude (peak-to-peak) in millimeters A. About 3971 earthquakes had been recorded during this period. Most of them were recorded only at one station. The bad quality of the recording instruments, low velocity of the registration and old identification of the phase could not allow estimation of the earthquakes' parameters. So these instrumental observations did not take very important part in the investigation of the seismicity. (The Earthquakes of the USSR, 1961)

In 40-ties the formation of regional network was finished. From the beginning of 1960 network was equipped by high sensitive seismographs of different types. At the end of seventies local seismic networks were established in the region of Enguri Dam (western part of Greater Caucasus) and Javakheti plateau (South Georgia). In eighties about 40 seismic stations were operated in Georgia. During the last years the number of seismic stations has been decreased (from 40 stations in Georgia in 1991 to 10 in 1997) due to political and economical problems. In 1998 with the help of Swiss Seismic Survey strong motion network of Georgia has been created.An existing seismological database includes the information about 57 000 earthquakes.

The instrumental period of seismology has begun in Georgia in the end of XIX century In 1899 the Tiflis (now Tbilisi) seismic station has been founded in the former Caucasian district of Russian Empire. The horizontal Rebert-Ellert pendulum has been installed on the station. The first seismogram has been recorded 6 December 1899. This gives start to the development of seismology in Caucasus. At the beginning of XX century some seismic stations were opened in Caucasus region. They were equipped by the low sensitive seismographs generally of mechanical type. In accordance with network development, the threshold magnitude has decreased from 4-4.5 in the early instrumental period, to 3.5 in forties, 2.5 since 1960 and less then 2.0 in eighties.