The first generation of seismological instrumentation

1957–1964: mechanical seismographs

 

Earlier in 1957, the building of the Seismological Station in Skopje (SKO) was completed at the location formerly selected by Prof. Jelenko Mihailović, which is, as said above, on the northeast slopes of the VodnoMountain in the Kisela Voda settlement in Skopje. Immediately afterwards, the first instruments, two middle‑period mechanical seismographs type MAINKA (EW and NS components, pendulum mass of 450 kg, registration with a needle over smoked paper put on a rotating drum, contact timing device WIECHERT), were mounted. The assemblage was done by Gigo Mileski, Vladimir Princ (from the Geophysical Institute at the Faculty of Natural Sciences and Mathematics of the University of Zagreb) and Dimitrije Traić (from the Seismological Survey of Serbia). It was with this equipment that the Seismological Station in Skopje started its activities on 1 July 1957. This is the date when publishing of results from seismological observations in seismological bulletins began, under the editorship of Gigo Milevski. In January 1960, Gigo Milevski went to work at the Geophysical Institute of the Faculty of Natural Sciences and Mathematics in Skopje. However, he served as honorary acting directorof the station up to 28 February 1961.

            On 1 March 1961, Dragan Hadžievski, graduated physicist from the Department of Physics at the Faculty of Natural Sciences and Mathematics in Skopje and graduated geophysicist from the Geophysical Institute at the Faculty of Natural Sciences and Mathematics in Zagreb, was appointed director of the Seismological Station in Skopje. Dragan Hadžievski carried out this function until 5 July 1988.

            Earlier in 1962, the University Council made a decision for establishment of a consultative board of the Seismological Station in Skopje. The first members of this board were: Miloš Pavlović (a geologist), the president of the board, Ordan Pečijare (a physicist), Josip Mozer (a physicist), Dušan Manaković (a geographer), Slavčo Bahčevandžiev (a physicist), all from the Faculty of Natural Sciences and Mathematics in Skopje, and Petar Miškovski, a jurist from the Secretariat for Internal Affairs of Republic of Macedonia.

On 15 February 1963, Dragan Hadžievski installed the middle-period mechanical seismograph type CONRAD (NS component, pendulum mass of 25 kg, registration with a needle over smoked paper put on a rotating drum). The seismograph was received from the Seismological Survey of Serbia in 1957.

 

The middle-period mechanical seismographs type MAINKA 2 Rubrika Za OPSER Sl Br  MAIKA nisalo i registrator od blizu

 (Left) The middle-period mechanical seismographs type MAINKA, N–S and E–W components (straight and on side), put in operation in the Seismological station in Skopje on 1 July 1957. (Right) The pendulum (a cylindrical mass of 450 kg) and the registration device (a needle over smoked paper put on a rotating drum) of one of the seismographs MAINKA.

 

The middle-period mechanical seismograph type CONRAD

The middle-period mechanical seismograph type CONRAD, N–S component, put in operation in the Seismological station in Skopje on 15 February 1963. The seismograph’s pendulum mass is 25 kg, and the registration is with needle over smoked paper put on a rotating drum.

 

            The strong earthquake of 26 July 1963 (04h 17min GMT, local magnitude 6.1) devastated the town of Skopje, damaged and put out of operation the seismographs at the seismological station. Dragan Hadžievski succeeded to put again into operation the CONRAD N-S component nearly 38 minutes after the beginning of the earthquake. His repairing of the MAINKA N-S component lasted nearly 2 hours and 32 minutes from the beginning of the earthquake. (The MAINKA E‑W component was heavily destroyed, and it was repaired after some days.) This enabled recording of the greatest number of aftershocks, and hence issuance of the seismological bulletin and reports. The latter were of a great importance for protection of the citizens.