120TH ANNIVERSARY OF SEISMOLOGY IN BULGARIA: MILESTONES, DEVELOPMENT AND ACHIEVEMENTS

The territory of Bulgaria is situated in the eastern part of the Balkan Peninsula, South-Eastern Europe, being a part of the Alpo- Himalayan seismic belt. The most important cities in Bulgaria lie in the vicinity of Neogene-Quaternary active faults. Due to these circumstances organized monitoring of earthquakes as well as development of seismological practice started in Bulgaria at the end of 19 th century. The foundation of seismology in Bulgaria was laid in 1891 by the meteorologist and also the first Bulgarian seismologist Spas Watzof, later honored with academic rank. Spas Watzof founded and organized a well managed service for regular observation of co-seismic and post-seismic effects of earthquakes. Soon after, in 1903, Bulgaria was accepted as a member of the International Seismological Association (the predecessor of the International Association of Seismology and Physics of the Earths Interior - IASPEI). It should be noted that foreign experts demonstrated scientific interest in cases of strong earthquakes that took place on the territory of Bulgaria in the beginning of 20 th century (Hornes, 1904; Grablovitz, 1904; Mihailovich, 1933; Richter, 1958) as well as on using instrumental records made in Bulgaria for their revolutionary discoveries (Reid, 1910; Mohorovicic, 1910). At present Bulgaria participates in international activities in the frames of the European Seismological Commission (ESC) a regional commission of the IASPEI, the International Federation of Digital Seismograph Networks (FDSN), the Balkan Geophysical Society and the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO). On occasion of the 120 th anniversary of the seismology in Bulgaria it is reasonably the results of studies covering such a long period and published in international and Bulgarian journals and monographs to be summarized and presented herein. The summary of the milestones, development and achievements in the field of Macroseismology, Instrumental seismology and Geodynamics in Bulgaria is chronologically presented. The paper aims also to spread more effectively the Bulgarian scientific information abroad as well as to popularize some seismic peculiarities and phenomena in the central-eastern Balkan Peninsula.