Seismic Local Networks of the Iranian Seismological Center
The Institute of Geophysics, affiliated with the University of Tehran, constructed the first seismic station in Tehran in 1958, to record and locate earthquakes. In the 1960s, the number of seismic stations increased to five (5) analogue stations installed in the cities of Tehran, Tabriz, Mashhad, Shiraz and Kermanshah. The stations of Tabriz, Mashhad and Shiraz were a subset of the World-Wide Standardized Seismographic Network (WWSSN). The Iranian Long Period Array (ILPA) consisted of seven (7) stations installed in the south-west of Tehran in 1975. In the early 1981s, some additional analogue stations were installed at Brojen, Minoodasht, Mahabad, Ghamsar-e-Kashan and Ghaleh-Ghazi by Institute of Geophysics. Until 1995, the above mentioned analogue stations were responsible for recording and reporting earthquake events throughout the nation. Digital seismological equipment was supplied and installed in Tehran and Tabriz seismic local networks in 1995, and gradually the local networks of Semnan, Quchan, Yazd, Sari, Esfahan, Shiraz, Mashhad, Kermanshah, Birjand and Khoram-abad in turn were installed and equipped with digital instruments. The new seismic local networks of Minab, Kerman, Shahr-e-Kord and Hamedan were installed in 2010. Seismic stations are equipped with three (3) component short-period, medium-band or broad-band seismometers. Today, the Iranian seismological network comprises 108 digital seismic stations in 20 seismic local networks, 4 digital seismic stations and 1 borehole stations which cover most earthquake-prone regions.