a station for recording oscillations of the earth’s surface caused by earthquakes and for the primary processing of the records obtained. Seismographic stations are subdivided into long-range and regional stations depending on the tasks they perform.
Long-range stations are designed to record seismic signals for the most part at epicentral distances greater than 2,000 km. These stations have standard seismological equipment: short-period seismographs that are highly sensitive in a passband of 10–0.7 Hz, broadband seismographs of medium sensitivity in a passband of 10–0.05 Hz; and, at some stations, long-period seismographs of medium sensitivity in a passband of 0.2–0.015 Hz.
Regional stations are designed to record nearby earthquakes with epicentral distances up to 2,000 km. These stations have short-period equipment and also record strong movements in a passband of 10–0,1 Hz.
In 1974 there were more than 2,000 seismographic stations in the world network, including more than 200 in the USSR. All seismographic stations record earthquakes according to Greenwich time and carry out primary processing of seismograms by measuring the arrival times of different seismic waves and the dynamic parameters of the waves. This information is sent by government communications channels to the appropriate processing centers and provides the raw data for seismological bulletins. Seismographie stations operate in conformity with instructions and guidelines prepared both at the centers of national seismological services and by international seismological organizations.
REFERENCESApparatura i metodika nabliudenii na seismicheskikh stantsiiakh SSR. Moscow, 1962.
Apparatura i metodika seismometricheskikh nabliudenii v SSSR. Moscow, 1974.
Z. I. ARANOVICH and N. V. KONDORSKAIA