Deprem Araştırma Bülteni (19. Sayı)
Batı Türkiye’de Deprem Etkinliği (Eylül- Aralık 1976).


Üçer, S. B., Alsan E., Ulusan N., Başarır E., Ayhan E., Tezuçan L., Kaptan C.

Summary.


This report contains the epicentre determinations of 800 earthquakes occurred in Western Turkey and surrounding areas during the period September-December, 1976. The data are from the 13 seismic stations which form the "Kandilli Observatory Network". Specifications related to these stations are given as a table in the text. These data are processed by computer, using the epicentre location program prepare in order to get odgin time, epicentre location and magnitude of the earthquakes. In addition to first P arrivals, S arrivals are also taken to increase the data. Balkan crustal velocity model, which is prepared the "Bureau Central Intemational de Seismologie" under the direction of Prof. J. P. Rothe for the Project of the "Survey of the seismicity of the Balkan Region'', is used in the computation. For magnitude determination, the signal duration of the events on the records is used station magnitudes (MB) were calculated according to the form'ula given below: MB: a + b log T + c delta where T is the signal duration and  epicentral distance. The average of the station magnitudes is adepted as the magnitude value of the earthquake and it is shown with MB. All determinations are listed in the text. This chronological list of earthquakes includes the origin time, location of epicentre and magnitude class (the classification goes from "a" to "f" and is for the vaIues 4.0≥ MB ≥2.0 with a step of 0.5 unit) as the fundamental parameters of the shocks. In addition; root- mean - square error of the time residuals (RMS), number of stations used in the location (NS), solution quality (A: good. B :fair, C : poor) and if there are, the determinations of other Seismological Centres, such as U.S.G.S. and C.S.E.M., and macroseismic information about the earthquakes are given in this list. Epicenters given in the list are plotted as monthly maps according to magnitude class and solution quality class. On these maps, tlhe epicentre distributions in Western Turkey for the Iast four months of 1976 show two main seismically active areas where high concentration of epicentres are observed: 1) Emet area 2) İzmir - Karaburun area Beside of these, some scatterings of epicentres can be distinguish in the region of investigation.