Examining the consistency of focal parameters published by national earthquake agencies of turkey

KOCA B., Scordilis E. M.

18th International Multidisciplinary Scientific Geoconference, SGEM 2018, Albena, Bulgaristan, 2 - 08 Temmuz 2018, cilt.18, ss.779-786 identifier

  • Yayın Türü: Bildiri / Tam Metin Bildiri
  • Cilt numarası: 18
  • Doi Numarası: 10.5593/sgem2018/1.1/s05.098
  • Basıldığı Şehir: Albena
  • Basıldığı Ülke: Bulgaristan
  • Sayfa Sayıları: ss.779-786
  • Anahtar Kelimeler: Consistency, Earthquake catalogs, Focal parameters, Turkey
  • Ankara Üniversitesi Adresli: Evet

Özet

© SGEM2018.Two national agencies are operating in Turkey providing routine analysis of earthquakes of Turkey and surroundings, Boğaziçi University-Kandilli Observatory and Earthquake Research Institution (BOUN–KOERI) and Disaster and Emergency Management Authority, Earthquake Department (AFAD–DDA). In the present work, we check the consistency of the focal parameters provided by these centers for a large number of recently occurred earthquakes. To perform this test, we used the solutions provided by International Seismological Centre (ISC) as reference ones against which the focal parameters provided by the two agencies under test are compared. The data set includes focal parameters of 46,738 earthquakes, covering the period 2000-March 2015, for which reviewed locations are provided by ISC and, at the same time, all necessary parameters from KOERI and DDA are available. The region covered by the data is bounded by the coordinates 35°-42°N and 26°-45°E extending over the whole area of Turkey and surroundings. The differences in the estimations of origin time, epicenter coordinates, focal depths and magnitudes, provided by KOERI and DDA and the respective estimations of ISC as well as their variation in space and with time are examined. Comparisons have been performed by using all available data as well as after keeping earthquakes with satisfactory azimuthal coverage of stations (GAP≤180°). The GAP (maximum angle between azimuths of the sites of two successive stations to the epicenter) is smaller for ISC, as it is expected since this agency is a collective one using stations of many regional networks all over the globe. Regarding the two examined centers, KOERI seems to prevail for GAP<180°. KOERI’s estimations of origin time are more compatible to ISC’s ones than those of DDA. The differences in epicenter estimations by KOERI and DDA from those of ISC are almost the same for 100°