Assessing components of ground-motion variability from simulations for the Marmara Sea region (Turkey)

John Douglas, Hideo Aochi

Research output: Contribution to journalArticlepeer-review

8 Citations (Scopus)
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Recent studies have shown that repeatable travel-path terms make a high contribution to the overall variability in earthquake ground motions. Having maps of such terms available for a given recording site would, theoretically, allow removal of this component from the aleatory variability of ground-motion models. The assessment of such travel path terms for a given site, however, relies on having recorded a rich set of earthquakes at that site. Given the relative youth of strong-motion networks the assessment of such terms from observations is currently difficult for most parts of the world. Ground-motion simulations, however, provide an alternative method to assess such terms.

In this article many dozens of earthquakes, distributed in a grid, are simulated for the Marmara Sea region (Turkey), which borders the megacity of Istanbul and is an area of high seismic hazard. Ground motions are simulated within a detailed 3D velocity structure model using a finite-difference method at 70 recording sites in the area (200 x 120km). Horizontal peak ground velocities from these simulations are regressed to derive a ground-motion model. Next, residuals from these GMPEs are computed to assess repeatable source, site and path terms and various components of ground-motion variability. These components are similar to those derived from real strong-motion data, thereby lending support to those estimates as well as showing the worth of simulations for this type of exercise.
Original languageEnglish
Pages (from-to)300-306
Number of pages7
JournalBulletin of the Seismological Society of America
Issue number1
Early online date5 Jan 2016
Publication statusPublished - 1 Feb 2016


  • ground-motion prediction
  • aleatory variability
  • strong ground motion
  • earthquake
  • Marmara
  • Turkey
  • seismic hazard
  • path variability
  • single-station sigma


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