English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Abstract. We use observations of surface waves in the ambient noise field recorded at adense seismic array to image the North Anatolian Fault zone (NAFZ) in theregion of the 1999 magnitude 7.6 Izmit earthquake in western Turkey. The NAFZis a major strike-slip fault system extending ∼1200 km across northernTurkey that poses a high level of seismic hazard, particularly to the city ofIstanbul. We obtain maps of phase velocity variation using surface wavetomography applied to Rayleigh and Love waves and construct high-resolutionimages of S-wave velocity in the upper 10 km of a 70 × 30 kmregion around Lake Sapanca. We observe low S-wave velocities (&lt;2.5 km s−1) associated with the Adapazari and Pamukova sedimentarybasins, as well as the northern branch of the NAFZ. In the Armutlu Block,between the two major branches of the NAFZ, we image higher velocities (&gt;3.2 km s−1) associated with a shallow crystalline basement. Wemeasure azimuthal anisotropy in our phase velocity observations, with thefast direction seeming to align with the strike of the fault at periodsshorter than 4 s. At longer periods up to 10 s, the fast direction alignswith the direction of maximum extension for the region (∼45∘).The signatures of both the northern and southern branches of the NAFZ areclearly associated with strong gradients in seismic velocity that also denotethe boundaries of major tectonic units. Our results support the conclusionthat the development of the NAFZ has exploited this pre-existing contrast inphysical properties.

Near-surface structure of the North Anatolian Fault zone from Rayleigh and Love wave tomography using ambient seismic noise