Ambient Seismic Noise Tomography of a Loess High Bank at Dunaszekcső (Hungary)

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• 作者：Gyöngyvér Szanyi ; Zoltán Gráczer ; Erzsébet Győri…
• 刊名：Pure and Applied Geophysics
• 出版年：2016
• 出版时间：August 2016
• 年：2016
• 卷：173
• 期：8
• 页码：2913-2928
• 全文大小：5,280 KB
• 刊物类别：Earth and Environmental Science
• 刊物主题：Earth sciences
  Geophysics and Geodesy
  
• 出版者：Birkh盲user Basel
• ISSN：1420-9136
• 卷排序：173

文摘

Loess high banks along the right side of the Danube in Hungary are potential subjects of landslides. Small scale ambient seismic noise tomography was used at the Dunaszekcső high bank. The aim of the study was to map near surface velocity anomalies since we assume that the formation of tension cracks—which precede landslides—are represented by low velocities. Mapping Rayleigh wave group velocity distribution can help to image intact and creviced areas and identify the most vulnerable sections. The study area lies at the top of the Castle Hill of Dunaszekcső, which was named after Castellum Lugio, a fortress of Roman origin. The presently active head scarp was formed in April 2011, and our study area was chosen to be at its surroundings. Cross-correlation functions of ambient noise recordings were used to retrieve the dispersion curves, which served as the input of the group velocity tomography. Phase cross-correlation and time-frequency phase weighted stacking was applied to calculate the cross-correlation functions. The average Rayleigh wave group velocity at the loess high bank was found to be 171 ms\(^{-1}\). The group velocity map at a 0.1 s period revealed a low-velocity region, whose location coincides with a highly creviced area, where slope failure takes place along a several meter wide territory. Another low velocity region was found, which might indicate a previously unknown loosened domain. The highest velocities were observed at the supposed remnants of Castellum Lugio.KeywordsSeismic interferometryambient noisegroup velocitytomographylandslidehigh bank