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Journal > Journal of Mathematical and Fundamental Sciences > Site Response Characteristics of Simeulue Island, Indonesia as Inferred from H/V Spectral Ratio of Ambient Noise Records

 

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Journal of Mathematical and Fundamental Sciences
Vol 48, No 2 (2016)
Site Response Characteristics of Simeulue Island, Indonesia as Inferred from H/V Spectral Ratio of Ambient Noise Records
Anggono, Titi ( Research Center for Physics, Indonesian Institute of Sciences, Kawasan PUSPIPTEK Serpong, Tangerang 15310)
Syuhada, Syuhada ( Research Center for Physics, Indonesian Institute of Sciences, Kawasan PUSPIPTEK Serpong, Tangerang 15310)
Hananto, Nugroho Dwi ( Research Center for Geotechnology, Indonesian Institute of Sciences, Jl. Cisitu Sangkuring, Bandung 40135)
Handayani, Lina ( Research Center for Geotechnology, Indonesian Institute of Sciences, Jl. Cisitu Sangkuring, Bandung 40135)
Article Info   ABSTRACT
Published date:
28 Aug 2016
 
Simeulue Island is an outer island arc off west of the Sumatra Island. The Island is located close to the interface of the subduction zone between Indo-Australian and Eurasian Plates. Seismic activities around the Island included devastating megathrust earthquakes, such as 2004 MW 9.2 Sumatra-Andaman and 2005 MW 8.7 Nias earthquakes. We investigate the site response characteristics using Horizontal-to-Vertical (H/V) Spectral Ratio method to the continuous ambient noise records from eight broadband seismometers. From the calculation, we generally observe strong peak of H/V spectral ratio which is caused by the strong impedance contrast at these area. However, sites BATU, LABU and DEHI show relatively flat H/V spectral ratio curves that caused by lack of sharp impedance contrast beneath the site. We also observe multiple peaks at several sites that may indicate the presence of a more highly weathered soil/clay layer on top of a more compact medium. H/V peak frequencies, which shows fundamental frequencies resonance of soil sites, generally are observed at range about 2.0 - 16.4 Hz. From the observed H/V spectral ratio, we suggest that the strong impedance contrasts may occur on the shallow part of the medium at 2 up to15 m depth.
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