A scenario of ground shaking hazard in intracratonic circular basins developed by basin-generated surface waves: an earthquake engineering perspective
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This paper presents the comparative scenario of ground motion amplifications in the 2D semi-cylindrical (SC) basin and 3D semi-spherical (SS) intracratonic basin caused by the basin-generated surface (BGS) waves and the associated spatial variations of average spectral amplification, differential ground motion (DGM) and average aggravation factor (AAF). The time-domain seismic responses of both the basins were computed using a recently developed 3D fourth-order accurate viscoelastic finite-difference algorithm based on the well-known GMB-EK rheological model. The analysis of simulated results revealed that AAF and DGM are comparable near the basin-edge in both the basins but the differences are increasing towards the centre of basins due to the focusing of the BGS-waves in the SS-basin. The obtained many-fold increase of 1D/2D-AAFs and DGM at the centre of the SS-basin as compared to the SC-basin reflects the inadequacy of 1D or 2D response of an intracratonic circular basin for the seismic hazard assessment. It may be inferred that the level of damage near the edges of the 2D and 3D circular basins may be comparable but unexpected damage may occur in the central part of a circular basin due to the focusing of the BGS-waves.
KeywordsSeismic responses of intracratonic circular basin Basin-generated surface waves Average aggravation factor and differential ground motion
The authors are grateful to the Ministry of Earth Sciences, New Delhi, for financial assistance through Grant No. MES-484-EQD. Authors are also grateful to the unknown reviewer for his valuable comments and suggestions that have led to the great improvements in the original manuscript.
- Bard PY, Bouchon M (1980a) The seismic response of sediment filled valleys, part 1. The case of incident SH-waves. Bull Seismol Soc Am 70:1263–1286Google Scholar
- Bard PY, Bouchon M (1980b) The seismic response of sediment filled valleys, part 2. The case of incident P and SV-waves. Bull Seismol Soc Am 70:1921–1941Google Scholar
- Bard PY, Bouchon M (1985) The two-dimensional resonance of sediment-filled valleys. Bull Seismol Soc Am 75:519–541Google Scholar
- Dobry R, Vucetic M (1987) Dynamic properties of seismic response of soft clay deposits. Proc Int Symp Geotech Eng Soft Soils Mexico City 2:51–87Google Scholar
- Graves RW, Pitarka A, Somerville PG (1998) Ground motion amplification in the Santa Monica area: effects of shallow basin edge structure. Bull Seismol Soc Am 88:1224–1242Google Scholar
- Moczo P, Bystrický E, Kristek J, Carcione JM, Bouchon M (1997) Hybrid modelling of P-SV seismic motion at inhomogeneous viscoelastic topographic structures. Bull Seism Soc Am 87:1305–1323Google Scholar
- Narayan JP, Kumar V (2012) Numerical study of effects of synclinal basement topography on ground motion characteristics (paper no. 3144). In: Proceedings of the 15th world conference on earthquake engineering (15WCEE), Lisbon, Portugal. Sept 24–28Google Scholar
- Narayan JP, Singh SP (2006) Effects of soil layering on the characteristics of basin-edge induced surface waves and differential ground motion. J Earthq Eng 10:595–614Google Scholar
- Pitarka A, Irikura K, Iwata T, Sekiguchi H (1998) Three dimensional simulation of the near fault ground motion for 1995, Hyogo-ken Nanbu (Kobe), Japan earthquake. Bull Seismol Soc Am 88:428–440Google Scholar