Inferring Seismic Response of Landslide-Prone Slopes from Microtremor Study
The difficulty in identifying factors controlling the dynamic response of landslide-prone slopes to seismic shaking makes desirable the development of reconnaissance techniques to reveal site resonance conditions that can favour seismically-induced slope failures. Tests were performed to derive information on the occurrence of directional resonance by analysing the azimuthal variations of the horizontal-to-vertical spectral ratios of ambient noise (HVNR) recorded by portable seismometers. In particular, data were acquired in an area of central Italy (Caramanico Terme), affected in the past by seismically-induced landslides, and in two areas of Taiwan (Tsaoling and Jiufengershan), where the 1999 Chi-Chi earthquake triggered giant landslides. The HVNR analysis demonstrated that the presence of a pronounced directional resonance can be recognised from data acquired under different ambient conditions and with different sensors. However, measurement repetitions and uncertainty assessment are fundamental to distinguish persistent features, attributable to site effects, from transient phenomena due to variable ambient conditions.
KeywordsSeismically-induced landslides Slope dynamic response Microtremors HVNR
- Arias A (1970) A measure of earthquake intensity. In: Hansen RJ (ed) Seismic design for nuclear power plants. MIT Press, Cambridge, MA, pp 438–483Google Scholar
- Bard PY (coordinator), The SESAME TEAM (2004) Guidelines for the implementation of the H/V spectral ratio technique on ambient vibrations measurements, processing and interpretation. SESAME European research project, WP12 – Deliverable D23.12, 62p. http://sesame-fp5.obs.ujf-grenoble.fr/Papers/HV_User_Guidelines.pdf
- Del Gaudio V, Wasowski J (2010) Advances and problems in understanding the seismic response of potentially unstable slopes. Eng Geol. doi: 10.1016/j.enggeo.2010.09.007
- Hu JC, Tang CL, Tseng CH, Lin ML, Chan YC, Chu HT, Lee JF, Wie JY (2009) Giant landslides induced by the 1999 Chi-Chi earthquake. In: Proceedings of the conference “the next generation of research on earthquake-induced landslides”, Jhongli, 21–26 Sept 2009, pp 141–147Google Scholar
- Nakamura Y (1989) A method for dynamic characteristics estimation of subsurface using microtremors on the ground surface. Q Rep Railw Tech Res Inst 30:25–30Google Scholar