Site Response Evaluation in a Volcanic Area Using H/V and 1D Wave Propagation Analysis

Abstract eng:
This contribution presents some results of a detailed site response analysis in a proposed wind farm site in South Iceland. The area under study is a valley Northwest of Mount Hekla in South Iceland, and the sites consist of layers of soft sand mixed with scoria/tephra sandwiched between layers of very stiff basalt. The analysis is based on Horizontal to Vertical Spectral Ratios (HVSR) of ambient vibrations as well as one dimensional equivalent linear wave propagation analysis. Wave propagation analysis, also known as site response analysis, is based on geotechnical data from the study area, mostly in the form of borehole logs. Fundamental site vibration frequencies obtained from HVSR and site response analysis were found to be consistent throughout the study area. Site fundamental frequencies inferred from average shear wave velocity in the upper 30m of the sites were found to be significantly larger—4 times on the average—than those inferred from elastic transfer functions. The response of the sites under several pulse-like and ordinary ground motions was computed. The results indicate that inelastic deformations of the soft layers cause reduction in fundamental frequencies of the sites and the corresponding amplification factors. This reduction was found to be strongly correlated with peak ground velocity of pulselike ground motions and peak ground acceleration of ordinary ground motions.

• Export as: BibTeX | MARC | MARCXML | DC | EndNote | NLM | RefWorks
• Add to your basket