Microtremor measurements at the University of Mississippi campus

Microtremor measurements provide an efficient means of evaluating the site effect. Simple operation, speed and relatively low cost of this technique promoted its widespread use in research and engineering practice. The measurements of microtremor patterns were made at more than 40 points throughout the campus during several months. Generally, at each point, three recordings each with at least 1 hour duration were obtained. Additionally at three selected points, long term (continuous for 48 hours) measurements were made. H/V spectral ratio was calculated for each points to determine the predominate frequency based on which the site effect evaluation and classification were carried out. The correlation analysis of vertical, North-South and East-West spectra with weather conditions (especially wind speed and direction) were performed for each long-term measurement points. In conclusion, a site effect classification map of the campus was prepared and influence of weather changes on microtremor spectral properties was evaluated. Finn, L.W.D., 1991. Geotechnical Engineering Aspects of Microzonation, Fourth International Conference on Seismic Zonation, Stanford, California, USA, August 1991, 199-259. Nakamura, Y. (1989). A method for dynamic characteristics estimation of subsurface using microtremor on the ground surface, QR of RTRI 30, No. 1, February, 25-33. Sylvette Bonnefoy-Claudet, Stéphane Baize, Luis Fabian Bonilla, et al (2008), Site effect evaluation in the basin of Santiago de Chile using ambient noise measurements, Geophys. J. Int. 1-13.