A low-cost instrumentation approach for seismic hazard assessment in urban areas

Abstract

The objective of the present study is to propose a low-cost instrumentation methodology for urban areas, in order to effectively record actual strong motion variations on an adequately dense grid during at least light intensity seismic events. The proposed methodology is an efficient alternative to usual microzonation studies, which, due to economic reasons, are typically based on relatively few actual recordings and then use theoretical assumptions to assess the strong motion distribution throughout the area under study. The availability of actual recordings on a dense grid, which is feasible to implement through this new approach, minimizes many theoretical uncertainties inherent in the usual studies. For this purpose, an autonomous triaxial accelerograph based on MEMS sensor technology has been designed and manufactured, together with custom developed software for device configuration and data retrieval. The production cost of the developed devices is an order of magnitude lower than the presently available commercial products, thus making economically feasible their deployment on a dense grid all over the urban area under study. As a pilot case, over 20 prototype accelerographs have been already installed on a high-seismicity urban area in Greece, aiming to record the local variability of strong motion within a relatively small area. The expected strong motion records are georeferenced and postprocessed with custom designed GIS-type software, in order to produce explicit seismic hazard maps of the considered urban area. The application of the above procedure requires minimum maintenance and human intervention at a fraction of the cost compared to available commercial solutions. © 2014 WIT Press.