A Multi-Step Assessment Scheme for Seismic Network Site Selection in Densely Populated Areas

Abstract

We developed a multi-step assessment scheme for improved site selection during seismic network installation in densely populated areas. Site selection is a complex process where different aspects (seismic background noise, geology, and financing) have to be taken into account. In order to improve this process, we developed a step-wise approach that allows quantifying the quality of a site by using, in addition to expert judgement and test measurements, two weighting functions as well as reference stations. Our approach ensures that the recording quality aimed for is reached and makes different sites quantitatively comparable to each other. Last but not least, it is an easy way to document the decision process, because all relevant parameters are listed, quantified, and weighted. Our assessment scheme incorporates seven fundamental steps: First, potential sites are identified and pre-evaluated in the office (step 1). Second, potential sites are visited during a site survey (step 2) and then classified using the first weighting function (step 3) that identifies those sites most suitable for test measurements (step 4). Test measurements are conducted and analyzed in order to quantify seismic background noise and site effects. The results of the analysis are evaluated using the second weighting function (step 6). Finally, the overall quality is assessed (step 7) by using reference stations and pre-defined quality benchmarks to insure that chosen sites are suitable for the designated monitoring purpose. We demonstrate the multi-step assessment scheme by applying it to a densification of an existing seismic network.