[1] 17 August (Mw 7.4) and 12 November 1999 (Mw 7.2) earthquakes have caused major concern about future earthquake occurrences in Istanbul and in the Marmara Region. Stress transfer studies and renewal model type probabilistic investigations indicate about 2% annual probability for a M w = 7+ earthquake in the Marmara Sea. As part of the preparations for the expected earthquake in Istanbul, an early warning system has been established in 2002. A simple and robust algorithm, based on the exceedance of specified threshold time domain amplitude and the cumulative absolute velocity (CAV) levels, is implemented for this system. Rational threshold levels related to new bracketed CAV window approach (BCAV-W) are determined, based on dataset of strong ground motion records with fault distances of less than 100 km, as 0.2 m/s, 0.4 m/s and 0.7 m/s related to three alarm levels which will be incorporated in the Istanbul earthquake early warning system. Citation: Alcik, H., O. Ozel, N. Apaydin, and M. Erdik (2009), A study on warning algorithms for Istanbul earthquake early warning system, Geophys. Res. Lett., 36, L00B05,

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Rapid improvements in telemetry technology and the general decrease in communication costs have raised a growing interest in low-cost wireless sensing units. This is especially the case for structural monitoring purposes, where they are becoming a more valuable alternative to conventional wired monitoring system. The main advantages associated with the use of wireless sensing unit include a considerable decrease in installation costs, decentralization of data analysis, and the possibility of broadening the functional capabilities by exploiting the use, at the same time and place, of different sensors. In this work, the design of a low-cost wireless sensing unit able both to collect, analyze, store, and communicate data and estimated parameters is presented. The suitability of a network of these low-cost wireless instruments for monitoring the vibration characteristics and dynamic properties of strategic civil infrastructures is validated during a ambient vibration recording field test on the Fatih Sultan Mehmet Bridge in Istanbul, Turkey.

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