- © 2009 by the Seismological Society of America
Rapid urbanization, the interconnection of economies and increasing dependence on technology makes modern society ever more vulnerable to natural disasters. This is particularly true when considering the growth of so-called mega cities (defined by the United Nations as metropolitan areas with populations exceeding 10 million), the majority of which are in the developing world. This has led to the recognition of the importance of early warning systems as one means of mitigating the potential human and economic losses resulting from natural disasters (e.g., International Strategy for Disaster Reduction 2005; United Nations 2006).
Considering earthquakes, many areas of major urbanization (e.g., Tokyo, Istanbul, Naples, Mexico City) are exposed to significant seismic hazard. Currently, several parts of the world have some form of earthquake early warning system (EEWS) either in operation or under development (e.g., Taiwan: Wu and Teng 2002; Japan: Horiuchi et al. 2005; California: Wurman et al. 2007; Istanbul: Erdik et al. 2003; Bucharest: Ionescu et al. 2007; Mexico City: Espinosa-Aranda et al. 1995). However, these systems usually involve the use of a relatively low number of sensors (from several to tens of units), a fact largely dictated by the high cost of such instrumentation. In addition, these systems must usually communicate their data to centralized processing and archiving facilities. An example of a standard centralized EEWS is the Istanbul Earthquake Rapid Response and Early Warning System (IERREWS; Erdik et al. 2003) operated by Kandilli Observatory and Earthquake Research Institute (KOERI) of Bogaziçi University (Figure 1A). This system is made up of 10 strong-motion stations that are installed as close as possible to the fault zone of the north Anatolian fault, which runs through the Marmara Sea to the south of Istanbul. In the IERREWS, a centralized philosophy of early …