Minima of the fluctuations of the order parameter of seismicity and earthquake networks based on similar activity patterns

Abstract

Natural time analysis has provided an order parameter for seismicity. It has been shown that the fluctuations of this order parameter exhibit characteristic minima before strong earthquakes both in global and regional scale. Here, we investigate how we can make use of the recent advances in earthquake networks, especially those based on similar activity patterns [Phys. Rev. E 86 (2012) 046107], in order to identify geographical regions appropriate for the identification of those minima which are precursory to the stronger earthquakes in these regions. We present an example in the region around eastern Mediterranean Sea where a proper selection of the areas in which the seismicity is studied in natural time may lead to order parameter fluctuations minima preceding all earthquakes of magnitude 7.1 or larger with no false alarms.