Current State of Art in Earthquake Prediction, Typical Precursors and Experience in Earthquake Forecasting at Sakhalin Island and Surrounding Areas

Despite of over a century of scientific effort, the understanding in earthquake forecasting remains immature. Moreover, even the theoretical possibility of earthquake forecasting is debatable. Especially problematic is a possibility of an effective shortand intermediate-term earthquake forecasting. The aim of this paper is to present the new evidence in support of possibility of the shortand intermediate-term earthquake forecasting. This possibility is shown through the discussion of seismic regime in the generalized vicinity of strong earthquake and through the description of an experience in an earthquake forecasting in the case of the Sakhalin Island and the surrounding areas. USGS/NEIC catalog and Harvard seismic moments catalog are used to construct the generalized space–time vicinity of strong (M7+) earthquake to reveal the robust typical long-, intermediate, and short-term precursor anomalies. The very essential increase in available information resulted from this procedure gives possibility to detail the character of precursors of strong earthquake. The typical parameters of the foreand aftershock cascades were detailed. A few other revealed precursory anomalies indicate the development of softening in the source area of a strong earthquake. The set of the precursory anomalies indicates the approaching of a strong event quite definitely. Thus one can conclude that the effective shortand intermediate-term earthquake forecasting appears to be possible in the case of essential increase of volume of statistical information available for the forecasting. The current state of art in the earthquake forecasting is illustrated by the case of experience in the earthquake forecasting for the Sakhalin Island and the surrounding areas performed in the Institute of Marine Geology and Geophysics of the Far East Branch of the Russian Academy of Science, Yuzhno-Sakhalinsk, Russia. Four examples of successful prognosis (three of them performed in a real time), and one false alarm took place. Thus, despite the evident deficient in available information the results of forecasting appear to be encouraging