Computational Technique for Onset of P-Wave for Seismic Alert System

Abstract

The disasters occurred during the major earthquakes result in destruction, losses of property and human life. In order to mitigate the damage impact, there is an urgent need for the design, development and installation of Seismic Alert System (SAS) for vital installations. The development of SAS requires real-time algorithms for fast determination of source parameters and their reliability estimation. Early warning can be generated by detecting the primary waves, which travel with higher velocity then the disaster waves. The computations of source parameters start after detecting the primary wave i.e. P-wave. The generated alert warning depends on the accurate detection of P-wave. The alert signal generated can be sent to the vital installations such as nuclear and thermal plants, fast running trains, hospitals etc. either for shutdown the activities or for resuming emergency facilities as per requirement. Therefore, for the development of SAS it becomes necessary to develop a computationally efficient method that can automatically determine the onset time of P-wave. This paper illustrates the computational technique for detecting the arrival of P-wave along with the analysis for early warning point of view by using the polarization attributes i.e. degree of polarization (DOP), Planarity (Planr) and Rectilinearity (Rect) of recorded seismic signal.