Calculation Method of Time History Including Large-scale Earthquake and Its Aftershock

Many aftershocks followed the 2011 off the Pacific coast of Tohoku earthquake after the main shock. There is a need to assess the seismic stability of railway facilities against large earthquakes in consideration of aftershocks. To this end prediction of aftershocks is necessary. This paper proposes a prediction method, which can calculate the magnitude and time lapses between aftershocks after a main shock, based on statistical processing on past earthquakes including aftershocks. Using the proposed method, preliminary calculations were conducted to obtain the time history for a main shock of magnitude 7.0, and its aftershocks. The effect of the aftershock on the damage to the structures was investigated using these waveform groups.