Statistical Prediction for the Numbers of Aftershocks by the Omori-Utsu Formula
The Omori-Utsu Formula is applied to the aftershock activity of the Tohoku-Oki Earthquake till the end of February 2021 in order to statistically predict the numbers of aftershocks. In the aftershock area there was a seismic activity before the main shock, and setting this activity as a stationary one (generating rate µ = 0.032: estimate from the seismic activity during October 1997 ~ December 2010), the Omori-Utsu model with µ fits well to the observed result as a whole. Yearly number of aftershocks predicted from the model approaches the median value for 10 years before the main shock, and the variation of numbers for the next 10 years becomes small.
Geospatial Information Authority of Japan
[Evaluation of Seismic Activities After "the 2011 off the Pacific Coast of Tohoku Earthquake" (March 9, 2021)]