People in Japan experience a tremor with an intensity of 3 and 4 on the Japaneses seven-stage seismic scale every so often that this one was not considered to be a big earthquake in the country. My parents were not surprised with this earthquake at all.
I think it is more alarming how Japan has been hit by typhoons recently. We usually get strong typhoons in July and August, but this year, we are getting bad ones in September and October. As far as I remember, we did not have bad typhoons around this time of year before.