Have a look at Hesse three articles.  They will help with your project.

Sarlis, N. V., Skordas, E. S., Varotsos, P. A., Nagao, T., Kamogawa, M., Tanaka, H., & Uyeda, S. (2013). Minimum of the order parameter fluctuations of seismicity before major earthquakes in Japan. Proceedings of the National Academy of Sciences, 110(34), 13734-13738.

Varotsos, P. A., Sarlis, N. V., & Skordas, E. S. (2014). Study of the temporal correlations in the magnitude time series before major earthquakes in Japan. Journal of Geophysical Research: Space Physics, 119(11), 9192-9206.

Ishigaki, A., Higashi, H., Sakamoto, T., & Shibahara, S. (2013). The Great East-Japan Earthquake and devastating tsunami: an update and lessons from the past Great Earthquakes in Japan since 1923. The Tohoku journal of experimental medicine, 229(4), 287-299.

The conference paper below is v.good paper for your required ;

https://www.google.iq/url?sa=t&source=web&rct=j&url=http://www.iitk.ac.in/nicee/wcee/article/13_826.pdf&ved=0ahUKEwj99_X-ldvNAhVE1RQKHdbkCdMQFggtMAM&usg=AFQjCNFNamEKbQ7lrRum7Xxw836GP1vALA&sig2=beJH8fnQ8Ks7g5X2GzaoIQ

Hi,

http://www.iris.edu/hq/webinar/ 

from here u can find tele-seismic data

The U.S. Geological Survey maintains an excellent online database of earthquakes, which can be filtered by several attributes, such as time, location, size, depth, etc.

http://earthquake.usgs.gov/earthquakes/

I found records of two large (M>6) earthquakes in Japan in 1968:

http://earthquake.usgs.gov/earthquakes/eventpage/iscgem818662#general

http://earthquake.usgs.gov/earthquakes/eventpage/iscgem818523#general

I hope this helps.

Scott Bennett, USGS

You can also try the International Seismological Centre (ISC).

http://www.isc.ac.uk/