The National Research Center for Disaster Prevention (NRCDP) is constructing a large scale network for observation of microearthquakes and ground tilt in the Kanto-Tokai area, as a part of the national program of earthquake prediction. The number of observation stations, being 49 as of April 1982, will total 66 when the program is completed in fiscal 1983.
NRCDP started the construction of three deep borehole observatories in and around Tokyo in 1970, and the program was completed in 1980. Those deep borehole observatories are included in the new network of the Kanto-Tokai area together with other existing observation stations of NRCDP.
All data are transmitted through telephone lines to NRCDP in the Tsukuba Science City by the Pulse Code Modulation Method. Application of new techniques such as network timing synchronization and high density transmission of digital data distinguishes the present telemetry system from conventional ones.
Stress is put on data processing systems as a prediction-oriented system. A computer system which is directly connected to the telemetry system carries out the filing of records and monitoring of crustal activities on a real-time basis. Further steps of data processing including hypocenter determination by semi-automatic method are executed by another computer system. These systems enabled us to complete the daily routine of seismic data within a half day since it was observed.
Playing an important role in monitoring the crustal activity, the Kanto-Tokai network is offering the high quality data, which is useful for a variety of studies on earthquake prediction, especially those for the prediction of the impending Tokai earthquake.