Japanese national program on earthquake prediction

Earthquake prediction studies in Japan have made progress since a national program was officially launched in 1965. A sum of 18 million dollars has been allocated for the program in addition to expenses for salaries, construction of observatories and other supporting routines. As a result, 17 crustal deformation observatories, 19 microearthquake observatories and 1 magnetic observatory, all equipped with modern instruments have been completed. It has also become possible to repeat the first-order levelling surveys along levelling routes of 20,000 km in length with an interval of five years.The program has been tested during the 1965—1966 Matsushiro activity of swarm earthquakes. Judging from the fact that long-term predictions could be issued to the public from time to time during the active period, the program would seem to be directed in the right direction. An anomalous land deformation has been found in an area south of Tokyo in 1969. An operation to investigate the anomaly has been carried out intensively over the area concerned with special emphasis on detecting the possibilities of a large earthquake occurring there.Intensification of the program orientated towards actual prediction is now under consideration. A more extensive program including a nation-wide network of geodimeter surveys, real-time monitoring of microearthquakes, real-time observations by oceanbottom seismographs and other disciplines is going to be planned.