Earthquakes which occur between the Japanese north-eastern_coast and the Japan Trench are called Off Tokachi earthquakes. Theseearthquakes contain many problems for Plate Tectonics. This theory asserts that these earthquakes are produced by direct pressure to the Trench. But, the mechanisms of these earthquakes go against this theory. For example, Fig.1 gives the radiation pattern classified by the quadrant theory, but observations at Hachinohe, Yamagata,, Matsushiro, Niigata, Utsunomiya, Hamada and Abashiri go against this type. Fig.2 shows the radiation pattern of the same earthquake as in Fig.1, but classified by the conical theory. This conical pattern is far more excellent than the quadrant type of Fig.1. The belowright figure shows the underground structure for making this pattern. Similarly, Fig.3 shows the radiation pattern classified by the quadrant theory, but obervations at Aomori, Akita, Wazima, Sumoto, Okayama, Koochi, Shimizu, Amamiooshima and Okinawa go against this quadrant type. So, this pattern also is not quadrant type. Yet, Fig.4gives the radiation pattern of the same earthquake as in Fig.3, classified by the conical theory. This is far more excellent than the quadrant type in Fig.3. The below-right figure shows the underground structure for making this pattern. Also, Fig.5 is the radiation pattern classified by the quadrant theory, but observations at Takada, Matsushiro, Toyama, Kanazawa, Kyoto and Owase go against the quadrant type. So, this pattern also is not quadrant type. Fig.6shows the radiation pattern of the same earthquake as in Fig.5, but classified by the conical theory. This conical pattern is far more excellent than the quadrant type in Fig.5. The below-right figure shows the underground structure for making this pattern. These quadrant types are classified by Dr. Masaj i Ichikawa.
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