MONITORING AND FORECAST

JAPAN,  Мs≥7.8

Seismic situation in Tokyo area after earthquake from 19 July 2008 off the east cost of Honshu  /20 July 2008/.

  Seismic processes in Japan in the recent months are developed very dynamically, but within the framework my approach it is thus far controlled!! I have such sensation, that nature accepted the call and decided to play with me into seismic chess according to my rules, but her laws! Rate - forecast of earthquakes. It has the multi-millennial experience of game and the unpredictable motions. My purpose, on the basis of the study of the played by it parties in the last one hundred years, recorded by seismographs, to guess its motions and to win in it one party. But it would like so that this party it would prove to be without the human victims. Last motion moves hope! 

    S.Ts.Akopian.

Situation in the system.

At present, on July 20, 2008, after earthquake dated July 19, 2008, M=6.8 off the East coast of Honshu☼, seismic situation in the system changed. There are some divergences relative to the determination of hypocenter and magnitude of this earthquake according to the data of different networks. For the calculations we accepted the magnitude of this earthquake 6.8, most unfavorable for Tokyo.  

To Tab.1 are given the values of the dynamic parameters of system Japan in July - August after this earthquake. Are there given the parameters of the point of the instability for the earthquake Fukushima Ken Oki, 1938.11.05 (zone D to Fig.1). As it was noted in the communication dated July 10, 2008, during the future seismic activity, the instability can move into the zone D (K=16.890, W=18.432). This it moves hope, that the track can pass unstable region in Tokyo area.    

Track on the cumulative energy (K=16.780) exceeded the values of Boso Oki (K=16.764), but through the entropy it is found in the unstable region of zones A, B, C (see Fig.1a, b and Tab.1). Thus far we do not abolish the previous forecast dated July 10, 2008. Strong earthquake from Ms=8.3 and with the depth of center to 25 km can occur in Tokyo region in the zone C (see Fig.1a,b) from July 25 to August 25, 2008. This is connected with the fact that first of all the unstable region of historical earthquake to 1703, Genroku of unindefinite, the secondly, the parameter W (entropy) steadier and more reliable. Track will leave unstable region on the entropy for the zones A, B, C only toward the end of August. In all this time it is necessary to be to vigilant and to follow the operational forerunners.  

Even if strong earthquake will not occur, system must react to the passage of track close to the zones of instability A, B, C by the moderate earthquake (or earthquakes) from M=6.0-7.0 in these zones, including Suruga bay and Izu peninsula, see Fig.1b. Such earthquakes will already be not foreshocks, but they will vice versa contribute to the displacement of the source zone of the expected strong earthquake from Tokyo area to the north, to the oceanic zone D.

Now the probability of strong earthquake from M>7.8 in the system it is equal to P=40% (on entropy P_W=60%, and on cumulative energy P_K=66%) (see Fig.2 and Tab.1). In the recent 3 months the probability grew by 5% (on the entropy by 2%, on cum. energy by 5%).  

Fig.1a. Japan. Controlled region of the forecast of earthquakes from M≥7.8. After three earthquake-indicators (on May 7, M6.7, on July 13, M6.9 and on July 19, M6.8, 2008) seismic situation in Tokyo area somewhat changed. The source of the expected strong earthquake it is thus far localized in central Japan, in the zone C, but has a tendency toward the migration to the North, to the zone D. Danger in the zone C (from July 25 to August 25, 2008, M=8.3) it remains, because of the uncertainty of the unstable region of earthquake to 1703, Genroku.

Fig.1b. Sagami Trough. The strong earthquake of M8.3 is expected in the zone C from July 25 to August 25, 2008. Supposedly, the source of the expected earthquake can coincide with the source of 1703 Genroku. In the zones A, B, C, including Suruga bay and Izu peninsula they can occur the moderate earthquakes from M>6.0.

Fig.2. Dynamics of an increase in the probability of strong earthquake in SS Japan on 20 July 2008. P the probability of strong earthquake (red region), Pk probability on the cumulative energy (vegetable), Pw probability on the entropy (dark-blue). P - with the line indicates the conditional probability (gray and blue).

Table 1. Increase in the dynamic parameters of the preparation of strong earthquake (Ms≥7.8) in SS Japan in July - August 2008, after earthquake dated July 19, 2008 and the nearest zones of instability.

In the figures is shown the epicentre, the intensity of seismic shake and the focal mechanism of source on July 19, 2008 earthquake off the east cost of Honshu, Japan.

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