Japan is the centre of great seismic activity. In two and a half years Japan has experienced, on the average, one disastrous earthquake since the beginning of the seventeenth century. During the last 1500 years this country had 223 destructive earthquakes.
Besides, there are such a large number of seismic shocks which only the seismograph can detect. Mino-Owari earthquake that occurred in this country on October 28, 1891, was the most destructive one.
About 60 percent area was affected by this earthquake, but the area of great damage was confined in a densely populated plain in the provinces of Mino and Owari. The report says that in one minute 7000 persons were killed, 1700 injured and about 20,000 buildings were destroyed.
Moreover, fire that followed this catastrophic earthquake added more to the destruction of human life and property. After-shocks continued for several months afterwards.
The ground was cracked and fissures opened. Volcanoes and sand craters came into existence. The underground drainage was disrupted. Railway bridges collapsed and railway lines were buckled. This earthquake created a long fault line which was 64 km long and oriented in northwest-southeast direction.
Another catastrophic earthquake that destroyed the cities of Tokyo and Yokohama is the Sagami Bay earthquake of September 1, 1923. The seismic shock was so strong that the floor of the Bay and the surrounding mainland had been twisted round in a clockwise direction.
It is interesting to note that this earthquake occurred at a time when the Japanese housewives were preparing their mid-day meal. Therefore the fire that broke out played greater havoc and loss of life and property than the earthquake itself.
There were vertical displacements of the ground ranging from several centimeters to a meter. The Sagami Bay earthquake killed about 163,000 people and it’s magnitude on the Richter scale was 8.3.
Another earthquake that hit Kobe, Japan, occurred in January, 1995, killed about 5500 people and its magnitude was recorded 7.2 on the Richter scale. Japan had another earthquake of great intensity that occurred in the vicinity of Kobe on January 17, 1998.
As a result of this disastrous earthquake more than 5000 persons were killed and a large number of buildings were ruined. There was huge loss of life and property.
Remember that the earthquakes occurring along the eastern coastal margins of Asia and island arcs are mainly due to the collision of the Pacific and Asiatic plates and the volcanic activity.