In modern cities, the leakage of gas, toxic gas and
radioactive substances can lead to secondary disasters
such as fire, poisons and radioactive contamination
due to the failure of underground pipelines, cutting off
of cables, water, power outages and blocking of communication.
In mountainous areas, earthquakes can also cause collapse
and landslide, often resulting in the burial of villages
and towns. The collapse of the rocks blocks rivers and
oceans and forms an earthquake lake upstream. In 1923,
a landslide occurred in Kanagawa Prefecture during the Kanto
earthquake in Japan and it falled down along the vally,
reaching a distance of 5,000 meters.
After earthquake, there are often serious casualties and
property damage and the affected zone will be directly influenced
by the earthquake and indirect secondary disasters.