What is secondary disaster?
What is secondary disaster?


The real fear of the earthquake is not just shaking.
In some cases, what is "secondary disaster" that exceeds the magnitude of the earthquake?




What is "secondary disaster"?

"Secondary disaster" is a disaster caused by the occurrence of an earthquake.
In addition to the tsunami that caused massive damage in the Great East Japan Earthquake and the fire that brought about major damage in the Great Hanshin-Awaji Earthquake, the secondary disaster also included
There are various things.
Yoichi
What is different between earthquakes and secondary disasters?

Hana
The "Tsunami" seen in the Great East Japan Earthquake is one of the secondary disasters.

fire

Fire is the second disaster with a high probability of occurrence due to earthquake occurrence.
Even with a small shake, neglecting the fire will have the potential to develop into a big fire.
The cause of the fire is not only the equipment which mainly uses gas / oil but also the fire by electric equipment equipment.
← Pictures of residential property spread due to the Great Hanshin-Awaji Earthquake
In addition, a fire whirl may occur due to the rising air current caused by the fire.
During the Kanto earthquake that occurred in 1923 (Taisho 12th year), this fire whirlwind occurred and it became a catastrophe.

○ Be careful when an earthquake occurs

· Switch off the devices in use. · Before evacuating, break the breaker (distribution board).
· When using the equipment again after the earthquake, please make sure that there is no gas leakage or abnormality in wiring equipment.

Tsunami

Regarding the disasters caused by the tsunami, in recent years the Tohoku District Pacific Offshore Earthquake that occurred in 2011 (Heisei 23),
Earthquake Soon I think that it is remembered that the great tsunami struck the town.
In the first place, the tsunami is caused by human disasters such as losing our lives, property of ship and harbor, physical damage caused by damage to houses,
There are also three kinds of indirect damage such as flooding and flooding of the fields.
The size of the damage of human disaster is not only the size of the tsunami.
It depends greatly on the time of occurrence of the earthquake and the living situation / evacuation situation of the town etc.

地割れ

Due to strong earthquake ground motion, cracks may occur on the ground surface. This is a crack.
Normally it is irregular crack, it is easy to be soft ground such as landfill land and sloping land.
Rockstones and landslides may occur in the mountains, and in some cases the terrain may change.
← Pictures of broken areas in the Niigata Chuetsu-Oki Earthquake (2007)

Liquefaction phenomenon

The liquefaction phenomenon occurs due to the fact that the ground of the land such as landfill is loose, the moisture of the ground increases and the ground weakens.
Unlike the others, landfill sites are evenly mixed with grains of earth and sand and water grains.
When a big earthquake occurs, the heavy soil moves downward, the ground particles move weakly as the water particles move to the plum.
The cars and buildings will sink and manholes will come up.
← Photo in liquefaction in Urayasu city, manhole pops out
Yoichi
Every second disaster was just what everything I've heard on television.

Shuntaro
Next will also introduce the two big disasters in the future that I have heard on TV.

NEXT / It does not always happen in Tokyo! Is it? Earthquake directly under the capital city