Earthquake mechanism
Earthquake mechanism


How does an earthquake originate in the first place?
This page explains how the earthquake occurs and the mechanism of the emergency earthquake bulletin.




What is the mechanism of the earthquake?

Shuntaro
I knew that an earthquake occurred, but I do not know even if it is told that it works.

Yoichi
Burn the monster from the inside of the earth! Does it hit and get up?

Tama
I do not think so! Or, did not you learn it in the science class?

Yoichi
I told you in a joke ...

Shuntaro
So, how do you get an earthquake?

Hana
Let's see this video.

MOVIE What is the mechanism of the earthquake?

* In this movie, we are introducing the mechanism of the earthquake by plate type (trench type). Please be aware that there are also earthquakes caused by other causes.

What is the mechanism of the Earthquake Early Warning?

The emergency earthquake bulletin predicts the scale of the earthquake and the epicenter by catching the P wave at the time of the occurrence of the earthquake,
It is a system to announce several seconds to several tens of seconds before a big tremor (S wave) comes.
This emergency earthquake bulletin will be announced by the Japan Meteorological Agency when an earthquake with a seismic intensity of 5 or less is predicted.

* In the vicinity of the epicenter, the earthquake shake occurs earlier than the emergency earthquake bulletin, or the predicted seismic intensity may differ.

When an emergency earthquake bulletin is issued

MOVIE When an emergency earthquake bulletin is issued

IMAGE When an emergency earthquake bulletin is issued
When an emergency earthquake bulletin is issued, an emergency earthquake flash chime sounds from the television,
The target area of the emergency earthquake bulletin will be displayed below the screen as shown on the left.





Yoichi
I have seen it!

Hana
I am a little scared, but if you see it, take actions calmly.

If an emergency earthquake bulletin is issued, let's take the following actions。

○If you stay at home ...

· Hide under the desk. · Open the door and secure an escape route · When leaving the fire, leave
· Turn on or turn on TV or radio

○If I was at school ...

· Hide under the desk. · Open the door and secure an escape route 
※ First of all, let's act calmly according to the teacher in the neighborhood and the chime of the broadcast in the school.

The most important thing is to act calmly .

Let's make a seismograph!

In making this Web site, I actually tried making a seismograph with PET bottle.
Shuntaro
Finally I made a seismograph itself!

Tama
Why do not you try making it next time?

MOVIE Let's make a seismograph!

MOVIE Let's move a seismograph!
IMAGE Structure of actual seismograph

To record the motion of the ground, it is necessary to create something that moves differently from the movement of the ground.
The closest thing is the weight of the pendulum.
Therefore, seismometers are used as seismometers with various cycle pendulums (springs).

* The actual seismograph is equipped with a damping device to prevent the weight of the pendulum from shaking even if the shake stops.


Yoichi
Almost OK, then in the end ...

Tama
Pleace wait! Because this site has not ended yet! Secondary disaster is the most dangerous thing!

NEXT / Scary than the earthquake! What is the fear of secondary disasters?