How does an earthquake occur in the first place?
On this page, we will explain the mechanism of earthquake occurrence and the mechanism of earthquake early warning.
Mechanism of earthquake
We talked about general class in a certain high school, disaster prevention in class.
The class is over and after school, good friends are having fun and talking.
Shun
I learned the mechanism of the earthquake at elementary school. Sasaki, do you remember?
Sasaki
Monster burns from the inside of the earth! You're not gonna get up, don't you?
Kaori
There will be no such thing!
Sasaki
Well then can you explain?
Kaori
…！
Hana
... Excuse me, can you see this ...?
Movie
What is the mechanism of the earthquake?
* In this video, we introduce the mechanism of plate type (subduction type) earthquakes. Please be aware that there are earthquakes that occur due to other causes.
Mechanism of earthquake early warning
The Earthquake Early Warning predicts the size and the epicenter of an earthquake by capturing P waves when an earthquake occurs,
Japan's unique system that announces a few seconds to a few tens of seconds before a big shake (S wave) comes.
This earthquake early warning will be released by the Japan Meteorological Agency when an earthquake with a seismic intensity of 5 or more is predicted.
* Near the epicenter, earthquakes may occur earlier than earthquake early warning, or predicted seismic intensity may be different.
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 earthquake early warning is issued, the chime of the earthquake early warning rang from TV and
The target area of the earthquake early warning will be displayed on the screen below as shown on the left.
Sasaki
I have seen it, I was surprised.
Hana
The chime sound is scary, but if it is issued, let's keep calm behavior in mind.
If the Earthquake Early Warning is issued, take the following actions.
○ If you are at home ...
・ Hide under the desk. ・ Open the door and secure the escape route ・ When the fire is on, leave
・ Turn on or leave the TV or radio
○ If you were at school ...
・ Hide under the desk. ・ Open the door and secure the escape route
※ First of all, let's calm down and act according to the nearby chime and the chime of the broadcast in the school.
The important thing is to to act calmly .
Let's make a seismograph!
In making this website, I actually made a seismograph using plastic bottles.
Shun
I finally made the seismograph itself.
Kaori
Would you like to make it with everyone next time?
Movie
Let's make a seismograph!
Movie
Let's move the seismograph
Image
Actual seismograph structure
To record ground movements, it is necessary to create something that is different from ground movements.
It is the weight of the pendulum that is close to it.
Therefore, in the seismometer, pendulums (springs) of various cycles are used as seismometers.
* The actual seismograph has a damping device to prevent the weight of the pendulum from shaking continuously even if the movement stops.
Sasaki
Finally, ...
Kaori
Wait! Because this site is not over yet! Even if the second disaster is the most dangerous!
Shun
Sasaki
Kaori
Hana
When an earthquake early warning is issued, the chime of the earthquake early warning rang from TV and 