Don't be surprised, but be alerted by this alert sound

For people you may have heard this alert sound but don't know what this is, I would like to explain. (Click above video to confirm the sound, if you are not sure.)

This is the alert sound sent by Meteorological Agency Japan to let us know the huge earthquake will hit the area where you are very soon.

Let me explain more detail.

Meteorological Agency defined the level of seismic intensity of ground motion at a scale of zero 0 to seven 7. (some degree is divided two levels so in total scale comes to 10 degrees.)
And we should be careful from Level 4, in which case hanging objects such as lamps swing violently. Dishes in cupboards and items on bookshelves may fall. Many unstable ornaments fall. Unsecured furniture may move, and unstable furniture may topple

This alert sound will be sent only to mobile phones device where level　4 is expected.

When you watch any TV program, of course, you will get early warning information on TV screen.
But this is not necessarily a useful information, because most TV programs is nation wide programs. For instance, in case level 4 earthquake happens in Tohoku area, it may not be felt that strong in Kanto area.

But this alert sound is different. Again, this alert will be sent 'ONLY' to the cell phones which are in exactly the area where more than level 4 ground motion is expected.

So unlike the alert from the TV, we really should be careful when you hear this sound.

That being said, recently we hear this sound too often wherever we are. And I feel it's very funny when you are in train cargo and start hearing this beep sound suddenly from 'EVERYBODY'S' pockets, handbags, and cargo will be filled with this strange sound. (The actual situation is not funny at all, though.)

This system is started since 2007. And the default setting of any mobile phones purchaed after 2007 is 'ON', regardless of the mobile phone carrier, Docomo, AU, Softbank. The only exceptional device is iPhone. It doesn't have features to receive such alert in default setting. Softbank telecom should do something.