It was about 17:00, when I was taking British Culture class.
Those noisy sounds were given from students' mobile phones.
One of my friends, whose phone had also been ringing loudly, told me that a big earthquake happened at Fukushima and we should be ready for protecting ourselves from shaking.
As you know, the shake was not strong here.
I was so surprised that the recent mobile phones have a service of ringing emergency alarm automatically.
Convenience must save our lives. (´∀｀）