During 2-9 pm yesterday, large magnetic field was observed especialy in the BS.
In this term, lightning has occurred near kamioka.
Please let me know if something strange behavior was happened.
Now (8/5 17:50) we can hear the thunderbolt.
At the timing of a lightning, VIS channel is also excited
e.g. 8/5 BS yaw & mag
[analysis of the lightning event in 8/5]
Spectrogram (left) & Q-transform (right) of Bz -> ~5Hz, 10-6T/√Hz
BS OpLev Yaw motion : ~20s period, ~2min damping
