SE will be losing money, but they are also insured against these kinds of things. This happening is unlikely, but possible, so of course SE have failsafes in place to prevent substantial monetary losses from downtime. BUT, this would possibly NOT be one thing you can get insured against... I honestly don't know, because I am not familiar with Japanese corporate insurance policies. All I know is that when I lived in Utah (an active EQ zone), I had to have additional EQ insurance on my home.

Anyone wanna enlighten me?