Lightning doesn't strike twice, but it appears earthquakes do

Yesterday morning, at about 1am, a small earthquake struck Osaka Bay. It woke us both up; but Emma couldn't recollect it happening the next morning, so I put it down to a vivid dream until I asked some teachers about it later in the day.

It happened again just after 4am this morning. Only very minor--we're both intact, and more importantly, our bottle of Lambrusco is still sitting happily on top of the buffet. To put things into perspective, around 20 percent of the world's earthquakes happen in Japan. I couldn't find any information online regarding yesterday's local earthquake, but it appears a larger one also struck north of Tokyo. I guess we should be surprised, then, that we hadn't encountered a tremor sooner.