iOS 9.3 is coming in the Spring and will introduce Night Shift as well as a number of other new features.
Early Earthquake Warning System in iOS 5 for Japanese Users
We weren't able to entirely explain or even activate the system, but despite the presence of english localization, it's reportedly intended for Japanese users according to 9to5Mac.
Japan's earthquake warning system was profiled by Time magazine earlier this year.
Japan has the most advanced earthquake early-warning system in the world. A nationwide online system launched in 2007, it detects tremors, calculates an earthquake's epicenter and sends out brief warnings from its 1,000-plus seismographs scattered throughout the country, one of the most earthquake-prone nations on the planet.The need for such a warning system was underscored by the devastating 9.0 earthquake and subsequent tsunamis Japan experienced earlier this year. iOS 5 users reportedly have the option to receive these early warnings in iOS 5 at the very bottom of the iOS 5 Notification Center settings pane. We were unable to activate the system from a U.S. based iPhone. The system is reported to be a common feature on Japanese mobile phones.