The Japanese version of Apple's upcoming iOS 5 will have an extra feature not found in other versions: earthquake warning notifications built right in.
The notifications, which will be tied to Japan's earthquake early-warning system, the most advanced in the world. The iPhone will notify people by locating you via GPS and then sending you a notification if you're within a certain distance from its epicenter.
One problem is that having these notifications on will drain your battery faster than if they were off. But that's small price to pay for the peace of mind that would come from knowing they were on, right?
Via 9 to 5 Mac