The latest beta of iOS 5 features an earthquake warning system for Japanese iPhone users. The feature constantly checks in with Japan's early warning system, which consists of over 1000 seismographs scattered throughout the country. The iPhone's earthquake warning system can therefore give users a few vital seconds--or, in some cases, even minutes--of warning in case of a disaster.

As useful as this earthquake warning system sounds, it's nothing new; other smartphones have had the option to connect to Japan's early warning system for years now. In fact, there's even third-party iOS apps that can connect to the system. Still, after this year's devastating earthquake Apple apparently feels the need to give users more direct access to the system.

Because the new feature constantly connects to Japan's early warning system, Apple warns that it may drain battery life. Of course, less battery life seems like a small price to pay, considering the protection this feature provides.

For users outside of Japan, it may not be too long before you see a similar option on your smartphone. Japan has had its early warning system online since 2007, and other countries are creating early warning programs. Mexico has a similar system, and California has an initiative scheduled to go online in 2013.