Normally earthquakes are detected with sensative instruments, under the care of trained seismologists. With the Twitter API (our Twitter API profile), the ability to detect and report quake locations may fall into anyone's hands.
Developers are often finding themselves as API providers in addition to consumers. The same is now true for me with my project, BuildaSearch. I recently released a BuildaSearch API for deeper site search integration, moving away from a more plug-and-play approach I took earlier on.