Did you just experience an earthquake? Find out how close and how big it was with iFeltThat, the most customizable worldwide earthquake app for the iPhone and iPod touch.

iFeltThat retrieves information directly from official USGS sources to show you seven days of microquake activity as low as magnitude 1.0 in most U.S. regions. Earthquake lists for U.S. regions show you precisely where an event occurred (not just "Northern California," but "5 mi SE of Santa Rosa, CA"). Rotate any list view to see the region-wide map.

In addition to 20 region-specific event listings around the world (visit support page for a complete list), iFeltThat features a Nearby region, which uses your current location as a center point. Add an unlimited number of center points from your Address Book to keep an eye on seismic activity near your family and friends (or your own hometown while you travel) down to magnitude 1.0 in the U.S. (4.5 elsewhere). Or set a center point from any event location around the world to monitor earthquake swarms within 500 miles of the center point.

View single-event and interactive region-wide maps in roadmap or satellite hybrid styles. All maps are pinch-zoomable and draggable, just like the Maps app. Optional one-touch zoom buttons in detail maps let you zoom in and out quickly for one-handed operation while on the go. Tap the Newer and Older buttons to navigate instantly from quake detail to quake detail without having to go back to the list.

Whenever a ••USGS Shake Map•• is available for an event, a special icon appears in that event's detail view. Tap the icon to see the Shake Map within iFeltThat. In fact, all related web pages (including direct access to North American and Pacific/Indian Ocean ••Tsunami Warnings••) appear inside the app. Also from inside the app, send an email with info, links, and a screenshot of an event detail screen/map to anyone you like.

Customize which four regions are ready to view at a single tap on the bottom bar. For each region list, set the minimum magnitude threshold and default map zoom level.

One earthquake may have brought you to iFeltThat. You'll be so intrigued monitoring unexpected earth movements near you and around the world that you may find yourself using IFeltThat more often than you check the weather or news.