Twitter recently posted a case study of the U.S. Geological Survey’s use of Twitter for earthquake detection (which we recently covered here).  The brief description:

One of the U.S. Geological Survey’s unique responsibilities is the monitoring and reporting of earthquakes, which affect the daily lives of people around the world. By mining real-time tweets, the USGS expands its suite of seismically derived information and obtains first-hand accounts of shaking seconds after an earthquake occurs.