Find the code on Github.
This is a fledgling framework for visualizing geotagged data, and the datasets provided by the USGS are nice to start with as they are clean, are updated every few minutes, are readily available, include multiple features for every event, and yield visually interesting results without much transformation.
The sketch generates both spherical and two-dimensional projections is a simple transform:
The datasets can be obtained at USGS in multiple formats. This sketch uses the CSV files, available through the "Spreadsheets" link. There are also real-time feeds, and it's interesting to see the variety of available sources from probability maps to live seismogram displays from any official monitoring station in the world.
The next steps could incorporate additional data like seismic probabilities, other geological hazards, geographic information, and yes, maybe even tweets. The statistical models used to predict earthquakes may also be fun to visualize. Also, support for the popular GeoJSON format seems critical.