Now my server (which is sort of low on disk space already) had a ton more useless crap installed that I don't need and don't really know what can be safely removed.
Anyway, on to the interesting part. Xearth for Windows has an "earthquake" feature where recent earthquakes are displayed as yellow circles on the earth image, with a size proportional to the magnitude of the earthquake. It was a fairly quick and dirty implementation because it just draws a circle on the screen without regard to the map projection at all. With the new overlay support in xearth, I thought a good way to implement earthquakes would be to render the earthquake circles onto a mostly-transparent PNG file, and then overlay that over the map image. Here's what you get:
If there are any earthquakes visible (there ought to be), they will appear as yellow circles. This is done by downloading the current earthquake list (magnitude 5 or greater) from the USGS, using XSLT to transform it into SVG, then converting it to PNG for use by xearth. The earthquake list is updated once an hour.