The USGS live seismographs are showing a lot of shaking worldwide. Most of it is low-level, but it is unusual for so many seismographs to be reporting shaking at the same time. There have been a number of incidents like this in the past few months. Current data is here. (This is being posted at 8AM Dec 25 2010, so if you look at the link later, it might show a more settled situation.) To see a video that shows the data as it appeared on December 21, click here. In 2010, there have so far been 24 earthquakes registering 7.0 or more on the Richter Scale. In an average year, there are 15.