I did a post in May 2008, too, about the drills, which helped explain the sirens.
There was a magnitude 3.0 earthquake north of Seoul in February, and since then and the larger quakes in Haiti and Chile, officials in Korea have been looking at how ready Korea is for a big one. In January, the Korea Times reported Seoul is unprepared for earthquakes:
Nearly nine out of 10 commercial and residential buildings in Seoul were built without earthquake-resistant technology, a recent research showed Tuesday.
According to research conducted by Seoul City, only 6,100 out of 628,000 buildings in the metropolitan city with 12 million people are resistant to an earthquake whose magnitude is tantamount to the one that virtually devastated Haiti last week, leaving huge numbers of casualties.
Only six percent of buildings in central Seoul, including Yongsan and Jongno, were designed with quake-resistant technology, while nearly 20 percent of buildings in southern Seoul, including Gangnam and Seocho were built to withstand major tremors, the research said.
Meanwhile, a state institute said Monday Korea is not safe from earthquakes such as the one that struck Haiti, calling for swifter emergency measures against the natural disaster.
Earlier this month the Korea Herald wrote "Korea is no longer 'earthquake-proof'" and I'll yield the floor to @koreangov for this one:
"Korea no longer 'earthquake-proof'" http://digs.by/1axF But no worry since Koreans still earthquake proof: http://digs.by/1axH
Here's that second article, and here's another example of that kind of reporting.
In that post about the February earthquake I put up this link from the Korea Meterological Administration which tracks international and domestic quakes. The last domestic one was on the 9th, a 3.2 off the coast of Chungcheongnam-do: