More Often All The Time
What we're experiencing is an exponential increase in media exposure of earthquakes and wider spread of seismographs. The limit is when every newspaper/news website/news channel reports every tremor of even the slightest shake of a seismograph needle, and seismographs are placed on every square meter of land and sea.
http://earthquake.usgs.gov/learn/topics/increase_in_earthquakes.php
The reason we're seeing this exponential increase as you put it, is that the earthquakes are becoming more powerful, more concentrated, and physically closer together. The media will give coverage in due proportion to earthquakes of this nature, especially since they're starting to produce "chain reactions" in some cases.
This earthquake in PNG was preceeded by a slightly smaller one in Vanuatu about 12 hours prior - then within 90 minutes to 2 hours after this one, we had 2 more within a fairly small radius (Indonesia and the Kermadec Islands).
The more of these we have at significant strengths like we saw on this earthquake, the more the media will report back and follow. For what it's worth though, our policy here is that we do not cover earthquakes unless they are at least 6.0 Magnitude, or they cause significant major damage.