Some believe the cause is due to rising activity from the sun.
The 11 year solar cycle sees increasing and decreasing periods of solar flares hitting earth (we are entering the maximum period, peaking in 2013). However, it is not solar flares that are the concern but Earthbound Coronal Mass Ejections, filaments and influence of coronal holes on the sun. CME's may have a close relationship with the startling rise in earthquake activity on Earth. A statistically significant relationship can't be ignored and some people have theorised a predictive model of looking at the effect of Earthbound CME's and resulting earthquake activity.
Targeting Coronal Hole 446, region covers 7 Degrees North Latitude across the equator to 9 Degrees South for this watch.
Possible areas that could receive a significant 6.9 magnitude earthquake are : Banda Sea, Flores Sea, Celebes Sea Regions in Indonesia, Northern Peru or Ecuador would be less likely but possible along the same latitude.
Significant filament eruption could indicate a polar region volcanic eruption or activation in the Iceland or Alaskan regions during this watch.
Recent images of solar activity 2011.04.30 Xray type flares: