Earthquakes have been too frequent in the past 30 days and many have been violent. Japan's 8.9 magnitude earthquake triggered a tsunami as high as 10 meters that devastated the city of Sendai. Some nuclear power plants have also been affected and an oil refinery is on fire.
Just for the month of March 2011, New Zealand, China and Japan have been hit by violent earthquakes within 11 days. I cannot recall anything similar to this chain of devastating tremors in the past. It is very alarming because the earths crust and plates could be shifting. Observations have come up that tremors of large magnitude may have an effect for volcanos to erupt.
A documentary at Discovery Channel has shown that subduction zones can trigger volcanic eruptions.