Is Earth on 'quake mode' again?

The recent two months have witnessed some unusually active seismic activities across the globe, as a string of powerful earthquakes have jolted Ecuador, Japan, Myanmar, Afghanistan and Indonesia, killing dozens of people and triggering several tsunami alerts.

Many cannot help wondering: Is this just coincidence, or is our planet once again on a "quake mode" that will trigger one major tremor after another?

Even experts find it difficult to draw a quick conclusion, but they have noted that both the magnitudes and frequencies of the recent quakes are still "within a normal range", Xinhua news agency reported.

It is hard to judge whether the Earth is experiencing another seismic active period, said Randy Baldwin, a geophysicist with the US Geological Survey.

He said the quake-prone zones around the world could see strong shocks coming at any time, but so far there have been no signs of connection between seismic activities in different zones.

The causes of the earthquakes are complicated, experts say, while pointing out that the geographic location of Japan and Indonesia, both of which sit right on the Circum-Pacific Seismic Belt, is the main factor behind their frequent quakes.

The belt, which extends all the way through the US Pacific coast, China's Taiwan, the Philippines and New Zealand, releases about three quarters of quake-discharged energy from the interior of our planet. It has earned a befitting name -- the Pacific Ring of Fire.

While it seems too early to sound the alarm against a new wave of disastrous earthquakes, some scientists insist that certain "high risk zones" do require a close watch.

The southern part of the Qinghai-Tibet plateau in China always has a high geological activeness, and is now entering a "clustering period" of massive quakes above magnitude 7.0, warned Xu Xiwei, a researcher at the Institute of Geology under the China Earthquake Administration.

"We have to make further studies to better understand the seismic trends in that region," said Xu.