The 7.1 magnitude earthquake in Yushu, northwest China’s Qinghai Province may be the first of a chain of earthquakes on the Qinghai-Tibet Plate this year, say earthquake experts.

Pushed constantly by the Indian Ocean tectonic plate, the Qinghai-Tibet Plateau is an earthquake-prone zone. Yushu County is at the center of the plateau and has suffered many strong earthquakes in its history. About 90 percent of major earthquakes in China have happened on the Qinghai-Tibet Plateau. Experts say a mere 7.1 magnitude earthquake will not have released all the underground energy. Therefore, in the next few months, a chain of earthquakes may occur in the area.

The Yushu earthquake displayed a typical "foreshock + major earthquake + aftershocks" pattern. A 4.7 magnitude earthquake happened one hour before the 7.1 magnitude earthquake on the morning of April 14. By the 11am that day, 18 aftershocks had hit the area. A magnitude 6.3 aftershock struck at 9:25 am.

The fault zone where the Yushu earthquake occurred belongs to the Bayan Kara area which is in a seismically active period. The 7.3 magnitude earthquake in Yutian, Xinjiang, the magnitude 8.0 Wenchuan earthquake in Sichuan, and Yushu earthquake happened on the northern, eastern and southern borders of the area.

After the May 12 Wenchuan earthquake in 2008, China experienced an active period, seeing 99 quakes stronger than magnitude 5, followed by a quieter period in 2009 with just two magnitude 6 quakes. The Yushu earthquake may be a sign that a new cycle of seismic activity has begun.