A group of Chinese scientists announced on Tuesday that what they discovered last September in Xinjiang Uygur Autonomous Region is the China's largest mud volcano group.

"Such a group of active mud volcanoes is very rare in China," said Xiao Jiang, director of the Wusu Tourist Bureau in the Xinjiang Uygur Autonomous Region.

"Tourists coming here will get a vivid knowledge about crustal movements and mud volcanoes."

The 36 volcanoes were discovered last year by scientists studying the area.

Researchers from the Xinjiang University found them oozing mud and seeping gas during their study tour last September north of the Tianshan Mountains. The volcanoes are in a 40,000-square- meter area at Baiyanggou Town, near Wusu.

"The maximum volcano crater is 1.6 meters in diameter and the smallest one is only the size of a bean," said Xiong Heigang, a professor with the School of Resources and Environment Science at the Xinjiang University.

Volcanoes spewing gas and mud differ greatly from traditional land volcanoes which spout lava and ash, Xiong said.

The emission from the mud volcanoes is greenish and brownish in colour.

"Petroleum is found floating in some craters," Xiong said.

He said the most active Wusu volcano erupts more than once every second. Others are less active.

The temperature of emissions is between 15 C and 25 C.

Geologists believe Wusu's volcanoes were formed about 1 million years ago when sand and mud beneath the surface was squeezed upwards by compressive forces and expelled at the surface.

Experts believe mud volcanoes often form and dissolve repeatedly underground but rarely break through the earth's surface.

Mud volcanoes are most often found in regions of the world rich in oil and natural gas.

Mud volcanoes have only been discovered in a few countries, like the United States, Mexico and New Zealand.

Wusu Tourist Bureau is considering a comprehensive plan to protect and promote the rare volcanoes.

(China Daily September 5, 2002)