The mud volcano in Yushan Village of Nanhua Township erupted again on April 12, creating a boiling pot of soup-like mud. Retired teacher Lai Ming-chang says that the mountain erupts once every three or four months, and that this is a normal release of energy rather than a sign of an impending major earthquake.

At about 7 a.m., Lai was told by a landowner that another eruption was underway. As soon as it started, the surface of the water began bubbling, and the smell of gases released from the water got stronger and stronger. Around noon, the force of the eruption started mounting gradually, and it had reached its peak by 3 p.m. Mud was pouring outward from the middle, getting higher and higher. "It looked as though there was a pot of boiling soup on a burner," bystanders said.

Being a long-time observer of these eruptions, Lai says that the last eruption occurred on January 9, and they generally last between 24 and 26 hours. The water inside the volcano will dry up again in three days, but when they seep out to form an underground lake, the volcano will erupt again.

Lai says that the mud volcano in the village is an artificial oil well from the period of Japanese occupation. Energy will be released in the form of a natural eruption when it reaches the saturation point. The cycle has nothing to do with the weather, nor is it a sign of an upcoming major earthquake. A major earthquake could hasten the eruption, however, as the energy accumulation would reach its saturation point sooner.

In the four years Lai has been observing the phenomenon, it erupted twice in 18 days at one point, and on another occasion erupted for two days and two nights without stopping. After that, the next eruption did not occur for five and a half months.

Accompanied by Mr. Huang Ming-feng, the director of General Affairs for the Yushan Elementary School, three students from the school went to collect data from the site for their science exhibit. The students, however, failed to collect gases with plastic straws during over a month of observing the site. "We used to only hear our grandpas and grandmas tell stories about this; it's really cool now to see it ourselves," they say, adding that after the water clears up, the center of the hole "seems like it has no bottom".

"I wonder how people dug it so long ago?" one of them says.