By George Bao
LOS ANGELES, Jan. 31 (Xinhua) - No volcano eruption is expected imminently in Yellowstone National Park in the United States as speculated by some news reports, geophysicist Peter Cervelli said on Monday.
News reports both from the United States and some foreign countries said scientists were predicting that the world's largest super-volcano in Yellowstone National Park, one of America's most popular national parks, could erupt in the near future.
Reports said Yellowstone National Park's caldera has erupted three times in the last 2.1 million years and researchers monitoring it say there could be in for another eruption.
They said that the super-volcano underneath the Wyoming park has been rising at a record rate since 2004 - its floor has gone up three inches per year for the last three years alone, the fastest rate since records began in 1923.
Asked to comment on the speculation, Cervelli of the Yellowstone National Park Volcano Science Center, told Xinhua in an interview that the eruption of a big volcano is possible, but it is " extremely unlikely it will erupt in a near term."
"You are talking about a volcano that has not been erupted for hundred thousand years or so. We do not really expect any imminent volcanic activity. There is no panic, there is no alarm. Basically things in Yellowstone are doing what they are always doing. It is a very active place geologically, but that does not mean a volcano is going to erupt imminently," Cervelli told Xinhua.
He said the volcano in the Yellowstone National Park is a very large volcano. It has three very large eruptions in the past 2.1 million years or so. The most recent eruption was 640,000 years ago.
He said a team of scientists are monitoring the Yellowstone National Park very closely with GPS and other advanced technology.
He said the volcano is quite well monitored. A few months ago, some scientists at the University of Utah and elsewhere threw out some observations where the GPS receivers had measured uplift of Yellowstone from 2004 and 2009.
He said the uplift was pretty consistent in that interval, but since 2009, the uplift slowed down.
Cervelli did not say whether the slowdown of uplift is a good sign or bad sign, but he stressed: "We think that all the activities that we have seen so far are normal activity for this volcano. It is not absolutely silent, it is not absolutely quiet. We do not expect it absolutely quiet because none of the active volcanoes all over the world are always quiet. The measurements from the GPS are not alarming. They are very interesting from a scientific view and they help us understand what's going on beneath the volcano. But they are not alarming."
He said over his career, he has participated in over 10 to 11 responses to volcanoes that actually did erupt.
"So I do have some experience in distinguishing signals or data we measured that pointing to the eruption and signals that are just part of the normal background behavior of the volcano. The signals received at Yellowstone are just part of the normal background," said Cervelli.
He said some people got to the television to give their opinions on whether the volcano will erupt, but if you have somebody who is educated and experienced and actually has worked at Yellowstone, " none of those people is alarmed," he affirmed.
He said the volcano research center will release its scientific report on a regular basis, and some intended to emphasize some points that are really not true.
He said if the volcano in Yellowstone did erupt, it will be the same size as the last eruption, which will be devastating and will have a very serious impact on global economy. Not only the United States, but the whole world will be impacted.
"But it is a very remote possibility. It does not happen very often especially on a time span of human life. I would say the chance of a big eruption in our life time is extremely very small. You are talking about something that is roughly the possibility of an asteroid striking the earth. You are talking about something that occurs on time of a hundred thousand to a million years. So it is not on the top of my list to be worried about. We do have all the instruments there to monitor the volcano. If something really bad would happen, we would know about it for months or even years in advance," said Cervelli.
The National Geographic News reported last week that beginning in 2004, scientists saw the ground above the caldera rise upward at rates as high as 2.8 inches (7 centimeters) a year. The rate slowed between 2007 and 2010 to a centimeter a year or less. Still, since the start of the swelling, ground levels over the volcano have been raised by as much as 10 inches (25 centimeters) in places.
"It's an extraordinary uplift, because it covers such a large area and the rates are so high," the National Geographic News quoted Bob Smith from the University of Utah, a longtime expert in Yellowstone's volcanism, as saying.
Scientists think a swelling magma reservoir four to six miles ( seven to ten kilometers) below the surface is driving the uplift. Fortunately, the surge doesn't seem to herald an imminent catastrophe, Smith said.
"At the beginning we were concerned it could be leading up to an eruption," said Smith.
"But once we saw (the magma) was at a depth of ten kilometers, we weren't so concerned. If it had been at depths of two or three kilometers (one or two miles), we'd have been a lot more concerned, " said Smith.
He said studies of the surge may offer valuable clues about what 's going on in the volcano's subterranean plumbing, which may eventually help scientists predict when Yellowstone's next volcanic "burp" will break out.