CODY (AP) - Geologists in Yellowstone National Park are scratching their heads over data that appears to show at least one rare eruption of Steamboat Geyser this week.

Typically, the world's tallest geyser will shoot water hundreds of feet in the air for 20 to 40 minutes, although some eruptions last longer.

Information collected this week indicates there may have been more than one eruption but none of them match the strong sustained bursts of water from last year's eruptions on April 26 and Sept. 13.

No one apparently saw the one or more eruptions this week so scientists are forced to piece together what happened using data from temperature monitors near the geyser and gauges that measure water flow and temperature more than a half-mile away along Tantalus Creek, which funnels water from Norris Geyser Basin into the Gibbon River.

Park geologist Henry Heasler said it's too early to understand exactly what happened, but added it was different from the eruptions last year.

"It's got all of us going 'wow, what's going on?"' he said.

Irving Friedman, a geologist who spent several years studying Yellowstone's geothermal features, looked at the data from Tantalus Creek on Thursday and was left with more questions than answers.

"This is like nothing we've seen before," he said.

Initial information showed high amounts of water flowing past the Tantalus Creek gauge on Sunday morning for about four hours and then for about 11 hours on Wednesday.

Temperature sensors also showed a significant rise in temperature between 12:31 a.m. and 12:33 a.m. on Wednesday.

Heasler said officials will first check all the park's measuring instruments to make sure they were functioning properly. If so, geologists will start examining the data and coming up with hypotheses.

Heasler speculated there could have been more than one eruption, more than one pulse of water in a short period of time or simply a different kind of eruption than has been seen at Steamboat in the past.

"Right now, the data just shows that the eruption was not typical," he said.

Geologists hope to use the information to create some of the most precise information ever about Steamboat's eruptions. In the past, most eruption data was based on eyewitnesses.

"That's much more like doing detective work where you interview people and try to find out things like how much their watch might have been off," Heasler said. "This time we know exactly what we're measuring and when we measured it."

Heasler said it could take weeks to analyze and understand the data from the latest Steamboat activity.

One key question always involves finding a connection between seismic activity in the park and Steamboat's eruption. Earthquake sensors in the park didn't register much activity when Steamboat apparently erupted.

"There's no evidence of any earthquakes going on that either caused it or resulted from it, so it was a very quiet time seismically," Heasler said. "It was almost an unusually quiet time."

Heasler also wants to know if there was any interaction between Steamboat and 10 new steam vents in a long line just north of the basin.

Meanwhile, the Park Service is trying to make as much information about the latest activity available to scientists and others who might have a theory about what happened.

Reports of eruptions at Steamboat started in 1878, when witnesses said huge rocks blasted into the air as the geyser exploded.

It erupted more frequently over the next several decades, sometimes shooting water 40 to 50 feet in the air, sometimes 300 feet. The geyser was dormant between 1911 and 1961 and then erupted three times in 1989, once in 1990, 1991 and 2000 and then twice in 2002.

Like other geyser enthusiasts, Heasler is searching for any kind of pattern in Steamboat's strange behavior.

"We had one last April 26 and now one on March 26. Is a pattern beginning to develop? Will we have another one in the fall? We just don't know," he said. "I'm just very, very pleased that Steamboat has become a little more active."