YELLOWSTONE NATIONAL PARK, Wyo. -- Yellowstone National Park geologists have reported the third eruption from the world's largest active geyser in the past six weeks. The National Park Service says a park visitor reported seeing a rare eruption of Steamboat Geyser on Friday.

Steamboat Geyser, in Yellowstone National Park's Norris Geyser Basin in Wyoming, erupts on Wednesday, July 31, 2013.
Robb Long / AP
Park geologists compared the report with seismic activity and the discharge of water and concluded the eruption probably started at 6:30 a.m.
The geyser also erupted on March 15 and April 19.
All three eruptions were smaller than the last major eruption that occurred on Sept. 3, 2014.