Scientists have been busy monitoring earthquake swarms in and around the Yellowstone Caldera.
University of Utah geophysics professor Bob Smith says they have come across three simultaneous earthquake swarms.
He calls the simultaneous swarms "remarkable."
Smith tells the Jackson Hole News & Guide the swarms have left many questions for scientists to ponder.
He says that's because concurrent swarms have never been detected in the past.
Temblors from the three quake swarms mostly hit in three areas: Lewis Lake, the Lower Geyser Basin and the northwest part of Norris Geyser Basin. A total of 130 earthquakes ranging from magnitude 0.6 to 3.6 were observed.
Yellowstone's recent earthquake swarms started on Sept. 10 and were shaking until about 11:30 a.m. Sept. 16.
Information from: Jackson Hole (Wyo.) News And Guide, http://www.jhnewsandguide.com