16 small quakes shake Yellowstone

YELLOWSTONE NATIONAL PARK, Wyo. (AP) — Sixteen small earthquakes with magnitudes up to 2.7 shook the park's Pitchstone Plateau last week.

The quakes were detected by seismographs operated by the University of Utah and partners.

They began last Monday, just before midnight. The largest occurred at 3:09 a.m. Tuesday, and the quakes continued until Wednesday, according to Bob Smith, a University of Utah professor.

The quakes occurred on the southern edge of a volcano caldera at the center of Yellowstone. The volcano last erupted 70,000 years ago.