Instruments around the 11,240-foot mountain have detected more than a dozen earthquakes too small to be felt since Sunday.
Sensors show that the quake swarm has been about five miles south of the summit beneath the Government Camp area at depths ranging from 1 1/2 to 3 miles.
The largest of the quakes, a magnitude 2.4, occurred Wednesday afternoon.
About 20 earthquake swarms have been detected at the mountain in the past decade. More than three-quarters of the roughly 400 quakes at Mount Hood since 1990 have occurred in such swarms.