YELLOWSTONE, Wyo. (ABC4) – The Yellowstone region was reportedly hit by over 150 earthquakes within two weeks, according to the U of U Seismograph Stations (UUSS).

The first in the series of earthquakes hit the region on March 16. The last earthquake hit on March 29. The ongoing swarm of quakes hit mainly beneath Yellowstone Lake, about three miles southeast of Lake, Wyoming.

According to UUSS, the smallest of the earthquakes measured only about 0.7 on the richter scale. The largest, which struck on March 29, registered 3.7 in magnitude.

The swarm of earthquakes began in a small cluster on March 17. The following two weeks had sporadic quakes ranging from one to five quakes per day. March 29 was the most active day, with a majority of the earthquakes hitting that Wednesday.

The United States Geological Survey (USGS) says the Yellowstone region experiences about 1,500 to 2,500 earthquakes per year. The majority of the earthquakes are too small to be felt but can easily be picked up by seismometers operated by UUSS.

The UUSS said swarms of earthquakes such as the one over the last two weeks are common and account for roughly 50% of the total amount of earthquakes at Yellowstone.

According to the USGS, there have been over 48,000 earthquakes in the Yellowstone region since 1973. Over 99% of those earthquakes are too weak to be felt by anyone. The USGS said most of the swarms contain only about 10 to 20 earthquakes and only last about one or two days. Even so, there are times of large swarms of thousands of earthquakes that can last for months on occasion.