The United States Geological Society has measured seven minor earthquakes in Maine in June, four over the past several days.

The strongest earthquake this month was near Swanville on June 7 and was a magnitude of 2.1.

The most recent series of earthquakes began on Sunday and the last was recorded Wednesday morning.

The USGS says earthquakes below a 3.0 magnitude are low intensity and are felt by few people, although many people reported hearing ‘a loud rumbling sound’ during the earthquake on June 7.