A "swarm" of earthquakes is how experts are describing the recent events on the Mid North Coast.
Senior Seismologist Phil Cummins told Triple M that the recent swarm of earthquakes is due to the slow build up on stress on the Australian Continent.
"That stress is on the plate boundaries from places like Indonesia and New Zealand, and this will lead to earthquakes" he said.
With recent earthquakes on the Mid North Coast, Bellingen recorded a tremor at a magnitude of 3.3, while another was register near Coffs Harbour at 4.2 magnitude at 1:28pm today.
Triple M listener Tony said he felt the Coffs Harbour tremor at Toormina, while others reported feeling movement around Bray Street and also in Lyons Road.
Coffs Harbour local Jamie said he heard a loud rumble for about 10 or 15 seconds in the middle of the city "sounding like someone was running upstairs".
Residents in South West Rocks and Wauchope are saying the quake "felt like a semi trailer hitting". Cracks have appeared on some homes.
It is unknown how long the tremors in the region will continue.
"Swarms are a little bit mysterious. We understand why we get earthquakes here and there in Australia, but to get a number of small earthquakes in one area in a small amount of time is a bit of a mystery", Mr Cummins told Triple M.