The British Geological Society has confirmed two earthquakes, just four hours apart, were recorded off the Fylde coast.
The first hit the Irish Sea, 25km from Fleetwood at 5.37am on Sunday.
The tremor measured 2.4 on the Richter scale and the BGS said it hit at a depth of 3km.
Residents also reported feeling a second tremor, which was slightly larger, in the same area.
The second earthquake hit at 9.58am and recorded a magnitude of 3.3 and depth of 5km.
The BGS said seismologists are now working to find out what caused the earthquakes.
Did you feel the tremors in your home?
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For more on this story, see Monday’s Gazette.