Firefighters received several calls just before 8pm last night.
It was previously thought the incident was caused by a fault at an electricity sub-station, but the authorities have now said this was not the case and the explosions are a mystery.
Caroline Mifsud, 37, from Saffron Walden, said: "My son heard an explosion and felt a shake and about ten minutes later there were police and fire engines everywhere. Everyone is talking about it on Facebook."
Police from Saffron Walden, Dunmow and Stansted and firefighters investigated the loud bangs and shaking, which had been reported by residents across the town centre and in villages further afield including Thaxted, Ashdon and Newport.
Paul Curtis, station officer in charge at Saffron Walden Fires Station, said: "It's a bit of a mystery.
"The power companies said there have been no reports of power loss and we investigated and could not find anything.
"We also checked with the military to see if they had conducted any training exercises."
.
Bollide activity? There's been an amazing amount of bollide activity in the UK skies the past 6 - 7months, it could easily have been a single bollide that exploded once intitially, but fractured into a large enough fragment for a second explosion, or a pair of twins reflecting each other. Saffron Walden does not historically, or usually experience this sort of acitivity, my Great Aunt used to live there for many years and lived there for the peace and quiet.