Taylor Swift's concerts in the US city of Seattle generated seismic activity equivalent to a 2.3 magnitude earthquake, a seismologist has said.

The data was recorded at Swift's sell-out Eras tour performances at Lumen Field on 22 and 23 July.

Seismologist Jackie Caplan-Auerbach said the activity was caused by Swift's fans or the sound system.

The shows beat the previous record in Seattle, known as the city's "Beast Quake" in 2011.

That was generated by American football fans celebrating Marshawn Lynch's touchdown for the Seattle Seahawks during a game against the New Orleans Saints.

Ms Caplan-Auerbach, a geology professor at Western Washington University, told CNN the difference between the NFL game and Swift's recent concerts was just 0.3, but the "shaking was twice as strong" and "absolutely doubled it".

"I grabbed the data from both nights of the concert and quickly noticed they were clearly the same pattern of signals," she said. "If I overlay them on top of each other, they're nearly identical."

The Seattle concerts were played in front of a total of 144,000 fans over two nights.

Posting on Instagram afterwards, Swift said: "Seattle that was genuinely one of my favourite weekends ever. Thank you for everything. All the cheering, screaming, jumping, dancing, singing at the top of your lungs."

Swift's Seattle concerts came towards the end of the US leg of the Eras tour - her first tour in five years.

Music concerts have been known to cause seismic activity before, for example during a 2011 Foo Fighters concert in New Zealand.