Earthquake jolts Christchurch awake as Canterbury aftershock sequence continues

Christchurch had a jolty start to the day after a 3.7 magnitude earthquake struck on Saturday morning, alerting over 2000 people.

The quake struck 10km east of the city at a depth of 6km just after 5am, GeoNet says, with 1174 of the 2191 felt reports describing it as 'light'.

"Good morning Christchurch - looks like a lot of you felt that quake! More than 2000 felt reports for this one, a M3.7 earthquake with light shaking," GeoNet tweeted.

"It's a reminder that ten years on, the Canterbury aftershock sequence is still ongoing."

According to a GeoNet forecast, there is an "unlikely" (38 percent) chance of one or more earthquakes of magnitude 5 to 5.9 striking the Christchurch aftershock zone between September 2020 and September 2021.

It is considered "very unlikely" (4 percent) that there will be a magnitude 6 - 6.9 earthquake in this time period.

And the probability is "extremely unlikely" (less than 1 percent) that there will be an earthquake of magnitude 7 or greater.

"As time passes the chance of further earthquakes generally becomes lower," GeoNet says.

"With every month that passes without a major aftershock, probabilities will continue falling. However, if another large aftershock occurs it can re-energise the system and spark a resurgence of earthquake activity for a month or so."