WELLINGTON, July 22 (Xinhua) -- A 3.9-magnitude earthquake with a depth of 7 km hit New Zealand's Christchurch at 8:43 a.m. local time on Monday.

"Just another reminder that the Christchurch aftershock sequence is still ongoing," New Zealand's GeoNet said on its Twitter account.

It came after a magnitude 3.5 earthquake on Saturday night.

According to the GeoNet website, Over 4,000 people reported they felt the jolt just before 9 a.m.

A 6.3-magnitude quake struck the city on Feb. 22, 2011, with a depth of only 4 km. The devastating quake killed 185 people, spanning more than 20 nationalities, including 23 Chinese students.