Christchurch's seismic activity is still trying to get back to normal - seven years after two destructive earthquakes shook the region.

A 7.1-magnitude quake in September 2010 and a 6.3-magnitude quake in February 2011 left devastation across the city - and since then the region has experienced over 20,000 earthquakes and aftershocks, according to the Christchurch Quake Map.

Just last week the city was rocked by four earthquakes - ranging from 3.1-magnitude to 4.0-magnitude quakes - with one quake waking up over 3800 people just after midnight on Sunday.

But GeoNet duty seismologist Anna Kaiser says this is typical behaviour for the Canterbury area, as it continues to take years for seismic activity to return to the low rate it was at before the 2010 quake.

"This week there's been a few quakes close to the central city and we get them further out as well, they're not a cause for concern," Ms Kaiser said.

"Since the quakes starting in 2010, there's been an increase in aftershocks - and we expect aftershocks every now and then."

While aftershocks will continue, the positive side is that the chances of a large magnitude earthquake happening in the region has dropped off since the height of the earthquake sequence, Ms Kaiser said.

"You can't rule out a big earthquake at any time, (but) the chances are becoming much less."