Thousands felt weekend quakes in Christchurch: GNS reveals what happened and why

Chris Lynch
Chris Lynch
Jun 17, 2024 |
Seismograph and Earthquake - 3D Rendering / Istock / Petrovich9
Seismograph and Earthquake - 3D Rendering / Istock / Petrovich9

Several widely felt earthquakes during the weekend in Christchurch earthquakes were within the expected behavior for the 2010 Canterbury aftershock sequence according to GNS Science. In the past week, the organisation recorded 10 earthquakes south-west of Christchurch, between magnitude 1.2 and 3.5.

The largest event occurred at 5:45 PM on Saturday 15 June and we received more than 4,000 felt reports.A GNS spokesperson said the M3.5 event was shallow at 4km deep, which explains why it was felt by many in the area surrounding the earthquake epicentre.

“Seismicity in the Canterbury region is still at higher levels than before 2010, this includes the earthquakes GeoNet is recording around Christchurch.

“However, this is within the expected behavior for the 2010 Canterbury aftershock sequence, even after more than a decade since the 2010-2011 earthquakes.

“GNS scientists continue to closely monitor and produce earthquake forecasts for the Canterbury region generated by our computer models, which you can view on our site.”

Aftershock sequences typically quieten down over time – but it can take years, decades or even centuries for seismicity in a region to return to a pre-influenced (before the mainshock) state.

“It is difficult to attribute small magnitude earthquakes to a specific fault, but the events we have recorded in the past week fall within the region that ruptured during the M6.2 February 2011 Christchurch earthquake and the area where we have recorded aftershock events over the past 13 years.”

“We understand that some people might find these earthquakes unsettling. The All Right? website has great resources where you can read and talk about any concerns that you have.”

“Even though the events of the past week are consistent with what we observed for the Canterbury region in the past few years, every earthquake is a good reminder to be prepared. And to remember that drop, cover, hold is the right action to take during an earthquake.”

Chris Lynch
Chris Lynch

Chris Lynch is a journalist, videographer and content producer, broadcasting from his independent news and production company in Christchurch, New Zealand. If you have a news tip or are interested in video content, email [email protected]

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