More than 400 whales beached themselves in a mass stranding at the sandspit at the northern end of Golden Bay on Thursday night.
About 300 died but the surviving 100 were successfully refloated at high tide about lunchtime today.
The 5.2 quake that struck the South Island this morning was another typical jolt that could be expected in a major aftershock sequence that has already produced more than 12,400 shakes since November's 7.8 event.
Scientists have also ruled out any suggestion the 9.19am quake, which struck 15km north-west of Culverden at a depth of 9km, was linked to the mass whale stranding at Farewell Spit.
GNS Science seismologist Dr Anna Kaiser said the location of the quake - not far from the epicentre of the November 14 Kaikoura Earthquake - wasn't surprising.
"Often, directly after a quake, aftershocks occur very tightly around the rupture area and sometimes we get those occurring over a wider area as time goes on, and as stresses settle down and everything is re-adjusting."
Just like the 5.1 quake that hit 10km north-east of Kaikoura on February 2, today's quake fell well within the bounds of aftershock probabilities.
The most recent, issued by GeoNet, show there is a 25 percent chance of one or more magnitude 6.0-6.9 earthquakes occurring within the next month - a decrease from 54 percent from the previous forecast last month.
The probability of a quake measuring over magnitude 7 was just three per cent this month - and 12 per cent this year.
That compared with an 89 per cent chance of one or more quakes above 5.0 this month - a prediction already borne out with Wednesday's quake - and between seven and 29 such-sized events this year.
Probabilities had fallen over time, although the sequence could well carry on for years.
Since November 14, more than 450 aftershocks had measured between 4.0 and 4.9, 53 ranged between 5.0 and 5.9, and four were greater than magnitude 6.0.
The epicentre of this morning's quake was located near Culverden, where the 7.8 Kaikoura Earthquake struck on November 14. Photo / GeoNet
No link with strandings
Kaiser also said there was no scientific evidence to link the quake to the strandings of hundreds of whales at Farewell Spit over recent days - something Herald readers had queried today.
Similar questions were raised in 2011 when 107 pilot whales beached themselves at the southern end of Mason Bay on Stewart Island just 48 hours before the deadly Christchurch earthquake.
University of Auckland marine biologist Dr Rochelle Constantine also said the quake and the recent mass whale strandings at Farewell Spit were likely unrelated.
"There's no strong evidence that strandings are linked to earthquake events. For marine mammals these events are mostly unconsequential to them."
Whales ended up getting beached for many reasons, Constantine said.
"There's a lot of complexity involved in it. It's not an uncommon event."
A mass stranding occurred on New Zealand beaches "roughly every year and a half", though Golden Bay got more than its fair share because it was easy for whales to get stuck in the shallow water.
"I think these whales just make a mistake," she said of the recent strandings.
Sometimes when one of the animals was unwell it would beach itself "and the others just stay with them because they are strongly socially bonded".
Big aftershocks to continue
Although the current rate of magnitude 6 and above earthquakes for the next month was about 10 times larger than what scientists would normally expect for long-term seismicity represented in the National Seismic Hazard model, forecast aftershocks had dropped significantly since November.
This reflected the time that had passed since the mainshock and the input of more data into the models.
GNS scientists have also calculated the probability of damaging earthquake shaking from aftershocks over the next year.
Damaging earthquake shaking was defined as MM7 on the Modified Mercalli Intensity (MMI) scale.
The MMI scale was different to earthquake magnitude and described the intensity and impacts of the shaking, which depended on the magnitude of the earthquake, how far away the earthquake was and the type of ground a person was standing upon.
At MM7 intensity shaking levels, it was difficult to stand, furniture and appliances move, contents are damaged, there was minor building damage and liquefaction could occur in susceptible sediments.
Maps showed the probability of MM7 shaking within the aftershock region, which included a three per cent probability for Wellington in the next year.
While this probability was considerably lower in Wellington than in the areas around Kaikoura, it was possible for shaking similar to what occurred during the mainshock to happen again in Wellington.
Christchurch's aftershock probabilities, meanwhile, were not greatly affected by the magnitude 7.8 Kaikoura earthquake.
