Seismologists have recorded more than 140 earthquakes of magnitude 4 or higher since a 7.2 earthquake caused householders to flee low-lying East Coast areas on Friday morning.

A magnitude 7.2 earthquake shook much of the North Island on Friday.

GNS Science experts are researching the relationship between them and the even bigger sea-floor quakes of magnitude 7.4 and 8.1 which hit the Kermadec Islands – 1000km – later on Friday morning.

Seismologist Matt Gerstenberger said there were questions about whether the East Cape jolt was a single rupture or something more complicated.

Gerstenberger said generally after a large earthquake a lot of quakes of varying size could be expected, but over time they would become fewer and smaller.

But he warned there is still an increased probability of a bigger event.