The first, a magnitude 3.1 event, occurred at 4:01 pm; it was followed at 4:05 pm by a magnitude 3.9 quake. The accompanying map shows their epicentres were in the vicinity of Motutapu Island.

They both occurred at comparatively shallow depths, about 5 km below the surface. They will have been felt very sharply by people, but not widely, and any felt reports much beyond greater Auckland are unlikely to be verified. The latter earthquake would not feel dissimilar to some of the larger aftershocks Christchurch folk have felt over the past few months, such as this magnitude 3.9 on February 22 2013.

Our Wairakei-based Duty Volcanologist does not see any evidence from the characteristics of the seismic waves that they are related to volcanic activity, nor are the earthquakes large enough to generate a tsunami.