The quake was felt strongly in both islands, and as of 8:30 pm we had received over 8000 felt reports from the public, with multiple reports of damage.
Current depth and location estimates of this event place it below the interface between the subducting Pacific plate and overriding Australian plate. Maximum peak ground acceleration recorded by GeoNet instruments is about one quarter of the acceleration due to gravity (0.26 g). This measurement was recorded in Woodville. Relatively strong shaking was also recorded on the Kapiti Coast (e.g. up to 0.2 g in Paraparaumu) whereas accelerations recorded in Wellington city were less than 0.05 g. In comparison, ground motions recorded in Wellington during the recent Cook Strait earthquakes ranged up to 0.26g.
We have calculated aftershock probabilities. In the first week of the aftershock sequence, we estimate that there will be about 23 aftershocks of magnitude 4.0 to 4.9, with the final number probably falling between 14 and 33. We also estimate about 2 aftershocks of magnitude 5.0 to 5.9 with the final number probably between 0 and 5. Although for this type of event we are expecting an under-productive aftershock sequence, so we should have less events and they should taper off quickly.