MCDEM have issued a tsunami threat for the initial earthquake. Our tide guages at Kaikoura, Wellington, and Castlepoint have recorded this. Please follow advice regarding tsunami via the Civil Defence website - anyone at the coast on the East Coast of New Zealand move to higher ground.
Thus far there have been approximately 45 aftershocks. It is difficult to predict an aftershock sequence because it is too soon after the initial earthquake to understand the pattern. We need more time and aftershocks to occur so we can get a better picture of what is going on.
Scientific information about the quake
Peak ground accelerations (PGAs) have been recorded up to 0.23g in Wellington. This is similar to the 2013 Lake Grassmere and Cook Strait earthquakes. The PGAs closer to the earthquake will be much larger. We are still working on calculating these values.
Our GPS stations record how land moved in response to the earthquake. Our station at Cape Campbell in Malborough moved two metres north.
Updated at 03:25am More information soon.