The Seddon earthquakes recorded at Ruapheu volcano’s far west drum

More strong earthquakes have rocked Wellington, capital city of New Zealand and much of the central part of the country.

The magnitude 5.8 occurred at 7.17 this morning followed by a 4.8 at only 5km deep, 35 km from Seddon. They are part of a quake storm that have affected the region since Friday, about 30 of them this morning. Today’s large quake is being treated as a quake in its own right, not an aftershock of Friday’s event.

A GNS seismologist Dr Anna Kaiser told the Herald

“Normally when we get this sort of thing the aftershocks will taper off with time,”

“But when we get one of these events there will be increased seismicity in the region and there’s always the possibility of a larger event but it’s unlikely.”

She added that people should be prepared for a large earthquake striking at anytime

You may be interested in an account of the 1966 Seddon earthquake http://nzetc.victoria.ac.nz/tm/scholarly/tei-NHSJ06_03-t1-body1-d1-d5.html a 6.1 at 22 km deep in the Cook Strait, which had about 40 aftershocks.

…An interesting phenomenon was observed a few hours before the earthquake struck. This was a large area of pure white foam in Cook Strait seen over an interval of one hour by Mr and Mrs G. Woolley of Seddon from their parked car at the mouth of the Wairau Diversion. They described the foam as being about five miles out from the coast, covering perhaps several acres aligned in a north-easterly direction.

The area of the foam appeared like some kind of disturbance within an otherwise calm sea. There is no way of knowing if this phenomenon was a precursor, related to the earthquake that was to follow, but the description suggests that it may have been the result of a significant release of gas from the sea floor…