Monitoring equipment on Raoul Island knocked out by Friday’s 8.1 magnitude quake is likely to be back up and running by the end of this week.

The quake struck the Kermadec Islands about 1000km north of New Zealand just before 8.30am, sparking a tsunami warning.

It was the second quake in the region on Friday, the first was a 7.4 magnitude.

GNS earth structure and processes manager Sally Dellow said they had no idea how much damage had been done to seismographs, a volcano camera, crater lake temperature sensors and two tsunami gauges.

“We are not entirely sure, there was lots of earthquake shaking and we lost communication with Raoul so at the very least we know that our communication equipment does not have a power supply.

“Beyond that, we are blind at the moment until we get a team on Raoul.

“This was a big earthquake and we are not sure what has gone wrong,” she said.

Dellow said a routine trip to the island was already planned for this week and a maintenance team would arrive on Wednesday morning on a Navy vessel.

“[At] this stage the plan is to spend three days on Raoul and then they will return to Auckland.”

She said while earthquakes could still be detected, the instruments provided much more detailed information.

“Its depth, magnitude and location to determine a lot more accurately when we have the instruments on Raoul working.

“That means any subsequent tsunami forecast can be a lot more accurate.”