The earthquake swarm continues around the Niagara Shipwreck and NZ’s major internet cable in the Gulf with a sizeable shallow magnitude 4.0 earthquake at 1:30pm this afternoon. This is now the 110th quake since the sequence began 30 months ago. It was the equal 3rd largest quake in the series and was felt across Northland, Hibiscus Coast, Great barrier Island and the Coromandel peninsula.
The primary seismic wave arrived at our Auckland based seismometer within 20 seconds.
The swarm is also in the same location as the major New Zealand international communication cable and the Niagara shipwreck. The communication cable carries 97% of New Zealand’s international communications. The Niagara ship was sunk on 19 June 1940 by a German marine mine and is still believed to be carrying up to 1000 to 1500 tonnes of oil and bars of gold.
The largest quake in the swarm sequence over the last 30 months was a magnitude 4.1 on 10th February 2019. For comparison, the Hauraki Gulf region next closet sized swarm was in 2007 with 13 shallow earthquakes over a 4 month period. For reference, GeoNet’s official statement on the earthquake swarm released on 10 February 2019 when the count stood at 39 quakes.