Earthquakes near Auckland are unusual at the best of times, so its not surprising that the three earthquakes that have occurred near Waiheke Island in Auckland’s Hauraki Gulf in the past 24 hours are attracting considerable interest.
The first event reported by Geonet was a magnitude 2.5 event 8 km deep at 11:35 p.m. last night (Tuesday). Another magnitude 2.5 earthquake occurred at the same depth 19 minutes later. Island residents have reported clearly hearing the rumble of the earthquakes, which is hardly surprising late at night in an area that rarely experiences such events.
This morning, at 11:08, a magnitude 3.3 earthquake was recorded slightly deeper at 9 km.
The Auckland Regional Council and the Institute of Geological and Nuclear Sciences co-operate to monitor the Auckland volcanic field of approximately 50 volcanoes for volcanic and seismic tremors. The Auckland Volcano-seismic Monitoring Network (AVSN) has recorded and published 15 earthquakes in the Auckland area since December 20th, 1995. The previously most recent event reported by AVSN was on November 30th last year, the largest being a magnitude 2.7 event at a depth of 5 km in May 1998.
Auckland is New Zealand’s largest city, and the City Council’s website reported a “usually resident” population of over 1.1 million in 2001, comprising 31% of New Zealand’s total population.