A report by GeoNet suggests that a magnitude 7 earthquake has been occurring underneath New Zealand’s North Island now for over 5 months. Citizens in the city of Wellington and in other places on the North Island have yet to feel anything either despite a magnitude 7 earthquake taking place 40km below the ground.
The earthquake is said to be New Zealand’s largest earthquake in 150 years yet nothing is felt at the surface and recording instruments are struggling to pick it up. The reason is that unlike “normal” earthquakes that release their energy in minutes, this is a silent or slow-slip earthquake that takes ages to release its energy over a longer period.
The current silent earthquake beneath New Zealand involves the Pacific and Australian tectonic plates and affects 100 square kilometers of land from Levin to Marlborough Sounds. Specialists expect it to continue, largely unnoticed, for another few more months.
“GeoNet’s continuously-running GPS instruments in Wellington and Kapiti show that the Pacific and Australian tectonic plates are slipping past each other more rapidly than usual. This has been going on since January of this year, and will most likely continue for several months.”
While slow-slide events are unlikely to cause any damage, they can trigger other damaging earthquakes so New Zealand definitely isn’t out of the woods yet.
Image courtesy of GeoNet