Deep earthquakes under the North Island and their shaking (intensity?)
On 12 January 2022 over 38,800 people reported feeling an earthquake in central New Zealand; many of these reports were far from the quake itself. We explore the science of deeper earthquakes in the North Island, and how we describe shaking intensity.
Why is shaking different from deep quakes?
We often get many felt reports from people located some distance from a deep earthquake and very few around the actual epicentre. People often ask, ‘how does that happen’? This M5.8 on Wednesday 12th January 2022, is a good example to explore. The quake was 25 km east of Stratford. A large number of felt reports came from the east and south of the North island, with only a few in the central plateau and further north. This distribution of felt reports is due to the earthquake's depth (nearly 190 km below the surface), location, and ‘what’s under our feet’.