Stokes Magnetic Anomaly

Stokes Magnetic Anomaly

A linear belt of deep-seated magnetic anomalies that extends along the western side of New Zealand has been named the Stokes Magnetic Anomaly after John Lort Stokes, the captain of HMS Acheron, who first recognised unusual magnetic features near Nelson during surveys in 1849–51. They are thought to be caused by a belt of volcanic and intrusive rocks, and are one of the features that has been offset about 480 kilometres along the Alpine Fault.

HMS Acheron was a hermes class wooden paddle sloop of the Royal Navy. Between 1848 and 1851 she made a coastal survey of New Zealand, the first such survey since Captain Cook .

Acheron, under the command of Captain John Lort Stokes, was despatched to New Zealand in January 1848, arriving in November the same year. In March 1851, due to a budget cut to the Hydrographer of the (Royal) Navy, Acheron was ordered to be laid up in Sydney, Australia and her crew returned to England