She said there had been at least 12 major aftershocks, one measuring 3.9 on the Richter scale.

In the twenty-four hours immediately after the event, there were eight major aftershocks, measuring between 5.5 and 6.0.

There were six major aftershocks over the next seven months, the last of which, on September 27, caused a damaging tsunami.

Between 64 and 104 major aftershocks, ranging in magnitude from 4.0 to 6.1, were recorded within 72 hours of the main quake.

A major aftershock (magnitude 7.1) can be seen at the closest stations starting just after the 200 minute mark.

In the first day alone, eleven major aftershocks were recorded with a magnitude greater than 6.2.

A major aftershock on August 17 (local date) had a magnitude of 6.8.

Three days later, on October 4, 1987, at 3:59 a.m., a major aftershock measuring 5.2 occurred, causing further damage.

The tower collapsed during the major aftershock which hit the Lyttelton area on 13 June 2011.

After two major aftershocks, the well suffered a complete loss of circulation.