How the ChCh Earthquake 'fused' residents to their city

Whether it was helping rescuers amid rubble or offering a hand to neighbours whose homes had been damaged, Christchurch residents profoundly pulled together after the city's devastating 6.3 earthquake.

That post-quake unity was famously captured in a term judged 2011's word of the year: munted.

A new study has further explored that sense of solidarity, finding how the disaster forged what psychologists call "identity fusion".

In a first-of-its-kind experiment, University of Otago researchers asked Christchurch residents to recall their experiences of the February 22 quake, in which 185 people lost their lives.

The study, which involved 200 participants who were older than 18 at the time, explored various levels of identity fusion, occurring when people endure a shared and life-defining event.

"We found that participants who we asked to recall the earthquake felt stronger connection to Christchurch when they endured more negative effects; when they felt more fear as they recalled the earthquake or if they suffered more harm – be that physical or psychological harm – due to the earthquake," lead author Keren Segal said.

Levels of harm were measured by participants' responses to questions about the earthquake's effect on their own personal situation - whether that was their physical or mental state, or effects on property and their workplace.

"What we found that was particularly influential and more influential than other measurements, was people's emotional and physical suffering that they endured due to the earthquake – so people who suffered more physically and psychologically felt more fused and connected to the city when they recalled the earthquake."

Segal said one of the most interesting findings concerned a question asking if people believed God was involved in the earthquake, or if the earthquake "happened for a reason".

"We found that people who attributed more agency or more intention to the earthquake were more fused to Christchurch, so they felt a stronger connections to the city.

"This is important for us because usually these kind of studies are conducted when you relate to an out-group threat like a terrorist attack or war."

In those situations, she said, people tended to fuse because they could say "somebody else did it".

"So it was interesting to find that intention – even if it is a supernatural one – influenced how strongly people would feel towards the city."

Supervising Professor Jamin Halberstadt pointed out this was the first study to show, experimentally, that negative events need not be caused by other people to create a sense of attachment to a community.

"Natural disasters, with no human cause, also fuse those affected by them, although the effect seems to be bigger when the disaster is attributed some kind of meaning," Halberstadt said.

"Understanding the fusing effects of events is important because fusion is a strong predictor of people's willingness to make personal sacrifices for the good of the group — something that is especially helpful when a community is rebuilding from a tragedy."