A Magnitude 7 or greater earthquake centred under Hyde, near Dunedin, would be much like the Darfield main shock of 2010 in relation to Christchurch, researchers say.
The shaking from that quake caused a good deal of building damage and liquefaction in Christchurch.
Further study, including recent earthquake simulation work, is shedding more light on the hazard that the Hyde Fault, about 50km from Dunedin, poses for Dunedin's unreinforced masonry buildings.
Prof Mark Stirling, a seismologist at the University of Otago's geology department, said research, including ground motion simulation work by Otago geology doctoral student Anna Kowal, was helping to clarify potential effects on Dunedin.
Australian PhD researcher Jonathan Griffin was also continuing other detailed work on aspects of the fault itself.
Prof Stirling, who heads the University of Otago earthquake science group, emphasised much more overall work had to be done, but the early findings had already vindicated the decision to undertake the first in-depth study of the Hyde Fault.
This research is contributing to seismic hazard and risk management in regions, including Otago, which are generally considered to be low seismicity zones.
Prof Stirling has compared the Hyde Fault and the main Darfield earthquake in 2010, which had caused a great deal of damage in Christchurch.
''The Darfield earthquake produced shaking strong enough to cause damage to unreinforced masonry buildings, and liquefaction in the city.''
The fault rupture displacements seen in the Hyde trenches were about 2m per event.
This was consistent with a fault rupture the length of the Rock and Pillar Range, and with a large earthquake, of magnitude 7 or more, he said.
It was still unclear exactly when the most recent big fault movement had happened at Hyde.
This could be more than 10,000 years ago, but this suggestion was ''extremely speculative'' and more research had to be completed, he said.
Prof Stirling was pleased with the research progress, including that from a hazards perspective.
''Our suspicions of it being active and a potential threat to Dunedin have been confirmed''.
