Scientists have found four potentially-active fault lines under Hamilton City (file photo).

Hamilton's not known for earthquakes, but it's on top of more fault lines than we knew.

University of Waikato researchers with echo sounders have found 25 potential fault zones in the bed of the Waikato River.

At least four of those might still be active, Dr Vicki Moon and Dr Willem de Lange say.

CHRISTEL YARDLEY/STUFF The new information doesn't mean a Hamilton earthquake is more likely, Dr Willem De Lange says, 'but there could be more shaking and more damage to infrastructure' (file photo).

One is in north Hamilton, around Osborne Road, and the Kukutaruhe Fault cuts through Hamilton from Temple View to Rototuna.

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Another two are in the southeastern Te Tatua o Wairere fault zone - a fault running between Rukuhia and Hillcrest, and a second branching out towards Tamahere.

UNIVERSITY OF WAIKATO This cutting in a Rototuna excavation was the first sign of a fault zone for University of Waikato researchers (file photo).

This information doesn't necessarily mean Hamilton is likely to get stronger earthquakes, de Lange said.

Initial results say the maximum earthquake magnitude for the city would remain at 6.8.

Nor does it mean earthquakes in the area are more likely, he said, "but there could be more shaking and more damage to infrastructure such as sewerage pipes, roads, and other services".

That would affect recovery efforts.

De Lange and Moon's research was funded by the Earthquake Commission and has been extensively peer reviewed, a University of Waikato statement said.

The project started when an excavation in Rototuna showed evidence of a fault zone, thought to have moved within the past 250,000 years.

The pair's next plans include looking into fault zones discovered during excavation for the Waikato Expressway.

WHICH ARE THE POTENTIALLY ACTIVE FAULTS?

Osborne Rd (northeast Hamilton)

Kukutaruhe Fault (running across Hamilton)

Two faults in the Te Tatua o Wairere Fault Zone (southern Hamilton)