There are multiple inferred inactive faults in the ranges but the area of the Wairoa North Fault was discovered to be seismologically active with low magnitude earthquakes after recordings began in the 1950s.

[1] The fault has 3 segments with potential for full rupture events every 12,600 years.

[2] To the north the faults now inactive extensions created the Clevedon Valley, and to the south these extensions separates the highest part of the Hunua Ranges from the Happy Valley basin.

[3] The fault appears to be along the eastern border of the Stokes Magnetic Anomaly System (New Zealand Junction Magnetic Anomaly) that essentially goes down almost the entire west coast of New Zealand.

[3] The Wairoa North Fault has had some notable seismic events in the past: