[5] A Mw 7.3–7.8 thrust earthquake followed at 07:42:16 UTC with its epicenter 170 km (110 mi) southeast of the first event at the southern end of its rupture zone south of New Ireland.

[7][8] This sequence of earthquakes killed two people, caused numerous homes to collapse, and triggered landslides in southern New Ireland.

Damage caused by the events and the following tsunami occurred in New Britain, Duke of York Island, western Bougainville and Buka.

The mainshock had a magnitude in the range Mw  8.0–8.2,[11][8] and was mainly strike-slip in type, although some component of dip-slip has been noted, particularly towards the southeastern end of the rupture.

[6] This earthquake had a magnitude in the range Mw  7.3–7.8 and was of thrust type, most likely caused by rupture of the plate boundary interface in the New Britain Trench subduction zone.

[7] This earthquake had a magnitude in the range Mw  7.3–7.8 and was also of thrust type along another part of the same plate boundary as the second shock.

Only a small increase in static stress has been modelled for the combined effects of the earlier two large earthquakes in the sequence.

[11] Unlike the two other large events and their subsequent aftershocks, this earthquake's epicenter was located inland, in Central/Inland Pomio Rural LLG.

[2] In addition, there was also an unrelated Mw 7.0 event on 29 October, occurring about 35 km (22 mi) southwest of Nissan Island.

The reason that the mainshock generated a tsunami may either be due to the change to a more dip-slip type motion at the southeastern end of the rupture or a result of lateral movement on the relatively steep bathymetric slope in that area.