It is associated with high earthquake and volcanic activity as part of the New Britain subduction zone within the Pacific Ring of Fire.

Many earthquakes occur in this area particularly around New Britain,[4][5][6] which has very complex tectonics and defining all the active plate boundaries has proved challenging.

[10] Accordingly, as the west-northwest motion of the North Bismarck microplate is similar to that of the Pacific plate, most of the Melanesian arc which is to the east of the New Ireland can be regarded as fixed on the Pacific plate.

[11] The line separating the North and South Bismarck plates is called the Bismarck Sea Seismic Lineation (BSSL), and this line is ill-defined, but is associated with shallow earthquakes,[6] with poor definition of BSSL associated earthquakes that become mixed with subduction associated earthquakes towards the southwest and New Ireland.

[9][2] These subduction associated earthquakes, unlike at the other plate boundaries, are often magnitude 7 or above and the area around southern New Ireland has a very high concentration of such.