Geoscience Australia recorded a Magnitude 7.1 Earthquake at a depth of 365 km off the northeast coast of New Ireland Island, Papua New Guinea, at 4.35 am local time on Monday 8 July 2013 (6.35 pm on Sunday 7 July, GMT). This is a very large quake - but unlikely to have caused any damage or casualties as it was so deep, and shock waves from Earthquakes lose energy rapidly as they pass through solid rock. Geoscience Australia estimate that the quake could have been felt across most of Papua New Guinea and the Solomon Islands, but witness statements have yet to emerge.
The location of the 8 July New Ireland Earthquake. Google Maps.
New Ireland lies on the North Bismarck Plate, one of a group of microplates caught in the collisional zone between the Pacific and Australian Plates. New Britain lies on the South Bismarck Plate, another of these microplates. There are a number of transform faults (faults where two tectonic blocks are moving past one-another horizontally) between these two microplates that cross eastern New Britain and southern New Ireland. This faulting is caused by an area of rifting (movement apart by two tectonic plates, with new crust being formed between them) to the north of New Britain and west of New Ireland, which is pushing the eastern part of the South Bismarck Plate southward with regard to the North Bismark Plate.
See also Magnitude 7.0 Earthquake under West Papua, Eruption on Mount Langila, Major Earthquake shakes New Ireland & New Britain, Eruption on Manam Motu and Earthquake shakes New Britain.
Follow Sciency Thoughts on Facebook.