Would you explain what you mean, please? See this link (click here). Wouldn't the subduction in PNG aggravate the already hot volcanoes in that area? When the Pacific plate subducts under Mt. St. Helens and Mt. Hood, it would heat up points in the cascades, therefore, how is this a different class? The whole Pacific Rim seems to be rattling like a pressure cooker and after the 7.6 and 7.7 in Fiji on August 19, volcanoes acted up in Hawaii and Japan, so it looks like there might be a relationship between the quakes and volcanoes.
Cross-section of the subduction zone below New Britain. From Johnson (1976).