Rockall part of the deeply eroded Rockall Igneous Centre that was formed as part of the North Atlantic Igneous Province, approximately 55 million years ago, when the ancient continent of Laurasia was split apart by plate tectonics. Greenland and Europe separated and the northeast Atlantic Ocean was formed between them, eventually leaving Rockall as an isolated islet. The RV "Celtic Explorer" surveyed the Rockall Bank in 2003. The Irish Light Vessel "Granuaile" (the same name as the steamer on the RIA 1896 botany survey) was chartered by the Geological Survey of Ireland, on behalf of the Department of Communications, Marine and
Nankai Trough This was concluded by Kanda et al., 2004, through inversion analysis of seismic data. Historically, the most recent large-scale earthquake to occur in the Nankai Trough was in 1944 off the Kii Peninsula. Using recent ocean bottom seismograph studies, it has been determined that most of the seismicity occurs near the trough axis (Obana et al., 2006). Along the western area of the Nankai Trough, seismicity appears to be related to irregularities in crustal structure such as fractures generated from the subducted seafloor, including backarc basin crust of the Shikoku Basin, as well as due to serpentization of uppermost mantle