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
Sagami Trough Sagami Trough The also Sagami Trench, Sagami Megathrust, or Sagami Subduction Zone is a long trough, which is the surface expression of the convergent plate boundary where the Philippine Sea Plate is being subducted under the Okhotsk Plate. It stretches from the Boso Triple Junction in the east, where it meets the Japan Trench, to Sagami Bay in the west, where it meets the Nankai Trough. It runs north of the Izu Islands chain and the Izu-Bonin-Mariana Arc (IBM). Megathrust earthquakes associated with the Sagami Trough, known as Kantō earthquakes, are a major threat to Tokyo and the Kantō Region