Ring of Fire world's 25 largest volcanic eruptions of the last 11,700 years occurred at volcanoes in the Ring of Fire. The famous and very active San Andreas Fault zone of California is a transform fault which offsets a portion of the East Pacific Rise under the southwestern United States and Mexico; the motion of the fault generates numerous small earthquakes, at multiple times a day, most of which are too small to be felt. The active Queen Charlotte Fault on the west coast of the Haida Gwaii, British Columbia, has generated three large earthquakes during the 20th century: a magnitude 7 event
Circum-Superior Belt margin. The last collision occurred on the southeastern portion of the Superior craton to produce the Grenville orogeny 1,100 million years ago. Because most of the Circum-Superior Belt was formed by widespread mafic-ultramafic magmatism 1,884 to 1,864 million years ago along the Superior craton margin during these orogenies, a number of different suggestions have been made to explain the questionable origins of this large igneous province. It is also not clear if the Circum-Superior Belt has a single origin or it has several origins. Suggestions include back-arc rifting, foredeep flexure, mantle plumes and the breakup of a microcontinent. The geochemical