Over on her Georney‘s blog, Evelyn Mervine has recently posted a nice piece with some spectacular images of columnar jointing. This seemed like a good opportunity to dust off some field photos, with some more examples of polygonal joint sets in lavas from a variety of settings, to illustrate the diversity of forms that cooling-contraction joints may take in volcanic rocks. The first example ...[Read More]
Chilean volcanoes: shaken, but not always stirred?
November 7th marked the 175th anniversary of one of the largest earthquakes to have struck northern Patagonia. The earthquake, which is estimated to have had a magnitude of 8, had an epicentre close to Valdivia, and was accompanied by significant ground shaking and subsidence as far south as Chiloe island, and a major tsunami that reached Hawaii. The eyewitness reports of the time have been well ...[Read More]