Mount Shasta or Úytaahkoo, the “White Mountain”

Volcanic activity in North America is surprisingly infrequent. In spite of there being no less than 255 volcanoes or volcanic features such as maars or volcanic fields listed for California (20), Oregon (65), Washington (21) and British Columbia (149), situated on or adjacent to the Cascades Range and above the subduction zone where the last…

Volcanic Hazards: Lahars

Lahars are called jökulhlaups in Iceland, or mudflows in other regions of the world. What are they? A lahar is a combination of water with volcanic ash and lots of other debris. The necesarry water can come out of many sources: Glaciers are one source: IngeB wrote a really nice post on Icelandic glacier runs. When…

The Decade Volcano Programme

The volcanic eruptions of Mount St Helens in 1980 and Nevado del Ruiz in 1985 made the general public aware of the dangers of co-existing with a large and potentially lethal volcano. It doesn’t take much imagination to see the possibilities of a lateral St Helens-type blast on a population of a great city as…