Geochemistry, Mineralogy, Petrology & Volcanology

GeoTalk: Explosive testing with Greg Valentine

Laura Roberts-Artal April 16, 2015

The Eastern Ukinrek Maar, Alaska. Credit: R. Russell, Alaska Department of Fish and Game, USGS.

Following his session at the EGU General Assembly, Greg Valentine (Buffalo University) spoke to Sara Mynott about how he creates model volcanoes, specifically maar-diatremes, and blows them up to better understand what goes on in an eruption… So what is a maar-diatreme? A diatreme is a vent-like structure, mostly made up of broken up bedrock and magma. Initially, you have a dyke that channels magm ...[Read More]

Imaggeo on Mondays: Pyroclastic flow, Montserrat

Laura Roberts-Artal March 9, 2015

Below the warm and tranquil waters of the Caribbean, some 480 km away from Puerto Rico, the North America Plate is being subducted under the Caribbean Plate. This has led to the formation of the Lesser Antilles volcanic arc; the result of the formation of reservoirs of magma as fluids from the down going North America Plate are mixed with the rocks of the overlying Caribbean Plate. The continued m ...[Read More]

Imaggeo on Mondays: An explosive cloud

Laura Roberts-Artal February 23, 2015

Karymsky volcano, 2004. Credit: Alexander Belousov (distributed via imaggeo.egu.eu)

One of the world’s most volcanically active regions is the Kamchatka Peninsula in eastern Russia. It is the subduction of the Pacific Plate under the Okhotsk microplate (belonging to the large North America Plate) which drives the volcanic and seismic hazard in this remote area. The surface expression of the subduction zone is the 2100 km long Kuril-Kamchatka volcanic arc: a chain of volcanic isla ...[Read More]

Imaggeo on Mondays: A Patagonia landscape dominated by volcanoes

Laura Roberts-Artal February 16, 2015

Imagine a torrent of hot and cold water, laden with rock fragments, ash and other debris hurtling down a river valley: this is a lahar. A by-product of eruptions of tall, steep-sided stratovolcanoes, lahars, are often triggered by the quick melting of snow caps and glaciers atop high volcanic peaks. The history of the Ibañes River and its valley, in southern Chile, are dominated by their proximity ...[Read More]