VOLCANIC ASH - From the 1980 eruption of Mount St. Helens, USA

​​​​
VOLCANIC ASH

From the famous 1980 eruption of Mount St. Helens, USA

The catastrophic eruption of Mount St. Helens in Washington State, USA on 18 May 1980 is one of the most famous in historical times. The eruption sent over three-quarters of a cubic mile of volcanic ash into the atmosphere which spread over a large area of the north west of the United States.

Volcanic ash consists of tiny, pulverised rock fragments created by the force of the eruption, shattering the magma and propelling it into the atmosphere where it is transported by winds, sometimes for thousands of kilometres. It can have a devastating effect on human health, agriculture and water supply.

The ash from this eruption resembles portland cement in colour and fineness. It consists chiefly of volcanic glass and plagioclase feldspar accompanied by minerals such as pyroxene, amphibole and quartz.

These samples are each contained in a small glass phial and provided with a comprehensive label.

Click on a picture for a larger image​​​​.