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Working Party Matters


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Landslides & Slope Instability


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

 

Subsidence & Collapse Hazard


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

 

Seismic Hazard


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

 

Flood Hazard


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

 

Tsunami Hazard


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

 

Volcanic Hazard


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

 

Gas Hazard


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

 

Fault Reactivation Hazard


Engineering Geologists | Planners & Developers | Finance & Insurance | Member of the Public

Volcanic Geohazard

Index | Diagnostic Characteristics | Geographic Occurrence | Investigation & Mitigation | Key Contacts & Expert Advice |  Photo Gallery  | Essential References & Further Reading | Definitions & Glossary |

Since 1700 AD volcanic activity has, destroyed cities, killed more than 260,000 people and had significant detrimental impacts on local economies and adversely affected the environment (IAVCEI IDNDR Task Group 1990).  Between 1980 and 1990 alone, over 600,000 people were directly unfavourable affected by volcanic eruptions through disruption to agriculture, damage to houses and infrastructure, evacuation and displacement (UNESCO 1993). Most reported deaths have actually been related to famine and drought that occur on the aftermath of a volcanic eruption rather than the direct influences of an eruption. It has been estimated that there are currently 550 active volcanoes with over 10% of the world’s population living in their vicinity and at risk from eruptions (Perterson 1986). However, only about 20% of these volcanoes are monitored to any extent.

Volcanic activity is a surface expression processes within the Earth’s interior which has led to the melting of rock and the consequent formation of magma. The magma subsequently travels towards the Earth’s surface where it is erupted from either a central vent or a fissure. Extruded magma may flow as lava or be exploded into the air by the rapid escape of gasses within the magma.

Volcanic eruptions are not continuous but occur as spasmodic events separated by periods of relative inactivity that may last for hundreds of years or many thousands of years. Between eruptions volcanoes are observed to emit steam and gases that issue from vents (fumaroles or solfataras). Throughout history many volcanoes that have appeared to be dormant have violently erupted.

The principal primary volcanic hazards. (Image Source: U.S. Geological Survey Fact Sheet 002-97 What are volcano hazards? Revised July, 2004 http://pubs.usgs.gov/fs/fs002-97/ )

 

Index | Diagnostic Characteristics | Geographic Occurrence | Investigation & Mitigation | Key Contacts & Expert Advice |  Photo Gallery  | Essential References & Further Reading | Definitions & Glossary |


Engineering Group Working Party on Geological Hazards