Volcanic eruptions
definition
The most common type of volcanic eruption occurs when magma is released from a volcanic vent. A volcanic eruption occurs when hot materials from the Earth’s interior are thrown out of a volcano. A significant eruption is classified as one that meets at least one of the following criteria: caused fatalities, caused moderate damage (approximately $1 million or more), with a Volcanic Explosivity Index (VEI) of 6 or larger.
Volcanic activity and volcanic eruption is usually triggered by alterations of tectonic plates, resulting in landslides or earthquakes.
Volcanoes are some of Earth’s most potent natural hazards and agents of change. They release enormous amounts of energy and material, engaging natural processes that can modify landscapes at a local, regional, and even global scale.
Many volcanic materials and processes can pose several threats to humans, animals, ecosystems. A powerful explosive eruptions drastically alter land and water for tens of kilometers around a volcano. In presence of massive eruptions, tiny liquid droplets of sulfuric acid erupted into the stratosphere can change our planet’s climate temporarily.
There are more than 1500 active volcanoes on Earth. With many millions of people living and working in their shadows, developing ways to co-exist safely with potential volcanic threat is essential. Volcano hazards have the potential to cause great harm and destruction, but whether or not you will be affected depends on the type of volcano (stratovolcano or shield volcano), the specific hazard, and your location relative to it.
threats to human life: Altough in this century volcanoes activities are not posing as one of the major threats of disasters, as in other centuries, it is existimated that 500 milion of people, mostly living in the developing world, are under the threats of hazards posed by volcanoes.
Eruptions often force people living near volcanoes to abandon their land and homes, sometimes forever. Those living farther away are likely to avoid complete destruction, but their cities and towns, crops, industrial plants, transportation systems, and electrical grids can still be damaged by tephra, ash, lahars, and flooding.
History: There were a total of 91,789 deaths (range: 81,703-102,372), 14,068 injuries (range 11,541-17,922), and 4.72 million people affected by volcanic events between 1900 and 2008. Inconsistent reporting suggests this is an underestimate, particularly in terms of numbers injured and affected
Volcanic eruption often cause temporary food shortages and volcanic ash landslides called Lahar.
Monitoring: GLOBAL VOLCANISM PROGRAM
World Organization of Volcano Observatories
If you are ON a volcano during an eruption:
- Move AWAY from hazard zones as fast as possible.
- You may be exposed to falling ash and volcanic rocks, lava flows, lahars, volcanic gases, and fast-moving torrents of hot rock and gas (pyroclastic flows).
- Your route to safety might be cut off. If you are on a snow and ice covered volcano, STAY OFF VALLEY FL‘Ō‘ōRS AND OUT OF LOW-LYING AREAS – lahars may occur.
- Pay attention to closure signs; they can save your life.
Actions to take after an eruptive event are dependent upon whether the eruption is continuing, the level of impact, and type of eruption. watch and listen for updates from local authorities; they will determine when to lift or revise evacuation orders and organize relief response.
Issue; the medium- to long-term health and environmental effects make volcanic risk management a crucial requirement for governments and business establishments in both mature and emerging economies. Just as volcanic eruptions are distinctive natural events, the challenges associated with volcanic risk management are mostly unique.
Sources
http://volcano.si.edu
https://www.nationalgeographic.org/news/plate-tectonics-volcanic-activity
https://volcanoes.usgs.gov/vhp/hazards.html
https://www.ifrc.org/en/what-we-do/disaster-management/about-disasters/definition-of-hazard/volcanic-eruptions/
