Volcanoes are notorious for their devastating effects, not only on human life but also on the global environment. Lava, emission of toxic gases, ash fall, lahars and landslides are some of the most dangerous hazards of volcanic eruptions.
The mention of the name, volcano, brings to mind the red hot lava, destroying and burning everything that comes in its way. But, lava flow is only a part of the hazards created by volcanoes. There are many more hazards of volcanic eruptions and some of them are potentially more dangerous than lava. Lava flows are usually slow and therefore, people can easily escape them. However, they can cause extensive economic loss by burning and burying buildings and crops.
Volcanic eruptions usually contain a number of harmful gases like carbon dioxide, sulfur dioxide, water vapor, hydrogen sulfide, hydrogen fluoride, hydrogen chloride, carbon monoxide, halocarbon and metal chlorides that can create a lot of changes in the Earth's atmosphere. The violent eruptions of volcanoes, insert these gases and compounds into the stratosphere, where the sulfur oxide converts to sulfuric acid. The sulfuric acid in turn condenses to sulfur aerosols, which are responsible for cooling the lower atmosphere, known as troposphere, by increasing the reflection of radiation from the Sun, back into space. On the other hand, they increase the temperature of the stratosphere by absorbing the heat radiated by the Earth.
The hydrogen chloride and hydrogen fluoride present in volcanic eruptions are important contributors to acid rain. These compounds get dissolved in water droplets, present in clouds and then fall back on Earth as acid rain.
Landslides and Lahars
Volcanic eruptions are generally accompanied by dreadful vibrations in the surrounding areas, which causes landslides. In the past, such landslides were responsible for burying surrounding cities.
Lahar or mud flow, is another danger posed by volcanoes. Lahars...