Extinct: This stage describes a volcano that is not likely to erupt in the near future if ever. Many volcanoes in this category haven’t been active for a long time and are now starting to show signs of decline, looking more like a passive hill than a powerful mountain that could explode at any moment. Unfortunately, many people fall into this category. They’ve given up on their dreams, are going through the motions in life with their talents and skills showing signs of atrophy, eroding away due to lack of use.
Dormant: A volcano in this category is also described as inactive. Whilst they aren’t erupting at present, below the surface there may be a lot of activity going on and they could explode at any moment. People in this category may not look as though they are firing on all cylinders at present, but at least they are preparing to do so. Perhaps they’re studying or being mentored, preparing themselves for the next stage of life. They may have clear goals and are focused on doing the important background work to build momentum towards them. They’re winning the important private battles of discipline, hard work and character development that lead to public victories in the future.
Active: An active volcano is what makes the news. They’re a magnificent sight, with lava, ash, smoke and steam spewing forth with unstoppable power. A person in this category is also an impressive sight. They’re on top of their game, with well-honed skills, recognized expertise in their field and a body of work that demands attention. All of the momentum built during their dormant stage has burst through, leading to successful outcomes that are admired by others.
Why do volcanoes erupt?: It seems like a pretty simple question when you first pose it, so let’s look into the answer, shall we. The simplest answer would seem to be that magma, being less dense than the rock surrounding it, tries to float to the surface. If the magma contains water and dissolved gasses, when the magma reaches the surface the water and dissolved gasses will suddenly expand into steam and gas, causing a violent eruption. There are several factors that will trigger a volcanic eruption, but three
Predominate: the buoyancy of the magma, the pressure from the ex solved gases in the magma and the injection of a new batch of magma into an already filled magma chamber. When rock inside the Earth melts, its mass remains the same, but its volume increases, producing magma that is less dense than the surrounding rock. This lighter magma rises toward the surface because of its buoyancy. When the density of the magma between the zone of its generation and the surface is less than that of the surrounding and overlying rocks, the will magma reach the surface and erupt. Magmas made of andesitic and rhyolitic components contain dissolved volatiles like water, sulfur dioxide and carbon dioxide.
The amount of a dissolved gas in magma at atmospheric pressure is zero, but rises with increasing pressure. So, in an andesitic magma saturated with water and six km below the surface, about 5 percent of its weight is dissolved water. When this magma moves toward the surface, the solubility of the water in the magma decreases, and so the excess water separates from the magma as bubbles. The closer it gets to the surface, more water ex solves from the magma, increasing the gas/magma ratio in the magma tube. When the volume of bubbles reaches about 75 percent, the magma turns into partially molten and solid fragments and will erupt explosively. The last major reasons that a volcano will erupt is when new magma enters a chamber that is already at capacity. The new magma can be of the same or different composition. Either way, the new magma causes some of the existing magma to move to the surface and erupt.