Interesting facts :D

Here some interesting facts that relate to volcano :)

1. There are 20 volcanoes erupting right now
Somewhere, around the world, there are 20 active volcanoes erupting as you’re reading this.

2. The tallest volcano in the Solar System isn’t on Earth
That’s right, the tallest volcano in the Solar System isn’t on Earth at all, but on Mars. Olympus Mons, on Mars, is a giant shield volcano that rises to an elevation of 27 km, and it measures 550 km across. 

Living near a volcano..

Plans  taken by people and government who live near a volcano: 

1) Listen to scientists. There are many new devices that can tell when a volcano will explode. Sometimes these warnings come days before an explosion. Although sometimes warning only come a few hours before the explosion, it still gives sufficient time to evacuate.

2) Usually governments would have set up a plan of what to do once a volcano has exploded. There need to be health workers, vehicles, and medical care ready to go. They need to have trucks prepared to move dirt. There should be food and water stored in a safe place.

3) Governments usually observe volcanoes activities very closely with the help of volcanologist. 

4) Government build walls in the way of lava to block or divert its flow


5) After a eruption, government would have a movement plan for the citizens. They would have allocated places to evacuate to.

Mt Erebus

Mount Erebus is the second highest volcano in Antarctica. It is located on Ross island, which is also home to three inactive volcanoes and one of which is Mount Terror. This volcano had been observed to active since 1972. Mount Erebus was discovered on January 27, 1841 by polar explorer Sir James Clark Ross who named it Mount Erebus after one of his ships, Erebus. This volcano last erupted in 2011. It is a composite cone volcano (stratovolcano).

Mount Erebus location^

Mount Erebus is currently the most active volcano in Antarctica. With a summit elevation of 3,794 metres, the summit contains a lava lake which is also one of the five longest lasting lave lakes on Earth. It has erupted 200 times between 1986-1990 alone. Mount Erebus is also a source of impurity in the snow. It is also a source of elevated levels of copper, zinc, cadmium, vanadium, arsenic, gold , lead and antimony.

                                     

Mount Erebus Lava Lake^

Case Study of Mount Erebus:

The system of Doppler radars was developed at GEOMAR in Kiel and at the Institute of Geophysics of Hamburg University. The portable system of three Doppler Radar instruments was temporarily installed on the crater rim of the active Mt. Erebus volcano in Antarctica in late 2005. The system observed eruptions from the active molten lava lake inside the crater and measured the speed of ejected material up to 15 times per second. The resulting data show a distribution of velocities of the exploding material, which is driven by the rapid expansion of a large gas bubble rising in the liquid volcanic magma conduit. The analysis of the data allows to calculate their accelerations of the exploding gas bubbles, gas pressures and size. For some eruptions, gas pressures of several atmospheres were measured, accelerating explosion fragments to velocities was above 650 km/h.

Read more about this case study at:

http://www.geophysics.zmaw.de/index.php?id=335

                                  

The Eruptions of Mount Erebus.

From late 1984 until early 2005, activity at Erebus volcano increased. Lava bombs up to 10 m in diameter were thrown up to 1 km above the Main Crater rim and over 1 km from the lava lake. Pure 1972 bombs are found 1.5 km from the crater, indicating that larger eruption occur periodically at Erebus.


Eruptions that took place in Mount Erebus:


1972-2011, 1963, 1957-58, 1955, 1947, 1915, 1912.

Advantage and Disadvantages of living near a volcano.

Advantages:

1) Volcanoes provide resources for energy extraction, also known as geothermal resources.  This involves heat from the earth's crust is being converted to energy. The big advantages to this type of energy are that it is very clean and the resources are nearly inexhaustible.

2) It will bring more tourism, and more tourism jobs available; this will bring more money in the local economy through: airport tickets, tourism guides/companies, hotels, restaurants and local showbiz companies eg. circus, dance shows etc.

3) More people will come to see the beautiful landscape made by the pyroclastic (molten   rocks) and mudflows, which harden overtime. They make great landscape for tourist to sightsee.

4) Though, the ash that comes and shadows over the crops and villages and destroys them, when mudflows hit the crops and farms (and not ash); eventually it becomes a better growth soil for the plants and farmland.

Disadvantages:

1) Transport and communication will be blocked; this will stop people getting out- or police and ambulance getting in, as the lava flows will cover and block the roads: communication with air patrol and outside help will be lost; as on the inside the roads are blocked for land transport. 

2) Crops ruined: when a cloud of ash overshadows the town/city, the cloud will collapse and

3) Sea - during a volcanic eruption earthquakes happen, and tsunamis may be created. Also, if it is a volcanic island, the island may be destroyed, and there is no escape.


4) Lava flow - these are very slow moving, but destructive as they cannot be stopped and they set fire to everything in their path.

5) Pyroclastic flow - these are impossible to outrun, travelling at about 300 km/h, and are extremely destructive


6) Mudflow/lahar - these are mud rivers that have the consistency of cement, and destroy everything in their path, including building

v breathtaking view of volcanoes attracts tourist

How are volcanoes formed?

How are volcanoes formed?



Most volcanoes occur where two tectonic plates meet. When two tectonic plates seperate, they create a gap, or fissure, and hot molten rock rises up through the fissure. This type of volcano is mainly found on the ocean floor and is mostly invisible. If a big enough fissure is formed, a lot of lava may ooze out of it, sometimes even enough to rise to the surface of the ocean and form an island.


If two tectonic plates coincide, it causes one plate to be forced beneath the other. The resulting friction generates a lot of heat, causing the magma to liquefy, and rise up in the form of lava. Only a few volcanoes on earth were formed like this, but their eruptions are the most violent and dangerous ones. This is on account of the fact that the friction greatly increases temperature, causing the gases to expand. This in turn generates a huge amount of pressure, literally throwing the lava out with great force, and to great heights. 


Finally, the last type of volcanoes form in the middle of a tectonic plate. In the course of normal tectonic movement, magma is pushed up little by little, till it enters crevices in the rock of the lithosphere. A volcano does not form every time this happens. However, if the overlying rocks are brittle, they give away to allow the magma to flow out onto the Earth's surface in the form of lava. This process is called a diapir, and such volcanoes are commonly called 'hotspots'. These are places that are connected by channels to the hot mantle of the earth.

Structure of Volcano

The Structure of a Volcano

Vent- An opening allowing the passage of air
Ash Cloud- The powdery residue left after burning
Dike- The barrier or obstacle of a volcano
Sill- Slab of stone at the foot of the volcano
Flank- The side of a volcano
Lava- Matter flowing from a volcano that solidifies as it cools
Crater- Mouth of a volcano.
Conduit- Channel or pipe conveying liquids such as lava
Summit- Highest point; apex
Throat- Entrance of a volcano

Here is a video on the structure of volcanoes :