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 :

Introduction on Volcano

A Volcano is a conical hill or mountain formed by material from the mantle being forced through an opening or vent in the Earth's crust. Volcanoes are found in three states - extinct, dormant and active. An extinct volcano will never erupt again. A dormant volcano has not erupted in 2000 years. An active volcano has erupted recently and is likely to erupt again. 

^Kilauea Volcano, Hawaii. It is one of the world's most active volcano. 

It last erupted in January 3 1983.

^Santa Isabel, Colombia. It is a extinct volcano. It last erupted in 1923.

There are many different types of volcanoes. There are 3 main type of volcanoes are composite, shield and cinder cone.

These volcanoes are typically tens of miles across and ten thousand or more feet in height. They have moderately steep sides and sometimes have small craters in their summits. They consist of layers of solid lava flows mixed with layers of sand- or gravel-like volcanic rock called cinders or volcanic ash.

Shield volcanoes have low slopes and consist almost entirely of frozen lavas. They almost always have large craters at their summits.This type of volcano can be hundreds of miles across and many tens of thousands of feet high.

These type of volcanoes consist almost entirely of loose, grainy cinders and almost no lava. They are small volcanoes, usually only about a mile across and up to about a thousand feet high. They have very steep sides and usually have a small crater on top.

Here is a picture of the other kind of volcano: