Introduction to Volcano. 

Volcano comes from the word ‘vulcan’. The story begins after the Roman God a fire, ‘vulcan’. It was said that his rage cause fire to spew out of the Earth (eruption). In scientific definition, volcano is a vent in the Earth’s crust through which lava team and ashes are expelled. It can be either continuous or at regular intervals.  It is also known as mountain or hill that have cuplike crater at the summit which form around a vent from the ash and lava expelled through it. It is also can be defined as an opening in the crust of the Earth in which molten rock called magma and gases can escape to the surface. The mountain that is formed from volcanic eruptions. 

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Cc   Distress of the Volcano. 

Between 1900 and 1986, volcanoes have killed an average of 845 people every year. Several ways on how volcanoes can be dangerous which are;

Hot lava flows : Lava can flows faster than walking speed . Buildings, roads and trees can be destroyed by the crushing weight and burning temperature of a lava flows.

Clogging ash or toxic fumes : During an eruption, volcanoes release vast amounts of water vapour, carbon dioxide and sulphur dioxide. If we encounter pure carbon dioxide we can suffocate without air. People have  been killed by  poisonous and acidic gases.

Rock bombs : During explosive eruption, volcanic ash is hurled up to 45 km in the air. Several cubic kilometers of ash can rain down, covering everything in a thick layer of ash.It might look a bit like snow, but it’s rock, and very heavy. Just a few centimeter of volcanic ash is heavy enough to collapse buildings and kill crops.

10 Most Dangerous Active Volcanoes Around The World.

Yellowstone Caldera, United States of America. 

It is known as a super-volcano that can wipe out the Western United States and change the course of human history. The last super volcano explosion identified occurred 640,000 years ago in Yellowstone. It does not have a cone shaped mountain, instead they form what are known as calderas.

Mount Vesuvius in Campagnia, Italy. 

It is one of the most dangerous volcanoes because of its history of the activities. 

The eruption cycle usually just 20 years and last erupted in 1944. 

Popocatépetl, Mexico

Popocatépetl is a large, glacier covered peak that lies around 35 miles from Mexico City.

The last eruption is in 2000 and it erupted more than 20 times since 1519. 

Sakurajima, Japan

Small explosion occurred from Sakurajima’s peak every year. 

The 700,000 residents of Kagoshima, who live just miles from the volcano exposed to 

a major eruption could have deadly consequences. 

Galeras, Colombia 

It is situated in Southern Columbia near the border with Ecuador. It has been active for 

1 million years and erupts frequently since 1580. 

Mount Merapi, Indonesia

It can be defined as a mountain of fire and the most active volcano in Indonesia. 

It produced more lava flow than any volcano in the world. 

Since 1548 , Mount Merapi regularly erupted and it have been active

for the last 10,000 years. 

Mount Nyiragongo, Democratic Republic of Congo 

In the African continent, Mount Nyiragongo is one of the active volcanoes. It is well known for

its large lava lake which frequently appears in its crater. 

Ulawun, Papua New Guinea

It is located in Papua New Guinea. Ulawun is one of the most active volcanoes. 

Eruptions from Ulawun originate from its central crater. 

Since 1700, 22 eruptions have been recorded.

Taal Volcano, Philippines

The Taal Volcano is a cinder cone volcano. It is located on the island of Luzon,

Philippines where it lies at the middle of Lake Taal.

Since 1572 , the Taal volcano recorded 33 eruptions.

Mauna Loa, Hawaii

Mauna Loa is the largest volcano in the world. 

It is also one of the 5 volcanoes that makes up the Island of Hawaii

in the middle of the Pacific Ocean.

At the past 700000 years, Mauna Loa has been erupted regularly 

and the most frequent eruption occurred in 1984. 

Types of the Volcano. 

Island Arc Volcano

         It occurs when two oceanic plates meet, one of them is sub-ducted beneath the other that is drawn into the mantle. Mass of the magma is generated. Generated magma rises upward to form island-arc volcanoes. Examples of island-arc volcanoes are Aleutians, Japan and Indonesia.

Hotspot Volcano

         It occurs from the area in the middle of the plate where magma rises from mantle. Magma will erupt through the plate. Eruption of magma creates a series of volcanoes. Examples : Hawaii, Galapagos, Azores and Yellowstone.

Ocean Ridge

It occurs when magma rises along a broad system of oceanic fissures. Fissure is 

a long narrow depression in a surface. These oceanic fissures generate volcanic structure

rise out of the sea. Example of the oceanic ridge is Iceland. 

Continental Margin

    

    
    
    


    

It occurs when there is a collision of oceanic plate with continental plate.

Oceanic plate is sub-ducted beneath the continental plate into the mantle.

Oceanic plate then causes the production and rise of magma. 

As a consequence, it leads to the formation of a chain of coastal mountains. 

Examples of the continental margin are Cascades and Andes.

Continental Rift

  

It occurs when there is a thinning of the crust.

The thinned crust causes tectonic plates separate a new ocean. 

As a result, magma will rise along the system of fissures.

Example of the continental rift is East African Rift Valley. 

Categories of the Volcano. 

Active - It erupts frequently or recently or is likely to. 

Dormant - It is temporarily inactive but not fully extinct. 

Extinct - It is never likely to erupt again and no longer volcanic. 

Structure Types of the Volcano.

Shield Volcano

Liquid lava emitted from a central vent has a collapse caldera.

Examples of the shield volcano are Kilauea, Mauna Loa, Fernandina, Karthala, Erta Ale,

Tolbachik and Masaya.

Strato Volcano

More viscous lava, much explosive (pyroclastic) debris, large, emitted from a central vent.

Examples of the strato volcano are Mount Saint Helens, Mount Rainier, Pinatubo,

Mount Fuji, Mount Merapi and Galeras. 

Flood and Plateau Bassalt

It is a very liquid lava. It flows very widespread and it can be emitted from the fracture.

Example of the flood and plateau bassalt is Columbia river plateau. 

Cinder Cone

It is an explosive liquid lava. It can be emitted from the central vent. If it is continued

long enough and may build up a shield volcano. 

Examples of the cinder cone are Mount Tabor and Mount Zion. 

Caldera

It is a very large composite volcano collapsed after an explosive period which

is frequently associated with the plug domes.

Examples of the caldera are Crater Lake and Yellowstone.

Volcanic Dome

It is a very viscous lava. It can be explosive and commonly occurs adjacent to the craters of

the composite volcanoes.

Examples of the volcanic dome are Mount Saint Helens Lava Dome and Mount Lassen. 

Magma and Lava.

Magma is a hot molten rock which is mixed with gases and mineral crystals

in the Earth's crust.

Lava is a magma that breaks through the Earth's surface and flows down the volcano.

It contains the molten rock expelled by the volcano during the eruption.

It is also known as the resulting rock after solidification and cooling.

There are three basic types of the magma:

1. Basaltic  - It has low silica content and low viscosity of the magma.

                    Easily for gases to escape.

                    Non-explosive eruption.

                                

2. Andestic - It has medium level of silica content.

                     It has intermediate viscosity of the magma.

                     Intermediate explosiveness.

                                

3. Rhyolitic - It has a high silica content and high gases viscosity.

                     Difficult for gases to escape.

                                

Furthermore, there are also three basic types of the lava:

1. Pillow lava 

It is erupted at a mid-ocean ridges and large intraplate volcanoes. The best way to detect

the pillow lava is by finding water lying sediment between individual pillow.

Sediment is generated once the pieces of the lava fall off during the rapid collapsing.

The rapid collapsing is commonly occurred when the lava flows under the water.

The pillow lava is formed from a low effusion-rate eruptions of fluid basalt lava.

This lava tends to have the thicker skins of glass and less vesicular skin. 

2. Pahoehoe

It has a smooth, billowy and ropy surface. Its flow tends to be relatively thin. 

3. A'a

It has a rough and generally clinker in the surface. Its flow tends to be relatively thick.

This lava flows rapidly with higher viscosity of the lava. 

Volcano Monitoring Method. 

Seismicity

The seismic monitoring at volcanoes is functioned to record and monitor

the earthquakes and tremor that accompany volcanic unrest.

Seismographic networks record the signals radiated from the volcanic seismic sources,

then seismologists analyze and interpret these signals and the patterns.

A refers to volcanic-tectonic (VT) earthquake. It is characterized by clear wave onset. 

It contains energy across a broad range of seismic of frequencies.

B refers to long-period (LP) earthquake.

It is characterized by dominant and lower frequency of oscillation.

C refers to volcanic tremor.

It is characterized by continuous or sustained ground oscillation at the restless volcano. 

D refers to explosion earthquake. 

The explosion normally occurred at the vent of volcano or at the shallow depth

beneath the vent. 

Ground Deformation

Ground deformation is important in quantifying the characteristics of the deformation over

the space and time which can give the vital information about the depth, volume of change and

geometry of gamma reservoirs below the ground.

There are six instruments that have been used to quantify the ground deformation:

1. Electronic Distance Measuring (EDM)

EDM measures the travel time of  a laser pulse between the two benchmarks.

After that, it converts the time to the distance. Measured distances are accurate to

within a few centimeters. 

2. Ground Tilt

It is a cylinder, 0.6-1.0 meter in length and filled with an electrolytic fluid

that contains a bubble. Electrodes sense the movement of the bubble as the instrument tilts.

Tiltmeter is placed in a sand-filled borehole in bedrock approximately at a depth of 2 meters.

Then, the tilt of the ground surface  can be measured. 

3. Triangulation

It functions as a measurement of the horizontal angles of a triangle.

The vertices are benchmarks that may be tens of kilometers distant from one another.

Any change in the angles over the time are used to determine the horizontal deformation

of the Earth's surface. 

4. Global Positioning System (GPS)

GPS is the ultimate tool for measuring three-dimensional displacements.

It measures the horizontal and the vertical displacements within accuracy of

a few millimeters using the processing software from NASA. 

    

5. Leveling

It is a method that measures the vertical elevations of benchmark.

Repeated leveling surveys along a series of benchmark can determine the elevation

changes over the time to sub-millimeter accuracy. 

6. Aerial Photography/Light Detection and Ranging (LIDAR)

LIDAR uses a  higher frequencies of light to survey the elevation of the ground surface. 

Direct Fumarole Sampling of Gases and Isotopes 

The method is suited for a long-term surveillance of volcanic systems because

it can produce and provide a detailed chemical analysis of the specific fumaroles

and vents. Volcanic gas samples are collected by inserting a chemically inert

and durable tube into a hot fumarole.

Gas samples are sent to an analytical lab for the analysis by ion and

gas chromatography. 

The composition of the gas or a change in the rate of gas emission

will provide additional information on what is happening inside the volcano.

For an example, an increase in the ratio of carbon to sulphur can be used

to indicate the arrival of a new batch of magma at the summit reservoir. 

Emission of Gas Plumes and Ash Clouds Monitoring

by Correlation Spectrometer (COSPEC)

COSPEC is an optical  instrument with an upward-looking telescope.

It is used  to measure sulphur dioxide emission rates from the volcano.

It measures the amount of  ultraviolet light absorbed by sulphur dioxide molecules

within a volcanic plume using the scattered sunlight as its light source. 

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Volcano Quote :)
By death the moon was gathered in long ago, ah long ago,
Yet still the silver corpse must spin,
And with another's light must glow.

Her frozen mountains must forget their primal hot volcanic breath,
Doomed to revolve for ages yet,
Void amphitheatres of death.

And all about the cosmic sky,
The black that lies beyond our blue,
Dead stars innumerable lie,
And stars of red and angry hue,
Not dead but doomed to die.

Written by Sir Julian Huxley.

Special Appreciation to Our Volcano Team HPY555
Muhamad Nazmie Bin Rahmad                2012460598
Abdul Muqit Bin Abdul Waled                    2012684816
Mohd Fareez Faisal Bin Saad@Asri         2012473818
Nur Syakila Binti Rohawi                           2012240676
Zayan Nabilah Rasyidah Binti Abd Razak 2012256104
Nornaizie Binti Che Nordin                        2012422802
Zarina Binti Sarkawi                                   2012267612