Hazards: Difference Between Volcanoes and Hurricanes/Typhoons - John, Na Li and Bettina

Distinguish between two chosen hazards in terms of their spatial extent, predictability, frequency, magnitude, duration, speed of onset and effects. (10 marks)

	Volcanoes	Hurricanes/Typhoons
Spatial Extent	Volcanoes can be located in specific areas: Around the edge of the Pacific Ocean Down the centre of the Atlantic Ocean In Southern Europe Down the East Coast of Africa Volcanoes are located on or near tectonic plate boundaries, specifically destructive and constructive boundaries. Their spatial concentration is limited, and their areal extent is also normally limited to the areas immediately around the volcanoes.	Typhoons' are what tropical storms are called that occur in the western pacific ocean. 'Hurricanes' are storms that occur in the North Atlantic and Eastern Pacific.Hurricanes/Typhoons or "cyclones" are often formed in areas of warm water in both the Atlantic and Pacific Ocean. They rotate counter clockwise in the Northern Hemisphere and clockwise in the Southern Hemisphere.
Predictability	The predictability of Volcanoes can be very difficult, but it is said that the beginning of a volcanic eruption is easier to predict rather than the end of the eruption. Volcanologists can try and predict the eruptions of volcanoes by looking for certain characteristics: Changes in the shape of a volcano Changes in the amount of gas being released Changes in the temperature Tectonic Activity (earthquakes)  Animal Behaviour Changes in Local Hydrology Mass Movements	These hazards are caused by the exchanges in temperature of the cool temperature of the air and the warm temperature of the water. Therefore, it can be predicted when a cold front and a warm front are near each other, or when a cold front overtakes a warm front. The larger the difference between the two temperatures, the larger the hazard will become.
Frequency	Non-explosive to gentle explosions occur frequently, or daily. However, very large volcanic eruptions with a plume height of >25km happens about once every 10,000 years.	Typhoons occur much more often in a year at an average of 25 to 30 typhoons per year, compared to about 10 to 15 hurricanes in one year.
Magnitude	The magnitude of volcanoes can be measured through the Volcanic Explosivity Index, or the VEI. the VEI specifically is characterised or distributes the magnitude through the plume height and the volume of the volcano.	The magnitudes of typhoons can be measured into five different levels of intensity. The different levels depend on the different speeds of the hurricane or typhoon. Category one moves at an average of 33-42 meters per second, category two with 43 to 49 meters per second, category 3 at 50 to 59 meters per second, category 4 with 58 to 70 meters per second, and category 5 with winds greater than 79 meters per second.
Duration	Volcanoes can last from about a day to a thousand years.	Hurricanes/Typhoons can last up to less than a day (the amount of time it hits land) up to more than a day.
Effects	Volcanoes cause both economic and physical damage.	Typhoons both cause immense amount of damage, both physically and economically.

This table was created by using the blog post we created, and using Kevin Y.'s blog and Michael I.'s blog

With this, it can be identified, that volcanoes are located in specific areas in the world as shown in the table above, while  hurricanes/typhoons occur almost every where, or in areas with both a cold front and a warm front. Volcanoes are very hard to predict and can be predicted through physical characteristics such as the movement of plates and the temperature, etc. However, hurricanes and typhoons can be predicted electronically, or with technology, as it is required to know where the cold front and the warm fronts are to predict the hazard. Volcanoes occur more frequently as they can potentially happen daily at a small scale, however, hurricanes and typhoons can happen at an average of 10 to 15 or 25 to 30 typhoons a year, depending on the area. The magnitude of volcanoes and typhoons/hurricanes can be measured differently as volcanoes are measured through their plume height, which is hot magma rising, and the volume of the volcano. Typhoons and Hurricanes on the other hand, can be measured with the speed of their wind, and the intensity. The duration of the two hazards are very different, as they can both last for a minimum of less than a day, however, volcanoes can potentially last to thousands of years while hurricanes and typhoons can last up to a few days. The effects of both the hazards are both economic and physical damage to the area it has hit. 

Characteristics and Spatial Distribution of Volcanes of Group D - John, Na Li and Bettina

Volcanoes are mountains or hills, that have a crater or vent through which lava, rock fragments, hot vapour, and gas are being or have been erupted from the earth's crust.

The Characteristics of a Volcano:
Duration: The duration of a volcanic eruption can last from less than a day to thousands of years. Shown in the table below, the biggest percentage of volcanic eruption duration is one to six months, with about 28% of the earth's eruptions, and 99% of the eruptions are within 20 years.

Length of Eruption	% of Eruptions	Cumulative Total %
< 1 day	10	10
1 day to 1 week	14	24
1 week to 1 month	20	44
1 to 6 months	28	72
6 months to 1 year	12	84
1 to 2 years	7	91
2 to 5 years	5	96
5 to 10 years	2	98
10 to 20 years	1	99
> 20 years	1	100

http://www.volcanolive.com/predictions.html

Magnitude: It is said that there is no single feature in measuring how big a volcano is, however, there is a scale that determines the magnitude of the eruption. The scale to measure the magnitude of the eruption is called the Volcanic Explosivity Index, or the VEI. 

VEI	Description	Plume Height	Volume	Classification	How often	Example
0	non-explosive	< 100 m	1000s m3	Hawaiian	daily	Kilauea
1	gentle	100-1000 m	10,000s m3	Haw/Strombolian	daily	Stromboli
2	explosive	1-5 km	1,000,000s m3	Strom/Vulcanian	weekly	Galeras, 1992
3	severe	3-15 km	10,000,000s m3	Vulcanian	yearly	Ruiz, 1985
4	cataclysmic	10-25 km	100,000,000s m3	Vulc/Plinian	10's of years	Galunggung, 1982
5	paroxysmal	>25 km	1 km3	Plinian	100's of years	St. Helens, 1980
6	colossal	>25 km	10s km3	Plin/Ultra-Plinian	100's of years	Krakatau, 1883
7	super-colossal	>25 km	100s km3	Ultra-Plinian	1000's of years	Tambora, 1815
8	mega-colossal	>25 km	1,000s km3	Ultra-Plinian	10,000's of years	Yellowstone, 2 Ma

http://volcano.oregonstate.edu/education/eruption_scale.html

Predictability: Volcanic eruptions are very difficult to predict, however, it is said that the beginning of a volcanic eruption is easier to predict than to predict the end of a volcanic eruption.
Volcanologists can try and predict the eruptions of volcanoes by looking for certain characteristics:

• Changes in the shape of a volcano 
• Changes in the amount of gas being released
• Changes in the temperature
• Tectonic Activity (earthquakes)
• Animal behaviour
• Changes in local hydrology
• Mass movements

Regularity and Frequency: Shown in the Volcanic Explosivity Index table, non-explosive to gentle explosions occur frequently, and daily, compared to very big volcanic eruptions with a plume height of >25 km, which happen about once every 10,000 years. 

Volcanic Features: There are many different features or types of volcanoes:
Volcanic Fissure Vents: which is a linear crack where lava emerges
Shield Volcanoes: have a broad, shield-like profile, and are formed by the eruption of low-viscosity lava. Shield Volcanoes are usually found in the oceanic setting rather than the continental setting
Lava Domes: are built through slow eruptions with highly viscous lava. Lava domes can potentially produce violent, and explosive eruptions, however, the lava generally does not flow far from the vent
Cryptodomes: these are formed when viscous lava forces its way up and produces a bulge such as the 1980 eruption of Mt. St. Helens
Volcanic Cones: these are results of eruptions of small pieces of scoria and pyroclastics that build around the vents
Stratovolcanoes: are composite volcanoes that are composed of lava flows
Supervolcanoes: a large volcano that can potentially produce devastation on an enormous scale
Submarine volcanoes: these are volcanoes that can be found in the ocean, and are sometimes active in shallow water
Subglacial volcanoes: these are volcanoes that are developed under icecaps
Mud volcanoes: these are formed through geo-excreted liquids and gases

Spatial Distribution of a Volcano:
Volcanoes can be found in continental settings or oceanic settings. This means that volcanoes can be found in either land or underwater.  
Volcanoes can be located in specific areas:

• Around the edge of the Pacific Ocean
• Down the centre of the Atlantic Ocean
• In Southern Europe
• Down the East Coast of Africa

Volcanoes are located on or near tectonic plate boundaries, specifically destructive and constructive boundaries. Their spatial concentration is limited, and their areal extent is also normally limited to the areas immediately around the volcanoes.

Examples
Mt. Pinatubo:

• Second largest eruption in the 20th century
• Located in the Philippines
• Ashes were about 5cm thick covering 4,000 square kilometers
• Affected weather around the globe - aerosol droplets reflecting sunlight causing cooling of the Earth (1.5 celsius) and reducing density of the ozone layer
• Has caused a total of 722 deaths and 200,000 individuals homeless

Mountain St. Helens:

• A volcano located in Washington in the United States
• Created a major eruption in the United States and is considered to be the most destructive in U.S. history
• Its type of volcano is a cryptodome, as the lava forced its way up
• On May 18, ash erupted from the volcano for about nine hours
• About fifty-seven people were known to be dead
• Two-hundred homes were destroyed
• 185 miles of road and 15 miles of railways were destroyed

Villarica Volcano in Chile:

• One of Chile's most active volcanoes
• Lava of basaltic-andesitic composition --> of only five volcanoes worldwide known to have an active lava lake within its crater
• Generates strombolian eruptions with ejection of incandescent pyroclasts and lava flows
• The upper part of the volcano is permanently covered by snow and has some 40km^2 of glaciers
• It is a stratovolcano
• Last eruption was in 2013
• Villaricca emerged as a volcano during the Middle Pleistocone and grew forming a large stratocone of similar dimensions to the current edifice. 100,000 years ago during the Valdivia Interglacial the ancestral Villarrica collapsed following an eruption and formed a large elliptical calder of 6.5 and 4.2 km in diameter
• Currently the volcano covers up an area of 400km squared and has volcume of 250km (cubed) according to estimates
• Spatial Distribution:
• Located in Chile
• Symmetrical edifice stands in the Chilean Central Valley as the westernmost of an alignment of three large stratovolcanoes
• Alignment is attributed to the existence of an old fracture in the crust, the North-West-West trending sinistral Gastre Fault Zone, the other volcanoes in the chain Quetrupillan and Lanin are far less active. This alignment is unusual as it crosses the N-S running Liquine-Ofqui Fault, around which most currently active volcanoes are aligned.