PREPARED BY:-Chirantan BanikME- 3rd Yr. Roll- 071020107010KALYANI GOVT. ENGG. COLLEGE

GUIDED BY:-Prof. Biswajit Maity,HOD, Dept. of Physics,KALYANI GOVT. ENGG. COLLEGE

Volcano : Definition:-Ans. Volcano is a mountain that forms when molten rock

(magma) is forced to the Earth’s surface. Volcano : stats Number of active volcanoes :-

20 erupting right now (50-60/year) (160/decade)

Volcano : Erupted materialGenerally, the erupted material from volcanoes is limited to Lava. Lava :- Magma that flows onto the Earth’s surface. Magma – Molten rock beneath the surface

There are three types of volcanoes:

A. Cinder Cones and

B. Shield Volcanoes

C. Composite Volcanoes Cinder cones are tall with steep sides. They are made up

of cinders, so even when they explode, they don’t do a lot of damage. They look a lot like a cone.

Shield volcano is called that because it looks like a warrior put his shield down. It is a gentle volcano and that’s why in Kilauea National Park on Hawaii, the park rangers will escort people close to the volcano when it erupts.

The most explosive and dangerous type of volcano is the Composite Volcano. These are like Mt. St. Helens in Washington state, and Mt. Fuji in Ja.pan.

Type Lava Volcano Effects

Icelandic Basalt None or Shield Fissure Flows

Hawaiian Basalt Shield

Strombolian Basalt-Andesite

Small Stratovolcano

Mild, Continuous

Vulcanian Andesite Stratovolcano Large eruption cloud

Plinian Andesite – Rhyolite

Stratovolcano Pyroclastic Flows

Caldera-Forming

Rhyolite Stratovolcano or None

Large Pyroclastic Flows

Phreatic Any Any Steam Blast

PollutionPollution SO2, HCl in Water Lava Flows Falling Ejecta Ash FallsAsh Falls Building Collapse Crop Destruction Air Traffic

affected

MudflowsMudflows Direct Damage

(Colombia, 1985) Floods (Several

Types)Blast (Mt. St. Helens,

1980) Pyroclastic Flow Pyroclastic Flow (St.

Pierre, 1902) GasGas (Lake Nyos,

Cameroon, 1986)

VEIClassification

Description

PlumeEjecta volume

Frequency

Example

0 Hawaiiannon-explosive

< 100 m < 104m³ daily Mauna Loa

1HawaiianStrombolian

gentle100-1000 m

> 104 m³ daily Stromboli

2StrombolianVulcanian

explosive 1-5 km > 106 m³ weeklyGaleras 1993

3Vulcanian /Pelean

severe 3-15 km > 107 m³ yearlyLassen 1915

4Pelean/Plinian

cataclysmic

10-25 km > 0.1 km³ ≥ 10 yrsSoufrière Hills 1995

5 Plinianparoxysmal

> 25 km > 1 km³ ≥ 50 yrsSt. Helens 1980

6Plinian/Ultra-Plinian

colossal > 25 km > 10 km³ ≥ 100 yrsPinatubo 1991

7Plinian/Ultra-Plinian

super-colossal

> 25 km > 100 km³≥ 1000 yrs

Tambora 1815

Mount Etna From Space

Pinatubo ash plume reaching a height of 19 km, 3 days before the climactic eruption of 15 June 1991

Mount Lamington(1951) Papandayan(1772) Kelut(1919) Unzen(1792) Ruiz(1985) Mount Pelee(1902 the largest in the 20th

Century) Krakatoa(August 1883) Tambora(April-June in 1815) Mount Vesuvius(AD79) Laki(1783)

Mount Lamington is a 1,680 meter-high volcano located in Papua New Guinea. Until 1951, residents of the surrounding Oro Province thought it was just a wooded mountain top. Late that night, on 18 Jan, smoke and lava oozed from the peak, and 3 days later, there was a huge explosion from the north side.

Situated on the Indonesian island of Java, Papandayan is a crater-filled semi-active volcano. In 1772, one side of the volcano exploded and avalanched into the surrounding 40 villages, destroying them completely. Over 3,000 villagers were killed.

1919 mud flow or “lahar” was the most devastating to date. The red hot “lakes” of magma, which began on that fateful day on May 19, flowed fast into nearby settlements and killed over 5,000 people.

The nearest miss since then was in October 2007, when 30,000 local residents had to be evacuated after the volcano was set on Red Alert. Kelut finally blew two weeks later, dusting villages up to eight miles away with ash.

Unzen The 1,500 meter volcano,

which is still active, had its most noteworthy destruction in 1792.

When several lava domes collapsed

a tsunami was triggered, killing over 15,000 people.

Ruiz in 1985, a staggering

23,000 people died, which was almost the entire population of the village of Armero , which was built on top of the dried magma.

The town was completely buried under the 40 mile-an-hour deadly flow, which cost Colombia an estimated $1,000,000,000.

Mount Pelee In 1902, the eruption,

which was the largest in the 20th Century, killed over 30,000 people.

the volcano didn’t fully blow until May 8th. Lava fountains, lighting, and toxic clouds travelling at speeds of 600 miles per hour spewed from the volcano.

temperatures of 1075 degrees boiled the city of Saint Pierre below – which continued burning for days,only two survivors.

Krakatoa In August 1883, there

were a series of extremely violent gigantic explosions with a force 13,000 times larger than the Hiroshima bombing.

The catastrophic explosion – which could be heard as far away as Perth in Australia, spewed over 21 cubic kilometers of rock, ash and pumice up to 70 miles high.

Officially, over 37,000 people were killed.

Tambora a gigantic 4,300 meters,

the series of explosions from April-June in 1815 rocked the whole world with after-effects, completely changing the stratosphere and ultimately causing the worst famines in the US and Europe in the 19th Century.

In total, over 71,000 people died as a result of burning, starvation or poison.

Mount Vesuvius Death toll was impressively

high at up to 25,000, when Vesuvius had its almighty eruption in AD79, it completely buried the town of Pompeii below, as well as devastating other nearby villages. The eruption column, which was a 20 mile tall spout of magma and rock, surged intermittently over twenty hours.

Laki In 1783, it caused nationwide

damage when it spectacularly exploded, killing over 50% of the livestock population in Iceland at the time due to the clouds of F & SO2. The resulting famine killed 25% of the population. The after-effects were felt all over the world, with Great Britain dubbing that summer “sand-summer” due to carried-over ash.

In North America, the winter of 1784 was the coldest on record. There was a record amount of snow in New Jersey, the Mississippi froze at New Orleans, and there was ice in the Gulf of Mexico.

Till date the success rate of most of these methods is around 10% - 25%.

There is no proper distinction between a dormant and an extinct volcano.

Wrong predictions can prove to be tremendously dangerous and have been so.

But, things are looking better in the recent past, the techniques have been modified effectively.