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Heimey 1973 -

VOLCANIC HAZARDS

Examples of Volcanic Disasters:

• Mount Vesuvius : A.D. 79 16,000 dead.

• Tambora, Indonesia 1815 92,000 died (mainly famine)

• Krakatoa – 1883 36,417 killed - mainly by tsunami

• St Pierre, Martinique - 1902 - 30,000 dead (pyroclastic flows)

• Nevado del Ruiz, Columbia, 1985 - >22,000 dead due to

mud/debris flows when eruption melted glaciers & snow.

• Lake Nyos, Cameroon: 1986 - 1,700 killed by carbon dioxide

• Mount Pinatubo, Philippines 1991 ≈500 dead. Now lahars…

• Monserrat - 1996-98 & continuing activity. <30 dead.

• Alternately : Kilauea, Hawaii, one of the worlds most active

volcanoes and lava destroys houses, roads etc. Yet many

people live happily alongside. Also Etna frequently erupts but

only 77 known to have been killed in a very long history.

Montserrat 1995 to 2010 & ?end – pyroclastic flow. Plymouth, capital of Montserrat – abandoned soon after the

eruption started in 1995, due to the pyroclastic flow risk.

Settlements

destroyed by

pyroclastic flows

and lahars

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Renewed activity with pyroclastic flows in February

2010 badly damaged the old airport to the NE of the

active Soufriere Hills area, and also affected the area

of the old capital, Plymouth. This was not a hazard for

people as the exclusion zone was being maintained.

However, since then things have been quiet, and quite

a few of the people who left Monserrat are now

returning. The new airport in the North of the island

has been receiving regular scheduled aircraft for some

time.

The tourist industry is also beginning to make a come

back – see www.visitmonserrat.com

http://www.volcanodiscovery.com/news.html

Volcanic Activity Saturday 3 February 2018www.volcanodiscovery.com

Karymsky Volcano, Kamchatka. Possible ash seen on

satellite image.

Suwanose-Jima, Ryukyu Islands, S of Japan. Exploded 2

Feb

Mayon, Luzon, Phillipines. Eruption reported.

Sinabung Volcano, N. Sumatra, Indonesia. Ash reported.

Dukono Volcano. North Maluku, Indonesia. Continuous ash

emission.

Fuego Volcano, Guatemala. Ongoing ash emission seen on

satellite image.

Suwanose-jima, Japan. Erupted 15 Jan 2018. Ash on

satellite image 2/2/2018.

Volcanic activity worldwide 2 Feb 2018: Fuego volcano,

Popocatépetl, Karangetang, Dukono, Reventado...

Dukono volcano, Indonesia. 26 March 2019

Ash to 7,000ft. This has disrupted local flights

from Morotai Island.

Bromo volcano, Indonesia. 22 March 2019

Ash to 10,000 ft.

Ambae volcano, Vanuatu Island, South Pacific

(N. of New Zealand). Eruptions Feb 2019.

Kilauea volcano Hawaii, May 2018 eruptions –

some evacuations of people.Krakatoa Volcano, Indonesia. 2009 Eruption.

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Krakatau erupting in 2018 – before the main eruption.

The violent explosion of 22 December, has made the whole

island bare of vegetation.

Ash rose to 60,000ft and the height of the volcano was

decreased from 338 m to 110 m.

The tsunami killed 431 people, 7200 were injured and 46,646

were displaced.

www.thetravel,com/20-images-of-volcanoes/

This site then goes on to show each as “20 Images

Of Volcanoes That Could Explode At Any

Minute”

You can also browse the site for other volcanoes

that can be visited.

e.g. www.thetravel.com/15volcanoes

will bring up 15 “active” volcanoes to visit, and 10 to

keep well away from!

The island of Tristan da Cunha is 10 km in diameter, a single

volcanic cone rising to 2,060 m (5,500m above the South

Atlantic ocean floor). Erupted in 1961, everyone evacuated to

England but returned in 1963, the settlement largely unaffected.

Distribution of World Volcanoes

Most, but not all, are near plate boundaries

N.B. In older books you will commonly find different terms:

basic is now mafic, acid is now felsic.

Continental crust has a much higher percentage of felsic

magma, some intermediate and some mafic magma.

Oceanic crust has mainly mafic magma - though sometimes

felsic magma e.g. Iceland is dominantly mafic magma with

basaltic lava most commonly – but Oraefi Volcano is felsic and

has produced devastating eruptions.

SiO2MAGMA

TYPE

TEMPERATURE

(centigrade)VISCOSITY

GAS

CONTENT

ERUPTION

STYLE

~50% mafic ~1100 low low nonexplosive

~60% intermediate ~1000 intermediate intermediate intermediate

~70% felsic ~800 high high explosive

Magma produces much gas as pressures fall - Mafic (basic)

lavas are very fluid – gas easily escapes. Felsic (acid) lavas are

very viscous, so gas cannot easily escape, so felsic volcanoes

are much more explosive and thus much more dangerous.

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Bardabunga, Iceland, 31 August 2014. Gas escaping through

molten lava produces “fire fountains”. (Mafic Magma)

Hekla, Iceland - fissure eruption, 1980 (Mafic magma)

In Iceland people rush off in their cars to see a new eruption!

YouTube : copy the titles and view for yourselves. Also

search for other volcano videos.

Good video: Published on 16 Dec 2014 (Hawaii)

Title: Lava flows in Pahoa - Eruption Update

Most incredible volcano expedition ever 2012 - the full

version

Title: Marum Volcano's famed lava lake on Ambrym Island,

Vanuatu.

Title: Terrifying Pyroclastic Flows Sinabung Volcano

Eruption in 4K Ultra HD

Mount St Helens before 1980 eruptions.

Mount St Helens:

30 March 1980

Ash lifted to 18,000ft

– significant hazard to

aircraft.

Mount St Helens: start of the great eruption of 18 May 1980.

The north side had been swelling for some weeks and suddenly

slipped downslope, releasing an enormous explosion of gas & ash.

Ash disabled flying aircraft and half the available helicopters on the

ground.

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Mount St Helens: 1st view of north slope after big explosion. Mount St Helens: Trees destroyed by pyroclastic flow.

Mount St Helens: no footprints from pickup – no survivors. Mount St Helens:mud and logs in melt floods for many miles.

Mud on tree shows

how deep the mud

flow was here.

Huge area of devastation

after the eruption. Far

bigger than predictions

because blast was

vented sideways.

57 killed, despite much

warning.

It is safer to have bigger

safety zones!

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Lava dome growing in the crater of Mt St Helens, 1984

Armero, Columbia, was completely destroyed by a lahar in

1985, with 23,000 killed. A remote eruption melted snow & ice

and the lahar surprised the town when it struck.

Armero had been previously destroyed by lahars in 1595.

The hazards from eruptions from Nevado del Rio were well

known to scientists and warnings had been given. There were

major risks from pyroclastic flows and lahars. The volcano had

been dormant for 69 years, but the new eruptive phase was

obvious with earthquakes and volcanic ash, including over the

town of Armero, 50 km from the volcano.

A risk map was available and in newspapers, but not widely

seen, & not easy to understand. People were advised to stay

indoors away from the ash, and a thunderstorm disguised a

renewed eruption phase, so that the lahar hit unexpectedly

burying and killing ¾ of the 28,700 people in the town.

The lahar moved at 12m/s (43kmph) and was 30m deep. It

was followed by a series of smaller lahars. Rescue efforts were

delayed by the mud.

In June 1991, the second largest volcanic eruption of the

twentieth century occurred in the Phillipines, only 90 km (55

miles) NW of Manila at Mount Pinatubo.

The eruption began in July 1990 with a massive earthquake.

In April 1991 explosions with limited ash triggered the start of

evacuations.

The eruption climaxed in the ejection of massive amounts of

volcanic ash and sulphur dioxide on 15 June 1991.

Despite over 200,000 people being evacuated, the ash, made

heavier by rain from a tropical storm, collapsed many roofs and

killed between 200 and 800 people.

However the climatic effect of the sulphur gases was

enormous. In 1992 & 1993 the Northern Hemisphere was

cooled by 0.5 to 0.6oC and the whole planet by 0.4 to 0.5oC.

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Following the 1991 Mt Pinatubo eruption more people have died

due to lahars (mud flows) than died due to the initial eruption.

Thick volcanic ash and heavy rain (frequent typhoons) produces

many lahars. 100,000 have lost their homes.

Lourdes, Pinatubo, part buried

by a lahar.

Huge volumes of glassy ash because the erupting magma was

chilled by erupting under a glacier.

Volcanic ash and aircraft - Eyjafjallajokull 2010

From: Geoscientist Online 15 April 2010

If your flight has been cancelled today because of

high level volcanic ash from Iceland, read this.

“Good evening ladies and gentlemen. This is

your captain speaking. We have a small

problem. All four engines have stopped. We

are doing our damnedest to get them going

again. I trust you are not in too much distress.”

Captain Eric Moody, flight announcement, 24 June 1982.

Volcanic eruption with ash in the Indonesia area!

Problems for aircraft from volcanic ash.

Volcanic glass can melt onto turbines and clog them.

The ash can sandblast and obscure windscreens.

The ash can clog sensors especially speed indicators

but also engine sensors.

Electrical effects can upset radio communication.

There will be a bigger Icelandic eruption some

time!

Laki –biggest ever historic lava eruption, 580km2, flowing up to 60km in 1783

If Volcanic vent in Oldham, lava might have flowed to Liverpool Pier Head!

Laki 1783 eruption - 14 cubic kilometres of lava and almost a

cubic kilometre of ash. Estimated killed over six million people

globally – world’s deadliest historical volcanic eruption.

Poisonous gases (hydrogen fluoride & others) killed many

people and animals in Iceland. 25% of people and over 50% of

animals dead from gases and starvation.

120 million tons of sulphur dioxide into the stratosphere, lowering

global temperatures. This caused crop failures in Europe,

droughts in India, famine in Egypt and Japan's worst famine

ever. MILLIONS starved to death.

Huge quantities of sulphur dioxide also drifted across Europe at

low level. Parish records in Britain indicate that 23,000 outside

workers died from sulphur dioxide poisoning in Britain!

Mississippi froze at New Orleans and ice on the Gulf of Mexico.

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Vesuvius & Naples. Blue on land is mainly SETTLEMENT! Pompei Street, with Vesuvius in background.

Crater of Vesuvius.Body cast and artifacts in store, Pompei.

Body cast at

Pompei.

Herculaneum.

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Herculaneum water gate – hot pyroclasic flow killed many here.Heimey, Iceland 1973. Ist night, Jan 27, 2am. A long fissure opens with “fire fountains”.

Heimey 1973 – 1st morning – 27 January. Fire fountains from fissure continue. Heimey 1973 – lava advancing on houses

Pipes carrying

large volume of

water to cool

lava. NB Steam

rising.

Fear of harbour

being blocked, =

the end for a

fishing town.

Heimey 1973 –

lava piled against

fish factory – later

repaired.

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Heimey 1973 – volunteers shovelling ash from roofs to prevent roof collapse

Safe to have people on site because basaltic (mafic) lava is so much less explosive.

Heimey 1974 –

clearing ash from

houses. Some

houses had been

completely buried and

some roofs collapsed.

Heimey 1974 – These

houses had been

completely buried and

quite a bit of ash has

already been removed.

There were problems

with steam damaging

buried houses, so

trenches were dug to

allow steam to escape.

Heimey – before 1973 eruption.

Heimey late summer 1973 Heimey Before and After the 1973 Eruption

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Popocatapetl volcano, just east of Mexico City. It is the most active volcano in Mexico

with 15 major eruptions since the Spaniards arrived in 1519 ( last major 1947). Over

25 million people live in the vicinity of Popocatapetl, including 18 million in Mexico City.

Popocatapetl Crater 1976 Volcanic ash east of Mexico City – many millions are at risk from volcanic hazards

Renewed activity in early 1990’s and mountain closed to visitors.

This picture was 16 April 2016 - lava fountain with incandescent

material thrown out NE to 3.5km and ash several km high (in night).

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Boiling water in pond, Geysir, Iceland.

Geysir Strokkur

at Geysir,

Iceland

Predicting future eruptions:

Study eruption history from records and geology (how far

lavas extended, pyroclastic flows?, lahars etc)

Monitor Earthquakes

Monitor gas emissions – changes in composition often warn

Swelling of the ground – instruments or simple observations

Hotspots – dead vegetation etc – ground observations

Start of ash/lava eruption. Satellite images useful in remote

areas.

Volcanic activity not all bad.

Geothermal power – Los Azulfres, Mexico (also New Zealand, Iceland)

Bathing in hot pools. Los Azulfres, Mexico Eggs for the picnic. Los Azulfres, Mexico

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Swimming in the hot pools at Landmannalauger is popular with

Icelanders & visitors.

Thank you for your attention

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