st pierre, martinique monserrat volcanic hazards alternately · 07/04/2019 1 heimey 1973 - volcanic...
TRANSCRIPT
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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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