Soufriere Hills, Montserrat, West Indies
Pyroclastic flows from Montserrat
dome collapses have flowed down the White River creating a new delta where
they entered the sea. It is uncertain if this delta will survive or be
eroded by seawaves
Soufriere Hills, a stratovolcano on the island
of Montserrat, began erupting on July 18, 1995. This is the first recorded
eruption of this volcano in historic time. The initial small phreatic eruption
produced minor ash that spread around the island. Periods of intense seismic
activity were associated with strong venting of steam and ash. A new vent
formed southwest of Castle Peak, an old volcanic dome.
November 16, 1999
The activity at the Soufriere Hills Volcano
was at a higher level between 5 November and 12 November. Distinct explosions
occurred on the 8 and 9 of November, followed by two hours of tremor. Both
explosions created steamy ash clouds which rose ~20,000 to 25,000 ft. above
the volcano. A light ash fell on Monserrat. Small pumice clasts were found
near the volcano. On 11 November, a small dome-collapse pyroclastic flow
occurred in the upper parts of the Tar River Valley.
November 9, 1999
Six ash venting episodes or small explosions occurred between 29 October-
5 November 1999. Maximum ash cloud height was 10,000 to 12,000 feet. There
were no new pyroclastic flow deposits for these events. The seismic network
network recorded a total of 115 rockfall signals, 40 volcano-tectonic earthquakes,
71 hybrid and 13 long period earthquakes.
November 5, 1999
On 26 and 27 October, the Soufriere Hills Volcano produced ash venting episodes,
small explosions or dome collapse events. New pyroclastic flow deposits
were observed in the Tar River Valley. The 26 October event created an ash
cloud that rose ~15,000 feet.
October 27, 1999
On 26 October, an ash cloud erupted from the Soufriere Hills Volcano.
August 23, 1999
Week of August 13-20, 1999: Activity at volcano remained low. On August
20th, two minor volcano tectonic swarms were recorded under the volcanic
edifice. 50 rockfalls and 84 volcano-tectonic earthquakes were recorded.
Unstable masses sit above Gages, Tuitt's and Galway's. Small rockfalls are
being produced in these areas.
August 6, 1999
On 3 August, the Soufriere Hills
Volcano released an ash cloud that reached 15,000 feet (~4.5 km) above sea
level.
July 21, 1999
The Soufriere Hills Volcano erupted on July
20. There was a moderate explosion and a dome collapsed which produced
a large pyroclastic flow in the Tar River Valley. The ash cloud rose above
15,000 feet.
July 6, 1999
On 17 June, pyroclastic flows were sourced
from the area of the dome above Tuitt's Ghaut. A light ash fall was deposited
in Salem and Old Towne. Between 11-18 June, a total of 120 rockfall signals
and 20 volcano-tectonic earthquakes were recorded. On 18 June, ash rose
to 7,000 feet (~2km) above sea level. On 2 July, an ash cloud rose 15,000
feet (~4.5) above sea level. On 4 July, ash rose to less than 25,000 (~8km)
above sea level. Residents of Montserrat are advised to keep listening to
the radio for any volcanic alerts.
June 11, 1999
On 5 June 1999, an ash plume rose to at least
12,000 ft (~3.5 km) above sea level. Pyroclastic flows went down the Tar
River and Tuittis Ghaut. A new scoop had been eroded into the dome above
Tuittis Ghaut, and a new ashy fumarole was visible in the depression. Up
to 1 cm of ash had been deposited in Salem and Old Towne.
January 20, 1999
A pyroclastic flow travelled
down the Tar River valley and reached the sea. A large ash cloud from
the event was blown to the northwest by strong winds. Further dome collapse
could occur at any time, as the dome remains unstable.
January
15, 1999
A small explosive event occurred at Soufrierre
Hills, sending an ash cloud to at least 15,000 ft. Light ash fall affected
areas to the northwest, including Salem, Old Towne and Olveston. No
pyroclastic flows were observed from this event.
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- January 13, 1999
- There was a violent eruption of Soufriere
Hills volcano at 6:30 am on January 13. A vertical ash column rapidly
rose to heights of 20,000 feet (~6,000 m). A great amount of thunder
and lightning occurred within this cloud. Ash from this plume fell to
the west over the area from Cork Hill to Plymouth. A pyroclastic flow
from the event moved down the Tar River valley to the sea. Steam clouds
were created as the flow contacted the water.
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- November 12, 1998
- The largest collapse of the dome since
July occurred on the morning of November 12. Pyroclastic flows were
sent down Gages valley, the White River Valley, and the Tar River Valley.
Flows down the Gages Valley flowed through Plymouth and reached the
sea. Other lobes from this flow spread into the Amersham area, and burning
was seen in the port area. The flows down the Tar River Valley also
reached the sea. Flows down the White River Valley reached the coast
and spread out over the new fan. An ash cloud from this event reached
25,000 ft (7500 m) and showered ash over the entire island. Further
collapses from the dome are expected.
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- November 2, 1998
- Further dome collapse on November 2 sent
pyroclastic flows down the Tar River Valley and into the White River.
The flows down the Tar River Valley reached the sea. An accompanying
ash cloud reached 10,000 ft (3000 m) and drifted west.
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- October 31, 1998
- Another small dome collapse occurred,
sending ash falls into populated areas north of Montserrat. Pyroclastic
flows were produced in the White River and Gages valley. Larger dome
collapses in the Galways area are possible in the near future.
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- October 26, 1998
- A small collapse of the dome occurred
on October 26, sending pyroclastic flows down the Tar River and White
River valleys. Flows down the Tar River Valley reached the sea. These
flows also reached the Tar River Estate House. Ash from this event fell
as far north as St. Peters. Ash clouds reached 20,000 to 25,000 ft (~6,000-7,500
m) high. About one inch of ash fell on Richmond Hill.
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- October 20, 1998
- A dome collapse occurred, sending pyrocalstic
flows down Gages Valley towards Plymouth. This pyroclastic flow stretched
about 2 miles (~3 km) from the edge of the dome. A plume rose above
the volcano and produced thunder and lightening. Ash from this plume
fell in Old Towne and areas to the south.
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- October 18, 1998
- Another partial collapse of the dome
today led to additional pyroclastic flows and an ash cloud reaching
7000 ft (~2000 m).
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- October 12, 1998
- A partial collapse of the northern side
of the dome on Soufrierre Hills Volcano caused pyroclastic flows in
two valleys on Montserrat. An associated ash cloud reached heights of
25,000 ft (~7500 m). Ash from this event also fell on the western side
of the island in the areas of Cork Hill, Old Towne, Olveston, Salem
and the Belham Valley.
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- July 3, 1998
- Major activity at Soufrierre Hills Volcano
on Montserrat began at about 3 a.m. on July 3rd. Intense earthquakes
for three to four minutes led to a major dome collapse. This collapse
produced pyroclastic flows for over two and one half hours. Most of
this flow activity occurred in the Tar River valley. Pyroclastic material
was deposited throughout the entire river. This material reached the
sea, increasing the size of the Tar River delta. Ash fell over the entire
island, as well as nearby Nevis and St. Kitts. An ash plume reached
heights of over 45,000 ft (14,000 m). Heavy rains around noon caused
mudflows from the volcano for about 30 minutes. Around 2 p.m., activity
began again. This time three to four minutes of seismic activity led
to a small explosion from the dome. A dark ash plume rose 10,000-15,000
ft (3,000-4,500 m) above the volcano. This ash moved west over Salem,
Old Towne and Olveston. The volcano is still very dangerous, and further
explosions and pyroclastic flows down all sides of the volcano are possible.
- December 26, 1997
- A major eruption occurred on the morning
of December 26 when the dome on Soufriere Hills Volcano collapsed. Most
of the material from this collapse traveled down the White River. A large
and destructive pyroclastic cloud moved down the White River with the
flow. This cloud moved over the villages of Morris, Reids, St. Patricks,
Trials, and Fairfield. Two explosions occurred shortly after the dome
collapsed. The ash plume from this event reached 36,000 ft (11,000 m).
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- November 27, 1997
- Large, slow moving pyroclastic flows occurred
over Galways Wall on November 27. These flows reached the new fan at the
end of the White River but did not enter the sea. There is still danger
of continuing pyroclastic flows and renewed explosive activity.
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- November 11, 1997
- A large dome collapse sent pyroclastic
flows down the White River Valley on November 4. This flow reached the
sea. The dome collapse lasted for more than one hour and contributed about
70 million cubic feet (2 million cubic meters) of material to the flow.
The ash cloud from the flow reached 10,000 ft (~3000 m). Steam and ash
venting has continued from the dome. Fumaroles also continue vigorous
venting on the northern face of the dome.
- There was another dome collapse on November
6. Pyroclastic flows from this collapse also traveled down the White River
and reached the sea. The ash cloud from these flows reached 15,000 ft
(~4500 m) and was blown west.
- Activity at the volcano has decreased since
these events, but the area is still very dangerous. Additional dome collapse
and renewed explosions could occur at any time.
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- October 28, 1997
- No explosions have occurred at Soufriere
Hills volcano on Montserrat in the last eight days. However, a new lava
dome began to grow on the volcano on October 22. It stands well over 250
ft (80 m) above the northeastern crater edge and is growing at a rate
of 280 cubic ft (8 cubic meters) per second. On October 28, earthquake
activity began to increase drastically at the volcano. This indicates
that new explosions and pyroclastic flows could be near.
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- October 2, 1997
- Three more explosions occurred over the
last 24 hours. Each of these explosions were followed by pyroclastic flows
down all sides of the volcano. Flows of pumice and ash reached the sea
through the Tar River valley and White River valley. They also reached
Farms, Dyer's and Plymouth. The large amount of material deposited on
the volcano during this activity allows each subsequent flow to travel
farther. Eruption columns rose to heights of 20,000 to 40,000 ft (6000-12,000
m) after each explosion. Ash and pumice clasts up to almost 1 inch (~2
cm) in diameter has fallen on inhabited areas of Montserrat from these
explosions.
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- October 1, 1997
- Over the last week, explosions have been
occurring at Soufriere Hills Volcano about every 9 hours. Three explosions
occurred on October 1. Each was followed by large pyroclastic flows, and
accompanying ash clouds were blown over populated areas. These flows moved
down the Tar River Valley nearly to the sea and down Tuitt's Ghaut to
Trant's. Ash clouds reached heights of 20,000 to 25,000 feet (6,000-7,500
m) and blew to the NW and out to sea. Ash and gravel sized rock fell over
populated areas to the north. Ash venting was seen after all three explosions.
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- September 26, 1997
- Two more explosions occurred after 8:00
pm on September 25. Both led to pyroclastic flows down Gages Valley. The
first was heard over much of Montserrat and dropped ash and pumice particles
on the northern part of the island in populated areas. Pieces of rock
up to 1 inch (2 cm) in diameter fell on parts of the island.
- The second explosion generated an ash plume
10,000 ft (3000 m) high. This explosion dropped ash and rock fragments
in Old Towne and pumice clasts as far north as St. Johns.
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- September 25, 1997
- A total of five explosive events have occurred
at Soufriere Hills volcano in Montserrat over the last two days. These
explosions have generated ash clouds over 10,000 ft (3000 m) high with
one reaching 20,000 ft (6000 m). The wind has blown most of the ash and
other particles to the west, but if the wind switches to the north, populated
areas of Montserrat could be showered with this material. Large pyroclastic
flows have accompanied each of these explosions. During one event, collapse
of the vertical ash column generated pumice flows.
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- September 23, 1997
- The eruption of September 21 that destroyed
the airport also wiped out any buildings remaining in Bethel and devestated
Tuitts' and Spanish Point. In light of this destruction and the fact that
the dome doesn't seem to have lost significant volume from these flows,
the British government is considering using force for the first time to
remove people from exclusion zones.
- Elton John, Paul McCartney, Sting, Eric
Clapton, Mark Knopfler and Phil Collins all performed at a concert in
London on September 15 to benefit the victims of the volcanic eruption
on Montserrat. The concert was shown on pay-per-view television on September
20 and was hoped to have raised around $1.6 million for relocation and
new housing.
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- September 21, 1997
- A large pyroclastic flow buried part of
the airport runway on Montserrat and set the terminal on fire on September
21. The flow traveled 3 1/2 miles (5.6 km) to the airport and into the
sea. Many fish and lobsters were found washed up on shore after the flow
heated the water to dangerously high temperatures. Thick ash also was
dropped across the entire island. The government of Great Britain has
vowed $64 million to replace housing, hospitals and the airport, which
has now been totally destroyed.
- September 9, 1997
- Scientists are now warning that a major
explosion at the Soufriere Hills volcano on Montserrat is likely imminent.
Over the past two days, several pyroclastic flows have occurred. These
flows continue to press farther to the north. Ash associated with these
flows was blown by Hurricane Erika northeast to Antigua. This has caused
problems for Antigua's airport, and many of its businesses were forced
to close. A plume of ash from Montserrat now stretches over 90 miles (165
km) to the northeast.
- The Montserrat Volcano Observatory is urging
all residents to move as far north as possible immediately. The southern
two-thirds of the island is now completely off limits. Over 5,000 residents
are now crowded into shelters at the northern tip of the island. The British
government has announced a five year plan to rebuild on the northern part
of the island. They have also offered $3,840 to anyone who wants to relocate
off the island.
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- September 3, 1997
- An 8 mile (15 km) wide plume of ash is
now extending about 57 miles (106 km) southwest of Montserrat. The dome
inside the Soufriere Hills volcano is growing at a rate of 6-7 cubic meters
per second. This is the most rapid rate of growth of the dome since the
eruption began in 1985. A major dome collapse is possible at any time
and could trigger major pyroclastic flows and large explosions which could
shower the entire island with ash and rock.
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- August 30, 1997
- Material on the north side of the dome
collapsed today, causing several pyroclastic flows down the northern side
of the volcano. Most of these flows have occurred in the regions of Gages
and Mosquito Ghaut. A fairly large ash cloud accompanied these flows.
This cloud reached heights of 7000-10,000 ft (2100-3000 m) and was blown
to the northwest. The flows reached the school at Harris village. Continued
explosions and flows can happen without warning. Flows are most likely
to occur to the northwest, and explosions could shower the entire island
with ash and rocks.
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- August 25, 1997
- The evacuation of Montserrat is continuing
very slowly even though scientists warn that a "massive, cataclysmic"
eruption is possible on the island. About 4,000 of the original 11,000
residents remain on Montserrat. Many of those who remain do so because
they feel the British government has not offered them enough compensation
for their losses. Adults have been offered approximately $4,000 and children
about $1,700.
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- August 19, 1997
- From 9:15 last night until about 12:35
this morning, there were continuous tremors and rockfalls and near-continuous
ash production. Gas plumes have been common, and occasional minor explosions
or ash emissions have been detected.
- Longer and more intense explosions may
occur, and Montserrat residents are advised to seek shelter under strong
roofs and wear helmets or whatever other head protection is available
in such a case. After explosions, small rocks and ash are likely to fall,
making driving dangerous. Masks should be worn when outdoors too.
- Pyroclastic flows are expected on all flanks
of the volcano, making entry unsafe into the exclusion zone, including
the Belham river valley. People living south of the Nates River were evacuated
overnight.
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- August 16, 1997
- An increase in activity has prompted authorities
to expand the exclusion zone and offer residents money and transportation
to neighboring islands.
- Details such as the exact amount of money
to be offered and who will be offered the deal first have yet to be disclosed.
- In the meantime, the governor of Montserrat
has ordered the evacuation of the towns of Flemmings, Hope, Olveston,
and Salem before nightfall, citing a report by the Montserrat Volcano
Observatory that the central part of the island is in more danger than
previously thought.
- Residents were advised to pack extra food,
water, medicine and any other personal items they wish to take.
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- August 8, 1997
- Soufriere Hills volcano erupted again on
Wednesday, August 6. Pyroclastic flows from this and past eruptions that
have reached Plymouth have virtually destroyed the capital city. Over
80% of the buildings there are either badly damaged or destroyed. The
August 6 eruption was explosive enough to shower even the safe zone at
the north end of the island with debris. Ash deposits in Plymouth have
grown up to 4 ft (1.22 m) thick. Officials have now ordered an evacuation
of the central region of the island, once considered safe. Plumes of ash
from this eruption have reached heights of 40,000 ft (12,000 m) and dropped
ash on the islands of Nevis and Antigua, which are over 25 miles (40 km)
away.
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- August 5, 1997
- There were two periods of earthquake activity
on August 5 which ended in violent explosions and large pyroclastic flows.
Large vertical plumes were generated from these explosions. Blocks of
pumice up to 3 inches (8 cm) in diameter fell around the volcano. Pyroclastic
flows travelled down the Tar river valley and into the sea. Flows also
travelled down Tuitts and Mosquito Ghauts. Some material overflowed from
Mosquito Ghaut into the Farrells Yard area. Ash was generated every 20-30
August 3, 1997
Pyroclastic flows from Soufriere Hills volcano
on Montserrat have reached the capital city of Plymouth. Many homes and
businesses can be seen burning from several miles away. Fire fighters
have been unable to stop these flames which threaten to consume the entire
city. Flows in Gages Valley have also caused fires in Gages Village. These
flows generated ash plumes which reached elevations of over 15,000 ft
(4500 m). Ashfalls occurred in Isles Bay, Ole Towne, Salem and several
other areas west of the volcano.
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In the wake of this event
and a June 25 event which left 10 dead and nine others missing, the
British government is considering permanently relocating all of Montserrat's
citizens off the island.
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