Mt St Helens Flashcards
From _____ 1980 there were signs an eruption could be immanent.
March
Mt St. Helens is a _________ volcano.
Composite
There were small ___________, a bulge appeared on the north side of the mountain called a __________ and ash and _____ were released.
Earthquakes cryptodome steam.
Good management meant that hazardous areas were _________.
Evacuated.
When the earthquakes began in March the ______ _______ __________ ______ started a round the clock monitoring system.
United States geological survey.
It included gathering seismic data measuring the rate of ______ growth ground temperature and sulphur dioxide emissions. ________ and seismic activity reports were issued _____.
Bulge volcanic daily.
USGS scientists issued warnings to the people in the area and gave recommendations about locations of _________ zones.
Hazardous
Based on these recommendations in March access to the volcano was __________ and the evacuation of around ____ people was started.
Restricted 2000
Despite monitoring the volcano, scientists could not accurately predict the eruption. The day of the eruption there were no unusual changes that could be taken as _______ signs.
Warning
A bulge on the _____ side of the volcano indicated that magma was moving up into the magma chamber.
North
__________ were used to monitor the changing size and shape of the mountain which would suggest volcanic activity was about to happen.
Tiltmeters
A tilt meter is an instrument designed to measure very small changes from the __________ level either underground or in structures.
Horizontal
The authorities used ____ eruptions to identify danger zones and evacuated residents from these areas, however some refused to leave and some scientists also ______ to help study the volcano.
Past stayed.
Emergency ___________ and _________ were on hand for when the eruption occurred.
Helicopters and airplanes
The scientists were unable to accurately predict when Mt St Helens would erupt and so people were reluctant to leave their homes for a ____ period of time.
Long
The experts did not predict that the eruption blast would be on the _____ side of the volcano.
North
As a result, the _________ zones were set up in the wrong place and so 90% of the people that died were outside of the exclusion zone in what were thaught to be ____ areas
Exclusion safe
Miami earthquakes began on the __ th _____.
20th March
A bulge appears on the north side of the mountain. This bulge is called a __________.
Cryptodome
___ and ______ were released
ash and steam
On the __ th ___ ____ there was a large earthquakes of magnitude . on the Richter scale followed by a massive eruption of volcanic material including rocks ash hot gasses steam and lava
18th may 1980 5.1
Pyroclastic flows ______ and floods were caused by the volcano.
Lahars - a type of mud flow or debris composed of a slurry of pyroclastic material rocky debris and water.
Floods were caused due to material being dumped in rivers and lakes __________ water.
Displacing
The eruption covered a ____km2 fan shaped area at the north of the volcano , the blast zone. The blast zone reached up to __km away from the volcano.
600 30
Shortly after there was another eruption of ash and steam. About ___ million tonnes of ash were deposited over an area of __,___km2
540 57,000
__ people were killed mostly by inhaling volcanic ash.
57
___ homes destroyed
200
__miles of railway destroyed.
15
___ km of main roads destroyed.
300
_ people died in a car going __ mph trying to outrun the ash.
2 70
Many areas had _ -_inches thick of ash, and some areas even had _ inches.
2-3 6
Ash clogged up some ___ _______ making it difficult to _____ as the ash altered the workings.
Car engines drive.
Everyone used masks, bandannas, ______ _______ and ______ over their mouths to prevent them breathing in the volcanic ash.
Coffee filters socks
__ bridges were destroyed
27
Wildlife suffered - ____ big game animals such as dear! elk and bears and many thousands of birds and small mammals were killed.
7000
The amount of ash was so great it could cover one squad mile of Manhattan to _ times the height of the Empire State Building.
3
Sediment dumped in ______ lake rose the water level by over __ meters.
Spirit 60
Every tree within __ km of the volcano was flattered.
30
__ million young salmon were killed whether affected breeding patterns and the fish market.
12
___meters was blown off the top of the mountain and a _ mile horseshoe radius that was ___ meters deep.
400 1 500
__ bridges destroyed.
27
The total cost of the damage was around . billion
1.1
__% of the crops in the area were damaged or destroyed. Fruit trees were particularly badly afafcted.
12
The second biggest cost was the clean up operation costing $___ million.
250
Estimated short term losses in Washington state reached over $___ million half of which was made up from the loss of the forest.
800
________ of people were made homeless.
Hundreds
Unemployment rose _______ at first however this did return to normal once clean up operations began.
Tenfold
__ logging trucks __ transport vehicles and __ railcars were damaged or destroyed along with . billion board feet of timber - people lost their jobs and livelihoods.
14 22 39 4.7
People moved ____ from the neighbourhood.
Away.
Resident left without some amenities for a while, for example water _________ and ______ removal for a while.
Treatment sewage
