#A & B
3) The term tephra defines all pieces of rock fragments ejected into the air by an erupting volcano.
Most tephra falls back onto the slopes of the volcano, enlarging it. But, billions of smaller and
lighter pieces less than 2mm in diameter (less than one-tenth of an inch), termed ash, are carried
by winds for thousands of miles. Falling ash, even in low concentrations, can disrupt human
activities hundreds of miles downwind, and drifting clouds of fine ash can endanger jet aircraft
thousands of miles away. When it has settled on and near the ground, volcanic ash threatens the
health of people and livestock, damages electronics and machinery, and interrupts power
generation, water and transportation systems, and telecommunications (USGS) The Eyjafjallajkull
volcano in Iceland erupted spectacularly in April 2010. The heat from the lava beneath the crater
of the glacier-covered summit quickly melted and vaporized the glacier ice above. Mud, ice, and
meltwater running off the volcano swelled local rivers and streams, flooding farmland and
damaging roads. Expanding gasses from the rapid vaporization of ice caused explosions that
resulted from the contact of water and magma. The hydro-phreatic explosions sent a plume of
steam and ash almost 7 miles (11km) into the atmosphere. The plume was driven southeast,
across the North Atlantic Ocean to northern Europe, by the prevailing winds. Fearing the damage
to commercial aircraft and potential loss of life that could result from flying through the ash cloud,
many European countries closed their national airspace and grounded flights for several days.
(after Britannica)Image left: 2010 ash plume from Eyjafjallajkull eruption. Image right: Composite
map of the volcanic ash cloud spanning 14-25 April 2010. View looking down onto the North Pole.
Source: Wikipedia a) Heat from magma can change water suddenly to steam, which can expand
to more than a thousand times the original volume of water. The sudden expansion results in an
explosive force that can blast a volcano to pieces and create large amounts of volcanic ash. Name
the type of explosion produced when water in groundwater, seawater, or even melting glacial ice
or snow comes into contact with magma. b) Referring to the ash plume map above, estimate the
percentage of the planet's circumference the ash plume traveled in the first 2 weeks of April 2010.
(Hint: Count the wedge-shaped sections that show dark and light gray ash. Divide the number of
sections with ash by the total number of sections. For example, 6 sections with ash divided by 24
total sections =6 divided by 24=.25 or 25% of the globe. Do not use these numbers. Count the
sections on the image above and show your calculations..
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A amp B 3 The term tephra defines all pieces of rock fra.pdf
1. #A & B
3) The term tephra defines all pieces of rock fragments ejected into the air by an erupting volcano.
Most tephra falls back onto the slopes of the volcano, enlarging it. But, billions of smaller and
lighter pieces less than 2mm in diameter (less than one-tenth of an inch), termed ash, are carried
by winds for thousands of miles. Falling ash, even in low concentrations, can disrupt human
activities hundreds of miles downwind, and drifting clouds of fine ash can endanger jet aircraft
thousands of miles away. When it has settled on and near the ground, volcanic ash threatens the
health of people and livestock, damages electronics and machinery, and interrupts power
generation, water and transportation systems, and telecommunications (USGS) The Eyjafjallajkull
volcano in Iceland erupted spectacularly in April 2010. The heat from the lava beneath the crater
of the glacier-covered summit quickly melted and vaporized the glacier ice above. Mud, ice, and
meltwater running off the volcano swelled local rivers and streams, flooding farmland and
damaging roads. Expanding gasses from the rapid vaporization of ice caused explosions that
resulted from the contact of water and magma. The hydro-phreatic explosions sent a plume of
steam and ash almost 7 miles (11km) into the atmosphere. The plume was driven southeast,
across the North Atlantic Ocean to northern Europe, by the prevailing winds. Fearing the damage
to commercial aircraft and potential loss of life that could result from flying through the ash cloud,
many European countries closed their national airspace and grounded flights for several days.
(after Britannica)Image left: 2010 ash plume from Eyjafjallajkull eruption. Image right: Composite
map of the volcanic ash cloud spanning 14-25 April 2010. View looking down onto the North Pole.
Source: Wikipedia a) Heat from magma can change water suddenly to steam, which can expand
to more than a thousand times the original volume of water. The sudden expansion results in an
explosive force that can blast a volcano to pieces and create large amounts of volcanic ash. Name
the type of explosion produced when water in groundwater, seawater, or even melting glacial ice
or snow comes into contact with magma. b) Referring to the ash plume map above, estimate the
percentage of the planet's circumference the ash plume traveled in the first 2 weeks of April 2010.
(Hint: Count the wedge-shaped sections that show dark and light gray ash. Divide the number of
sections with ash by the total number of sections. For example, 6 sections with ash divided by 24
total sections =6 divided by 24=.25 or 25% of the globe. Do not use these numbers. Count the
sections on the image above and show your calculations.
