Name
: Vinodaarshini Vigneswaran
Year
: 12
Subject
: Earth and Environmental Science Yr. 12
Teacher’s name : Ms. Urbaniak
Stratovolcano- pyroclastic flow investigation
Contents
Page number
Introduction
3-5
Plan and designing
6-8
Conducting
9-18
Processing
19-29
Evaluation
30
Bibliography
31
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Stratovolcano- pyroclastic flow investigation
1.0 Introduction
Analyzing the impacts of geohazards, particularly the volcanic eruptions, by measuring
the distance travelled by the pyroclastic flow are the basis of this experiment. Geohazards
means the risk of damage caused by a geological process. Sometimes hazards are not
obvious until pointed out. For example, we wash our hands to avoid biohazards such as
viruses and bacteria even though they are too small to see. We are told that some foods
are poisonous (a biohazard) so we don’t eat them. All geological hazards (geohazards)
could be considered inactive until they are triggered. When the hazard occurs, it may then
be called an event, accident, emergency, incident, or disaster. The study and monitoring
of geohazards helps us to better prepare ourselves and respond to these geological
events when they do occur. Geohazards can be small features that have an impact only
on their local area such as a small landslide that partially blocks a road or track through
to large earthquakes that affect entire cities. They can also be very large events that have
a widespread impact such as large tsunami.
Volcanoes are a type of geohazard.
Volcanic eruptions may involve either
the quiet or explosive ejection of lava,
ash, and gases, as well as other
associated phenomena, commonly
pyroclastic flows and lahars (also called
mudflows). All these events constitute
hazards.
The greatest hazard is associated with
stratovolcanoes found near subduction
zones (figure 1.1). These volcanoes may
erupt violently at reasonable frequent
intervals through geologic time. During
eruption, large ash columns may be
produced, and winds will distribute
volcanic ash and larger fragments from
these to great distances beyond the
volcano, causing nearby towns and cities
to be smothered in ash.
Figure 1.1 The picture shows the Eruption of Mt
Ruapehu in July 1997. Photo taken from
Ohakune.
Closer to the volcano, townships located near river valleys are in great danger from lahars
or mudflows which are mixtures of ice, crater lake waters, ground water or rain water, and
debris from the flanks of the volcano. Lahars travel down existing river valleys at high
speeds pushing the river water ahead of them and causing extensive flooding and silting
of river channels - which may lead to further flooding after the eruption. Lahars possibly
account for the greatest loss of life. The most violent eruptions may produce hot
pyroclastic flows which are turbulent mixtures of searing hot gases and tephra which
move down the slopes of a volcano away from the vent.
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Stratovolcano- pyroclastic flow investigation
Pyroclastic flows are giant clouds of hot gases and ash particles formed by collapse of
the buoyant ash column. They travel at tremendous speeds, too fast for anything or
anyone to escape, and because they are so hot they incinerate everything in their path.
These are the most fearsome events. Volcán de Fuego (Spanish for "Volcano of Fire") is
one of the most active volcanoes in the world and is located 44 kilometers
from Guatemala City. It is a stratovolcano (figure 1.2) that has had more than 60
eruptions since 1524, including a major eruption in 1974 which produced pyroclastic
flows that destroyed the region's winter harvest and ashfall that covered nearby cities.
The 3 June eruption is one of the deadliest in the country, including the Santa María
eruption of 1902 and the Santiaguito dome collapse of 1929, which killed hundreds. The
most eruptive phase began in 2002 and produced an explosive eruption in 2012 that
forced 33,000 people to evacuate but had no reported deaths. The population around the
volcano is estimated to be 54,000 within 10 kilometers and more than one million within
30 kilometers .
Many of these volcanoes are characterized by
magmas of intermediate (or andesitic) bulk
composition (55–70 wt % SiO2) with H2O contents
ranging from 3 to 6 wt % and typically display both
dome‐building and explosive activity during the
same eruption. Some examples include the 2010
eruption of Gunung Merapi and the 2014 eruption
of Gunung Kelud, both located in Java, Indonesia,
and both having a bulk magma composition of
basaltic andesite (55–60 wt % SiO2). Both of these
eruptions were characterized by the collapse of
viscous lava domes, along with explosive events,
all generating pyroclastic density currents
(PDCs).
Figure 1.2 The picture shows the Eruption
of Volcan De Fuego in January 25, 2017.
Photo taken from Climate in Guatemala.
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Stratovolcano- pyroclastic flow investigation
1.1 .1 Purpose
To analyze the impacts of geohazards, particularly the volcanic eruptions, by measuring
the distance travelled by the pyroclastic flow.
1.2 .2 Aim
To investigate the effects of pyroclastic flow from the stratovolcano eruptions on
humans, infrastructure and the environment
5
Stratovolcano- pyroclastic flow investigation
Plan and designing- Stratovolcano
2.1 Investigation set up
Figure 2.1.1: Diagram of Stratovolcano Investigation Set-up
PH probe, used to
measure the PH level
inside and outside of
the bag.
Bread, represents
the crust nearby
the stratovolcano.
Popsicle sticks,
representing the
houses (2cm apart
from each other).
Glass rectangular
tray, used to hold
the set-up.
Plants, representing
the environment
near the
stratovolcano.
Bi-carb,
representing the
SiO2 content in
magma chamber.
Plastic bottle,
representing the
stratovolcano.
Zip-lock bag,
representing the
magma chamber and
holds the 200ml of
vinegar and bi-carb.
Figure 2.1.1: The above diagram shows the set-up of the pyroclastic flow- stratovolcano
investigation. It is a representation of a stratovolcano. The bowl which is 13.5cm tall and
21cm wide is used to hold the set-up of the stratovolcano. There are three different
experiment with different amount of Bi-carb, representing the SiO2 level in the magma.
The various amount of Bi-carb in the 200ml of vinegar had a reaction which represents
the pyroclastic flow from the stratovolcano. However, the popsicle stick represents the
houses and plants represent the environment. The popsicle sticks are arranged 2cm apart
from each other to measure the pyroclastic flow accurately. The food coloring is used to
show the direction of the lava flowed. The angle (30) represents the angle of elevation
and the bread around it acts as the slope of a stratovolcano. The Ph and the time taken
for the vinegar to travel was observed throughout the experiment.
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Stratovolcano- pyroclastic flow investigation
2.1.2 Table of Variables
Figure 2.1.2: Table of Variables from the observations taken during the
stratovolcano experiment
Constant
(The same)
•
•
Ratio (Volcanic Eruption Index) of Bi-carb – vinegar
The amount of vinegar
Independent
(changed)
•
The amount of bi-carb
Dependent
(measured)
•
•
•
•
•
•
The effects (displacement and distance of lava)
The time (seconds)
The Ph of the lava inside and outside of the bag
The temperature of the lava inside and outside of the bag
The pulse rate of the pyroclastic flow
The pressure inside of the bag.
Figure 2.1.2: The above table is providing the variables (constant, independent and
dependent) of the effects on infrastructure and humans by pyroclastic flow from
stratovolcano investigation. The ratio (Volcanic Eruption Index) of Bi-carb - vinegar was
kept the same throughout the investigation. However, The amount of bi-carb
is the prominent change in this investigation. The effects (displacement and distance of
lava), the time (seconds), the Ph of the lava inside and outside of the bag, the temperature
of the lava inside and outside of the bag, the pulse rate of the pyroclastic flow and the
pressure inside of the bag were measured throughout this investigation.
2.1.3 Materials and Equipment
Figure 2.1.3: Materials and Equipment for the effects on infrastructure and
humans by pyroclastic flow from the stratovolcano experiment
•
•
•
•
•
•
•
•
200ml of Vinegar
Bi-carb
Food coloring
Popsicle stick
Zip lock bag
Plastic water bottle
A measuring cup
A temperature probe
•
•
•
•
•
•
•
A Ph probe
Timer
Ruler
Phone
Playdough
Plastic plants
Rectangular
glass tray
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Stratovolcano- pyroclastic flow investigation
2.1.4 Method and Procedure
Figure 2.1.4: Method and procedure from the Stratovolcano- pyroclastic flow
experiment
1. Prepare the materials and equipment required for the experiment.
2. Set-up the investigation according to the set-ups in figure 2.1.1. Conduct the
investigation in groups of three/four.
3. Spread butter on the bread which is representing the subduction plate. Butter is
used to hold the bi-carb on the bread.
4. After this, put 1 tsp (8g of Bi-carb) on the bread and ensure it is accurate before
subducting it into the zip lock bag containing vinegar.
5. Once this is prepared, the testing takes place. While the testing takes place, the
pH and temperature should be monitored at all time.
6. Altogether there will be three experiments with three tests each.
7. Ensure there’s enough time to conduct three investigations in the time provided.
8. As the investigation is conducted, team members are to observe and take pictures
of the progress.
If there’s no change in observation, add pressure to the zip lock bag.
9. At this point of time, the change in temperature and PH is observed.
10. Observe the pulse rate of the lava from the stratovolcano as the reaction of the
vinegar and bi-carb takes place in the experiment.
11. Repeat the above steps for each testing and experiment.
12. Jot down the observations in a table of observation and measurements.
13. Clean up your place and return the materials and equipment to the place it was
retrieved from.
2.1.5 Hypothesis
As the amount of Bi-carb increases, the distance travelled by the eruption increases, as
the time progresses.
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Stratovolcano- pyroclastic flow investigation
Conducting (Stratovolcano- pyroclastic flow Investigation)
3.1 Table of Observations and Measurements
Figure 3.1.1: Table of Observations and Measurements of the Ph and the time
taken for experiment 1 (1tsp Bi-carb: 200ml vinegar).
Test 1
Test 2
Test 3
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Stratovolcano- pyroclastic flow investigation
Figure 3.1.1: The above figure shows the measurements of pH inside and outside of the
zip lock bag as the time progressed. The pH inside the bag is observed to increase
gradually and the pH outside the bag is observed to stay constant throughout the
experiment. This could be due to the lesser reaction rate between the vinegar and bi-carb
ratio.
From these three testing of the 1 st
experiment, test 1.3 was the most
successful one. As shown in figure
3.1.1, the right amount of pressure
was applied, and the time taken for
the eruption to occur was faster
than the other tests. This could be
due to the increase in amount of Bicarb reacting with the vinegar at a
faster rate.
Figure 3.1.1 This picture shows the set-up of experiment
3 after eruption.
Lava Bomb
Due to the fast eruption in test 3, the solution
of vinegar and bi-carb reached 12cm away
from the impact site which means it travelled
approximately 12km from the stratovolcano.
As shown in figure 3.1.2, a lava bomb is
observed 16 cm from the impact site. Lava
bombs are formed when a volcano ejects
viscous fragments of lava during an eruption.
They cool into solid fragments before they
reach the ground.
12 cm from impact site
Figure 3.1.2 This picture shows the patch of blue
coloured solution (lava) soaked into breads (crust).
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Stratovolcano- pyroclastic flow investigation
Figure 3.1.2: Table of Observations and Measurements of the Ph and the time
taken for experiment 2 (2 tsp Bi-carb: 200ml vinegar).
Test 2
Test 1
Test 3
Figure 3.1.2: The above table of measurements show the pH level inside and outside of
the bag in the 2nd experiment. The pH level inside the bag is observed to increase
gradually in three of the tests whereas the pH level outside the bag is observed to stay
constant. These results show how the pH level inside the bag is increasing as the reaction
of vinegar and bi-carb takes place. There were a few observations jotted down for each
of the tests.
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Stratovolcano- pyroclastic flow investigation
Test 2.1 -Displacement
of pyroclastic flow :
14cm from impact site
Test 2.2 -Displacement
of pyroclastic flow : 4cm
from impact site
Point of eruption
for all three tests
Test 2.3- Displacement of
pyroclastic flow : 4cm from
impact site
Figure 3.1.3 The above pictures shows the point of eruption for three different tests. The eruption rate
is observed.
Effect on houses
(infrastructure)
Figure 3.1.4 This picture shows the effect the
pyroclastic flow has on the infrastructure.
Figure 3.1.4 shows the effect of the
pyroclastic flow on the houses which were
arranged 2cm apart from each other from
the stratovolcano. Volcanoes are a
geohazard and it does have an effect on
the
infrastructures,
houses
and
environment. .
Figure 3.1.1 shows the points of eruption of three of
the tests in the 2nd experiment. As per observation,
the displacement of the lava from the impact site
varied for all three of them. This could be due to the
different amount of pressure applied to the zip-lock
bag (magma chamber of stratovolcano). The more
pressure applied, the more the distance of the
pyroclastic flow travelled over time.
Another factor which might have effected the
displacement is the leveling of bread surrounding the
stratovolcano (plastic bottle). The higher the level of
bread near the stratovolcano, the lesser the
pyroclastic flow travels from the impact site. However,
the displacement of the pyroclastic flow in test 2.1 is
14cm from impact site, test 2.2 and 2.3 is 4cm from
the impact site.
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Stratovolcano- pyroclastic flow investigation
Figure 3.1.3: Table of Observations and Measurements of the Ph and the time
taken for experiment 3 (3 tsp Bi-carb: 200ml vinegar).
Test 2
Test 1
Test 3
Figure 3.1.3: The above table of measurements show the pH level inside and outside of
the bag in the 3rd experiment. The pH level inside the bag is observed to increase and
decrease gradually in three of the tests whereas the pH level outside the bag is observed
to stay constant. These results show how the pH level inside the bag is increasing as the
reaction of vinegar and bi-carb takes place. There were a few observations jotted down
for each of the tests.
13
Stratovolcano- pyroclastic flow investigation
Test 3.2- Displacement of
pyroclastic flow : 4cm from
impact site
Figure 3.1.5 This picture shows the
pyroclastic flow soaking to the bottom
of the crust.
Figure 3.1.5. shows the pyroclastic flow soaking into the bread crust as soon as the eruption
occurs. As from previous observations from different experiments, the main reason of the
inaccurate result is that the pressure applied to the zip lock bag (magma chamber) is inconsistent.
However, the pyroclastic flow is observed to not have much impact after 4cm from impact site
because bread wasn’t arranged uniformly, its in an angular instead. Most of the bottom of the
breads absorbed most of the liquid. The solution in the bag was observed to be close to none as
all of the solution erupted outside.
Test 3.3- Displacement of
pyroclastic flow : 6cm from
impact site
Figure 3.1.5 This picture shows the
pyroclastic flow backfiring from the
eruption.
As for figure 3.1.5, the eruption was observed to go up to a height of 8cm and then flowed to the
crust. The vertical eruption could be due to the massive amount of pressure being released from
the magma chamber as the bi-carb soda bread slab was subducted into the vinegar solution. The
solution was observed to backfire and soak through the bread where the stratovolcano was
located. However, 6 cm of the houses were destroyed as volcanoes are a geohazard. The bread
in the zip lock bag stayed intact whereas the vinegar became saturated as there weren’t any
reaction occurring at this point of time. The dissection of the experiment took place as the bread
was observed to soak 6cm in depth near the stratovolcano.
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Stratovolcano- pyroclastic flow investigation
Figure 3.1.4: Table of Observations and Measurements of the Temperature and
the time taken for 3 experiments.
Experiment 1
ent 1
Experiment 2
Experiment 3
Figure 3.1.4: The above table of measurements show the average temperature for
each of the experiments as the time progressed. For all these three experiments, the
temperature is observed to decrease gradually as the time increased. This is due to the
endothermic reaction of the vinegar and bi-carb soda. The release of temperature from
the reaction allows the temperature inside the bag to decrease. However, the
temperature remained constant when the reaction stopped occurring.
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Stratovolcano- pyroclastic flow investigation
3.2 A Flowchart
Figure 3.2.1: Diagram of the process through the stratovolcano- pyroclastic flow
investigation
To begin, we need to make sure we have all the
materials for the investigation. The vinegar will be
constant (200ml), but the Bi-carb quantity varies
from 8g to 16g and 24g. Then arrange the
popsicle 2cm apart from each other. The vinegar
is contained in a zip lock bag.
Finally, observe the pH of the lava before and
after the investigation is conducted. Observe
if there’s any differences in the pH level inside
and the outside the zip lock bag. Record all
the observations and measurements in a
table, ready to be finalized in a report.
Arrange the materials and equipment
according to figure 2.1.1. make sure the plastic
bottle makes an angle of 30 to the horizontal
surface. The amount of Bi-carb varies from
1tsp to 3tsp. Follow the steps given in figure
2.1.4. Repeat it 3 times.
Then, observe the experiment while conducting,
the time is measured as the vinegar and bi-carb
solution travels across the distance. From this
16 can be
information, the displacement of the lava
determined. Make sure to take pictures of the
experiment.
Stratovolcano- pyroclastic flow investigation
3.3 A Diagram of Changes and Alterations
Figure 3.3.1: Diagram of Changes and Alterations in the Stratovolcanopyroclastic flow Investigation
Part A: Adding playdough as a barrier to decrease the area of the rectangular glass
tray.
Part B: Shortened the height of the stratovolcano.
17
Stratovolcano- pyroclastic flow investigation
Part C: Added a magma chamber using zip lock bag.
Figure 3.3.1: The above diagrams show the changes and alterations made over the
duration of testing. Part A shows the adding of playdough to the experiment to decrease
the surface area of the rectangular glass tray. Part b shows the decrease of height of the
stratovolcano for the experiments. Finally, part c shows the adding of magma chamber
underneath the stratovolcano.
The diagram in part A shows the playdough barrier added to the experiment. The group
was thinking how to decrease the surface area of the glass rectangular tray and figure
out a solution. The playdough barrier was kept only for the testing before the actual
experiment took place as the group figured out new solutions to the problem. The
playdough acting as a barrier was holding up the stratovolcano in place and not allowing
the solution to leak through the crust where the houses and the plants were placed.
However, part b showing the shortening of the stratovolcano’s height as it was a disruption
and the group weren’t getting any results. The slope of the stratovolcano was kept the
same, but the height of the stratovolcano was decreased to get better results. After the
height of the plastic bottle (representing the stratovolcano) was shortened, the eruption
of the pyroclastic flow was observed more clearly, and the results were close to accuracy.
The slope of the plastic bottle allowed the pyroclastic flow to go into the bread
(representing the crust).
Finally, the diagram in part c shows the zip lock bag (representing the magma chamber)
being added to the experiment as the group thought it was a good idea to have a
subducting bi- carb soda slab into the magma chamber containing vinegar. This made
the whole experiment to go smoothly and accurate results of the eruption of the
pyroclastic flow was obtained.
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Stratovolcano- pyroclastic flow investigation
Processing (Stratovolcano Investigation)
4.1 Calculations
Diagram 4.1.1 Calculations to find the velocity of the pyroclastic eruption from the
stratovolcano
Displacement
Formula:
𝑽𝒆𝒍𝒐𝒄𝒊𝒕𝒚 =
𝑫𝒊𝒔𝒑𝒍𝒂𝒄𝒆𝒎𝒆𝒏𝒕
𝑻𝒊𝒎𝒆
Bi-Carb
Pyroclastic flow
vv
Vinegar
Experiments
conducted
Time taken for the
pyroclastic flow
travelled (s)
Test 1.1
Displacement from
the Stratovolcano
(cm)
4cm
Test 1.2
4cm
7.7s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
Test 1.3
12cm
11.47s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
12𝑐𝑚
=1.046cm/s
11.47𝑠
Test 2.1
14cm
12.52s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
14𝑐𝑚
=1.118cm/s
12.52𝑠
Test 2.2
14cm
13.96s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
Test 2.3
4cm
9.16s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
4𝑐𝑚
=0.437cm/s
9.16𝑠
Test 3.1
6cm
7.92s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
6𝑐𝑚
=0.758cm/s
7.92𝑠
Test 3.2
4cm
7.93s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
4𝑐𝑚
=0.504cm/s
7.93𝑠
Test 3.3
6cm
6.91s
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
9.2s
Velocity of the pyroclastic
flow (cm/s)
𝑉𝑒𝑙𝑜𝑐𝑖𝑡𝑦 =
4𝑐𝑚
9.2𝑠
4𝑐𝑚
7.7𝑠
= 0.435cm/s
= 0.519cm/s
14𝑐𝑚
13.96𝑠
6𝑐𝑚
6.91𝑠
=0.429cm/s
=0.868cm/s
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Stratovolcano- pyroclastic flow investigation
Diagram 4.1.1: The above diagram shows the calculation of the velocity of pyroclastic
eruption from the stratovolcano. As per observation, the displacement from the
stratovolcano (cm) increases and then decreases. The houses are placed 2cm apart from
each other to ensure an approximate result. The higher the displacement from the
stratovolcano the longer the time taken for the pyroclastic lava to travel. The velocity is
calculated by using the above formula. Velocity is directly proportional to the displacement
of pyroclastic flow from stratovolcano and inversely proportional to the time taken for the
pyroclastic flow to travel to the houses, infrastructure and environment. From the above
results, the velocity increases, decreases and increases, over the period of time.
Diagram 4.1.2 Calculations to find the pressure of the vinegar inside the bag during the
eruption
Formula:
𝑵𝒖𝒎𝒃𝒆𝒓 𝒐𝒇 𝑴𝒐𝒍𝒆𝒔 × 𝑮𝒂𝒔 𝒄𝒐𝒏𝒔𝒕𝒂𝒏𝒕 × 𝑻𝒆𝒎𝒑𝒆𝒓𝒂𝒕𝒖𝒓𝒆
𝑷𝒓𝒆𝒔𝒔𝒖𝒓𝒆 =
𝑽𝒐𝒍𝒖𝒎𝒆
Constant values:
Number of Moles: 4.165 mole in
200ml of Vinegar
Gas Constant: 8.314 J/Mol
20
Stratovolcano- pyroclastic flow investigation
Experiments
conducted
Time when the
eruption happened
(seconds)
Temperature when
the eruption
happened (C)
Pressure inside the zip lock bag
when eruption happened (kPa)
0s
1.1
1.2
1.3
2.1
2.2
2.3
3.1
3.2
3.3
5s
3s
3s
2.2s
8s
7s
3s
2.3s
2.3s
18.5C
18.5C
18.5C
19C
18C
17C
17C
17.5C
16.5C
5s
10s
30s
20.18
20.18
20.05
20.15
20.08
20.11
20.08
20.04
20.18
20.22
20.15
20.08
20.08
20.118
20.15
20.15
20.15
20.08
19.98
20.04
20.15
20.08
20.08
19.94
19.94
19.98
20.04
19.87
19.94
19.87
19.87
19.87
20.049
20.09
19.98
19.87
Diagram 4.1.2: The above diagram shows the different experiments conducted, the time
when the eruption happened, temperature when the eruption happened and the pressure
inside the zip lock bag when eruption happened. The time for eruption in experiment 2.2
is 8s. This could be due to the less pressure applied to the zip lock bag- therefore slowing
down the vinegar-Bicarb reaction. However, the time taken for the eruptions to occur in
all the tests were close to each other. The temperature increases and decreases when
the eruptions happened. As per observation, the pressure inside the bag is consistent
throughout the experiment. The time is selected according to the change in temperature.
The above results only shows pressure inside bag as when the volcano erupts, the
pressure is released.
21
Stratovolcano- pyroclastic flow investigation
4.2 Table of averages
Diagram 4.2.1 Table of averages for the displacement of the lava from the
stratovolcano.
Tests
Time (seconds)
1.1
1.2
1.3
2.1
2.2
2.3
3.1
3.2
3.3
9.2s
7.7s
11.47s
12.52s
13.96s
9.16s
7.92s
7.93s
6.91s
Displacement of the
pyroclastic flow from the
stratovolcano (cm)
4cm
4cm
12cm
14cm
14cm
4cm
6cm
4cm
6cm
Average Displacement of
the pyroclastic flow from
the stratovolcano (cm)
= 7.56 cm
Diagram 4.2.1: The above table shows the average displacement measurements from
each of the testing in each experiment. The displacement of the pyroclastic flow is
observed to increase and decrease gradually, and the time progressed. The time of the
eruption for each the test is jotted on the table above. The average displacement of the
pyroclastic flow was 7.56cm.
Diagram 4.2.2 Table of averages for the pressure inside the zip lock bag.
Tests
1.1
1.2
1.3
2.1
2.2
2.3
3.1
3.2
3.3
Time (seconds)
5s
3s
3s
2.2s
8s
7s
3s
2.3s
2.3s
Average pressure inside the
bag (kPa)
20.10 kPa
20.12 kPa
20.13 kPa
20.08 kPa
20.08 kPa
19.99 kPa
19.97 kPa
20.00 kPa
19.997 kPa
22
Stratovolcano- pyroclastic flow investigation
Diagram 4.2.2: The above diagram shows the average pressure inside the bag during the
eruption as the time progressed. The time of the eruption is jotted on the table above.
However, the pressure inside the bag during the eruption time, for each test is observed
to be consistent. The highest amount of pressure was observed in test 1.3 of experiment
1 (20.13) and the lowest amount of pressure inside the bag was observed in test 3.1 of
experiment 3 (19.97kPa).
Diagram 4.2.3 Table of averages of pH inside the bag for all the tests
Time
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
pH 1- Test 1
(average)
3.6
3.6
3.6
3.6
3.6
3.7
3.7
3.7
3.8
3.8
3.8
3.8
3.8
3.8
3.8
pH 1- Test 2
(average)
3.13
3.27
3.4
3.84
4.1
4.23
4.33
4.5
4.77
4.93
4.97
5.03
5.07
5.1
5.1
pH 1- Test 3
(average)
3.33
3.77
4.33
4.47
4.9
5.07
5.27
5.37
5.5
5.63
5.67
5.7
5.73
5.73
5.77
Diagram 4.2.3: The above diagram shows the table of averages of the pH level inside the
bag for all the test as the time progressed. For all the three tests, the pH level is observed
to increase tremendously. This is due to the reaction of the vinegar and bi-carb inside the
bag which is causing the solution to be more neutral. The most highest pH level (5.77)
observed was in experiment 3, at the 30-minute point. However, experiment 3 is observed
to have a higher rate of increase in pH level rather than experiment 1 and 2.
23
Stratovolcano- pyroclastic flow investigation
Diagram 4.2.4 Table of averages of pH outside the bag for all the tests
Time
2
4
6
8
10
12
14
16
18
20
22
24
26
28
30
pH 1- Test 1
(average)
4
4
4
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
4.1
pH 1- Test 2
(average)
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
5.73
pH 1- Test 3
(average)
5.17
5.17
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
5.1
Diagram 4.2.4: The above diagram shows the averages for the pH level outside the bag
for all the tests as the time progressed. The pH level for all these tests are observed to
be almost constant as there wasn’t much solution reaching the pH probe and when the
pyroclastic flow erupts the pH level stays the same. However, the highest average pH
level observed was in experiment 2 where the level of 5.73 stayed constant throughout
the experiment.
24
Stratovolcano- pyroclastic flow investigation
4.3 Graphs (Stratovolcano Investigation)
Figure 4.3.1: Graph of the pH inside bag for all tests vs the time taken for the lava
to travel in the investigation.
Figure 4.3.1: The above graph shows the graph of the average pH level inside the bag
for all the test against the time taken for the experiment (seconds). The most prominent
trend observed is the gradual increase of the pH level of test 3 over the period of time.
Test 1 is observed to stay almost constant whereas test 2 is observed to increase after 4
seconds into the experiment. However, the steepest increase of pH level is observed in
test 2 between 14 and 16 seconds into the experiment. This could be due to the increase
of reaction rate when the bi-carb slab was subducted into the magma chamber containing
200ml of vinegar. The measurements for the pH level was observed only for 30 seconds
as the endothermic reaction took place very fast. The observation of the bread and the
effect took place throughout the experiments.
25
Stratovolcano- pyroclastic flow investigation
Figure 4.3.2: Graph of the pH outside bag for all tests vs the time taken for the
lava to travel in the investigation.
Figure 4.3.2: The above graph shows the graph of the average pH level outside the bag
for all the test against the time taken for the experiment (seconds). The graph above
shows a common trend as the results of the pH level outside the bag was almost constant.
However, test 2 is observed to remain constant throughout the experiment. This is due to
the pyroclastic flow not reaching the pH probe throughout this experiment. The graph
proves that the pH level outside the bag didn’t get effected by the pyroclastic flow from
the stratovolcano. The measurements for the pH level was observed only for 30 seconds
as the endothermic reaction took place very fast. The observation of the bread and the
effect took place throughout the experiments.
26
Stratovolcano- pyroclastic flow investigation
Figure 4.3.3: Graph of the average temperature for all tests vs the time taken for
the lava to travel in the investigation.
Figure 4.3.3: The above graph shows the graph of the average temperature of the
pyroclastic flow (C) against the time taken for the experiment (seconds). The most
prominent trend observed is how the temperature is decreasing for all the experiments in
various time period. The steepest slope is observed in test 2 between 16 and 18 seconds
into the experiment. This could be due to the reaction rate increasing as the vinegar and
bi-carb is combined. However, in test 3, between 7 and 24 seconds, the temperature is
observed to stay constant before it decreased from 15C to 14C. The temperature of the
pyroclastic flow was only observed for 30 seconds as the endothermic reaction doesn’t
take much time. The observation on the set-up was taken, as the time progressed.
27
Stratovolcano- pyroclastic flow investigation
4.4 Diagrams
Figure 4.4: Diagram showing how the pyroclastic flow from the stratovolcano
effected the houses and environment
Pyroclastic flow
Plan view
Bi-Carb
Elevation view
Figure 4.4: The above diagram shows the before and after picture of the pyroclastic flow
from the stratovolcano. The main purpose of this experiment was to investigate the effect
of the pyroclastic flow to the infrastructure, house and the environment. In the plan view,
it is clearly showing how the pyroclastic flow from the stratovolcano has destroyed some
of the houses and the plants as the eruption occurs over time. This proves that volcanoes
are a geohazard to humans and the environment. The houses are arranged 2cm apart
from each other to have a better understanding and observation of the displacement of
the pyroclastic flow.
The diagrams from the elevation point of view shows how the pyroclastic flow is erupted
and the effect it has on the houses, plants and the crust itself. For this experiment, vinegar
represented as the mantle and the bi-carb represented as the SiO2 concentration. The
release of pressure and energy is due to the endothermic reaction of the vinegar and the
28
bi-carb. However, the effects of the pyroclastic flow was well-observed by the group and
the results were a good proof.
Stratovolcano- pyroclastic flow investigation
4.5 Discussion of Results of the stratovolcano- pyroclastic flow
It was initially predicted that, the more the amount of Bi-carb was subducted into the
vinegar (magma chamber), the more the distance travelled by the pyroclastic flow as the
time progressed. From the results obtained and observed, this hypothesis wasn’t
accurate as there were a few problems arising throughout the experiment. Although the
predictions were inaccurate, there were many observations taken for all the experiments.
As per observation, the stratovolcano is a geohazard and it definitely has an effect
towards infrastructure, humans and the environment. The most farthest distance reached
by the pyroclastic flow was 14 cm in both test 2.1 and 2.2. This means that if this was a
real-life stratovolcano, it would’ve effected anything which is 14km from the impact site.
However, this could be due to the increase in the amount of bi-carb which represents the
SiO2 content in the magma. The eruption of the pyroclastic flow of the stratovolcano
observed in this experiment can be related to the 2018 Volcán de Fuego eruption. It was
a series of volcanic explosions and pyroclastic flows from the Volcán de Fuego (Spanish
for Volcano of Fire) in Guatemala on Sunday 3 June 2018. The eruption
included lahars, pyroclastic flows, and clouds of volcanic ash, which left almost no
evacuation time and caused over one hundred people confirmed killed. It was the
deadliest eruption in Guatemala since 1929.
However, the pressure inside the bag was observed to be consistent throughout the
experiment but the pressure applied to the magma chamber was big. This caused a
bigger eruption due to the solution going from high pressure to low pressure. The
pyroclastic flow is the hot gas which travels at a very fast speed and this was observed
throughout the experiment. The stratovolcano has a pyroclastic flow because the volcano
layers consist of lava and ash. The SiO2 content was also used as a slab to subduct into
the vinegar solution because Stratovolcanoes are common at subduction zones, forming
chains and clusters along plate tectonic boundaries where oceanic crust is drawn
under continental
crust (continental
arc
volcanism,
e.g. Cascade
Range,
central Andes, Campania) or another oceanic plate (island arc volcanism,
e.g. Japan, Philippines, Aleutian Islands).
The pH level inside the bag was observed to become more neutral because the vinegar
and the bi-carb solution was concentrated by the end of the experiment. The pH level
outside the bag was almost constant as the pyroclastic flow doesn’t have much of an
effect outside (atmosphere). The temperature inside the bag was observed and the group
made a conclusion on why the temperature was decreasing over the period of time. It is
because when sodium bicarbonate and vinegar mix, they react with each other and one
of the things that is made out of is carbon dioxide gas. The reaction needs heat to make
it happen, so it takes heat from its surroundings, leaving the bottle feeling cold.
29
Stratovolcano- pyroclastic flow investigation
Evaluation
Before I say anything, this year has been a speed track, and everything is moving too
fast. But knowing that I’ll be continuing what I love studying in university next year makes
me happy. Year 10 Core, year 11 and 12 EES is always revolved around the concept of
volcanism and earth processes. I enjoy studying the geological aspect of the Earth as it
gives me the opportunity to be aware of why volcanoes erupt and how is an earthquake
triggered. As this is my last report, I was excited to choose a topic relating to the concepts
learned and start an investigation with a group of peers who are as curious as me.
Investigations and writing a report has always been my favorite since the very beginning.
Not only that, choosing what I want to experiment gives me an opportunity to think about
what to do relating to the concepts learned during theory lessons. The lessons on how
volcanoes are formed, the plate boundaries, the plate tectonic settings and the processes
gave me and my peers an idea of what can be tested and observed over the certain
period of time. Without any hesitation, planning for our investigation was made. Instead
of complicating the investigation, we thought it through thoroughly and did a few test runs
before making the final decision. Throughout this investigation, I have succeeded in
learning many things, that I can apply not only to the classroom environment, but also the
working environment, and of course in my life in general. In relation to the EES year 12
course, I learned all about the volcanoes and how they are functioning. The integration of
the rock cycle, earth processes, Bowen’s series and geohazards help me understand
everything in more depth.
This investigation has given me a platform to learn many new skills, and to get into the
right mindset in anticipation of how I will need to perform in the working world, in the near
future. I learnt many things about time management and teamwork. Without teamwork
and communication skills, I believe this investigation wouldn’t be a success. Through the
process of writing up the investigation report, I have developed so many skills which I
believe will benefit me in future. I sure have developed my technology literacy. Now, I
would be confident to use a google spreadsheet and drawing for a simple table or even
a graph and beautiful diagrams.
In the upcoming years, I would love to improve my time management skills and I’m looking
forward to being more organized. However, I will also need to plan the investigation
beforehand in order to be more prepared for the actual investigation. This investigation
tested my creativity skills, determination, teamwork, confidence, efficiency and time
management skills. I was able to achieve all this, and in doing so, learnt much about the
way I work among my peers; and what areas I must improve or develop which would be
helpful in a professional working environment, in future. I’m now aware that I’m ready for
a university learning environment.
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Stratovolcano- pyroclastic flow investigation
Bibliography
•
Impacts of pyroclastic flow, (2016), by Advancing Earth and Space
Science [ONLINE]. Available
at: https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2015JG003316
•
Volcán de Fuego - Wikipedia. 2018 [ONLINE] Available at:
https://en.wikipedia.org/wiki/Volc%C3%A1n_de_Fuego
•
Volcán de Fuego 2018 eruption 2018. [ONLINE] Available
at: https://en.wikipedia.org/wiki/2018_Volc%C3%A1n_de_Fuego_eruption
•
What are geohazards? [ONLINE] Available
at: http://www.learnz.org.nz/geohazards152/what-are-geohazards
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