In the Path of a Killer Volcano
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University of Oregon *
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Course
310
Subject
Geology
Date
Dec 6, 2023
Type
Pages
4
Uploaded by ColonelFlagHummingbird40
In the Path of a Killer Volcano
Questions:
1. In the predictions of the 1980 Mount St Helens eruption, what did volcanologists get
right, and what did they get wrong?
In the predictions of the 1980 Mount St Helens eruption, the volcanologists got the
possible time of eruption but they didn’t successfully get the size as well as the lateral
direction of that blast.
2. Who first noticed the renewed activity of the Philippine volcano?
from the nearby convent first noticed the renewed activity of the Philippine volcano.
3. What are the three possible explanations for earthquakes beneath a volcano?
he three best possible explanations for earthquakes beneath a volcano are the magma
content that can be rising from the earths crust, the mountain ranges that releasing off
steam and the tectonics stressors with the earths curst.
4. On the flight to the Philippines, USGS volcanologists passed over Katmai Volcano,
Alaska, which erupted in 1912. Why was this relevant to Mt Pinatubo?
The relevance of passing over Katmai Volcano in Alaska to Mt. Pinatubo lies in the fact
that both volcanoes are associated with the Pacific Ring of Fire, a region known for its
high volcanic activity. Studying Katmai Volcano's eruption in 1912 and its subsequent
behavior provides insights into volcanic activity patterns and helps in understanding
potential hazards in other volcanic regions like Mt. Pinatubo.
5. What did carbon dating of incinerated trees reveal about the eruptive history of
Pinatubo?
Carbon dating of incinerated trees revealed the eruptive history of Mt. Pinatubo by
determining the age of the trees buried by volcanic deposits. By dating these trees,
scientists can establish the timing and frequency of past eruptions, helping to predict
future volcanic activity and assess the volcano's eruption history.
6. What are the three primary methods of
monitoring volcanic activity
, meaning
watching closely when it is threatening to erupt? (meaning BEFORE it erupts)
Seismic Monitoring: This involves the detection and analysis of volcanic earthquakes
and ground tremors caused by magma movement and volcanic processes.
Gas Emissions Monitoring: Volcanoes often release gases like sulfur dioxide (SO2) and
carbon dioxide (CO2) before eruptions. Monitoring changes in gas emissions can
provide early warning signs.
Ground Deformation Monitoring: Measuring ground surface changes, such as swelling
or bulging, using techniques like GPS or InSAR, can indicate magma movement
beneath the volcano.
7. Which method tells you if magma is moving beneath the volcano, perhaps rising
toward the surface to erupt??
Three primary volcano monitoring methods are seismic for earthquakes, gas emissions
for pre-eruption signs, and ground deformation, notably indicating magma movement
beneath the volcano.
8. Which method tells you if the volcano is plugged and may be nearing eruption?
Detecting a reduction in seismic activity can provide valuable insights into the state of a
volcano and its potential for eruption. When a volcano becomes sealed or plugged, the
magma beneath the surface becomes trapped, leading to an accumulation of pressure.
Over time, this pressure can lead to an eruption. A decrease in seismic activity serves
as an indication that pressure is mounting within the volcano, as fewer earthquakes are
occurring to release this built-up pressure.
9. What is a
pyroclastic flow
? What is the typical temperature and speed of a
pyroclastic flow?
A pyroclastic flow is an swiftly moving mixture of scorching gas and volcanic materials
(commonly referred to as tephra) that travels across the ground, emanating from a
volcano at typical speeds of approximately 100 km/h (30 m/s) or about 62 mph.
However, these flows can achieve even higher speeds, reaching up to 700 km/h (190
m/s), or roughly 435 mph. The combination of gases and tephra within these flows can
attain temperatures around 1,000 °C (1,800 °F). Pyroclastic flows stand as the most
lethal among volcanic dangers and possess the capability to traverse great distances
from the volcanic source.
10. What is a
lahar
?
A lahar is a mudflow or debris flow that is produced when volcanic ash and water mix.
Lahars can be extremely destructive, and can travel at speeds of up to 100 km/h (62
mph). They can bury entire towns and villages, and can even cause tsunamis.
11. Geological interpretations have consequences. The film refers to two other
significant failures to accurately predict volcanic activity. What were they, and how do
they illustrate the issues facing volcanologists in this situation?
The eruption of Mount St. Helens in 1980 was anticipated by geologists, although they
miscalculated the eruption's magnitude and destructive impact.
In contrast, the eruption of Nevado del Ruiz in 1985 caught geologists by surprise,
resulting in a devastating lahar that tragically claimed the lives of more than 23,000
individuals.
12. What did the spine or dome of fresh magma indicate?
The swelling or uplift of fresh magma suggested an increase in volcanic activity. As the
magma ascended towards the crust, it indicated a heightened potential for an eruption
13. How many people died in the actual eruption? How many were successfully
evacuated?
The eruption of Mount Pinatubo in 1991 resulted in the tragic loss of approximately 300
lives. Many people were successfully evacuated from the surrounding areas, thanks to
timely warnings and evacuation efforts.
14. How does this eruption compare in volume to St Helens in 1980?
The eruption of Mount Pinatubo in 1991 was larger in volume compared to the eruption
of Mount St. Helens in 1980. Pinatubo's eruption expelled around 10 cubic kilometers of
material, while St. Helens' eruption was significantly smaller, releasing approximately 1
cubic kilometer of material.
15. How long after the evacuation did the volcano erupt?
A volcano is a natural geological vent or opening in Earth's crust that allows molten
rock, ash, and gases to escape, often resulting in eruptions and the formation of new
land.
16. How much time passed between the first big eruption and the climactic eruption of
June 15? And how long did these eruptions continue?
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The first signs of activity at Mt. Pinatubo began in April 1991, when earthquakes began
to occur around the volcano. By June 7, the volcano had begun to erupt, sending ash
and steam high into the sky. Over the next week, the eruptions intensified, culminating
in the climactic eruption of June 15. This eruption sent an ash cloud about 22 miles (35
km) into the atmosphere, and ash and debris could be seen as far away as Manila, the
capital of the Philippines. The eruption lasted until early July, with smaller eruptions
occurring until October.
17. Ash from the eruption circled the globe within weeks. What were the effects on
global climate, and for how many years?
The effects of the Mt. Pinatubo eruption on global climate were far-reaching. Ash from
the eruption circled the globe within weeks, and its effects were felt for several years
afterwards. The eruption resulted in a cooling of the Earth's atmosphere by about 0.5°
Celsius (0.9° Fahrenheit). This cooling led to shorter and milder El Niño events over the
next few years, as well as a decrease in the intensity of the Asian monsoon.
18. Would you consider this a successful prediction of a volcanic eruption? Why or why
not?
When it comes to predicting volcanic eruptions, the Mt. Pinatubo eruption can be
considered a success. Scientists were able to detect the signs of an impending eruption
weeks before it occurred, allowing them to warn people in the area to evacuate. While it
is impossible to predict the exact date of an eruption, the Mt. Pinatubo eruption provides
an example of how careful monitoring and analysis of geological data can help us better
understand and prepare for volcanic activity.