1. Explosive volcanic eruptions can have both short and long term impacts on society, such as destroying landscapes with lava flows and ash clouds that disrupt transportation. 2. The 1991 eruption of Mt. Pinatubo cooled the Earth's surface for almost two years by injecting ash into the atmosphere. 3. Volcanoes can also have economic benefits, including providing fertile soil, attractions for tourism, and resources like geothermal energy, sulfur, and building materials. However, the major concern is reducing the negative impacts of eruptions to minimize loss of life and property damage.

1. Volcanic Eruption:
Are you prepared?
Grade 9, Module 3 Lesson 1.3
(Teachers’ Guide for Discussion)
MA. RACHEL B. ESPINO
Teacher I, Science
Buhatan NHS, Sorsogon City

2. How do volcanic eruptions
affect the society?
Explosive volcanic eruptions pose both short-term
and long-term hazards. Lava flows and lahars can
wipe out the flanks of mountainsides. Volcanic ash
can blanket the landscape for miles, and ash clouds
can disrupt aircraft travel, such as the incident in
2013 when a volcano in Iceland caused a shut down
in all air flights in Europe. On longer time scales,
eruptions can inject massive quantities of ash into the
atmosphere, greatly reducing the solar heating of the
Earth and potentially interrupting the global food
supply for several years.

3. In 1991, Mt. Pinatubo in the Philippines erupted, and
strong winds spread the aerosol particles from the
plume around the globe. The result was a
measurable cooling of the Earth's surface for a period
of almost two years.
Volcanoes also affect people positively. For example,
the eruption of Mt. Pinatubo has created spectacular
scenery. People became creative also by making
earthenware out of the ash fall. Likewise, the eruption
of Mt. Musuan in Bukidnon has produced very rich
soil for farming years after its eruption in 1867.

4. Economic Value of Volcanoes
1. Stream from fumaroles (fissures or hols from
which steam and other hot gases escape) is
harnessed to produce geothermal energy, in
turn used to generate electricity.
2. The gases released are 94% steam mixed
with carbon dioxide, sulfur dioxide,
ammonia, methane and helium. Sulfur
dioxide is made into sulfuic acid. ammonia is
used in fertilizers. Methane is used for fuel.
Helium is used in smelting and in filling
ballons and dirigibles.

5. Economic Value of Volcanoes
3. Ammonium carbonate, sodium carbonate
and boric acid are derived from steam and
hot water.
4. Hydrogen sulfide gas oxidizes to form water
and sulfur which is responsible for larger
sulfur deposits.
5. Traprock is used to build roads.
6. Pumice is used for grinding and polishing.
7. Tuff is used as building stone.

6. Economic Value of Volcanoes
8. Lava and volcanic ash make the soil that
covers wide areas around a volcano fertile.
9. Volcanoes add beauty to the landscape and
attract tourist.

7. Despite the advantages that people get from volcanic
eruption, the major concern now is how to reduce the
negative effects of the disaster to reduce loss and
save lives.

8. Signs of an Impending Volcanic Eruption:
1. Increase in the frequency of volcanic
quakes with rumbling sounds;
occurrence of volcanic tremor.
2. Increased in the frequency of volcanic
activity; change in color of steam
emission from white to gray due to
entrained ash.

9. Signs of an Impending Volcanic Eruption:
3. Crater glow due to presence of magma
at or near the crater.
4. Ground swells (or inflation), ground tilt
and ground fissuring due to magma
intrusion.
5. Localized landslides and rock falls from
the summit area which is not
attributable to heavy rains.

10. Signs of an Impending Volcanic Eruption:
6. Noticeable increase in the extent of
drying up of vegetation around the
volcano’s upper slopes.
7. Increase in the temperature of hot
springs and crater lake.
8. Noticeable variation in the chemical
content of springs, crater lakes within
the vicinity of the volcano.

11. Signs of an Impending Volcanic Eruption:
9. Drying up of spring well around the
volcano
10. Development of new thermal areas
and/ or reactivation of old ones;
appearance of solfatara.
(A solfatara is a volcanic vent emitting
only sulphurous gases and water
vapour or sometimes hot mud.)

12. Key Facts About Protecting Yourself After
a Volcanic Eruption:
1. Pay attention to warnings, and obey
instructions from local authorities. For
example, stay indoors until local health
officials tell you it is safe to go outside.
2. Listen to local news updates for
information about air quality, drinking
water, and roads.

13. Key Facts About Protecting Yourself After
a Volcanic Eruption:
3. Turn off all heating and air conditioning
units and fans, and close windows,
doors, and fireplace and woodstove
dampers to help keep ash and gases
from getting into your house. Listen to
local news updates for information
about air quality, drinking water, and
roads.

14. Key Facts About Protecting Yourself After
a Volcanic Eruption:
4. Exposure to ash can harm your health,
particularly the respiratory (breathing)
tract. To protect yourself while you are
outdoors or while you are cleaning up
ash that has gotten indoors, a
disposable particulate respirator (also
known as an “air purifying respirator”)
may be considered.

15. Key Facts About Protecting Yourself After
a Volcanic Eruption:
5. Stay away from ashfall areas, if
possible. Avoid contact with ash as
much as you can.
6. Keep your skin covered to avoid
irritation from contact with ash. Wear
goggles to protect your eyes from ash.

16. Key Facts About Protecting Yourself After
a Volcanic Eruption:
5. Stay away from ashfall areas, if
possible. Avoid contact with ash as
much as you can.
6. Keep your skin covered to avoid
irritation from contact with ash. Wear
goggles to protect your eyes from ash.

17. Key Facts About Protecting Yourself After
a Volcanic Eruption:
7. Do not travel unless you have to.
Driving in ash is hazardous to your
health and your car. Driving will stir up
more ash that can clog engines and
stall vehicles.
8. Replace disposable furnace filters or
clean permanent furnace filters
frequently.

18. Key Facts About Protecting Yourself After
a Volcanic Eruption:
9. If your drinking water has ash in it, use
another source of drinking water, such
as purchased bottled water, until your
water can be tested.
10. Clear roofs of ash. Ash is very heavy
and can cause buildings to collapse.Be
very cautious when working on a roof.
Ash can be slippery and make it easy
to fall.

20. Suggested Videos
• Pinatubo’s Tragedy: Philippines (is a
documentary about the effects of the
Mt. Pinatubo eruption in 1991 and how
Filipinos cope up with the tragedy.)
http://youtu.be/bbSAjT12k7s

21. Suggested Videos
• Mount Vesuvius : Documentary on the
Formation and Dangers of the Vesuvius
Volcano (is a documentary about the
eruption of Mt. Vesuvius in Naples as shown
by the haunting images of people who were
“frozen” in time. It is suggested that the
teacher guide the students in watching
because of some poignant scenes )
http://youtu.be/bbSAjT12k7s

22. Additional References:
• http://solidearth.jpl.nasa.gov/PAGES/v
olc03.html
• http://www.bt.cdc.gov/disasters/volcan
oes/after.asp