DRRR|WEEK 7

Question 1

Is an opening the earth’s crust through which lava, volcanic ash, and gases escape.
They are formed through plate convergent, through the hotspot, and subduction of plates.

Answer 1

VOLCANO

Question 2

Volcano can be classified into 3

Answer 2

By activity
By composition and structure
By eruption

Question 3

active, potentially active and inactive.

Answer 3

By activity

Question 4

shield volcano, cinder cone, and the composite or the stratovolcanoes.

Answer 4

By composition & structure

Question 5

explosive eruption, quite or fissure eruption.

Answer 5

By eruption

Question 6

An agency which serves as the arm of the government to study, record, gives forecast and warning about the behavior of certain volcanoes while helping in the mitigation process on the effects of volcanic eruption.

Answer 6

PHIVOLCS (PHILIPPINE INSTITUTE OF VOLCANOLOGY AND SEISMOLOGY)

Question 7

CLASSIFICATION OF VOLCANOES(3)

Answer 7

Active Volcano
Potentially Active
Inactive Volcano

Question 8

Erupted within historical times (last 600 years); has historical traditional accounts (written or oral).

Answer 8

Active Volcano

Question 9

Landform is young-looking but with no records of eruption.

Answer 9

Potentially Active

Question 10

No recorded eruptions, long-period inactivity is evident from too much weathering and erosion of deep and long gullies (valleys).

Answer 10

Inactive Volcano

Question 11

ashfall reached Manila, devastated provinces of Pampanga, Zambales and Tarlac.

Answer 11

Pinatubo June 1991

Question 12

Lahar events that occurred after major eruptions such as during Typhoon Luming and Dinang in 1981, Typhoon Reming in 2006. The 1814 euption of Mayon buried the famous church of Cagsawa.

Answer 12

Mayon 1984, 1993, 2000-2001, 2009 eruption

Question 13

1965 eruptions killed many people in Taal Volcano Island and the lke coastal communities.

Answer 13

Taal Volcano 1911, 1965

Question 14

Volcanic eruptions are not limited to the areas of dry land only. They can occur anywhere where the conditions are right.
Many of the most active plate margins are on the seafloor.
The processes that form volcanoes are essentially the same above and below water.
The conditions underwater are different to those on dry land; there’s a lot of water and that means more pressure and a lower temperature, both of which have an influence on how the volcano forms and how it is weathered.

Answer 14

UNDERWATER VOLCANOES

Question 15

The most common type of monitoring volcanic eruptions is by________

Answer 15

seismicity

Question 16

Another way of monitoring volcaninc eruption is the study of _______

Answer 16

ground deformation

Question 17

Most active volcanoes have ________ where volcanic gases escape to the surface. It is relatively easy to monitor the temperatures of these gases, and an anomalous increase in temperature might be a sign that magma has moved closer to the surface.

Answer 17

fumaroles

Question 18

A number of people are studying ways using _____________________

Answer 18

satellite data to monitor volcanoes

Question 19

are phenomena arising from volcanic activity that pose potential threat to persons or property in a given area within a given period of time. Volcanic eruptions can have drastic impact on our lives. They can affect the property we own, the land we live in, the water we drink, and even the air we breathe. In serious cases, people may have to leave their homes and move to safe areas. Below are some of the volcano hazards and its impacts in the Philippine
setting.

Answer 19

Volcanic hazards

Question 20

are stream-like flows of incandescent molten rock
erupted from a crater or fissure. When lava is degassed and/or very viscous, it tends to extrude
extremely slowly, forming lava domes.

Answer 20

Lava Flows

Question 21

are showers of airborne fine- to coarse-grained volcanic particles that fallout from the plumes of a volcanic eruption; ashfall
distribution/ dispersal is
dependent on prevailing wind direction

Answer 21

Ashfall or tephra fall

Question 22

rarely threaten human life because lava usually moves slowly – a few centimeters per hour for
silicic flows to several km/hour for basaltic flows. Most characterize this as quiet effusion of lava. Major hazards of lava flows – burying, crushing, covering, burning everything in their path.

Answer 22

Lava flows

Question 23

The intense heat of lavas melt and burn. As lava flows are hot and incandescent, areas it covers are burned (forest, built up areas, houses).

Answer 23

Lavas can burn

Question 24

Lavas can bury homes and
agricultural areas under meters of hardened rock.
Areas affected by lava flows once solidified are also rendered useless and will not be useful anymore (for agriculture, etc) for years due to the solid nature of the lava deposit. Lavas can also block bridges and highways, affecting mobility and accessibility of people and communities. Collapsing viscous lava domes can trigger dangerous pyroclastic flows.

Answer 24

Lavas can bury

Question 25

Ash suspended in air is also____________
__________ as the abrasive ash can cause the engines to fail if the suspended ash is encountered by the airplane

Answer 25

dangerous for aircrafts

Question 26

Burial by_____________________,
break power and communication lines and
damage or kill vegetation. Even thin (<2 cm) falls of ash can damage such critical facilities as
hospitals, electric generating plants, pumping stations, storm sewers and surface-drainage systems and sewage treatment plants, and short circuit electric-transmission facilities, telephone lines, radio and television transmitters

Answer 26

tephra can collapse roofs of buildings

Question 27

are turbulent mass of ejected fragmented volcanic materials (ash
and rocks), mixed with hot gases (200oC to 700oC to as hot as 900oC) that flow downslope at very high
speeds (>60kph). Surges are the more dilute, more mobile derivatives or pyroclastic flows

Answer 27

Pyroclastic flows and surges
(Pyroclastic density current)

Question 28

are rapidly flowing thick mixture of volcanic sediments (from the pyroclastic materials) and water, usually triggered by intense rainfall during typhoons, monsoons and
thunderstorms. Lahar can occur immediately after an eruption or can become long-term problem if there
is voluminous pyroclastic materials erupted such as the case of 1991 Pinatubo eruption. Lahars can also
occur long after an eruption has taken place such as the lahars at
Mayon Volcano after the 1984 eruption.

Answer 28

Lahars

Question 29

Pyroclastic flows and surges are potentially
highly destructive owing to(4)

Answer 29

their mass
high temperature
high velocity
great mobility

Question 30

Pyroclastic flows can(3)

Answer 30

• Destroy anything on its path by direct impact
• Burn sites with hot rocks debris
• Burn forests, farmlands, destroy crops and
  buildings

Question 31

Deadly effects

Answer 31

asphyxiation (inhalation
of hot ash and gases)
burial
incineration (burns)
crushing from impacts.

Question 32

have destroyed many villages and lives
living on Pinatubo and Mayon Volcano because
most people live in valleys where lahars flow.

Answer 32

Lahars

Question 33

can block tributary stream and form a lake. This can submerge villages within the valley of the tributary that was blocked, there is also the danger of the dammed lake breaching or lake breakout and if this
happens, this puts to danger the lives of people in communities downstream

Answer 33

Lahars

Question 34

can bury valleys and communitieswith debris
can lead to increased deposition of sediments along affected rivers and result to long-term flooding problems in the low-lying downstream communities

Answer 34

Lahars

Question 35

• gases and aerosols released into the atmosphere, which include water vapor, hydrogen sulfide, sulfur dioxide, carbon monoxide, hydrogen chloride, hydrogen fluoride

Answer 35

Volcanic gases

Question 36

massive collapse of a
volcano, usually triggered
by an earthquake or volcanic eruption.

Answer 36

Debris avalanche or volcanic
landslide

Question 37

are volcanic materials directly ejected from the
volcano’s vent with
force and trajectory

Answer 37

Ballistic projectiles

Question 38

sea waves or wave
trains that are generated by sudden displacement of water (could be generated during undersea eruptions or debris avalanches)

Answer 38

Tsunami-

Question 39

are large waves generated that are associated with volcanic eruption

Answer 39

Volcanic tsunamis

Question 40

In the Philippines, we use a system of Volcano Alert Signals to define the current status of each volcano. The alert levels range from 0 to 5. The alert levels are used to guide any appropriate response from the
Local Government Units (LGUs).

Answer 40

Volcano Alert Levels

Question 41

for volcanoes is a delineated and identified
where no permanent habitation is recommended due to the possible impact of various hazards at any time.

Answer 41

The Permanent Danger Zone (PDZ)

Question 42

illustrate potential for ground-based volcanic impacts—lava flows, pyroclastic flows, ashfall, volcanic gases, and more far-reaching hazards
(such as lahars) in valleys that drain the volcano. To help understand the areas
that may be affected by specific volcanic eruption phenomena, hazard maps are used. These maps show areas that can be affected and areas that are safe.

Answer 42

Hazard maps

Question 43

are generated for various uses and are most useful in determining risks of living in identified potentially hazardous areas. Hazard maps
can also help people to become aware of specific dangers (lava flow, pyroclastic flows, ashfall, lahars, etc) they might face in the event that a volcano reactivates.

Answer 43

Hazard maps

Question 44

Basic Parts of Hazard Maps(3)

Answer 44

1. Map Title
2. Legend
3. Scale

Question 45

tells you what the map is all about

Answer 45

Map Title

Question 47

details of what each symbols/ colors mean

Answer 47

Legend

Question 48

refer to the bar scale as this helps determine distances

Answer 48

Scale