Volcanic Hazards

Question 1

Hazards associated with volcanoes and its materials, whether or not the associated volcano is currently erupting.

Answer 1

Volcanic Hazards

Question 2

What are the two types of Volcanic Hazards?

Answer 2

a. Direct Hazard
-Hazards directly associated with an on-going eruption.
b.Indirect Hazard - Hazards indirectly associated with an eruption.

Question 3

(direct hazards)
Rivers of lava extruded from the volcano.

Answer 3

Lava flow

Question 4

(direct hazard)
Pyroclastic materials ejected into the atmosphere that fall due to gravity.

Answer 4

tephra fall

Question 5

(direct hazard)
A blast directed horizontally which comes from the slopes of the volcano.

Answer 5

Lateral blast

Question 6

(direct hazard)
Expelled during eruptive phases at huge amounts, high temperatures and extreme speed which can be toxic to life.

Answer 6

volcanic gases

Question 7

(direct hazard)
A hot mixture of volcanic debris and tephra that is saturated with water that occurs directly related to an on-going eruption.

Answer 7

Syn-eruptioon lahar

Question 8

(direct hazards)
Hot flows of a mixture of pyroclastic materials and hot gases. These include Pyroclastic flows, pyroclastic surges, and base surges.

Answer 8

Pyroclastic density flows PDCs

Question 9

(indirect hazard)
A cold mixture of volcanic debris and tephra that is saturated with water that occurs when old volcanic materials are remobilized.

Answer 9

post-eruption lahar

Question 10

(indirect hazard)
Massive debris avalanches. due to blasts from the eruption.

Answer 10

landslides

Question 11

(indirect hazard)
Tsunamis caused by submarine eruptions or massive landslides that mobilize large amounts of water, causing large waves.

Answer 11

Volcanic tsunami

Question 12

(indirect hazard)
Oscillating movement of water within an enclosed or limited body of water

Answer 12

Seiche

Question 13

(indirect hazard)
Fractures and fissures caused by bulges from the ground due to rising magma.

Answer 13

Ground deformation

Question 14

(indirect hazard)
Remobilized pre-existing pyroclastic materials

Answer 14

Secondary PDC

Question 15

(indirect hazards)
Heat and tremors from volcanic eruptions and their materials can cause man- made structures and materials to collapse and cause a cascade of events which can lead to explosions and fire.

Answer 15

Secondary fire and explosions

Question 16

Discuss the 6 precursors or signs of an impending volcanic eruption.

Answer 16

I-Increase in volcanic quakes/tremors
L-Localized mass wasting processes that are not attributed to external processes
G-Ground deformation or swelling due to rising magma.
R-Rising volume outputs of volcanic gases and recognizable variation in chemical contents of nearby emission sites.
I-Increase in heat, causing increased steaming, with a color variation from white to gray due to accompanying ash, drying up of vegetation, springs and wells, and rising temperatures in hot springs, wells, and craters
D-Development of new or reactivation of old thermal areas.

Question 17

The original agency for volcano monitoring in the Philippines, established in June 20, 1952 through the RA 766, before being later renamed to Philippine Institute of Volcanology (PHIVOLC) in March 17, 1982 through EO 784, after which was reestablished as the current PHIVOLCS when the seismology monitoring was transferred to the institute from PAGASA

Answer 17

COMMISSION ON VOLCANOLOGY (COMVOL)

Question 18

The official Philippine agency established on September 17, 1984 that is mandated to mitigate disasters that may arise from volcanic eruptions, earthquakes, tsunamis, and other related geotectonic phenomena.

Answer 18

PHILIPPINE VOLCANOLOGY INSTITUTE OF AND SEISMOLOGY (PHIVOLCS)