Volcanic hazrads

Question 1

Nature of volcanic hazrads and it;s relation ot plate tectomnics?

Answer 1

Constructue:

• Balastic lava flows:
• low visocuity (runny) as hotter - faster
• balastic eruptions frequent and lenghty but not very violent

destructive:
- Andesitic + Rhyoltic lava flows
- high visocuity as cooler - slower
- Infrequent and short but violent

most volacnic eruptons occur at these margins

Question 2

Pyroclastic flows/ Nuee Adrente?

Answer 2

= mix hot gas, ash and volcanic rock

• flows down side volcanoe at high speeds and dis
• therefore can cause widepsread detsrution

Question 3

lava flows

Answer 3

=- Balstic or A + R
vicsuit affected by heat
speed affect by visocuity / steepness volcanoe slope
- most flows slow so time preapre, however destrucitive

Question 4

Volcanic Gases?

Answer 4

• CO2 / SO2 released from lava as gas when eruption occurs

- cause restaoyr issues

Question 5

Pyroclatic Fallout/Tephra and Ash fallout?

Answer 5

PF/T = mateirla ejected from volanoe and falls to ground
AF = fallout mostly ash
- consist of large mateirla and small material
- larger, deposted eralier sp arge closer volacnoe and finer futher away
- large tephra - damge builindgs/ kill
- finer mateirla - think layer - kill ege, block rtransport , repsiroty issues

Question 6

Mudflows/ Lahards?

Answer 6

= occurs when volcanic materila mixes with large amounts water

• high speed
• bury / detsiy habitats / infa

Question 7

Acid rain?

Answer 7

= SO2 + water vapour - H2SO4 - acid rain

• damage veg
• erode buildings
• dry as dust and cause repistaoyr issues

Question 8

Pirmary vs secondray volcanicn hazards?

Answer 8

Primary: - hazad that caused directky by eruption

• Nuee Adrents
• Lava flows
• Volcaninc Gases
• PF/T + AF

Secondary - hazrad caused by primary hazards

• Lahras / Mudflows
• Acid rain

Question 9

mag, freq, regulairty + pred of volacnin hazrads?

Answer 9

• Mag = VEI )Volcani explosivity index) -0-8 based on amount materialejected and hieght
• Freq = Less freq more volent
• Regulairty = volcnaoes can erupt regular intervals or dormant for hydnarded yrs and reupt many times in quick sucession
• Predictability = Reg of reuption can help scientist predict when it will happen again - small eruption + changes in shape can tell whether earthqyuake imminet

Question 10

Risk managment deisgned to reduce imapcts of volancie hazard?

Answer 10

1 - Mitigation through S + L term responses : ST = reduce impacts before, during, soon after hazrad e.g evacuation,
LT = reduce impacts future reuptions :
1 - Prevention: can;t stop erution but can prevnt it affecting ppl e.g prevnt development land surroudning volcanoe
2 - Prepardness: - monsitroing sytmes and plan evaution, stop entranec in area, indd make emergcney kit, comm set up search and rescue teams
3 - Adaptation: strengthen buildings so will not colalpse if layer ash lands on them, capatilsie e.f farming (ash increases fertility) , tourism