Volcanoes Flashcards
What is tephra?
solid matter ejected by a volcano into the air
What are pyroclastic flows?
fast-moving currents of hot gas and volcanic debris, that travel own the slope of volcanoes during an eruption
What is a mudflow/lahar?
A flow of wet material down the side of a volcano consisting of erupted
ash, debris, mud and water
What type of volcano is Mt Mayon?
composite
What are the names of the 3 major cities surrounding Mt Mayon?
Tobaco, Legaspi, Ligao
What date in 2018 did Mt Mayon start erupting?
13th January 2018
What was done as soon as PHIVOLCS raised the alert level from 1 to 2?
evacuation of 40,000 people from 6km evacuation zone (13/01/2018)
Give 3 short term impacts of the 2018 eruption of Mt Mayon
- no deaths
- 68,000 evacuated in 58 evacuation centres
- schools/colleges shut
- flights cancelled
- roads blocked
How much damage was done to agriculture following the 2018 eruption?
US $3.4 million
What are some challenges to managing the risk of an eruption?
- no warning signs
- lack of functioning government
- local people may not understand the risk
- it relies on understanding from past eruptions
- tourists
How many hygiene packs were provided? Over how long? (Mt Mayon response)
50,000 over 10 days
Name 3 countries that advised against tourism to Mt Mayon after its eruption in 2018?
UK, USA, Canada
How did the ‘Cash for Work’ scheme help the country to recover from the 2018 eruption of Mt Mayon?
US $1million from Filipino government.
- unemployed farmers were able to work
- work helped rebuilding and recovery
How long were food packs provided for after the 2018 eruption?
100 days
What is the VEI?
Volcano Explosivity Index
What type of magma do Icelandic, Hawaiian and Strombolian volcanoes produce?
basaltic
What type of magma do Vulcanian and Vesuvian volcanoes produce?
basaltic, andesitic and rhyolitic
What are 3 hazards associated with phreatic eruptions?
toxic gases, lahars, tephra
How many people live within 15km of Mt Vesuvius?
3 million
How many people would have to be evacuated if Mt Vesuvius were to show signs of a near eruption?
600,000
What can be used to monitor the seismic activity of volcanoes?
seismometers and seismographs monitor microquakes which suggest rising magma
What is ground deformation and how can it be used to predict volcanic eruptions?
change in shape of the land caused by rising magma. It can be measured using tiltometers to suggest if an eruption is near
How is the upward movement of magma monitored?
magnetometers, change in magnetism within a volcano suggests an eruption is near
What are 3 things that can cause lahars?
- eruptions ejecting water from a crater lake
- eruption-induced heavy rainfall mixing with volcanic material
- pyroclastic flows entering streams
How many people live in Legaspi?
200,000
What was the 6km evacuation zone expanded too?
9km
Give an example of a lahar…
Nevado Del Ruiz eruption, killing over 20 000 people in Armero, Columbia
