Hazard mitigation Flashcards
Despite monitoring advances what % of eruptions are forecasted timely?
5%
What % of volcanic signals are unrest without eruption?
33%
How can volcanic eruptions be catergoried by level? (mitigation/ planning)
1-4 1 no activity 4 is actively erupting
What is the ideal way for levels to be applied to a hazard?
STepwise with level 4 for when disaster happens
What are one of the most important factors for the outcome of a hazard?
social chracteristics
What will a no eruption vulnerable population look like?
Poor governance
Low social capital
Poverty/ poor well being
Marginalisation/ disenfranchisment
What are the characteristics of a resilient no eruption population?
Good governance
High social capital
Sustainable livelihoods/ good well being
Shared understanding of risk
What will a high intensity/ wuick onset do to a vulnerable population?
Incomplete evacuation
Casualties/ loss of life
Distrust
Trauma
What will a high intensity/ wuick onset do to a resilient population?
High conformity with evacuation trust and tolerance of uncertainty
Why is communicating risk so important?
Need to put across in a way which is understood by those without scientific knowledge
What is a use of mapping for volcanic hazards to educate the population?
3d map for monseratt which shows control of topography and why the south cant be inhabited
What does communication need to consider?
specific groups, the local understanding and perception of risk, issues of trust, administrative structures
How can trust be damaged for mitigation and subsuquent alerts?
Inconsistent communication, lack of clarity on uncertainty, or poorly explained decision
making
What is an example of an inconsistent communication?
Heighted seimicity led to 73,000 being evacuated for 4 months with no eruption- mayon phillipines/ radon Italian
What are co-eruptive warning systems?
Automated warning sstems that apply to certain hazards i.e lahar sirens
What are some examples of direct interventions for volcanic hazards?
reduction of lahar/PDC
hazards (e.g. Sabo dams, banks/channels)
What are the problems with direct interventions for volcanic hazards?
Installations require maintenance (channels can fill with sediment over time)
Insufficient design can potentially increase risk (false impression of protection, and suitability for worst-case scenario – see also Japan tsunami, sea walls)
WHat is key for monitoring the movement of ash and so2 progress?
Satellite images
What are sabo dams and channel flows designed for?
Slow debris and contain large particles
What time was the risk map released for armero?
10th of nov with lahar on the 13th problem was planning metting scheduled fir 15th after event occurred
What is the history of Kelud indonesia?
Several eruptions in past century – thus a good historical record and well-understood hazard
Moderate explosive eruptions
Associated lahar hazards (crater lake)
Also PDCs, ashfall
What recent activity has there been at Kelud Indonesia?
Explosive eruption in 1990
Effusive eruption in 2007
Highly explosive eruption in 2014
What hazard was Kelud particulary vulnerable to?
Lahars due to crater lakes
What was the effect of the 1919 Kelud eruption?
100 villages destroyed, >5000 deaths, lahars travelled 38 km in 1 hour
Led to establishment of Indonesia Volca.
Survey and direct intervention – tunnels to drain crater lake
What monitoring and interventions are there at Kelud?
Sabo dam network
GPS, tilt
Crater lake temperature
Gas emissions
Seismic network
What were the pre-eruption factors for 2014?
Increased lake temperature
Large increase in number of VT events
Deep and shallow seismicity
What were the mitigation/ planning stratergies for the 2014 phillipines eruption?
Pre-event evacuation of >100,000 people (densely populated region)
Recognition of potential for tephra fall, PDC and lahar hazards
In many areas, rapid post-event recovery
