Volcanoes/Volcanic Eruptions – Vulnerability Assessment

Mount St. Helens[3]

Volcanic eruptions are most likely to occur in the Pacific Rim states and the danger area around a volcano covers approximately a 20-mile radius, although there is some danger to people within 100 miles or more. Airborne ash from a volcano can affect people hundreds of miles away from the eruption. The most common volcano-related hazards are ash (tephra), lahars, lava and debris flows, avalanches, and pyroclastic flows.[1]

If you live near a volcano, you should know about the potential hazards in case of a major eruption and are prepared to leave that area if necessary, but your risk of injury or death from the volcano is much less than from other natural hazards such as fires, hurricanes, tornadoes and floods.

The vulnerability you are to volcanic hazards is a product of many factors, some important of which are:

  1. the present or probable activity of the volcano,
  2. your location or distance to the activity and time spent in that given area,
  3. the likelihood of hazards during that time in that particular area, and
  4. your preparedness to react in the proper way to potential hazards.

Volcanic Eruption Vulnerability Assessment Questions

To assess your vulnerability to the threat of a Volcanic Eruption to your family and property, perform an assessment to determine if you have knowledge of, are prepared and/or have a plan by answering the following questions:

General All-Hazard Questions:

  • Have you determined the disaster risks in your locale and the hazards that accompany them?
  • Do you know the emergency warning signals and alert notifications used in your community?
  • Have you instructed family members how to shut off water, gas and electricity to your house?
  • Have you made the necessary property preparations to reduce the damage from the hazard?
  • Do you have a backup generator in case of a prolonged power failure?
  • Have you purchased insurance (property, health, life, and/or hazard type)?
  • Have you made the necessary financial arrangements in case of a sudden evacuation and power outage that shuts down local ATMs and banks?
  • have you organized important documents and records and stored them in a portable lock box or safe-deposit box?
  • Have you performed a home inventory video taping the contents stored them in a portable lock box or safe-deposit box?
  • Does your family have an established Emergency Communication Plan and evacuation plan in place and asked an out-of-state person to serve as the “family contact”?
  • Have you assembled a shelter-in-place Emergency Supplies Kit in case you have to shelter at home and you are without power?
  • Have you assembled a mobile Emergency Supplies Kit that can serve as a “grab and go” bag?
  • Are you or someone in your family trained in first aid and CPR?
  • Have you made they necessary preparations and arrangements for pets, seniors, and the disabled?
  • Have you familiarized yourself with the emergency plans of your family member’s employment building, school, day care center, or nursing home?

Hazard Specific Questions:

  • Do you know and understand the hazards associated with volcanic eruptions: earthquakes, tephra, volcanic gases, lava flows, debris avalanches, landslides, and tsunamis, floods, pyroclastic flows, and lahars?
  • Have you made evacuation plans and have you established a backup route?
  • Do you have a pair of goggles and a throw-away breathing mask for each member of the household?

Volcanic Hazard Vulnerability Map

By studying volcanic deposits, scientists can produce hazard maps. These maps indicate the types of hazards that can be expected in a given area the next time a volcano erupts. Dating of these volcanic deposits helps determine how often an eruption may occur and the probability of an eruption each year. Monitoring of a volcano over long periods of time will indicate changes in the volcano before it erupts. These changes can help in predicting when an eruption may occur.

The following map indicates the vulnerable regions of Volcanic Hazards based on activity over the past 15,000 years:[2]


  1. Seattle Office of Emergency Management: http://www.seattle.gov/emergency/publications/documents/SHIVA.pdf
  2. Image Source: http://maps.redcross.org/website/Maps/Images/NationalLevel/volcano.gif [Accessed July 14, 2013]
  3. Image Source: http://www.fs.usda.gov/mountsthelens [Accessed July 14, 2013]