Above: The mud on these trees reveal the depth of a lahar that swept down the Muddy River
during the 1980 eruption of Mount St. Helens.
Your job is to indicate which parts of Hazard City will be the most dangerous should Lava
Mountain erupt. You are to focus on the neighborhoods of Riverside, Walnut Heights, and Hickory
Estates and indicate which of the five volcanic hazards (tephra, lahars, pyroclastic flows, lava
flows, volcanic gases) present a risk to human life. It is important to note that your answers
should be based upon the danger of people being killed, and not on the danger to property. You
should also note that some hazards can present a high risk to some parts of town, while at the
same time present a low risk to other parts of town. Your criteria:

Low Risk: If Lava Mountain erupts without warning, it is unlikely that deaths will occur in
this area from this hazard.

High Risk: This is a dangerous area. If Lava Mountain erupts without warning, people
could be killed here.
Volcanic Hazard Assessment Worksheet
Your worksheet is a hazard matrix with six columns representing the volcanic hazards, and
three rows representing the residential communities that you have been assigned to assess. Here
is an example of what you are to do:
If you think that Tephra presents a high risk to the people who live in Riverside, then circle "high"
in the appropriate cell of the worksheet. Continue for the remaining hazards and neighborhoods
until you have completed the assessment. Don't forget, your answers should be based upon the
danger of people being killed and not on the danger to property.
Good luck in your work!
Volcanic
Hazard
Assessment
Tephra
(Ashfall)
Lahars
(Mudflows)
Pyroclastic
Flows
Lava
Flows
Volcanic
Gases
Low
Low
Low
Low
Low
High
High
High
High
High
Low
Low
Low
Low
Low
High
High
High
High
High
Low
Low
Low
Low
Low
High
High
High
High
High
Riverside
Hickory
Estates
Walnut
Heights
Your Name: ________________________________________________________________
Section / Time: _____________________________________________________________