GEOLOGY 102 LECTURE 25
VOLCANIC HAZARDS
1. Volcanic Hazards
a. Depend on what type of _________________ & nature of ________________
i. Many are local effects
b. Ash Fall
i. Cover the largest _________ and the greatest number of _________________
ii. If the ash is wet, problematic
iii. Can generate powerful electrical fields
iv. Commonly associated with ___________________ eruptions
v. What about airplanes?
c. Lava Flows
i. Seldom threaten lives – move too ___________________
ii. Burn everything in their paths
d. Lahar
i. Source: ________________________, _______________________________,
______________________________, _______________________________
ii. Wash ash from slopes
iii. Destruction of buildings, bridges, roads, and vegetation in it’s path
iv. Ex: ______________________________________
(1) ___________________ greatest risk, ash moves ___________________
(to ___________________)
(2) lahars travel ___________________
v. Commonly associated with ___________________ eruptions
e. Gases
i. Steam can be toxic, only hazardous close to crater (within 1-2 km)
ii. However, gases that are erupted into the ___________________ can do
damage
iii. Result in ___________________ and the formation of ___________________
iv. Reflect energy coming from the ________, decreasing the amount of sunlight
reaching & heating the Earth’s surface
v. May contribute to ___________________ loss and ______________ change.
f. Tsunamis
i. Japenese word for “______________________________________”
ii. Seismic sea waves caused by disturbances on the ___________________
iii. Result from submarine ___________________, debris __________________,
underwater ______________________________________
2. Volcano Monitoring
a. Remote sensing, seismicity, gas, hydrology,
ground deformation, geophysical
b. Predicting volcanic eruptions
i. Change in ___________________
ii. Change in ___________________
iii. ___________________ activity
iv. ___________________ emission & steam
Video titled, “ Perilous Beauty: The Hidden Dangers of Mount Rainier”
Here are some points you should notice
During footage of Mt. St. Helens
What was the style of eruption?
What types of hazards are associated with it?
What is the plate tectonic setting and magma composition?
Mount Rainier
How does this compare with Mt. St. Helens?
What are the potential triggers of mudflows for Mt. Rainier?
What are the potential triggers for mudflows (lahars) not associated with a volcanic
eruption?
How can we monitor a volcano for a potential eruption and its related hazards?
What can you, the average citizen, do if you potentially live in harms way?
What would you do and where would you go if there was a lahar or eruption on Mt.
Rainier?