Transcript TODAY`S ANNOUNCEMENTS - NAU jan.ucc.nau.edu web server

Today…
• Just a quick review
• An exercise to think a bit about
volcanoes and tectonics
• Warning systems
• Perhaps the lava flows video
Results of the “voting”
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Tornadoes and atmosphere
Hurricanes
Tsunami
Wildfires
Impacts and extinctions/coastal
hazards/climate change (tied)
No promises, I’ll see what I can do (some
material is covered better in the book than
other stuff)
Your clickers, please
The exam Wednesday was
• Like the first one -- okay, but surely not
easy
• Way harder than the first one
• Way easier than the first one
• Saved by my 3x5 card…
We looked at a couple of boundary
types that have volcanoes. These
are…
1. Transform and convergent
2. Convergent and divergent
3. Divergent and transform
Are there commonly
volcanoes along transform
boundaries?
1. Yes
2. No
Why not (pick your best
answer)?
1. No source of mantle melting (like subduction)
2. No pulling crustal slabs to bring
asthenosphere to the surface (like spreading)
3. No other way to get asthenosphere close to
the surface
4. Volcanoes get pulled apart along the strikeslip fault faster than they can grow
Why is there no
asthenosphere near the
surface in a transform zone?
To do, today, with at least
one other person
1. State why “Iceland” and/or “Hawaii” are
neither island arcs nor continental arcs:
what critical ingredient is missing?
2. Iceland and the Big Island of Hawaii are
both hot-spot volcanoes. Why is Iceland so
much larger than the Big Island?
– to answer this you need to look at a
map (coming up) to convince yourself
there’s a difference in size
– to answer this you need to look at the
tectonic map, either in your book or in
the front of the room
• what happens at hot spots?
• what are the tectonic settings of the
Big Island and Iceland?
• why is Iceland so much bigger?
(this slide is just so you can
see the difference)
~ 135 km
Hawaii
~400 km
Iceland
Some terms you need to know
• Extinct: completely dead
• Dormant: sleeping, could become
active
• Active: any time, starting tomorrow
• Frequency:magnitude concept
Alert-level systems
• Most commonly used is the color
scheme
• Newly minted “common terminology”
scheme
GREEN:
Volcano is in a normal, non-eruptive state.
Or, after a change from a higher level:
Volcanic activity considered to have ceased and volcano reverted to its
normal, non-eruptive state.
YELLOW
Volcano is exhibiting signs of elevated unrest above known background
levels.
Or, after a change from a higher level:
Volcanic activity has decreased significantly but continues to be closely
monitored for possible renewed increase.
ORANGE
Volcano is exhibiting heightened unrest with increased likelihood of
eruption.
Or: Volcanic eruption underway with no or minor ash emission.
RED
Eruption is forecast to be imminent with significant emission of ash into the
atmosphere likely
Or: Eruption is underway with significant emission of ash into the
atmosphere.
NORMAL
Typical background activity of a volcano in a non-eruptive state.
Or, after a change from a higher level:
Volcanic activity considered to have ceased, and volcano reverted to its
normal, non-eruptive state.
ADVISORY
Elevated unrest above known background activity.
Or, after a change from a higher level:
Volcanic activity has decreased significantly but continues to be closely
monitored for possible renewed increase.
WATCH
Volcano is exhibiting heightened or escalating unrest with increased
potential for eruptive activity.
Or: A minor eruption is underway that poses limited hazards.
WARNING
Highly hazardous eruption underway or imminent.