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”

• 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 strike-slip fault faster than they can grow

Why is there no asthenosphere near the

surface in a transform zone?

1. State why “Iceland” and/or “Hawaii” are neither island arcs nor continental arcs: what critical ingredient is missing?

To do, today, with at least one other person

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 ~400 km

Hawaii 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.YELLOWVolcano 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.ORANGEVolcano is exhibiting heightened unrest with increased likelihood of eruption.Or: Volcanic eruption underway with no or minor ash emission.REDEruption is forecast to be imminent with significant emission of ash into the atmosphere

likelyOr: Eruption is underway with significant emission of ash into the atmosphere.

NORMALTypical 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 itsnormal, non-eruptive state.

ADVISORYElevated unrest above known background activity.Or, after a change from a higher level:Volcanic activity has decreased significantly but continues to be closelymonitored for possible renewed increase.

WATCHVolcano is exhibiting heightened or escalating unrest with increasedpotential for eruptive activity.Or: A minor eruption is underway that poses limited hazards.

WARNINGHighly hazardous eruption underway or imminent.