All About Volcanoes the Basics

Activity 1 All about Volcanoes The basics

About this unit Volcanoes in Tucson: how did A-Mountain form?

You’re going to investigate what Tucson was like when it was a hotbed of volcanic activity around 27 million years ago. From your own research you’ll ﬁ gure out how A-Mountain formed. But ﬁ rst we need to cover some background information. In this unit, you will:

✓ Review the basics of volcanoes (Activity 1) ✓ Research an active volcanic system (Activity 2) ✓ Study some actual volcanic rocks (Activity 3)

Who Cares? A January 20, 2002 CNN Headline described the eruption of Mount Nyiragongo in the Democratic Republic of Congo:

“Lava edged with black crust inched through the eastern Congolese city of Goma on Saturday, nearly two days after Mount Nyiragongo erupted, killing more than 40 people and forcing thousands to flee.”

What caused these deaths and why?

? Above. The World Health Organization’s compound in Why was the death toll so small for a city of roughly half a million Goma. AP photo from CNN.com residents?

What kinds of eruptions would have caused more deaths? For exam- ple, when Vesuvius erupted in 79 AD, debris buried the town of Pompeii, killing 3500 people.

Getting Down to Business The questions in this exercise help you ﬁ ll out the chart on the following page that will be your primary resource for information on volcanoes. Use the internet and any reference materials provided by your teacher to get the necessary information for your chart. Be as thorough and detailed as you can here; it will make the rest of the volcano research much easier.

4 A Sense of place · Earth and Environmental Science in the Community Type 1 - Shape 2 - Eruption Style 3 - Lava Type 4 - Hazards 5 - Rocks

Strato or Composite

Cinder Cone

Shield

Giant Caldera or Rhyolite Caldera Complex

Fissure or Flood Basalts Columns 1 and 2: Volcano Shape and Eruption Style Use the following websites for reference:

http://www.cotf.edu/ete/modules/volcanoes/vtypesvolcan1.html http://volcano.und.nodak.edu/vwdocs/vwlessons/volcano_types/type_can.htm

For each of the 5 volcano types listed in the chart ﬁ ll out Columns 1 and 2.

Column 1 Shape (column 1) Describe what the volcano type looks like. Are these volcanoes usually high mountains with snowy peaks or ﬂ at features? Where are these kinds of volcanoes are usually found? Draw a little cartoon it if helps you remember the shape.

Column 2 Eruption style (column 2) When these volcanoes erupt, what is it like? Is there a lot of lava, gas or ash? Is the eruption violent or calm? Is it a big or small event? Would you feel safe watching the volcano erupt close-up or would you want to be far far away?

Column 3 Column 3: Lava Type Use the following website for reference:

http://www.cotf.edu/ete/modules/volcanoes/vtypeslava1.html

The type of lava (or magma) determines the way that a volcano will erupt. Once you learn about lava types, assign a lava type to each volcano type. You won’t ﬁ nd the answers in the reading; you’ll have to connect what you learn about lava type to what you know about volcano shape and eruption style.

1. a) In one sentence, what is viscosity?

b) What word that you know would describe your deﬁ nition of viscosity?

2. High viscosity will make lava ﬂ ow faster / slower (circle one)

3. Silica makes a lava more / less viscous (circle one)

A Sense of place · Earth and Environmental Science in the Community 5 ? Hint: think about shaking 4. Gas in lava makes it more / less explosive (circle one) a bottle of soda vs. shaking a [See hint at side] bottle of milk and opening the cap, which one will explode? 5. Describe the behavior of the lava with the following features: a. High viscosity and low gas content:

b. High viscosity and high gas content:

c. Low viscosity and low gas content:

d. Low viscosity and high gas content:

? Above. Mt. St. Helens 1980 eruption. USGS photo. In Column 3, write the lava types that would create the eruption types listed in Column 2. Lava types ? High viscosity & low gas Use the combinations of high/low viscosity and high/low gas content ? High viscosity & high gas as your lava types [see sidebar]. Remember that some of the volcano ? Low viscosity & low gas types may have multiple eruption styles and therefore have more ? Low viscosity & high gas than one lava type.

Column 4 Column 4: Volcanic hazards Use the following website for reference:

http://www.cotf.edu/ete/modules/volcanoes/vhazards.html

Lava fl ows, ash fl ows, ash falls, earthquakes, tidal waves, poisonous gases, mudfl ows, rock avalanches and explosive blasts cause a lot of damage.

For each hazard, think about the kind of volcano that produces it. In Column 4 of the chart list the potential hazards associated with each volcano type - there’s often more than one.

Column 5 Column 5: Rocks What kinds of rocks do each of these volcanoes produce? The answers might not be obvious now; write down what you do know, include your guesses, and you can complete this column later.

6 A Sense of place · Earth and Environmental Science in the Community