The Wrath of Vulcan: Volcanic Eruptions

Prepared by

Ronald Parker
Earlham College Department of Geosciences
Richmond, In...
Volcanic Eruptions


What is a volcano?
An erupting vent through which molten rock surfaces.
 A mountain built from magm...
Volcanic Eruptions
In 79 C.E. Mt. Vesuvius erupted violently.
 Pyroclastic flows destroyed Pompeii, killing 20,000.
 A r...
Volcanic Eruptions


Unpredictable, dangerous.
Build large mountains.
 Blow mountains to bits.




Eruptions can…
Prov...
Volcanic Materials


The products of volcanic eruption take three forms:
Lava flows – Molten rock that move over the grou...
Lava Flows
Lava can be thin and runny or thick and sticky.
 Flow type depends on viscosity via composition.
 Composition...
Lava Compositions


Lavas with high silica / low Fe and Mg are called...




Lavas with low silica / high Fe and Mg are...
Basaltic Lava Flows
Mafic lava – Very hot, low silica, and low viscosity.
 Basalt flows are often thin and fluid.


They...
Pahoehoe


Pahoehoe (pa-hoy-hoy) - a Hawaiian word
describing basalt with a glassy, ropy texture.
Pahoehoe forms when ext...
A’a’


A’a’ (ah-ah) is a Hawaiian word describing basalt
that solidifies with a jagged, sharp, angular texture.
A’a’ form...
Lava Tubes
A cooled crust forms on top of a basalt flow.
 A conduit – a lava tube – develops in the flow.
 Tubes prevent...
Columnar Jointing
Solidified flows may contract with vertical fractures
that are hexagonal in cross-section.
 Columnar jo...
Pillow Basalts
Underwater, basalt cools instantly; it cannot flow.
 It cools to form a rounded blob called a pillow.


T...
Andesitic Lava Flows


Higher SiO2 content makes andesitic lavas viscous.
Unlike basalt, they do not flow rapidly.
 Inst...
Rhyolitic Lava Flows


Rhyolite; the highest SiO2 – the most viscous lava.

Rhyolitic lava rarely flows.
 Rather, lava p...
Pyroclastic Debris
Fragmental material ejected from a volcano.
 Glass shards, fragmented lava in a range of sizes.


Ash...
Pyroclastic Debris


Tephra – Deposits of pyroclastic debris.
Volcanic agglomerate – Lapilli and bombs near the vent.
 T...
Pyroclastic Flows


Pyroclastic flows (or, nuée ardentes - French):
200oC - 450oC avalanches of hot ash that race downslo...
Lahars
Tephra is readily moved by water as a debris flow.
 Known as lahars, these flows are often deadly.


Lahars move ...
Volcanic Gas


1 to 9% of magma may be gas.



Carbon dioxide (CO2) – Second in abundance.





Water (H2O) – Most ab...
Volcanic Gas
Gases are expelled as magma rises (P drops).
 SO2 reacts with water to form aerosol sulfuric acid.




Sty...
Volcanic Architecture


Volcanoes have characteristic features.
A magma chamber.
 Fissures and vents.
 Craters.
 Calde...
Magma Chamber


Located in the upper crust.
Usually an open cavity or area of highly fractured rock.
 Contains a large q...
Magma Chamber
Some magma rises via a conduit to the surface.
 Magma may also erupt along a linear tear, a fissure.


Fis...
Vents
A vent is a lava outlet on a volcano.
 Vents can form anywhere on the volcano.


Summit vent – Located at the top ...
Craters
Crater – A bowl-shaped depression atop a volcano.
 Craters are up to 500 m across; 200 m deep.
 Form as erupted ...
Caldera


A gigantic volcanic depression.
Much larger than a crater.
 1-10s of kilometers across.


Magma chamber empti...
Crater Lake Caldera, Oregon
Shapes and Sizes
Magma type governs volcano shape and size.
 Categories:


Shield volcanoes – Largest.
 Cinder cones – ...
Volcano Types


Shield volcanoes.
Broad, slightly domed-shaped (like an inverted shield).
 Lateral flow of low-viscosity...
Volcano Types


Cinder cone – Conical piles of tephra.
The smallest type of volcano.
 Built of ejected lapilli-sized fra...
Volcano Types


Stratovolcanoes (composite volcanoes).
Large, cone-shaped volcano.
 Composed of alternating layers of la...
Eruptive Style


Will it flow, or will it blow? Two dominant styles.
Effusive eruptions – Produce lava flows.
 Explosive...
Eruptive Style


Effusive eruptions – Produce lava flows.
Lava flows stream away from vents.
 Lava lakes can form around...
Eruptive Style


Explosive eruptions – Produce pyroclastic flows.
Caused by gas pressure in the more viscous magma.
 Pre...
Eruptive Style


Phreatomagmatic eruptions – Less common style.
Volcanic eruption where magma interacts with water.
 Som...
Controls on Eruptive Style


Viscosity – Controls the ease of lava flow.
Basalt – Low-viscosity lava flows away from vent...
Tectonic Settings
Plate motion is a dominant control on volcanism.
 Volcanic types are linked to tectonic settings




...
Hot Spot Eruptions


Oceanic hot spot – Plume under an oceanic plate.
Basalt erupts at the seafloor and forms a growing m...
Hot Spot Eruptions


Continental hot spot – Cuts a continental plate.


Often erupts both basaltic and rhyolitic materia...
Hot Spot Eruptions


Continental hot spots.


Flood basalts – Voluminous lava eruption above a plume.
Thinned lithosphe...
MOR Eruptions
Most lava erupts along the mid-ocean ridge (MOR).
 MOR-produced oceanic crust covers 70% of Earth.
 Basalt...
Convergent Boundaries


Most volcanoes form at convergent boundaries.
Volatiles from subducting plate initiate melting.
...
Continental Rifts


Yield an array of volcano types reflecting...
Partial melting of the mantle (mafic magmas).
 Partial...
This concludes the
Chapter 9
The Wrath of Vulcan: Volcanic Eruptions

LECTURE OUTLINE

earth

Portrait of a Planet

Third ...
Op ch09 lecture_earth3 -1, volcanoes
Op ch09 lecture_earth3 -1, volcanoes
Upcoming SlideShare
Loading in...5
×

Op ch09 lecture_earth3 -1, volcanoes

290

Published on

A volcano is an opening, or rupture, in the surface or crust of the Earth or a planetary mass object, which allows hot lava, volcanic ash and gases to escape from the magma chamber below the surface.
On Earth, volcanoes are generally found where tectonic plates are diverging or converging. A mid-oceanic ridge, for example the Mid-Atlantic Ridge, has examples of volcanoes caused by divergent tectonic plates pulling apart; the Pacific Ring of Fire has examples of volcanoes caused by convergent tectonic plates coming together. By contrast, volcanoes are not usually created where two tectonic plates slide past one another. Volcanoes can also form where there is stretching and thinning of the Earth's crust in the interiors of plates

Published in: Education, Technology
0 Comments
0 Likes
Statistics
Notes
  • Be the first to comment

  • Be the first to like this

No Downloads
Views
Total Views
290
On Slideshare
0
From Embeds
0
Number of Embeds
0
Actions
Shares
0
Downloads
41
Comments
0
Likes
0
Embeds 0
No embeds

No notes for slide

Op ch09 lecture_earth3 -1, volcanoes

  1. 1. Chapter 9 The Wrath of Vulcan: Volcanic Eruptions LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  2. 2. The Wrath of Vulcan: Volcanic Eruptions Prepared by Ronald Parker Earlham College Department of Geosciences Richmond, Indiana
  3. 3. Volcanic Eruptions  What is a volcano? An erupting vent through which molten rock surfaces.  A mountain built from magmatic eruptions.  Volcanoes are a clear result of tectonic activity.  Volcanoes pose a number of hazards to humans.  Mexico City.  Seattle, U.S.  Naples, Italy.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  4. 4. Volcanic Eruptions In 79 C.E. Mt. Vesuvius erupted violently.  Pyroclastic flows destroyed Pompeii, killing 20,000.  A record of Roman life was preserved under ash.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  5. 5. Volcanic Eruptions  Unpredictable, dangerous. Build large mountains.  Blow mountains to bits.   Eruptions can… Provide highly productive soils to feed a civilization.  Can extinguish a civilization in a matter of minutes.   Eruptions affect climate. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  6. 6. Volcanic Materials  The products of volcanic eruption take three forms: Lava flows – Molten rock that move over the ground.  Pyroclastic debris – Fragments blown out of a volcano.  Volcanic gases – Vapor and aerosols that exit a volcano.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  7. 7. Lava Flows Lava can be thin and runny or thick and sticky.  Flow type depends on viscosity via composition.  Composition depends on silica (SiO 2), Fe, and Mg.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  8. 8. Lava Compositions  Lavas with high silica / low Fe and Mg are called...   Lavas with low silica / high Fe and Mg are called…   Silicic, felsic, or rhyolitic. Mafic or basaltic. Lavas with moderate silica, Fe and Mg are called…  Intermediate or andesitic. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  9. 9. Basaltic Lava Flows Mafic lava – Very hot, low silica, and low viscosity.  Basalt flows are often thin and fluid.  They can flow rapidly (up to 100 km/hr).  They can flow for long distances (up to several 100 km).  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  10. 10. Pahoehoe  Pahoehoe (pa-hoy-hoy) - a Hawaiian word describing basalt with a glassy, ropy texture. Pahoehoe forms when extremely hot basalt forms a skin.  With flow, the skin is rolled into ropy ridges and furrows.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  11. 11. A’a’  A’a’ (ah-ah) is a Hawaiian word describing basalt that solidifies with a jagged, sharp, angular texture. A’a’ forms when hot flowing basalt cools and thickens.  With flow, lava crumbles into shards and fragments.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  12. 12. Lava Tubes A cooled crust forms on top of a basalt flow.  A conduit – a lava tube – develops in the flow.  Tubes prevent cooling, facilitating flow for miles.  Lava tubes become caves that can transmit water.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  13. 13. Columnar Jointing Solidified flows may contract with vertical fractures that are hexagonal in cross-section.  Columnar jointing indicates lava.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  14. 14. Pillow Basalts Underwater, basalt cools instantly; it cannot flow.  It cools to form a rounded blob called a pillow.  The pillow surface is cracked, quenched glass.  Lava pressure ruptures a pillow to form the next blob.  The process repeats to form a mound of pillow basalts.   Common on the MOR. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  15. 15. Andesitic Lava Flows  Higher SiO2 content makes andesitic lavas viscous. Unlike basalt, they do not flow rapidly.  Instead, they mound around the vent and flow slowly.  The outer crust fractures, creating rubble.  Andesitic lava flows remain close to the vent.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  16. 16. Rhyolitic Lava Flows  Rhyolite; the highest SiO2 – the most viscous lava. Rhyolitic lava rarely flows.  Rather, lava plugs the vent as a lava dome.  Sometimes, lava domes are blown to smithereens.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  17. 17. Pyroclastic Debris Fragmental material ejected from a volcano.  Glass shards, fragmented lava in a range of sizes.  Ash – Powdery glass shards.  Lapilli – Pea- to plum-sized material.  Blocks and bombs – Apple- to refrigerator-sized.  Blocks – Pre-existing rock torn from the volcano. Bombs – Streamlined fragments of ejected lava. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  18. 18. Pyroclastic Debris  Tephra – Deposits of pyroclastic debris. Volcanic agglomerate – Lapilli and bombs near the vent.  Tuff – Lithified ash with or without lapilli.  Air-fall tuff – Accumulations of ash that fall like snow. Welded tuff (ignimbrite) – Tuff that is deposited while hot. Hot pyroclastic flow material that fuses before cooling. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  19. 19. Pyroclastic Flows  Pyroclastic flows (or, nuée ardentes - French): 200oC - 450oC avalanches of hot ash that race downslope.  Moving up to 300 kph, they incinerate all in their path.  Immediately deadly; they kill everything quickly.  Many famous examples: Vesuvius, Mt. Pelée, Augustine.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  20. 20. Lahars Tephra is readily moved by water as a debris flow.  Known as lahars, these flows are often deadly.  Lahars move rapidly (up to 50 km/hr).  They have the consistency of wet cement,.  A distinct hazard to people living in volcanic valleys.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  21. 21. Volcanic Gas  1 to 9% of magma may be gas.   Carbon dioxide (CO2) – Second in abundance.   Water (H2O) – Most abundant dissolved gas. Sulfur dioxide (SO2) – Rotten egg smell. Magma composition controls gas content.  Felsic magmas are gas-rich; Mafic magmas are less so. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  22. 22. Volcanic Gas Gases are expelled as magma rises (P drops).  SO2 reacts with water to form aerosol sulfuric acid.   Style of gas escape controls eruption violence. Low viscosity (basalt) – Easy escape; mellow eruption.  High viscosity (rhyolite) – Difficult escape; violent.   Gas bubbles in rock are called vesicles. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  23. 23. Volcanic Architecture  Volcanoes have characteristic features. A magma chamber.  Fissures and vents.  Craters.  Calderas.  Distinctive profile.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  24. 24. Magma Chamber  Located in the upper crust. Usually an open cavity or area of highly fractured rock.  Contains a large quantity of magma.   Some magma cools here to form intrusive rock. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  25. 25. Magma Chamber Some magma rises via a conduit to the surface.  Magma may also erupt along a linear tear, a fissure.  Fissure eruptions may display a “curtain of fire.”  Fissures evolve into discrete vents.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  26. 26. Vents A vent is a lava outlet on a volcano.  Vents can form anywhere on the volcano.  Summit vent – Located at the top of the volcano.  Flank vent – Located on the side of a volcano.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  27. 27. Craters Crater – A bowl-shaped depression atop a volcano.  Craters are up to 500 m across; 200 m deep.  Form as erupted lava piles up around the vent.  accentuate by summit collapse into conduit.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  28. 28. Caldera  A gigantic volcanic depression. Much larger than a crater.  1-10s of kilometers across.  Magma chamber empties.  Volcano collapses into it.  Crater Lake, Oregon.  Yellowstone National Park.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  29. 29. Crater Lake Caldera, Oregon
  30. 30. Shapes and Sizes Magma type governs volcano shape and size.  Categories:  Shield volcanoes – Largest.  Cinder cones – Smallest.  Stratovolcanoes – Intermediate in size.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  31. 31. Volcano Types  Shield volcanoes. Broad, slightly domed-shaped (like an inverted shield).  Lateral flow of low-viscosity basaltic lava.  Have a low slope and cover large geographic areas.  Mauna Loa on Hawaii is a good example.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  32. 32. Volcano Types  Cinder cone – Conical piles of tephra. The smallest type of volcano.  Built of ejected lapilli-sized fragments piled up at a vent.  Slopes are at the angle of repose.  Often symmetrical with a deep summit crater.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  33. 33. Volcano Types  Stratovolcanoes (composite volcanoes). Large, cone-shaped volcano.  Composed of alternating layers of lava and tephra.  Often symmetric; can be odd shapes from landslides, etc.  Examples include Mt. Fuji, Mt. Rainier, Mt. Vesuvius.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  34. 34. Eruptive Style  Will it flow, or will it blow? Two dominant styles. Effusive eruptions – Produce lava flows.  Explosive eruptions – Blow up.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  35. 35. Eruptive Style  Effusive eruptions – Produce lava flows. Lava flows stream away from vents.  Lava lakes can form around the vent.  Can produce huge lava fountains.   Commonly basaltic, these eruptions create shields. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  36. 36. Eruptive Style  Explosive eruptions – Produce pyroclastic flows. Caused by gas pressure in the more viscous magma.  Pressure is released explosively.  Create stratovolcanoes.  May create calderas.  Blanket the landscape with tephra.   Andesitic and rhyolitic compositions. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  37. 37. Eruptive Style  Phreatomagmatic eruptions – Less common style. Volcanic eruption where magma interacts with water.  Some phreatomagmatic eruptions can be cataclysmic.  A magma chamber breaches and admits water. Water flashes to steam and blows the entire volcano apart. Examples: Santorini, Krakatau. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  38. 38. Controls on Eruptive Style  Viscosity – Controls the ease of lava flow. Basalt – Low-viscosity lava flows away from vent.  Felsic – High-viscosity lava builds-up at the vent.   Gas Pressure – Greater P favors explosive style. Basalt – Low-viscosity allows gas release.  Felsic – High-viscosity prevents gas release.   Environment – Where eruption occurs important. Subaerial lava flowing on land cools slower than…  Submarine lava, which is quickly quenched.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  39. 39. Tectonic Settings Plate motion is a dominant control on volcanism.  Volcanic types are linked to tectonic settings   Hot spots - Where mantle plumes cut the lithosphere. Oceanic hot spots. Continental hot spots and flood basalts. Mid-ocean ridges – Spreading axes.  Convergent boundaries – Subduction zones.  Continental rifts – Incipient ocean basins.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  40. 40. Hot Spot Eruptions  Oceanic hot spot – Plume under an oceanic plate. Basalt erupts at the seafloor and forms a growing mound.  A volcano builds above sea level to form an island.  Then basalt will not quench and can flow long distances.  Lava builds upward and outward and the island grows.  Submarine slumps remove large masses of the volcano.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  41. 41. Hot Spot Eruptions  Continental hot spot – Cuts a continental plate.  Often erupts both basaltic and rhyolitic material. Basaltic – Makes up the mantle plume. Rhyolitic – Basalt melts the granitic crust it passes through. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  42. 42. Hot Spot Eruptions  Continental hot spots.  Flood basalts – Voluminous lava eruption above a plume. Thinned lithosphere erupts magma from long fissures. Lava spreads over large areas; great thicknesses stack up. With time, a shrinking plume creates “normal” volcanoes. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  43. 43. MOR Eruptions Most lava erupts along the mid-ocean ridge (MOR).  MOR-produced oceanic crust covers 70% of Earth.  Basalt erupted from fissures quenches as pillows.  Pillow mounds are pulled apart with plate motion.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  44. 44. Convergent Boundaries  Most volcanoes form at convergent boundaries. Volatiles from subducting plate initiate melting.  Arc volcanoes develop on overriding plate.  May cut through oceanic or continental crust.  The “Ring of Fire” dominates Pacific margins. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  45. 45. Continental Rifts  Yield an array of volcano types reflecting... Partial melting of the mantle (mafic magmas).  Partial melting of the crust (felsic magmas).   Examples: East African Rift.  Basin and Range.  Mid-continent Rift.  Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions
  46. 46. This concludes the Chapter 9 The Wrath of Vulcan: Volcanic Eruptions LECTURE OUTLINE earth Portrait of a Planet Third Edition ©2008 W. W. Norton & Company, Inc. Earth: Portrait of a Planet, 3rd edition, by Stephen Marshak Chapter 9: The Wrath of Vulcan: Volcanic Eruptions

×