chapter 6 volcanoes n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Chapter 6 – VOLCANOES PowerPoint Presentation
Download Presentation
Chapter 6 – VOLCANOES

Loading in 2 Seconds...

play fullscreen
1 / 20

Chapter 6 – VOLCANOES - PowerPoint PPT Presentation


  • 99 Views
  • Uploaded on

Chapter 6 – VOLCANOES. Volcanoes & volcanic hazards. Volcano Vent where lava, solid rock debris, volcanic ash, & gases erupt from inside Earth onto its surface Can be explosive or non-explosive Mt. St. Helens Kilauea. Volcanoes & volcanic hazards. Lava

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Chapter 6 – VOLCANOES' - betha


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
volcanoes volcanic hazards
Volcanoes & volcanic hazards

Volcano

Vent where lava, solid rock debris, volcanic ash, & gases erupt from inside Earth onto its surface

Can be explosive or non-explosive

Mt. St. Helens

Kilauea

slide4
Lava

Molten rock that reaches Earth’s surface

Magma

Molten rock, which may include fragments of rock, volcanic glass & ash, or gas

Beneath Earth’s surface

Volcanoes & volcanic hazards

eruptions landforms materials
Eruptions, landforms & materials

Eruption types: Hawaiian

Shield volcano

Broad, flat volcano with gently sloping sides

Largest volcanoes

Built of successive lava flows

May also produce flood basalts or lava plateaus

eruptions landforms and materials
Eruptions, landforms and materials

Eruption types: Strombolian

More explosive than Hawaiian

Create loose volcanic rock called spatter cones or cinder cones

Smallest volcanoes

eruptions landforms and materials1
Eruptions, landforms and materials

Eruption types: Vulcanian

More explosive than Strombolian

Can generate clouds of ash up to 10 km

Produce pyroclastic flows

Hot volcanic fragments (tephra) that flow very rapidly

eruptions landforms materials1
Eruptions, landforms & materials

Eruption types: Plinian

Most violent eruptions; ash columns over 20 km

Produce stratovolcanoes

Composed of alternating layers of solidified lava & pyroclastic material

Steep sided

eruptions landforms materials3
Eruptions, landforms & materials

Viscosity

Degree to which substance resists flow

Less viscous = runny

More viscous = thick

Dissolved gases

Up to ~10% of magma

Water vapor, carbon dioxide, sulfur dioxide, etc.

eruptions landforms materials4
Eruptions, landforms & materials

Volcanic materials

Pyroclasts

Tephra

Ash

Agglomerates

Tuff

eruptions landforms materials5
Eruptions, landforms & materials

Volcanic materials

Pahoehoe flows

A’a flows

Lava tubes

Vesicles

Columnar jointing

Pillow structures

eruptions landforms and materials2
Eruptions, landforms and materials

Other volcanic features

Crater

Caldera

Resurgent dome

eruptions landforms and materials3
Eruptions, landforms and materials

Other volcanic features

Thermal spring

Geyser

Fumarole

eruptions landforms and materials4
Eruptions, landforms and materials

Other volcanic features

Fissure eruptions

Flood basalt

Lava plateau

volcanic hazards
Volcanic hazards

Primary effects

Lava flows

Pyroclastic flows

Volcanic gases

volcanic hazards1
Volcanic hazards

Secondary effects

Fires

Flooding

Mudslides (lahars)

Debris avalanche

volcanic hazards2
Volcanic hazards

Tertiary and beneficial effects

Landscape changes

Climate changes; regional & global

Benefits:

Replenishes minerals & fertility

Geothermal energy

Specific mineral deposits

predicting eruptions
Predicting Eruptions

Establish volcano’s history

Active

Dormant

Extinct

predicting eruptions1
Predicting Eruptions

Monitor changes & anomalies

Microseismicity

Tilting or bulging

Volcanic gases

Changes in ground or surface water temperature