Alex Chen, Kareem Elhossieni, Ellie Markes

Diagram

Different

• Volcanic domes is a solid rock that forms when lava is eruptedfrom a vent.

• If the lava is viscous enough, it will pile up above the vent toform a dome rather than move away as a lava flow.

• The sides of most domes are very steep• Most domes are composed of silica‐rich lavas that have a low

gas content.• lavas contain enough gas to cause explosions within a dome

as it is being formed.

Type of Lava

• It produces Aa lava. Aa lava is sharp and pointy when it solidifies.

Example

• Chaitén Volcano Lava Dome, Chile.• It stands out because Reduced volcanic emissions and clear 

skies over southern Chile reveal Chaitén volcano’s new lava dome. 

• The dome almost completely fills the caldera left behind after Chaitén’s last eruption, which ended about 9,400 years ago. The bare rocky surface of the dome is brown

• gray ash and tephra cover the landscape to the east (right).• This is an active volcano

Bibliography• http://vulcan.wr.usgs.gov/LivingWith/VolcanicFacts/misc_volcanic_facts.h

tml• http://pubs.usgs.gov/gip/volc/types.html• www.geology.sdsu.edu/how_volcanoes_work/Domes.htm• http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=43100

• http://www.volcano.si.edu/faq/index.cfm?faq=03

How many Active volcano's are in the world?

• There are approximately 1,500 active volcanoes worldwide.

How many active volcanoes known?

Erupting now: perhaps 20

Each year: 50‐70

Each decade: about 160

Historical eruptions: about 550

Known Holocene eruptions (last 10,000 years):

about 1300

Known (and possible) Holocene eruptions: about 1500

How do volcano's decrease global temperatures

• Volcanoes have a minor effect on temperature (sulfur clouds reflect light back into space), and a minor effect on ozone levels.

How can some volcanoes instead of decreasing global temperatures, 

increase them?

• The volcano's released heat into the air from the lava explosion.