alex chen, kareem ellie markes
TRANSCRIPT
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.