Lets Learn More About Pompeii Click on the images below!
Slide 3
D. Types of Eruptions Quiet Eruptions Happen if magma is thin,
runny, & flows easily Occur in Hawaii and Iceland Produce
pahoehoe and aa Low Silica Explosive Eruptions Happen if magma is
thick & sticky Gasses (pressure) build up within thick magma
Cause very forceful eruptions High Silica
Slide 4
Slide 5
On May 18, 1980, at 8:32 a.m. Pacific Daylight Time, a
magnitude 5.1 earthquake shook Mount St. Helens. The bulge and
surrounding area slid away in a gigantic rockslide and debris
avalanche, releasing pressure, and triggering a major pumice and
ash eruption of the volcano. Thirteen-hundred feet (400 meters) of
the peak collapsed or blew outwards. As a result, 24 square miles
(62 square kilometers) of valley was filled by a debris avalanche,
250 square miles (650 square kilometers) of recreation, timber, and
private lands were damaged by a lateral blast, and an estimated 200
million cubic yards (150 million cubic meters) of material was
deposited directly by lahars (volcanic mudflows) into the river
channels. Fifty-seven people were killed or are still missing. USGS
Photograph taken on May 18, 1980, by Austin Post.
Slide 6
Different Eruptions Result In DIFFERENT VOLCANIC LANDFORMS
Slide 7
E. Landforms from Lava and Ash 1.Shield Volcanoes a.Form by
thin layers of lava that pour out of a vent and harden on
previously formed layers Ex. Mauna Loa, Hawaiian Islands
Slide 8
Slide 9
E. Landforms from Lava and Ash 1.Shield Volcanoes a.Form by
thin layers of lava that pour out of a vent and harden on
previously formed layers Ex. Mauna Loa, Hawaiian Islands 2.Cinder
Cone Volcanoes a.Form by ash, cinders, and bombs that erupt from
thick and stiff lava. b.Material piles up in a cone-shaped pile Ex.
Paricutin, Mexico (shown in Intro Video)
Slide 10
Slide 11
E. Landforms from Lava and Ash 1.Shield Volcanoes a.Form by
thin layers of lava that pour out of a vent and harden on
previously formed layers Ex. Mauna Loa, Hawaiian Islands 2.Cinder
Cone Volcanoes a.Form by ash, cinders, and bombs that erupt from
thick and stiff lava. b.Material piles up in a cone-shaped pile Ex.
Paricutin, Mexico (shown in Intro Video) 3.Composite Volcanoes
(think combo) a.Erupt both lava and ash b.Volcano slopes are
cone-shaped and its layers alternate from lava layers to ash layers
Ex. Mt. Fuji, Japan & Mt. St. Helens, Washington
Slide 12
Slide 13
E. Landforms from Lava and Ash 1.Shield Volcanoes a.Form by
thin layers of lava that pour out of a vent and harden on
previously formed layers Ex. Mauna Loa, Hawaiian Islands 2.Cinder
Cone Volcanoes a.Form by ash, cinders, and bombs that erupt from
thick and stiff lava. b.Material piles up in a cone-shaped pile Ex.
Paricutin, Mexico (shown in Intro Video) 3.Composite Volcanoes
(think combo) a.Erupt both lava and ash b.Volcano slopes are
cone-shaped and its layers alternate from lava layers to ash layers
Ex. Mt. Fuji, Japan & Mt. St. Helens, Washington 4.Caldera
a.When huge eruptions occur, they can sometimes empty the main vent
AND magma chamber. b.The mountain looks like a hollow shell as the
top of the mountain collapses inward. Ex. Crater Lake, Oregon
Slide 14
Slide 15
HOMEWORK DUE: THURSDAY 1-26-12 Read Read Textbook pages 187-188
Answer Section 2 Review Question #s 2 and 4 Continue to work on
your Volcano Brochure