2. Let’s Learn More About Pompeii Click on the images below!

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

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.

6. Different Eruptions Result In… DIFFERENT VOLCANIC LANDFORMS

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

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)

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. Helen’s, Washington

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. Helen’s, 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

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