Chapter 4 -Volcanism & Extrusive Rocks

Photo Credit: S. Young

Effects on Humans

• The Growth of Hawaii• Geothermal Energy• Effect on Climate• Volcanic Catastrophes• Eruptive Violence and Physical Characteristics of

Lava

Cascades Volcanoes

Mt. St. Helen’s Eruption Sequence

Gary Rosenquist Photo Sequence - Mt. St. Helen’s, May 18, 1980

~8:27 PDT8:32:47.0 PDT8:32:49.2 PDT8:32:53.3 PDT8:33:03.7 PDT8:33:18.8 PDT

Mt. St. Helen’s Animation

Mt. St. Helen’s Plinian Eruption Column - May 18, 1980

From: USGS http://vulcan.wr.usgs.gov/

Mt. St. Helen’sMay 18, 1980 Devastation

Post May 18, 1980 Crater and Resurgent Dome

From: USGS http://vulcan.wr.usgs.gov/

Caldera Collapse

Crater lake - Wizard Island - 5 kBP Eruption Mt. MazamaCrater lake, Wizard Island, OR8 kBP Eruption Mt. Mazama

From: http://www.igoweb.org/~wms/personal/photos/2000/craterLake/

Pyroclastic Flows

St. Pierre Devastation, Mt. Pelee, Martinque, May 8, 1902

Extrusive Rocks and Gases

• Scientific Investigation of Volcanism• Gases

Extrusive Rocks

Volcanic Textures Table

Obsidian Hand Specimen

Andesite Hand Specimen

Andesite Photomicrograph

Vesicular Basalt

Pumice

Volcanic Bombs

Volcanic Tuff Photomicrograph

Types of Volcanoes

• Shield Volcanoes• Cinder Cones• Composite Volcanoes• Volcanic Domes

Basic Volcano Types

Karymsky Volcano, Kamchatka, Russia

Shield Volcano

Basaltic Fire Fountaining and Lava Flows

Summit of Mauna Loa

Pahoehoe Lava Flow

Aa Lava Flow

Spatter Cone

Olympus Mons, Mars

Volcanic Eruption, Io