volcano place where magma reaches the surface magma
- Slides: 52
volcano: place where magma reaches the surface
magma: liquid, molten rock underground lava: magma that reaches the surface • lost gas, gained rock
MID-OCEAN RIDGE: occurs where plates are moving apart • lava flows out smoothly and fluidly from cracks
SUBDUCTION ZONE: occurs at subduction boundaries • usually explosive and erupted material is mostly lava
HOT SPOTS: areas of volcanic activity in lithospheric plates
Hawaiian Islands are an example
• • Viscosity: the measure of a material's resistance to flow (Ex: water is thin, so it has a low viscosity) Factors affecting viscosity of lava: - Temperature - Composition
two types of lava: • felsic: much silica, lightcolored, slow moving (continental crust)
• mafic: low silica, dark-colored, fast moving (oceanic crust)
Aa Lava Pahoehoe Lava
Pahoehoe
Aa
Aa
Pillow lava from Hawaii Click me!
• many magmas contain dissolved gases that are given off • water vapor, carbon dioxide (CO 2), sulfur (S) • magmas with more gases have more explosive eruptions
tephra: solid fragments ejected from a volcano ash (fine, glassy fragments) lapilli (walnut sized particles) blocks (hardened lava) bombs (ejected as hot lava) Sometimes called pyroclastic material
Factors that determine the violence of an eruption: • Composition of the magma • Temperature of the magma • Dissolved gases in the magma
Examine video clips of erupted materials.
Other Volcanic Hazards 1) Ash in the atmosphere can disrupt air travel and, in severe instances, affect climate. Mount Pinatubo, Philippines - Plane on its tail because of weight of ash in 1991 Lascar (northern Chile) erupted in 1993. Eruptions such as this can send large amounts of fine ash particles high into the atmosphere, where they sometimes remain for years. The ash particles scatter incoming sunlight, shading and slightly cooling Earth's surface. Some very large eruptions can have a measurable effect on climate worldwide.
• http: //www. livescience. com/31127 -iceland-volcano-ash-plume-trouble. html
Other Volcanic Hazards 2) Lahars - Mudflows made up of volcanic debris. They flow like liquids, but because they contain suspended material, have a consistency similar to wet concrete. Lahars can travel at speeds of over 50 mph and reach distances dozens of miles from their source.
Other Volcanic Hazards 3) Volcanic Gases - Most of the gas released in an eruption is harmless water vapor (H 2 O), but volcanoes also produce carbon dioxide, sulfur dioxide, hydrogen sulfide, fluorine gas, and other gases. All of these can be deadly. Lake Nyos, Cameroon – 1986. 1, 700 people and 3, 500 livestock died when suffocated by CO 2 from the lake bottom.
• composed of quiet lava flows • form gently sloping, domeshaped mountain • basaltic (mafic) magma
largest = Mauna Loa in Hawaii
• Made mostly of pyroclastic material • Formed from explosive eruptions • Not very high, narrow base, steep sides • Granitic (felsic) magma
http: //volcano. oregonstate. edu/cinder-cones
http: //www. bbc. co. uk/science/earth/collections/mount_vesuvius
• built up of alternating layers of rock and lava • explosive eruptions at first with tephra, then quiet with lava • forms large, cone-shaped mountains • made of felsic and mafic magma
Mount Rainier (left) and Mount Hood (right)
Mount Fuji
- A dome mountain forms when _____.
- Oni magma volcano tamer
- Hot magma rises to the surface
- The farther reaches of human nature
- Axon terminus
- The news reaches bogota
- Food adulteration reaches new height
- What stops following montag once he reaches the river?
- Artificial rupture of membranes
- Refraction of light
- When a wave reaches a boundary it
- Is a disturbance that transfers energy
- A disturbance that transfers energy
- Millions billions trillions chart
- Look at each picture
- Curved surface area of cone
- Lateral and total surface area
- Spin coat
- Thẻ vin
- Tư thế ngồi viết
- Bàn tay mà dây bẩn
- Mật thư tọa độ 5x5
- Các châu lục và đại dương trên thế giới
- Bổ thể
- Từ ngữ thể hiện lòng nhân hậu
- Tư thế ngồi viết
- Giọng cùng tên là
- Thơ thất ngôn tứ tuyệt đường luật
- Hát lên người ơi alleluia
- Hươu thường đẻ mỗi lứa mấy con
- Diễn thế sinh thái là
- Vẽ hình chiếu vuông góc của vật thể sau
- Phép trừ bù
- Công thức tiính động năng
- Thế nào là mạng điện lắp đặt kiểu nổi
- Tỉ lệ cơ thể trẻ em
- Lời thề hippocrates
- đại từ thay thế
- Vẽ hình chiếu đứng bằng cạnh của vật thể
- Quá trình desamine hóa có thể tạo ra
- Các môn thể thao bắt đầu bằng từ đua
- Hình ảnh bộ gõ cơ thể búng tay
- Khi nào hổ mẹ dạy hổ con săn mồi
- Dot
- Thế nào là sự mỏi cơ
- Phản ứng thế ankan
- Trời xanh đây là của chúng ta thể thơ
- Voi kéo gỗ như thế nào
- Thiếu nhi thế giới liên hoan
- điện thế nghỉ
- Tia chieu sa te
- Một số thể thơ truyền thống
- Thế nào là hệ số cao nhất