* Your assessment is very important for improving the workof artificial intelligence, which forms the content of this project
Download Chapter 12 Section 4
Lōʻihi Seamount wikipedia , lookup
Sidoarjo mud flow wikipedia , lookup
Axial Seamount wikipedia , lookup
Craters of the Moon National Monument and Preserve wikipedia , lookup
Itcha Range wikipedia , lookup
Mount Pleasant Caldera wikipedia , lookup
Mount Garibaldi wikipedia , lookup
Level Mountain wikipedia , lookup
Llullaillaco wikipedia , lookup
Mount Meager massif wikipedia , lookup
Large igneous province wikipedia , lookup
Mount Pinatubo wikipedia , lookup
Cerro Blanco (volcano) wikipedia , lookup
Lascar (volcano) wikipedia , lookup
Mount Edziza volcanic complex wikipedia , lookup
Olympus Mons wikipedia , lookup
Mount St. Helens wikipedia , lookup
Volcanology of Io wikipedia , lookup
Wells Gray-Clearwater volcanic field wikipedia , lookup
Volcano (1997 film) wikipedia , lookup
Mount Vesuvius wikipedia , lookup
Nevado del Ruiz wikipedia , lookup
Cascade Volcanoes wikipedia , lookup
Mount Pelée wikipedia , lookup
Cerro Azul (Chile volcano) wikipedia , lookup
Silverthrone Caldera wikipedia , lookup
Chapter 12 Section 4 Volcanoes Chapter 12 Section 4 – What You’ll Learn - page 373 Before you read - write the reading’s objectives in this space: 1 – _____________________________________________ ________________________________________________ ________________________________________________ 2 – _____________________________________________ ________________________________________________ ________________________________________________ ________________________________________________ Chapter 12 Section 4 – What You’ll Learn - page 373 Before you read - write the reading’s objectives in this space: 1 – Describe the types and causes of different types of volcanic eruptions 2 – Explain the patterns of occurrence of volcanoes and its link to plate tectonics. What are faults? _________________ _________________ _________________ _________________ What is decompression? _________________ ____________________________________________ ____________________________________________ Why is decompression important to volcanism? ____________________________________________ ____________________________________________ 1 What are faults? Weaknesses along Earth’s crust where movement takes place. What is decompression? The release of pressure due To movement of fault lines. Why is decompression important to volcanism? Decompression changes (lowers) the melting point of rock. The rock can become liquid at the same temperature. Convection keeps our mantel flowing: As fluids heat they Expand becoming less dense And more buoyant. Due to lower density fluids will rise Once fluids rise away from the heat source they cool and sink. As long as there is a heat source the cycle begins again. Cools, Spreads, and Sinks Heat Rises Cycle Begins Again 2 Why does magma rise?_________________________ _________________________________________ _________________________________________ Where does most surface lava occur? _________________________________________ _________________________________________ _________________________________________ _________________________________________ ________________________________________ 3 Why does magma rise? Heated rock is less dense causing it to rise. It will surface as long as it has a path to follow (cracks or fissures). Where does most surface lava occur? On or near boundaries of plates and above hot spots What solids erupt from volcanoes? What are Pyroclasts? ___________ ___________________________ ___________________________ Globule or volcanic bomb–________ ___________________________ ___________________________ ___________________________ Ash ________________________ ___________________________ ___________________________ Blocks ____________________ _________________________ Volcanic Bomb – notice rain drop type shape Volcanic Ash Volcanic Block 4 What solids erupt from volcanoes? What are Pyroclasts? All solid materials expelled by a volcano. Globule or volcanic bomb– cooled globs of lava (solid material) Volcanic Bomb – notice rain drop type shape Ash - dust (smallest particles) falls furthest from source. Volcanic Ash Blocks – chunks of solid material ripped from the volcano during eruption. Falls closest to source. Volcanic Block What is the most common volcanic gas? __________ What other gases can be expected? ____________ ___________________ All of gasses that are expelled are super heated!! Evidence has shown that volcanoes contribute enough greenhouse gas to affect climate long after the eruption has ended! 5 What is the most common volcanic gas? Water vapor What other gases can be expected? Carbon dioxide and sulfur compounds All of gasses that are expelled are super heated!! Evidence has shown that volcanoes contribute enough greenhouse gas to affect climate long after the eruption has ended! Pyroclastic flow – the most dangerous part of a volcano The flow looks like ground-hugging grey smoke, but consists of a mixture of poisonous gas, ash, globules, and dense hot lava blocks. Pyroclastic flow is what covered Pompeii The Tambora volcano in Indonesia erupted in April 1815, but North America and Europe did not notice its effects until months later. In 1816, known as "the year without a summer", gases, ashes and dust arrived over the Iberian Peninsular and reached the stratosphere, where they remained long enough to create "an enormous sun filter". Krakatau: The Last Days Pyroclastic Flow Clip Anak (Child of) Krakatau has grown at an average rate of five inches (13 cm) per week Today What is viscosity? ____________________________ _________________________________________ What is more viscous, water or syrup? ______________ _________________________________________ What affects viscosity? ________________________ _________________________________________ Which tube has the most viscous material? ____________________ 6 What is viscosity? A measure of the resistance of a fluid to flow. What is more viscous, water or syrup? Syrup – more resistant to flow. What affects viscosity? Heat, composition, and gas content. Which tube has the most viscous material? Far right Volcanoes erupt in different ways. Viscosity will affect the kind of eruption. Eruptive style is strongly linked to temperature and composition and can be linked to the type of plate boundary associated with it. How will thick magma erupt? _________________ ______________________ How does runny, low silica, high temperature magma erupt? _____________________ 7 Volcanoes erupt in different ways. Viscosity will affect the kind of eruption. Eruptive style is strongly linked to temperature and composition and can be linked to the type of plate boundary associated with it. How will thick magma erupt? Cause pressure to build and will explode. How does runny, low silica, high temperature magma erupt? Quiet, free flowing eruptions. Click me Click me Plate Boundary Setting Most of Earth’s volcanoes lie in subduction zones where continental and oceanic materials are being mixed and partially melted. 8 What are hot spots? ___________________________ __________________________________________ __________________________________________ Examples include: Hawaii and Yellow Stone National Park Where do scientists think they come from? ____________ __________________________________________ 9 What are hot spots? Volcanically active sites that arise in places where large quantities of magma move to the surface in large, column-like plumes. Examples include: Hawaii and Yellow Stone National Park Where do scientists think they come from? Extra heat in the Earth’s mantle. Volcanoes are classified according to their size, shape, and the materials that compose them. Cinder cone volcanoes form ________________________ ___________________________________________ These volcanoes are small. 10 Volcanoes are classified according to their size, shape, and the materials that compose them. Cinder cone volcanoes form when the primary eruptive products are large fragments of solid material. These volcanoes are small. Shield volcanoes are _______ and _______ made from ______________of Basaltic lava. 11 Shield volcanoes are broad and flat made from many layers of Basaltic lava. Composite volcanoes form from _____________________ ____________________________________________ ____________________________________________ 12 Composite volcanoes form from alternating explosive events that produce pyroclastic materials, and lava flows The figure below compares actual size of average volcanoes Can you match the volcano to it’s type? Section Check Question 1 Where do most volcanoes occur? 13 Section Check Question 1 Where do most volcanoes occur? Answer Most volcanoes occur at plate boundaries where huge pieces of the crust pull apart or push together. As a result, the crust often fractures, allowing magma to reach the surface. Question 2 Section Check What type of volcano is formed by an explosive eruption followed by a quiet eruption? A. cinder cone volcano B. composite volcano C. fissure eruption D. shield volcano 14 Question 2 Section Check What type of volcano is formed by an explosive eruption followed by a quiet eruption? A. cinder cone volcano B. composite volcano C. fissure eruption D. shield volcano Answer The correct answer is B. Composite volcanoes erupt explosively releasing large quantities of gas and ash. They are followed by quieter eruptions that form a lava layer over the ash. Section Check Question 3 How does a hot spot volcano form? 15 Section Check 4 Question 3 How does a hot spot volcano form? Answer A volcano forms above a hot spot when magma erupts through the crust and reaches the surface. Hot spot volcanoes may lie in the middle of plates far from any plate boundaries or near or on plate boundaries.