Plate Tectonic features Volcanoes Plate Tectonic features

Definition Vent in Earth’s surface out of which lava, debris, and gases are released Magma and gases build up, resulting in explosions i. Can be explosive: lava, rock, ashes ii. Less gas means less explosive but with more oozing lava

B. Magma varies i. Runny ii. Thick and sludge-like

Terms Magma chamber: large underground pool of magma Lava: magma, once it reaches the surface Crater: bowl-shaped basin in the top of the volcano Vent: central tube which magma travels through

V. Volcanic bombs: larger material thrown out by the force of an explosive eruption VI. Ash, gas, steam: material thrown out by volcanoes

Image Image we associate with volcanoes is a result of volcanic activity Mountain-like mounds formed from the hardened matter spewed during explosions i. Can occur from a few weeks to millions of years

Danger Level Flows of lava can reach 2000 degrees fahrenheit Burns all in its path, including entire towns Can include boulders of hardening lava Mud caused by rapidly melting snow can strip land of its nutrients and topsoil

D. Ash and gases can burn lungs and can be toxic II. In the past 300 years, the estimate is that over 260,000 have died from volcanic activity and its aftermath

Activity Most common along plate boundaries 90% of all volcanoes are found along the Ring of Fire along the edges of the Pacific Ocean II. Of all volcanoes on Earth, about 1900 are said to be active Show some level of activity and are likely to explode again

III. Dormant volcanoes are not currently active but are likely to be so at some time in the future IV. Extinct volcanoes are those expected never to be active again

Types of Volcanoes Composite Characteristics: i. Steep sides and cone-shaped ii. Made of layers of ash and lava iii. Lava is sticky, not flowing very far iv. Eruptions tend to be often and gentle Example: Mount Etna in Italy

II. Shield Characteristics: i. Gently sloping sides ii. Runny lava covers a wide area iii. Gases escape easily here iv. Eruptions tend to be pyroclastic Example: Mauna Loa in Hawaii

C. Pyroclastic: i. Mixture of hot steam, ash, rock, and dust ii. Can roll down sides of volcanoes extremely quickly

Supervolcanoes What makes it “super” Massive scale (at least 1000km³ of debris, while normal volcanoes spew 1km³ of debris) Forms a depression called a caldera rather than a cone shape Often surrounded by a ridge of higher land

D. Erupts less frequently - hundreds of thousands of years between eruptions II. Example: Yellowstone At a volcanic hotspot

Why Studied To predict future eruptions To gather info about Earth’s surface and interior Soil near volcanoes is very fertile due to minerals that act as fertilizer to plants i. Igneous rock, that formed from hardened magma: basalt contains iron and rhyolite contains silica

B. The slower the magma cools, the larger the crystals in the igneous rock

Tops of underwater mountains Islands Tops of underwater mountains