X

Download UNDERSTANDING VOLCANOS PowerPoint Presentation


Login   OR  Register
X

Share page



  Preview

               
Home / Travel & Tourism / Travel & Tourism Presentations / UNDERSTANDING VOLCANOS PowerPoint Presentation

UNDERSTANDING VOLCANOS PowerPoint Presentation

slidesfinder By : slidesfinder

On : Nov 15, 2014

facebook   twitter   google plus  
In : Travel & Tourism

Embed :
521
views

0
downloads
Login / Signup - with account for


  • → Make favorite
  • → Flag as inappropriate
  • → Download Presentation
  • → Share Presentation
  • Slide 1 - UNDERSTANDING VOLCANOS Dr. Walter Hays, Global Alliance For Disaster Reduction
  • Slide 2 - ESSENTIAL KNOWLEDGE FOR SOCIETAL SUSTAINABILITY A FRAMEWORK FOR UNDERSTANDING THE IMPACTS OF VOLCANIC ERUPTIONS ON PEOPLE AND THEIR COMMUNITIES
  • Slide 3 - GLOBAL DISTRIBUTION OF 1,500 ACTIVE VOLCANOES
  • Slide 4 - ERUPTIONS OF MOUNT MERAPI May 15, and June 6 - 8, 2006
  • Slide 5 - LOCATION IN CENTRAL JAVA
  • Slide 6 - MOUNT MERAPI RECEIVED CLOSE ATTENTION ON APRIL 18
  • Slide 7 - INDONESIA’S MOUNT MERAPI ERUPTED ON MAY 15, 2006 Mount Merapi, a stratovolcano, emitted lava, debris, and a pyroclastic flow (or cloud) on May 15.
  • Slide 8 - MAY 15, 2006 ERUPTION Hot ash released.
  • Slide 9 - MAY 15, 2006 ERUPTION Volcanic ash turned everything white
  • Slide 10 - MAY 15, 2006 ERUPTION School children wore masks to counter adverse health effects of breathing volcanic ash.
  • Slide 11 - MAY 15, 2006 ERUPTION Volcanic ash covered crops and vegetation.
  • Slide 12 - MAY 15, 2006 ERUPTION Volcanic ash covered automobiles and affected jet airline traffic.
  • Slide 13 - MOUNT MERAPI ERUPTED AGAIN ON JUNE 6-8, 2006 Mount Merapi volcano emitted lava, debris, and pyroclastic flows (superheated clouds of gas) on Tuesday, June 6 and Wednesday, June 7.
  • Slide 14 - EXPLOSIVENESS OF JUNE 8 ERUPTION SENT 15,000 FLEEING
  • Slide 15 - EVACUATION 11,000 from three districts evacuated to schools and otheren “safe haven” emer-gency shelters.
  • Slide 16 - MANY CHOSE TO EVACUATE Many citizens chose to evacuate. Evacuation was ordered. Villagers remembered the 1994 disaster.
  • Slide 17 - MANY CHOOSE NOT TO EVACUATE Many citizens chose not to evacuate because shelters are boring and they wanted to provide for livestock and tend crops.
  • Slide 18 - ESSENTIAL KNOWLEDGE ON VOLCANOES
  • Slide 19 - Plate tectonics and volcanic activity Global distribution of volcanoes Most volcanoes are located within or near ocean basins Basaltic rocks: in oceanic and continental settings Granitic rocks: in continental settings
  • Slide 20 - The nature of volcanic eruptions Three physical characteristics of a magma control its viscosity, the physical property that ultimately determines the “violence” or explosiveness, of the eruption: Composition Temperature Dissolved gases
  • Slide 21 - The magma affects the severity of a volcanic eruptions In summary Basaltic Magmas = mild eruptions Rhyolitic or Andesitic Magmas = explosive eruptions
  • Slide 22 - The nature of volcanic eruptions Viscosity is a measure of a material’s resistance to flow Factors affecting viscosity Temperature - Hotter magmas are less viscous Composition - Silica (SiO2) content
  • Slide 23 - The nature of volcanic eruptions Higher silica content = higher viscosity (e.g., felsic lava such as rhyolite) Lower silica content = lower viscosity (e.g., mafic lava such as basalt)
  • Slide 24 - The nature of volcanic eruptions Dissolved gases Gas content affects magma mobility Gases expand within a magma as it nears the Earth’s surface due to decreasing pressure The violence of an eruption is related to how easily gases escape from magma
  • Slide 25 - Materials extruded from a volcano Lava flows Basaltic lavas exhibit fluid behavior Types of basaltic flows Pahoehoe lava (resembles a twisted or ropey texture) Aa lava (rough, jagged blocky texture) Dissolved gases 1% - 6% by weight Mainly H2O and CO2
  • Slide 26 - Materials extruded from a volcano Pyroclastic materials – “fire fragments” Types of pyroclastic debris Ash and dust - fine, glassy fragments Pumice - porous rock from “frothy” lava Cinders - pea-sized material
  • Slide 27 - Materials extruded from a volcano (continued) Pyroclastic materials – “fire fragments” Types of pyroclastic debris Lapilli - walnut-sized material Particles larger than lapilli Blocks - hardened or cooled lava Bombs - ejected as hot lava
  • Slide 28 - Volcanoes General features Opening at the summit of a volcano Crater - summit depression < 1 km diameter Caldera - summit depression > 1 km diameter produced by collapse following a massive eruption Vent – surface opening connected to the magma chamber Fumarole – emit only gases and smoke
  • Slide 29 - Volcanoes Types of volcanoes Shield volcano Broad, slightly domed-shaped Generally cover large areas Produced by mild eruptions of large volumes of basaltic lava Example: Mauna Loa on Hawaii
  • Slide 30 - Volcanoes Cinder cone Built from ejected lava (mainly cinder-sized) fragments Steep slope angle Small size Frequently occur in groups
  • Slide 31 - Volcanoes Composite cone (stratovolcano) Most are located adjacent to the Pacific Ocean (e.g., Fujiyama, Mt. St. Helens) Large, classic-shaped volcano (1000’s of ft. high and several miles wide at base)
  • Slide 32 - Mt. St. Helens – prior to the 1980 eruption
  • Slide 33 - Mt. St. Helens (after the 1980 eruption)
  • Slide 34 - Volcanoes Composite cone (stratovolcano) -continued Composed of interbedded lava flows and pyroclastic debris Most violent type of activity (e.g., Mt. Vesuvius)
  • Slide 35 - Volcanic Hazards Nuée ardente – A Fiery pyroclastic flow made of hot gases infused with ash and other debris Also known as “glowing avalanches” Move down the slopes of a volcano with velocities approaching 200 km/hour
  • Slide 36 - Volcanic Hazards Lahar – volcanic landslide or mudflow Mixture of volcanic debris and water Move down slopes of volcano and stream valleys with velocities of 30 to 60 miles/hour
  • Slide 37 - volcanic hazards Pyroclastic flow Felsic and intermediate magmas Consists of ash, pumice, and other debris Material ejected at high velocities Example: Yellowstone plateau
  • Slide 38 - Other volcanic landforms Caldera Steep-walled depressions at the summit Generally > 1 km in diameter Produced by collapse Example: Crater Lake, Oregon
  • Slide 39 - Other volcanic landforms Fissure eruptions and lava plateaus Fluid basaltic lava extruded from crustal fractures called fissures Example: Columbia River Plateau Lava domes Bulbous mass of congealed lava Associated with explosive eruptions of gas-rich magma
  • Slide 40 - Other volcanic landforms Volcanic pipes and necks Pipes - short conduits that connect a magma chamber to the surface Volcanic necks (e.g., Ship Rock, New Mexico) - resistant vents left standing after erosion has removed the volcanic cone
  • Slide 41 - Shiprock, New Mexico
  • Slide 42 - Intrusive igneous activity Most magma is emplaced at depth in the Earth Once cooled and solidified, it is called a pluton
  • Slide 43 - Intrusive igneous activity Nature of plutons Shape - tabular (sheetlike) vs. massive Orientation with respect to the host (surrounding) rock Concordant vs. discordant
  • Slide 44 - Intrusive igneous activity Types of intrusive igneous features Dike – a tabular, discordant pluton Sill – a tabular, concordant pluton (e.g., Palisades Sill in New York)
  • Slide 45 - Intrusive igneous activity Types of intrusive igneous features Lacolith Similar to a sill Lens or mushroom-shaped mass Arches overlying strata upward
  • Slide 46 - Intrusive igneous activity Intrusive igneous features continued Batholith Largest intrusive body Surface exposure > 100+ km2 (smaller bodies are termed stocks) Frequently form the cores of mountains
  • Slide 47 - Plate tectonics and igneous activity Global distribution of igneous activity Most volcanoes are located within or near ocean basins Basaltic rocks: oceanic and continental settings Granitic rocks: continental settings
  • Slide 48 - Plate tectonics and igneous activity Igneous activity at plate margins Spreading centers Greatest volume of volcanic rock is produced along the oceanic ridge system
  • Slide 49 - Plate tectonics and igneous activity Igneous activity at plate margins Mechanics of spreading Decompression melting of the mantle occurs as the lithosphere is pulled apart Large quantities of basaltic magma are produced
  • Slide 50 - Plate tectonics and igneous activity Subduction zones Occur in conjunction with deep oceanic trenches Location of partial melting of descending plate and upper mantle Rising magma can form either An island arc if in the ocean A volcanic arc if on a continental margin
  • Slide 51 - Plate tectonics and igneous activity Subduction zones are associated with the Pacific Ocean Basin The region representing the Pacific Rim is known as the “Ring of Fire” Location of majority of world’s explosive volcanoes
  • Slide 52 - Plate tectonics and igneous activity Intraplate volcanism Occurs within a tectonic plate Associated with mantle plumes Localized volcanic regions in the overriding plate are called a hot spot Produces basaltic magma sources in oceanic crust (e.g., Hawaii and Iceland) Produces granitic magma sources in continental crust (e.g., Yellowstone Park)
  • Slide 53 - Volcanoes and climate The basic premise Explosive eruptions emit huge quantities of gases and fine-grained debris A portion of the incoming solar radiation is reflected and filtered out
  • Slide 54 - Volcanoes and climate Past examples of volcanism affecting climate Mount Tambora, Indonesia – 1815 Krakatau, Indonesia – 1883
  • Slide 55 - Volcanoes Can Impact Regional And Global Climate Modern examples Mount St. Helens, Washington - 1980 El Chichón, Mexico - 1982 Mount Pinatubo, Philippines - 1991
Smoker Free PowerPoint Template

Smoker

Views : 487

Swans Free PowerPoint Template

Swans

Views : 437

Drone Free PowerPoint Template

Drone

Views : 4021

Male Female Free PowerPoint Template

Male Female

Views : 557

Female Mosquito Free PowerPoint Template

Female Mosquito

Views : 461

4g Free PowerPoint Template

4g

Views : 347

Nature Abstract Free PowerPoint Template

Nature Abstract

Views : 513

Air Baloon Free PowerPoint Template

Air Baloon

Views : 914

Health Tips Free PowerPoint Template

Health Tips

Views : 1027

Good Friday Free PowerPoint Template

Good Friday

Views : 912

Car Free PowerPoint Template

Car

Views : 523

Jaguar Free PowerPoint Template

Jaguar

Views : 1067

Coffee Free PowerPoint Template

Coffee

Views : 819

Anniversary Free PowerPoint Template

Anniversary

Views : 569

Interior Free PowerPoint Template

Interior

Views : 518

Credit Debit Card Free PowerPoint Template

Credit Debit Card

Views : 414

Domino Free PowerPoint Template

Domino

Views : 562

Firefighters Free PowerPoint Template

Firefighters

Views : 1231

Quit Smoking Free PowerPoint Template

Quit Smoking

Views : 572

Email Symbol Free PowerPoint Template

Email Symbol

Views : 458

Description : UNDERSTANDING VOLCANOS Dr. Walter Hays, Global Alliance For Disaster Reduction Volcanoes Composite cone (stratovolcano) -continued Composed of interbedded lava flows ......

Tags : UNDERSTANDING VOLCANOS

Shortcode : Get Shareable link